Supplementum

Suplement XXXI

Reveche, Feliciano R. A preliminary study on the reproduction and feeding habits of Dermogenys viviparus Peters. Philippine Agriculturist 11: 181-190.

 

A PRELIMINARY STUDY ON THE REPRODUCTION AND FEEDING HABITS OF DERMOGENYS VIVIPARUS PETERS

By FELICIANO R.  REVECHE

 

INTRODUCTION

In the summer of 1921, Mr. D. Villadolid, of the Department of Entomology, College of Agriculture, while making preliminary study pn the feeding habits of the fish fauna of Molawin creek, had occasion to collect a few living specimens of Dermogenys viviparus Peters for some biological experimentation. In connection with this study, he found out that this species of fish is a voracious feeder on mosquito larvae. In June, 1922, Mr. W. D. Tiedeman, of the International Health Board of the Rockefeller Foundation, who is working in cooperation with the Philippine Health Service, arrived at Los Baños and made his headquarters at the College of Agriculture, to study malaria condition in Laguna Province and the possibilities of economic control. He interested in fish as a possible means of checking the rapid multiplication of mosquitoes. This fish was then mentioned to him by Prof. H. E. Woodworth, of the Department of Entomology, as possible material to work with. The present is a report on the feeding habits, method of reproduction, local distribution and life history of Dermogenys viviparus Peters. This work was begun in the latter part of July, 1922, and ended at the close of November of the same year. The work was done in the College of Agriculture, University of the Philippines.

 

GENERAL INVESTIGATION

 

1. DESCRIPTION OF DERMOGENYS VIVIPARUS  PETERS

Among the Tagalog people the name “Patlay” and “Kansusuit” are synonymous terms, and these are applied to either of the two fish, Dermogenys viviparus Peters or Zenarchopterus philippinus Peters. Dermogenys viviparus Peters, the subject of this paper, is smaller than the other. For the purpose of uniformity, it would be better to adopt the term “Patlay” to Zenarchopterus philippinus Peters and the term “Kansusuit” to Dermogenys viviparus Peters, for the simple reason that the people more commonly use “Kansusuit” for D. viviparus. The term “Patlay” seems to be commonly applied to a fish having long, slender body and capable of swimming very fast; on the other hand, the term “Kansusuit” seems to be applied to small fish with a body not well adapted to swim rapidly. The former is more characteristic of Zenarchopterus philippinus. Peters and the latter to Dermogenys viviparus Peters. Peters (1) described this fish as follows: “Tail fin convex; dorsal fin shorter than annal fin; its first ray inserted behind first annal ray; annal fin inserted after 9/16 of the total length; head semi-flattened; length of head equals 5/16  of the total length; apex of beak yellowish speckled with black, three lines extend from the neck toward dorsal fin, membrane between first and second annal ray, second and third dorsal parts basally spotted behind the operculum with black. Number of scales along longitudinal line 45, transverse 12 to 13, dorsal 10 to 11, annal 14 to 15. Total length 95 mm.”

‚Experiment Station Contribution No. 107. I Identified by Dr. A. W. C. T. Herre, of the Bureau of Science. Fowler and Bean, of the Academy of Natural Science of Philadelphia, identified some Philippine specimens which they found labeled Dermogenys viviparus Peters as Hyporhamphus  neglectus. It cannot be determined where these specimens originated. To check this however, a bottle of specimens was sent by Mr. W. D. Tiedeman. Field Director of the Rockefeller Foundation in the Philippines, under whom this work was undertaken.

Peters further states, „this species is in its whole body structure very similar to the preceding but considerably larger and one could perhaps consider both as one, but due to the rounded and not two lobed tail fin, as well as to the short dorsal fin, one distinguishes an easily recognizable subgenus of the remaining Hemirhamphus for which reason this name Dermatogenys (Dermogenys) suggested by von Kuhl and van Hasselt was adhered to.

„Dr. Jagor brought this last species from the island of Samar from the river Basey, as is shown in the foregoing specimen ‚with living young and developed eggs”.

Distinct external characteristics of both sexes. —

The female, as a rule, is much larger than the male. The average measurement which is taken from 175 specimens of adult females is 73.5 millimeters in length, and the average measurement of the male, taken from 95 adult specimens, is 52 millimeters in length.

The measurement is taken from the tip of the beak to the tip of the tail. All these specimens were caught in the Molawin creek, Los Baños, Laguna.

The caudal fin of the male is beautifully marked with black and pale orange. This marking at the tail is sometimes present in the female, but is not as clear as in the male. The soft rays of the dorsal fin of the male are colored black, and this marking is absent in the female. The ventral fin of the male is also colored pale orange and sometimes little black marks are mixed with it. In the case of the female, the ventral fin is whitish brown, the marks predominating at the soft rays on attaining old age. On the ventral side of the beak of both sexes is a thin fleshy protrusion which runs from the base of the beak to its tip. This protrusion is distinct reddish orange in male, and orange in the female. In the case of the female, there is a protuberance just anterior to the anus which is orange in color. This is absent in the male.

2. THE ALIMENTARY CANAL AND CONTESTS

.
a. Method of investigation.—

The stomach contents of the fish were determined by dissecting the stomach and making water mounts of its contents. Examination was made under a dissecting microscope (X24) or under a binocular microscope (X40).

b. Digestive system.—

The alimentary canal of the female fish is a simple tubular organ. It is almost pale white in color, and is situated ventrally to the two sacs of the ovary. It may be resolved into three parts. The most anterior part which is a short, small tube is supposed to be the rudimentary oesophagus, and next to it is a dilated and enlarged portion which may be termed the stomach which covers one-third of the length. The posterior part which makes about two-thirds of the length is termed the intestine. The length of whole digestive canal is approximately 34 millimeters. The width varies because the most anterior portion is a small, short tube and next to it portion is a small, short tube and next to it is a dilated part which is the stomach and is approximately 4 millimeters in width. The most posterior part which is the intestine is about 2 millimeters in width. On each ventro lateral side of the alimentary canal are two blood vessels running parallel and terminating; at the posterior portion, about two-thirds of the length. This description of the alimentary canal is taken from one specimen, 92 millimeters in length and 12.5 millimeters in depth.

c. Stomach contents.—

Extensive dissection of the alimentary canal of the fish was done with subsequent examination of the stomach contents. Among those things that were conspicuous in the stomach were mostly portions of body parts of insects and arachnids, such as the wings of insects, legs of spiders, heads and legs of ants, legs and abdomens of small locusts, and exuviae of some kinds immature insects.

3. OBSERVATION OF FEEDING HABITS

Observations of the feeding habits of this fish were made in Molawin creek and in confinement. The fish is provided with a long beak, the lower lip being very much longer than the upper. The fish, therefore, must necessarily be a surface feeder. It could hardly get food at the bottom of the water. If the food happened to be at the edge of a stone or anything that will hinder its progress, the beak is used. Large food is broken into pieces by the mouth before it is swallowed. Oftentimes the young fry are in schools of from twenty to thirty individuals with a few large ones.

They are usually found in a slow current of water or near the water edges in the creek or river. They are found abundantly in quiet, shady places of the creek. This is also true with the adult fish, but the latter is often found in more or less rapid currents in which they oftentimes stay and swim. Most of the time are found on the surface of the water, arranged one after another against the current. They seem to be waiting for their prey to come along with the current of the water. They are very sensitive to noise or disturbances in the water. They react to it positively thinking it possible to be a chance for prey, but are easily frightened at the sight of their enemies. Fighting was observed between individuals in a group over the possessions of a piece of food. If they happened to be of about equal size, they fought hard and strong. The used their beaks as a means of offense and defense.

At night they behave in a very different manner. Most of them are found along the water edges especially in small indentations and stagnant places, swimming around and actively looking for food. They are very active at night, swimming from place to place. This fish is positively phototropic. The writer had occasion to catch a large number of these fish during the night, by attracting them with a lantern into the net.

In pools where this fish was artificially reared, food was given once a day. This food consisted mainly of larvae of both anopheles and culex mosquitoes. Later dried shrimps and white ants or termites were given. The dried shrimps were cut into small pieces before they were given and as such they could be easily swallowed by the fish. Of all this food, the writer found that the fish prefered the anopheline larvae. This might possibly have been due to the fact that the anopheline larva places itself parallel to the surface of the water. It could he, therefore, readily seen by the fish which feeds on things floating on the water. It may be that in nature it prefers water insects as examination of the stomach contents would seem to indicate.

The following table shows how readily anopheles larvae are eaten by this fish when in confinement. It remains to be seen how this would be modified under natural conditions.

TABLE I. Showing the eflicicncy of Dermogenys viviparus items in eating mosquito larvae in an artificial container.

 

4. METHOD OF REPRODUCTION

Examination of reproductive organs. In the differentiation of the males from the females, the external anatomy was first studied, followed by the dissection for the internal organs. In this connection particular attention was paid to the number of fetuses and developed embryos inside the ovary sacs. The ovary of this fish is V-shaped in form, and is composed of two sacs. Oftentimes, one of these sacs is shorter than the other. Generally, the color of the ovary is silvery with black markings at the side of each sac. The ovary is located dorsally to the alimentary canal, the latter running straight between the two sacs. It extends from the cloaca to the level of the liver. The arrangement of the fetuses inside the ovary sacs can be seen from outside, due to the fact that the sac membrane is transparent. The young fetuses in the sacs overlap each other. The position of the fetuses in the sacs is not the same. Oftentimes the heads of the fetuses point toward the cloaca and at other times they point toward the blind portion of the ovary sacs. The most common number of fetuses is five in each sac. This number increases with the size and age of the fish. In the ovaries there are always found developed embryos and eggs. Measurements of the young fetuses, which supposedly are about to be delivered, were taken.  The average length is 18 millimeters.

Table II.¹ — Showing the relative length of the ovary sacs in relation to the total length of the fish with the number of fetuses and embryos found in the ovary sacs.

Specimen             Length of fish.                  Ovary sac            Length of                                          Number of fetuses and
number.                                                           Number.            Ovary sacs.                                     embryos in the ovary sacs.
.                           Millimeter                                                    Millimeter                                        Fetuses                        Embryos
1                               63                                          1                          18                                           4                                           7
.                                                                               2                          18                                            5                                          6

2                             120                                         1                         35                                          10                                          7

.                                                                              2                         35                                          11                                           4

3                              50                                          1                         10                                           —                                           7
.                                                                              2                         10                                           2                                            4

4                             85                                           1                          25                                          4                                             3
.                                                                              2                         20                                          5                                             2
5                            63                                            1                         20                                           3                                             6
.                                                                             2                         12                                           7                                             4

6                            60                                           1                          13                                           5                                              5
.                                                                              2                          13                                           4                                              6

7                            65                                           1                          15                                          —                                              3
.                                                                             2                          15                                          —                                              4

8                           98                                            1                          25                                          5                                               4
.                                                                              2                          25                                         5                                                6

9                           60                                            1                          18                                          3                                                2
.                                                                             2                          18                                          5                                                3

10                         54                                           1                           16                                          5                                                9
.                                                                             2                            16                                        4                                               10

11                       100                                           1                           30                                      11                                                  2
.                                                                            2                            30                                       5                                                  7

12                         75                                          1                             20                                       4                                                  7
.                                                                           2                             20                                      —                                                   6

 

 

¹ For lack of space only twelve specimens were noted in this table. It is shown in the above table that the length of the ovary sacs vary according to the length of the females. Generally, the larger or older females have more young fetuses and embryos in the ovary sacs while the smaller or the younger the females the less the number of fetuses. The fact that the young fetuses arc not found in some cases in the ovary sacs of the females may indicate that this fish has a resting period.

 

5. LIFE HISTORY

Couples of Dermogenys viviparus Peters were confined in separate compartments, fed with mosquito larvae or termites, and kept under close observations. As soon as eachfemale produced young, the latter were transferred to Lot B1, B2, B3, B4, B5, B6, B7 as shown in the succeeding table. Other couples selected from this stock were transferred
and confined in another compartment shown as C1, C2, C3, C4, C5, C6, C7, C8, C9, in the same table.

Table III. Showing intermix between parturition and life history of Dermogenys viviparus Peters under confinement.

 

It is worthy of note that a single female gave birth to 5 sets of 5 young each at intervals averaging about 8 days and that these young gave birth to their first group of 2 or 3 young at the average age of only 83+ days.

a. Notes on the stages in the development of the young embryo.¹

1. In the first stage of development, the young embryo is enveloped by a thin membrane (called the chorion, in mammals). The eyes are already developed. The tubular heart is already functioning. On the dorsal part of the embryo running from the most posterior part of the head are black dots which terminate at the anterior part of the dorsal fin. This stage is characterized by the presence of a large amount of yolk.

2. In the second stage, the same characteristic features are found as in the first stage, but differ only in that in the second stage the embryo proper is larger, while the yolk is much diminished in bulk and quantity.

3. The third stage is practically the same as the second stage, but the yolk is distinctly reduced in size and quantity, and the embryo is very much larger. There are black dots appearing very conspicuously in that part of the body mentioned above. The eyes are larger.

4. In the fourth stage, the membrane or chorion which envelopes the embryo seems to bulge out but the young embryo is still coiled in the ovary sacs of the mother. The yolk is greatly diminished in quantity by this time.

5. In the fifth stage, the young fetus appears to be complete in its organs of locomotion. The black dots appearing more prominently. On each side of „the young fetus there is a lateral line which begins from the sides of the pectoral fins and terminates at the caudal fin. At this stage of development, small protrusions are visible on the upper beak just anterior to the eyes one on each side. An experiment was was performed to find out whether the young fetuses would live when artificially taken out from the ovary sacs of the mother. The result was that they only lived for two or three days, and in most cases died after three days. Food was given but they would not eat.

b. Young.—

The young are born alive. They come out one by one through the cloaca. When outside of the mother’s body, they immediately swim to the surface of the water to get air. They look sluggish and inactive, but they can hardly be caught with the hand unaided. The average length of the newly born young is nineteen to twenty millimeters. At this stage, the beak is a little projection at the lower lip.  The orange and black markings are absent on both sexes and their distinct color is whitish gray. An attempt made to measure the growth of some of these young failed because they were lost after three days. However, they grew one or one and one-half millimeters in length a day.

c. Growth.—

As the young fish grows, its activity increases. The young easily penetrate the pools and water edges seeking food The female fish attains the mature stage when it is about fifty to sixty millimeters in length, and the male attains ‚maturity at about fifty-five millimeters. At this stage of development, they begin to mate. The markings at this stage become distinct on both sexes so that one can easily tell the males from the females.

¹ Notes:- It must be noted that beginning from the first stage the young embryo appears to be transparent to the unaided eyes but however, the most discernible organsare the organs of sight and functioning heart.

The female starts giving young at the age of 81 to 85 days. She gives two or three young at the first time. As the female ages, the number of young increases. This generalization is based upon the observation obtained from females reared in confinement. Commonly, an old female will give five young at each parturition, and the maximum number one has been noted to produce is ten.

The record of one female (female A,) shows that from the time she was placed in confinement up to the time she was placed in confinement up to the time she was accidentally killed a period of 75 days, she was able to produce 42 young. So far this work tends to show that the fish is able to live under artificial conditions and can reproduce a number of young if care is given.

6. HABITAT

a. Natural.——

The natural habitat of this fish is the ditch, creek, river or other small stream. In Balanac river near Magdalena, Laguna, this fish was observed and was found to inhabit places of slow current or stagnated places in the river.

b. Ability to live and reproduce under artificial conditions:

Dermogenys viviparus Peters lives and reproduces fairly well in pools which have free circulation of water, and has been found to thrive just as well in stagnant water. The size of the pool where this fish was reared is about four by five meters. It is divided into several lots. In lot 1, enclosed by a wire screen, twenty females and twelve males were introduced in August, 1922, and in November, 1922, the number of the fish in this lot altogether was 332. Most of the females that were introduced in this lot were 73 millimeters long and when they were counted again and examined, some of them had grown to 130 millimeters in length. The males did not exceed 67 millimeters in length. A single female fish under these conditions of confinement produced 15 offspring in the course of three months which, if there were no period of sexual inactivity, would mean 60 for the year. Bearing in mind that the rate of bearing offspring increases with age, this number will be considerably increased.

7. DISEASE

One diseased condition of Dermogenys viviparus Peters was encountered in the pools. The attacking organism (a fungus) belongs to the genus ACHLYA¹ which is a free living organism in the water. It grows anteriorly near the eyes of the fish at the beginning and finally affects the eyes. The fish becomes blind and dies afterward. It appears as a white filamentous growth at the head of the fish and is easily recognized. However, it is rarely found attacking this fish.

8. DISTRIBUTION IN LAGUNA PROVINCE

The fish is more or less evenly distributed through the province of Laguna. The fish may be found in the upper courses of most rivers and small streams in the province. The writer found it in abundance in Molawin creek of Los Baños, in ditches in Masiit in Calauan, in ditches in the town of Magdalena, and in ditches and creeks in San Juan, Loñgos. This fish does not seem to frequent the lower courses of the streams. In all the places visited by the writer the fish was not observed in places near the mouth of streams. In Molawin creek this fish is very scarce within about a kilometer of its mouth, but is plentiful towards the source. In Laguna de Bay and small lakes of San Pablo such as Bunot, Tikiw, Kalibato, and Sampaloe, the fish is not found.

 

¹ Statement from Prof. F. P. Prof. F. P. McWhorter of the Department of Plant Pathology, College of Agriculture. Experiment Station Contribution No. 108.

Association with other fish.—

In the creeks, this fish is seen associated with another very small fish which belongs to the genus Gobio. The latter fish stays mostly at the bottom of the water, and wherever Dermogenys viviparus Peters is present the former scenis to be present too. In a pool where this fish was confined, dalag (Ophiocephalus stratus) was introduced, to find out, whether the Dermogenys would be eaten by it. Some of the Dermogenys were found wounded, but none were eaten. This fish lives fairly well with top minows (Gambusia affinis) in pools. In a one-half barrel filled with water where both were confined in the insectary of the Department of Entomology, they have not attacked each other.

SUMMARY AND CONCLUSION

Dermogenys viviparus Peters is locally found in the province of Laguna in more or less shady places of old streams, ditches, creeks, and rivers. The fish is a highly beneficial fish because of its predacious habits on mosquito larvae. It is a surface feeder and feeds voraciously on anopheline larvae. A small “Kansusuit” (Dermogenys viviparus Peters) has eaten 78 anopheline larvae in 5 hours and 38 minutes. The development of the young embryo may be divided into five stages. The young are born alive. The small fish is generally more active than the large ones.

The female Dermogenys matures at the age of 81 to 85 days. She produces two or three young the first time, and as she grows older more young are given out at each parturition. The older female usually gives five young every eight days. This may vary at different seasons of the year and there may be a period or periods of sexual inactivity each year. The fish lives and reproduces fairly well under artificial conditions.

White ants or termites are the best food if it is is reared artificially. Dermogenys viviparus Peters has some possibilities as a so-callod “mosquitofish”. It is a surface feeder by nature and, in confinement, will eat anopheles mosquito larvae readily. It has been known to maintain itself in places needed and other voracious fish are present. In spite of all this, it has not been demonstrated as yet to be of economic importance in mosquito control although it may be under some peculiar conditions. The fact that the fish is so widely distributed and yet is not found in any one place in sufficient numbers to control breeding, shows that there must be many natural enemies to be overcome. It is true that the removal of grass and weeds from the edges of streams may help by making food more easily available. However, in a section of Molawin creek which is rocky and contains no weeds, we found anopheles breeding in spite of the presence of the fish. Further work is necessary to demonstrate the practical possibilities of the use of this fish in mosquito control.

ACKNOWLEDGMENT

The author is greatly indebted to Mr. W. D. Tiedeman for his valuable help in the preparation of this paper,  also to Dr. A. W. C. T. Herre of the Bureau of Science and Dean C. F. Baker of the College of Agriculture.

The ilustrations were drawn by Mr. Aniano Estores.

BIBLIOGRAPHY

PETERS, Monatsberichte d. Akadeime d. Wissenschaften zu Berlin. Page 132, 1865.

ILLUSTRATIONS

Plate I A. Stages in the development of the young embryo.
1. First stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 mm.. . . . X-S
2. Second stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3.5 mm… . X-%

3. Third stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..~7 mm.. . . . X-S

4. Fourth stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 mm.. . .X-8

5. Fifth stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 mm.. . . X-3

B. Dorsal view of the head of a newly born Dermogenys viviparus Peters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X-15

C. Lateral view of a newly born Dermogenys  viviparus Peters . . . . . . X-3

D. Ovary sacs showing the arrangement of the young fish and matured eggs inside . . . . . . . . . . . . . _ . . . . . . . . . . . . . . . . . . . . . . . . . X-4

E. Ovary sacs showing the young fish inside, nearly ready to be delivered . . . . . . . . X-4

F. Ventral view of the entire alimentary canal and its relation to the ovary sacs of the female Dermogenys viviparus Peters. . .. X-2

Plate II.

1. Lateral view of the male.

2. Lateral view of the female.

Plate III. D. viviparus Peters, showing the arrangement of scales and fins.

PLATE 1

LINKS:

http://www.biodiversitylibrary.org/item/109287#page/144/mode/1up

http://archive.org/stream/monatsberichted13berlgoog#page/n283/mode/2up

http://www.mypalhs.com/forums/showthread.php?88231-Fish-Available-Locally/page22

http://pets.webshots.com/photo/2602612170049495152LHRjBN

.
http://books.google.pl/booksid=F9irAAAAIAAJ&pg=PA45&dq=viviparus+++peters&hl=
pl&sa=X&ei=u0u6UM_2HI7YsgbPsYHQDg&ved=0CDAQ6AEwAA#v=onepage&q=
viviparus%20%20%20peters&f=false

 

2012/12/01 | Supplementum

Suplement XXX

Kosmos, 1887, R. 1, s. 286-287
I. Rozprawy naukowe
E. Janeta. Dr. Prof. Wiadomości zoologiczne

Tęczownik

Tygodnik niemiecki Das Ausland (1876, 297) podaje z pisma P. Carbonniera, przedstawionego paryskiej akademii umiejętności (Comptes rendues z 6go grudnia 1875) następującą wiadomość o tej zajmującej rybce.

W r. 1873 wysłano z Kalkuty do Paryża przesyłkę żywych ryb, między niemi także tęczownika (rainbowfish), odznaczającego się pięknem ubarwieniem i długą nitkowatą szczecią zastępującą jak u niego tak u powinowatych gatunków płetwę brzuchową. Rybka ta tylko 1 ½ cala długa żyje w stawach i rowach w okolicy nadgangesowej.

Uwagi godną własnością tej rybki jest budowanie gniazdka dla ikry i młodych. Gdy się zbliża czas tarła, przybywa samczyk (mleczak), rozpościera piękne płetwy swoje i krąży naokoło samicy  (ikrzaka), przedstawiając się jej w przepysznem ubarwieniu swojem. Poczem samiec zaczyna budowę gniazda. Wynosi on w gębie na powierzchnią wody trochę zielenicy (Conferva). Aby takowa nie tonęła znowu, lecz pozostała na powierzchni wody, tęczownik wypuszcza z siebie bąbelkami powietrze, które usadowiwszy się pod rośliną, podtrzymuje takową. Tę robotę powtarza tęczownik kilka razy i tworzy tym sposobem pierwszego dnia  małą wysepkę mającą 3 cale średnicy. Bąbelki powietrza spływają zwolna w jeden bąbel. Następnego dnia tęczownik powietrze wydycha pod środkiem owej wysepki zielenicowej, która skutkiem tego podnosi się ponad powierzchnię wody, tworząc jakoby kopułę. Około niej urządza teraz samczyk z zielenicy poziomo położone koło do ¾ cala szerokie, tak że cała ta budowa przybiera postać maleńkiego miękkiego kapelusika z okrągłą główką i szerokim brzegiem, wzniesionego nad powierzchnię wody o 5 do 6 centym. (22.5 do 27 linij). Przyciskaniem gębą i piersiami ryba gładzi wewnętrzne ściany, usuwając wystające części zielenicy lub ugniatając je. Teraz dopiero przybywa samica, trze się, wydaje ikrę i oddala się, nie wracając więcej, tak że piecza o płód zupełnie zostawioną jest samczykowi. Zbiera on też gębą ikrę poprzyczepianą do zielenicy,  zanosi do gniazdka i tam  porządnie układa, aby leżała w jednej płaszczyźnie, usuwa się z gniazdka, ściąga otwór, okrąża potem całą budowę i puszcza pod nię tu i owdzie bąbelek powietrza, jeżeli jest gdzie uszkodzona. Po upływie 70 godzin podnosi samczyk gniazdo do góry, bąbelki powietrza pękają a budowa opada, przykrywając wykluwające się młode. Aby się takowe nie rozpraszały, urządza on z brzegu owego roślinnego pokrowca nowe ogrodzenie; od czasu do czasu zbiera młode i zanosi je w pyszczku do środka gniazdka. Lecz coraz częściej powtarzająca się ucieczka młodych przekonuje go, że czas pieczy jego na schyłku. Trwa ona od czasu zburzenia gniazda 8 do 10 dni.

Spostrzeżenia te robiono w Paryżu w małem akwaryum, obejmującem 12 litrów (11.5 kwarty). Woda miała zawsze 23 do 25° R. ciepłoty. Jedna parka tych rybek w lecie 1875 roku trzy razy się tarła, wydawszy każdy raz najmniej 150 jajek.

*

*                                                    *

Biesiada Literacka 1877 t. 3 nr 69 s. 266.
Wydawca: Unger Gracyan
Właściciel praw: PAN Biblioteka Kórnicka

Z KSIĘGI ŚWIATA.

Dziworyba

Mała rybka zwana tęczówką indyjską, wykryta obecnie przez Carbonniera, przyrodnika francuzkiego, w stawach i kanałach krajów skrapianych przez rzekę Ganges, przedstawia ustrój i obyczaje ciekawe.

Długość jej przechodzi zaledwie półtora cala polskiego — ubarwioną jest prześlicznie, a długie włókienko mięsne zastępuje w jej budowie płetwy brzuchowe.

Tęczówka podobnie jak ptaszę buduje sobie gniazdko.

Gdy czas niesienia jajek zbliży się, samiec zaczyna urządzać dla nich kolebkę w topieli wodnej. W tym celu zbiera źdźbła roślinne i nieco mchu i porzuca to na powierzchnię wody. Z powodu gęstości gatunkowej tych roślinek, opadłyby one wkrótce na dno — od czego jednak spryt budowniczego? Podsuwa się on pod nie, chłonie powietrze i wyrzuca jego bańki, które tem samem nie pozwalają im obniżyć się w topiel. Powtarza tę czynność ciągle i wytwarza z nich w końcu wyspę pływającą, której średnica dochodzi półczwarta cala polskiego. Nazajutrz samiec gromadzi podobny zapas powietrza i z roślinek tych formuje w ten sposób rodzaj kopuły, unoszącej się na wodzie.

Po ukończeniu budowy zewnętrznej gniazdka, architekt stara się zabezpieczyć je od rozbicia. W tym celu z tychże materyałów tworzy naokoło kopuły obręcz horyzontalną, co nadaje całości postać kapelusza nieco pogiętego z szerokiem rondem.

Pozostaje mu tylko wykończyć gniazdko wewnątrz — a więc wciska się w nie pyszczkiem i piersią prasuje, gładzi pilśń owego kapelusza, poczem wprowadza doń małżonkę.

Po zniesieniu jajek samica porzuca dach małżeński na zawsze, pozostawiając samcowi cały trud macierzyński, któremu zresztą poświęca się ochoczo czuły ten ojciec. Zbiera on jajka za pomocą pyszczka i pomieszcza je w gniazdku, ustawiając w porządku, poczem zwęża otwór wejściowy.

Po upływie siedmdziesięciu godzin, samiec przebija kopułę gniazdka, która opada wraz z zarodkami młodych na dno wody. Nie dość na tem, inteligentna ta rybka osłania w ten sposób gniazdko, że potomstwo nigdy zeń przed czasem wypaść nie może. Dziesiątego dnia od opuszczenia się tego pomieszkania w wodę, młode rybki zwinne i żwawe wydostają się na wolność, a przez ten cały czas samiec czuwa nad niemi troskliwie.

Linki:

http://www.sbc.katowice.pl/publication/16459

http://www.wbc.poznan.pl/dlibra/plain-content?id=111289

http://archive.org/stream/annalsmagazineof4171876lond#page/172/mode/2up

http://archive.org/stream/annualrecordofsc1876bair#page/320/mode/2up

2012/11/26 | Supplementum

Suplement XXIX

Proceedings of the Zoological Society, 1960, 13, 29-38.

On the life history of Colisa lalius (Ham.). By Late H.  K.

 Mookerjee and S.  R.  Mazumder*, Department of Zoology,

 University of Calcutta, (with twenty-three text-figures)

(Ms. received August 17, 1957. Read May 5, 1960.)

* Now Superintendent of Fisheries, Government of West Bengal.

AUTHOR’S ABSTRACT

The paper deals with bionomics, nest-building habit, sexual dimorphism, jealousy between two ripe females, breeding, development, food and rearing of Colisa lalius. The duration of spawning, period of hatching and the time required for the formation of different organs have been recorded. The developing eggs have been critically observed.

INTRODUCTION

Colisa lalius (Ham.) belongs to the group of labyrinthine fish and is commonly called dwarf gourami (Innes, 1907). In Bengal, it is named differently in different localities, such as ‚Lai Kholisa’ at Goulpara (Day, 1878) and ‚Tabaicha’ in the district of Noakhali.

It finds favour with the aquarists and is also considered as an edible fish. It is found in plenty in East Bengal (now Eastern Pakistan) and not to that extent in West Bengal. This fish is well known for its larvaecidal habits. On account of its diverse utility, its culture deserves to be augmented.

For its successful culture, a knowledge of its life history, breeding andrearing is necessary, but only some scanty descriptions of the morphology and the breeding habits of this fish are known (Carbounier, 1876; Day, 1878;  Innes, 1907 and 1935; Jones, 1946).

MATERIAL AND METHOD

Details of laboratory and field studies undertaken by the authors on the life history of Colisa lalius (Ham.) during the year 1942-43 are given in this paper.

The collection of eggs, fry and adolescent fishes was also made under natural conditions so as to correlate the rate of growth in nature with that under laboratory conditions.

Different stages were preserved at an interval of five to thirty minutes according to the needs for study. Embryonic and early larval stages were fixed in the Smith’s fixative and finally preserved in 4% formaldehyde. The post-larval and adult stages were kept in 4% formaldehyde.

OBSERVATIONS

General Biology:

Colisa lalius belongs to the family Osphronemidae. It inhabits the fresh water ponds, ditches, paddy fields, rivers, etc. of East Pakistan and West Bengal. It is a hardy fish and possesses accessory air-breathing organs.

It is a surface as well as bottom feeder. It is seen frequently to come to the surface of water  to inhale air and it dies if prevented from doing it. It is rather timid (Innes, 1907).

The male is vertically banded  with scarlet and light blue. The dorsal and caudal fins are barred with scarlet dots. The anal fin has a dark band along its base and red outer edge.

It has been found by experiment that the fish thrives in the aquarium.

Breeding colouration:

During the breeding season  the scarlet colour and bluish tinge in the male become  intensified, while in the female the dark lateral band on the body becomes prominent. The colouration develops before spawning, but gradually loses its intensity afterwards.

Breeding season:

Mallen and Lanier as quoted by Jones (1946) say that it breeds several times during the summer at a temperature of 75°F. In Bengal this fish was observed to breed in natural conditions though much has been recorded regarding its breeding habits in aquaria.

This is a bubble-nest builder. Innes as quoted by Jones (1946) attributed to it the merit of building a bubble-nest with bits of plants. This fish was observed to build up nests of bubbles in paddy fields and in seasonal tanks, but never in stagnant perennial tanks. During breeding season after or during rains they are found to migrate to paddy fields or other seasonal waters from the stagnant perennial waters. They migrate by water courses and not by land route. Both the male and the female build nests of bubbles to which are added bits of Hydrilla, Ceratophyllum or Spirogyra sp. When the construction of the nest is complete, the female goes just below the nest and the male starts sexual sports with the female in various ways culminating in spawning. The eggs float on the surface of water and the female transfers those eggs which have got outside the boundary of the nest into it. The sexual sport is repeated a number of times till all the eggs are laid. Then the male and the female are seen to guard the eggs. The temperature and the pH of water at the time of spawning were 82°F and 7.7 respectively.

Breeding under Laboratory condition:

The spawning behaviour in the aquarium was observed to be almost similar to that under natural condition. The observation on breeding habits was also confirmed by breeding in the laboratory.

Duration of spawning:

The duration of spawning was determined by direct and indirect methods. The direct method is to note the period from the time of first extrusion of the ova and its fertilization to the time of its last extrusion and impregnation during a spawning operation. Indirect method is to measure the time from the moment of earliest hatching to that of last hatching of whole lot of eggs extruded during a particular spawning. During the experiment the spawning party being hardly disturbed, the duration of spawning was found to be from two to two and a half hours. Under disturbed condition the spawning operation stops temporarily and if repeatedly disturbed, it stops altogether.

Jealousy between two ripe females:

When a mature female was introduced in the aquarium in which a male and a female of C. lalius had been engaged in spawning activities, the process was found to be delayed. The spawning female tried to drive out the rival female to deprive the latter of the chance of mating with the male partner of the spawning party.

Description of imptegnated eggs:

The eggs are small, almost circular, non-adhesive and lighter than water. They float on the surface and remain more or less collected within the nest. They are almost invisible. On extrusion, they are invested by a single layer of capsule or zona radiata. There is a clear space called perivitelline space.

Development:

The earliest stage of egg was collected about 5 minutes after the egg-laying and fertilization. It is highly laden with yolk and more or less spherical in shape measuring on an average 0.7 mm in diameter. The early embryonic development follows the same processes as have been observed in Wallago attu (Bloch & Schneider), the only difference being the presence of a mass of oil globules at the distal end of vegetal pole enclosed by a thin layer of protoplasm (Mazumdar, 1957). A number of oil globules persist until the larva hatches out. In the 60 minutes old egg, the protoplasm has aggregated to form a cap-like structure on the yolk mass known as blastodisc, and the swelling at this stage is known as blastodisc, and the swelling at this stage is  is perhaps at its maximum, and the size of the egg as a whole is 0.79 mm (Text-fig. 1).

Cleavage:

At the seventy minute stage, the first cleavage commences. The first cleavage is indicated by a slight dipping in the middle of the blastodisc at the animal pole. Four minutes later the blastodisc is divided, but not separated from each  other (Text-fig. 2) and the two blastomeres are formed. Within two hours’ time five cleavages take place resulting in the formation of a thirty-two celled stage up to which the cleavage can be followed easily. The second division is meridional and perpendicular to the first and the third parallel to the first. The fourth division is parallel to the second (Text-figs. 3-5).

Yolk  invasion:

On further divisions the loose cells at the basal region spread out in thin layers with a very faint and indistinct margin over the yolk. Fifteen minutes later the cells form a regular blastoderm layer extending over one-eighth of the circumference of the yolk with a very faint indistinct margin and within about six hours the blastoderm invades the yolk completely leaving a space representing the position of the blastopore. During the process of yolk invasion signs of the commencement of the formation of embryonic ridge or neurocord are observed (Text-figs. 7-10).

Embryo formation  and hatching:

By the eighth hour the multilayered ridge is fully formed along the anteroposterior axis. The head of the embryo appears arrow-shaped with two lateral projections attached to the neurocord anteriorly. Behind this region the hind brain is formed and the mesoblastic somites are visible. Later, the heart is formed and the mesoblastic somites increase to twelve in number. The optic rudiments on each side arise as solid epidermal outgrowths. The heart becomes tubular and pulsation commences. Kuffer’s vesicle appears anterior to the tip of the tail. A groove appears in the region of the hind brain and the blastopore closes. The groove extends backward and forward and the brain is distinguished into fore, mid and hind regions. At first, some pigments make their appearance on the yolk and nape and with age these become dense. Some pigments aggregate on the head and the tail. The epiblastic involution for the formation of the optic cup is visible as also a thin membranous finfold which gradually broadens. The otocysts are formed of the thickened area on the hind brain. The tail becomes free from the yolk mass. The rate of heart beat now is 160 per minute and the muscle segments double in number. The notochord appears vacuolated. All the embryonic developmental processes take place within twenty one hours of fertilisation (Text-figs. 11-12). At this stage the embryo hatches out,  the hatching temperature being recorded at 85° to 86°F and the pH-value during these processes 7.7.

Newly hatched larva:

On emergence, the larva measures 1.5 mm in length (Text-fig. 13) and comes to rest on the water surface upside down. The head and trunk still remain attached to the yolk-mass. The median fin-fold extends ventrally to posterior margin of the yolk-sac. The mouth is not open. Epiblastic involutuon of the optic outgrowth deepens to form lens and the border of the otocysts becomes thickened. The tail is bent towards ventral side and symmetrical in form. The vent lies behind the yolk-sac.

Six hours old larva: The lower lip is formed. The pectoral fin-buds appear. Pigments appear on the inner border of eyes and along the ventrolateral region of the body. Lens has taken the globular form. The tail is straightened.

Eight hours old larva: The nerve ganglia and neural arches are under formation. Segmentation of vertebral column commences. The larva measures 2 mm in length (Text-fig. 14).

Twenty eight hours old larva: The eyes have gradually become horse-shoe-shaped and the pupils, black. Yolk-mass is greatly reduced. Chromatophores are arranged longitudinally on either side of the notochord. The larva measures 2.56 mm in length (Text-fig. 15).

Forty five hours old larva: The mouth opens and the larva feeds on protozoans. The anterior margin of the upper lip becomes trunketed, but it is protruded in the middle. The narial aperture lies in front of each eye. The pectoral fins elongate. The larva increases to 2.63 mm in length (Text-fig. 16).

Four days old larva: Gape of the mouth increases. The air-bladder is visible and globular.

Five days old larva: Neural and haemal spines are under formation. Yolk is fully absorbed. Heart is divided into auricle and ventricle. The larva is capable of active swimming and starts feeding. The larva increases to 2.66 mm in length (Text-fig. 17).

Seven days old post larva: The dorsal profile is convex. There are pigment dots on the snout. The body is transparent. Chromatophores are visible on the margin of the lower and upper lips. Body is greenish from above. The length of the larva is 3 mm (Text-fig. 18).

Nine days old post larva: The ventral profile is concave. Abdomen is reduced in girth and white. Stomach hangs down. The larva measures 4.45 mm. in length.

Eleven days old post larva: The tail is asymmetrical. Hypurals and kidneys are formed. Small and large pigment dots are formed on the body and the head. Colour along the dorsal is greenish while on the abdomen, yellow. The caudal fin shows the usual number of fifteen rays. The mouth is deflected above. The larva increases to 5.5 mm (Text-fig. 19).

TEXT-FIGURE 1. Lateral Egg, collected 60 min. after extrusion, 2. Egg, 1 hr. 14 min. after fertilisation, 3. Egg, about 1 hr. 24 min. after fertilisation, 4. Egg, about 1 hr. 31 min. after fertilisation, 5. Egg. about 1 hr. 46 min. after fertilisation, 6. Egg, about 2 hrs. after fertilisation, 7. Egg, about 4 hrs. after fertilisation, 8. Egg, about 4 hrs. 15 min. after fertilisation, 9. Egg, about 4 hrs. 45 min. after fertilization, 10. Egg, about 6 hrs. after fertilization, 11. Egg, about 9 hrs. 30 min. after fertilization, 12. Egg, about 12 hrs. after fertilization, 13. Larva after hatching, 14. Larva 8 hrs. after hatching, 15. Larva, 28 hrs. after hatching, 16. Larva, 48 hrs. after hatching, 17. Larva, 6 days after hatching, 18. Post larva, 7 days old, 19. Post larva, 11 days old, 20. Post larva, 14 days old,

Thirteen days old post larva: The vertebral column becomes segmented in 24 pieces excepting the urostyle. Pelvic fin buds appear. The larva has turned opaque. Blood circulation is established in the caudal region. Colour of the blood is golden. On the next day blood gets a reddish tinge. The larva attains a length of 6.4 mm (Text-fig. 20).

Fifteen days old post larva: Dorsal fin-fold is greatly absorbed and only a vestige is continuous with the caudal fin. Ventral fin fold is continuous with the caudal.  The dorsal and the anal fins show 17 and 19 rays including spines respectively. Gill area gives out red colour.

Twenty days old post larva: The opercular bones are clearly differentiated. The pelvic fin shows the usual number of one ray. The pectoral fin shows six rays. The rays including spines on the dorsal fin are 23 (15/8). The length of the larva increases to 12 mm (Text-fig. 21).

Thirty days old post larva: It measures 19 mm. Scales are in formation. Pelvic fins have elongated. There are twelve vertical bands found along the lower half of the body. The anal fin shows 30 (17/13) rays including spines.

TEXT-FIGURE. 21. Post larva, 20 days old, 22. Post larva, 30 days old, 23. Post larva, 39 days old,

Abbreviations
For Text-figures 1 to 23

A.— Anal fin; C.— Caudal fin; D.— Dorsal fin; E.— Eye; P.— Pelvic fin; H.— Head; a.b.— Air bladder; a.p.— Animal pole; b.d.— Blastoderm; bl.— Blastodisc; b.m.— Blastomere; b.p.— Blastopore; e.r.— Embryonic  ridge; K.— Kupfer’s vescicle; l.— Lens; m.— Mouth; m.f.— Median fin-fold; o.— Operculum; o.g.— Oil globule; o.l.— Otocyst; p.b.— Pectoral bud; p.s.— Pervitelline space; v.b,— Vertical band; v.m.— Vitelline membrane; v.p.— Vegetal pole; y.p.— Yolk Plug; y.s.— Yolk-sac.

Thirtynine days old post larva: It becomes 20 mm in length. Vertical bands become very prominent. There lies a black spot on the caudal peduncle. Dorsal side is greenish, abdomen and beyond is scarlet-white. Head is yellowish brown and marked with black pigments (Text-fig. 23).

Forty one days old post larva: It is 22 mm long. The scales are fully formed. All the fins show their usual number of fin rays and spines. The post larva attains the size of a young adult.

Rearing:

Rearing in the laboratory was started as soon as the eggs hatched out and several factors, such as enemies, oxygen supply, light, food etc. were taken into account. The larvae were collected with a flat moderately large petri dish and distributed  to a number of glass aquaria with the pH of water at 7.8. The enemies, such as the larvae and pupae of dragon and damsel flies were removed. The larvae needed oxygen and a requisite area of space at the surface of water. This necessity of space was experienced in rearing the larvae of A. testudineus.  (Mookerjee and Mazumdar, 1946). Necessary steps were taken to avoid congestion and pollution of water by aerating water with motor tube (Mookerjee, 1940) and with plants. Four larvae below 3 mm in length could be harmlessly accommodated in a square inch and the number could be doubled by oxygenation with motor tube. As for the fry of 3 mm to 20 mm in length, 3 to 6 square inches for each and from 20 to 40 mm, 11 sq. ft. for each were found to be sufficient. In all these cases, depth of water was 10 inches. For the young and the adult during experiment a space 41 cubic feet for each was allowed.

The aquaria with plant were found to keep the water clean and provide extra oxygen. In the case of laboratory rearing, Hydrilla verticiliala, Vallisneria spiralis and Myriophyllum sp. were found suitable.

Aquaria practically got 6 to 8 hours direct sun which proved to be of some help for the growth of some plants that ultimately aided the fish in oxygenation. Light was also found to encourage the growth of some unicellular and multicellular algae that form the food for fishes. Algae in its turn also helped the growth of some crustaceans, such as Daphnia, Cyclops etc. and the protozoa, on which the fishes are dependent. Light also prevented the growth of disease producing bacteria and fungi.

The mouth of the larvae having opened they were fed with protozoa, such as Paramoecium, Coleps, Chaenia and other cilliates and flagellates from the culture. Gradually they learnt to take unicellular and multicellular algae from the fourth or the fifth day, but preferred protozoa. The small crustaceans, such as Daphnia and Cyclops were introduced on the seventh day of hatching, but they could not be ingested before the 11th day. From the 20th day they commenced to take small mosquito larvae and gradually took to crustacean and insect diets. Then the fry were fed with different artificial food, such as gram flour, coarse flour and with natural animal food, such as D. pulex, D. longispina, Cyclops leuckarti, Ceriodaphnia rigaordi, Cypris, Rotifers, etc. and and vegetable food, such as Closterium, Oscillaloria, Cosmarium, etc. for three months during which they attained 40 mm in length. Thereafter some were planted in ponds and others were reared in the laboratory with artificial and natural food.

It was observed that regulation of food is necessary. The excess of food forms congestion and produces troubles for the fish from lack of oxygen. The artificial food in excess caused polution of water resulting in the growth of bacteria and diseases. In order to avoid such polution of water the residual foods were removed by siphon (Mookerjee, 1942) and the foods were regulated. The changing of water during larval period was done by a rubber tubing and care was taken against the escape of the larvae and any mechanical injury to them.

 Food:

Food of fry: To determine the nature of the food of fry recourse was taken  to direct method of dissecting the fry and examining their gut contents. Eighty specimens were examined from 2.8 mm to 20 mm in length. The examination showed that the fry from 2.8 mm took fresh water cilliates and flagellates.

Fry bigger than 5.5 mm began to take small crustaceans, such as Daphnia, Cyclops, etc. and unicellular algae. Fry from 12 mm stage onwards took small mosquito larvae, worms etc. Food of fry under natural condition, thus determined, comprises both plant and animal organisms such as, Scenedesmus, Ulothrix, Cosmarium, Closterium, Diatoms, Paramoecium, Chaenia, Euglena, Rotifers, Cyclops, Cypris, and Mosquito larvae and also take the vegetable diets such as Closterium, Cosmarium, Oscillatoria, Scenedesmus and Chlorella vulgaris. They were also fed with certain artificial food stuffs, such as coarse flour, powdered meat, powdered blood, gram flour, dried and powdered shrimps made into tablets with egg albumen.

Food of adult fish: The natural food for the adult was determined by the microscopical examination of the gut contents of 100 specimens. The fishes were collected from different localities, such as paddy fields, ponds and markets. The examination of the gut contents revealed the presence of certain animal diets, such as Paramoecium, Stylonichia, Colpoda, Euglena, Rotifers, Nematodes and some eggs, Daphnia, Cyclops, Cypris and Mosquito larvae and its eggs and certain aquatic vegetable diets such as Oscillatoria, Closterium, Ulothrix, Chlorella, Diatoms and some other aquatic vegetations. This fish had liking for small mosquito larvae and crustacean food but of these were preferred.

ACKNOWLEDGEMENT

The authors are indebted to the University of Calcutta for affording necessary facilities for conducting this work.

REFERENCES

CARBOUNIER, M. 1876. Nidification du poisson arc-enciel (Colisa vulgaris) Ann. Mag. Nat. Hist., 17: 172—174.

DAY, F. 1878. Fishes of India. Text Supplement, London 375.

INNES, WM. T. 1907. Gold Fish Varieties and Tropical Aquarium Fishes. 90—91.

INNES, WM. T. 1935. Exotic Aquarium Fishes, Philadelphia.

JONES, S. 1946. Breeding and Development and Development of Indian Fresh Water and Brackish Water Fishes. J. Bomb. Nat. Hist. Soc., 19: 458.

MAZUMDAR, S. R. 1957. On the spawning habits and early development of Wallogonia attu. Proc. Zool. Soc., 10: 99—105.

MOOKERJEE, H. K. 1942. Easy Method of Cleaning Aquarium or Ponds. Indian Fanning, 12: 641—642.

MOOKERJEE, H. K. 1940. A Cheap Method of Oxygenation in Fish Culture. Ind. J. Vet. Sc. and Ani. Hus., 10: 289—90.

MOOKERJEE, H. K., AND MAZUMDAR, S. R. 1946. On the Life History, Breeding and Rearing of Anabas testudineus (Bloch) J. Department of Science, Cal. Uni., 2: 101—140.

Suplement XXVIII

Pakistan Journal of Science, 1950, 3(1) : 39-40.

 Spawning behaviour and early stages
 in the Development of a larvivorous
 fish Colisa lalia Hamilton.

Utility of Colisa lalia as a larvivorous fish has been demonstrated in the field and in the laboratory by experiments and observations extending over a period of twelve years (Hamid Khan 1943). This little fish, not more than 3 inches in length, breeds successfully in ponds and in aquaria, and is a „bubble-nest builder.”

The first account of nidification of Colisa (Trichogaster) fasciata was given by Paul Carbonnier (1875). Innes (1942) gives a detailed account of nest building in the family Anabantidae to which Colisa belongs. „The outstanding feature of the breeding of this family of fishes is the floating nest of bubbles which they construct and in which the eggs are placed, hatched and the young tended. These bubbles are formed by the male as he comes to the surface, draws a little air in his mouth and envelops it in a filmlike saliva. When released, the globule naturally floats to the surface. Endless repetition of this act piles up what looks like a little mound of very fine soap-bubbles,” (Innes. 1942). As there are no salivary glands in fish, by ‚saliva’ Innes probably means mucus secreted by mucous cells present in the buccal cavity.

The present study is the result of observations recorded in spawning behaviour of Colisa lalia, kept in aquaria in the Laboratory and in ponds in the Punjab. During winter male is not easily distinguishable from female. But in April and May it starts assuming its nuptial colour of red and blue stripes on its body and fins. The fish, however, spawn in July and August, temperature of water ranging from 74°F. to 80°F. One pair spawned as late as October.

It has been observed that in an aquarium with large number of male and female of Colisa lalia, nest is built by a male during the day, but is destroyed during the night by the other jealous males. It is best to separate a pair at the approach of breeding season and keep it in an aquarium. The male immediately afterwards starts constructing the nest, invites the female to the nest, where the eggs are laid by the female and placed in the nest. An interesting case was observed when a ripe female was introduced in an aquarium having a spent male, the female chased the male which ran away whenever the female approached. The spent male was taken  out and a mature male was introduced in that aquarium. The reaction was reverse, the male chased the female. But after a time they settled down, the male constructed the nest next day and invited the female to lay the eggs.  Colisa lalia incorporates bits of plants in the nest such as fine leaves of Hydrilla (Hamid Khan, 1943). The nest measures 3.4 inches to 4 inches in diameter and 2 inches above water surface. In one case the nest was not so compact and measured  6 inches in diameter. Each nest contains 100 to 400 eggs.

After spawning the male takes charge of the nest and drives the female away. If the female is not removed from the aquarium, it is likely to be killed by the male. The male keeps the bubble-nest compact by producing more bubbles after the eggs are laid. The egg measures 1 mm. in diameter and has a large amount of yolk with an oil globule which keeps the egg buoyant.

Outlines of the embryo become defined 7 hours after fertilization. Two hours later eyes are visible, head end is swollen and there are 21 somites on the body. Twelve-hour stage shows 27 somites, heart has made its appearance, pigment cells are also present and eyes are prominent, wrigling movement has started. Otocyst is visible. The blood circulation is simple. The eggs hatch out in about 26 hours. Just before hatching eyes have become prominent but without pigment, and yolk circulation is established. Four hours after hatching pectoral fin has appeared as a lobe. Tail is elongated and blood circulation has extended almost to the tail. In some cases three fin rods are visible in the Caudal fin. Fifteen hours after hatching, yolk sac is much reduced, pectoral fins are well developed and heart is Three Chambered. Forty-eight hours after hatching, yolk sac is almost completely absorbed, mouth opens for respiration, gills are functioning, simple gut is formed, but anus is not yet open.

Sixty hours after hatching, yolk is totally absorbed, anus is open, and food is in the simple tubular gut.  Pectoral fins are well developed. The nest has disappeared and the little ones  start moving about. At this time the male, as also been reported by the previous authors (Innes, 1942) starts eating the little ones. It becomes necessary to remove the male at this stage to save the progeny. In wild state the little ones protect themselves by concealing themselves in the weeds.

Curiously enough Colisa has almost completely disappeared from the pond where they used to breed in large number. At one time 293 nests were counted in one day in July. This disappearance seems to be correlated with the absence of Hydrilla, which has also disappeared from that pond. In a pond where Colisa is introduced, Hydrilla appears to be a necessity not only for the nest building but also for the protection of young ones.

HAMID KHAN BHATTI

Zoology Laboratory
University of the
Panjab, Lahore,

REFERENCES

Innes, W. T. (1942) Exotic Aquarium Fishes. Innes Publishing Co.. Philadelphia, U.S.A.

Khan, H. (1943). „On the relative value of certain Larvivorous fishes from the from the Punjab, with notes on their habits and Habitats.” Ind. Journ. Vet. Sci. 13-4-1943.

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Pakistan Journal of Science,  pages 78-81

On the distribution of taste buds in certain teleost fishes

„””A knowledge of the senses and instincts of fishes is necessary for making Fisheries a success. Feeding habits and the sense of taste are, in this respect, perhaps, as important as any other aspect of fish-life, because without a knowledge of these it is not possible to manipulate economically such processes as the ‚stocking of tanks’.

Anatomical studies on the organs of taste in fishes date back to 1827 when Weber observed the taste-buds on the peculiar palatal organs of Carp. Taste- buds, or the terminal-buds, as they were called in this case, were observed in the outer skin of fishes by Leydig (1851). A strict distinction between the terminal- buds and the ‚neuromasts’ or the organs of the lateral line system, was first established by Schulze (1870). Merkel’s (1880) interpretation of both the terminal buds and the neuromasts as the orgns of touch created a great deal of confusion which was finally resolved by the studies  of Herrick (1902) who confirmed the conclusions of Schulze and showed that the very nerve-supply of the two systems was different.

A typical taste-bud consists of a bundle of sensory cells resting on a papilla of corium or submucosa  and accompanied by the supporting or sustentacular cells. A small pore in the epidermis, called the sensory pore, keeps the refractive processes of the sensory cells in  communication with the outside. Typical taste-buds have been described by various authors working on the histology of the skin (Bhatti, 1938) or the alimentary canal (Dawes, 1929, Rogick, 1931, Al- Hussaini, 1949). Except for a brief reference by Al-Hussaini (1949) no attempt has been made to correlate the number or localisation of taste-buds with the nature of food or with feeding habits.

The present study was undertaken to find out the structure and distribution of taste-buds in some fresh-water teleost fishes and to correlate the findings with the feeding habits. The fishes selected for this study are Rita rita Ham., an insectivorous fish which feeds also on molluscs;  Ophicephalus gachua a piscivorous fish; Cirrhina mrigala Ham., a bottom-feeder herbivorous fish and Colisa (Trichogaster) lalia Ham., a larvivorous fish.”””

„””Colisa lalia. — Taste-buds are present in Colisa lalia in the skin, buccal cavity and the pharynx, with their relative frequency increasing in the same order, becoming quite numerous in the pharyngeal lining. In the buccal cavity the taste-buds are almost as tall as broad. The number of sensory cells in these taste-buds is large and their refractive processes remain more or less parallel. In pharynx taste-buds of two shapes are met with. Some taste-buds are globular with their refractive processes apparently meeting in a point. The number of sensory cells in these taste-buds is quite large. Other taste-buds are flask-shaped, with a round body and a long neck formed by refractive processes.Taste- buds of shapes somewhat in between the two types described are also met with.”””

„””Colisa lalia is a larvivorous fish and seems to have a taste for mosquito larvae and Crustacea. Like Rita rita, this fish has its sight subordinated to its sense of taste so far as the seeking of food is concerned. Experiments on the feeding of this fish were made by Hamid Khan (1943). He found that these fish, when given charcoal pieces of the size of mosquito larvae, would readily eat them, but would immediately spit them out. These observations are substantiated by the distribution of taste-buds in this fish. „””

Hamid Khan

Zoology Laboratory, Ahsanul Islam
University of the Panjab, Lahore.

 __________________________________
______________________
____________

J. Annamalai Uni., Sei., 27, 81-89 (1966-69)

— 81—

BIOLOGY OF COLISA LALIA (HAMILTON – BUCHANAN)

OF ANNAMALAINAGAR WATERS

by V. G. KRISHNAMURTHY and P. GOVINDAN

Department of Zoology, Annamalai University, Annamalainagar

Introduction

A detailed account of the biology of Colisa lalia distributed in the freshwaters of different regions is found in the works of Innes, and Mellan and Lainer (quoted by Jones, 1946), Axelrod and Schultz (1955), Axelrod (1956), Forselius (1957), Mookerjee and Mazumder (1960) and Abraham (1962). The present study subscribes further to the knowledge on the biology of this species confined to the waters of Annamalainagar. Also, it is considered that a knowledge on this aspect would be desirable for a study undertaken by one of us (V.G.K.) on the morphology, development and secretory activity of the corpuscles of  Stannius in this species (Krishnamurthy, 1964, 1967, 1968).

Material and Methods

The fry of C. lalia were collected from the boating canal, Annamalainagar during July – August, 1961 and February – March, 1962 and reared separately in cement tanks for observations of their growth. These tanks were provided with plants such as Vallisneria sp., Hydrilla sp., Lemna minor and Myriophyllum sp.

The fry at the time of catch measure each 6 mm in length. About 100 fry were transferred every fortnight from the stock to a petri-dish filled with water; and the total length of each fry was measured with a paraffin coated centimeter checker paper fixed to the bottom of the dish.

After recording the measurements the fry were returned to the tanks. The adults were  taken out of water and measured  with a metric scale; while measuring they were able to withstand the exposure to air, since they breathe by

— 82—

suprabranchial organs. The mean values of growth during fortnightly intervals were calculated separately for the summer-bom and monsoon-born fishes and the respective curves were drawn for these values. A few of the fry from each sample after removal of their head and tail were fixed in Bouin’s fluid. These were decalcified in formol-nitric (10: 1.5 v/v) and after usual procedure embedded in paraffin wax. Deparaffinised sections, 8 microns in thickness, stained in Delafield’s haematoxylin-eosin and Heidenhain’s haematoxylin were used to examine the condition of the gonad in relation to the length of the fish.

Observations

Day (1958) considers that Colisa (Cuvier and Valenciennes), the generic name, is a  synonym for Trichogaster (Bloch and Schneider). Smith (quoted by Abraham, 1962) is of the opinion that all the Indian species belong to the genus Colisa and all the Southeast Asian species belong to the genus Trichogaster. Colisa one of the seventeen genera of the family Anabantidae, suborder Labyrinthici, includes four species namely, chuna, fasciata, labiosa and lalia. C. lalia originally inhabited the Ganges and Jumna rivers (Forselius, 1957). It spread far south and till 1944. it was confined to north of the Krishna district especially in the Godavari waters, when the Madras Fisheries Department stocked this species in the Madras waters. Since then it has established itself widely in almost all the freshwaters of the Madras State including the uphill waters of Ooty and Yercaud (Abraham. 1962).

This species is reported to grow to a maximum length of 60 mm. It exhibits chromatic sex dimorphism. The males have a mosaic of red and green alternating bands on a blue-grey background. The colour especially is males is intensified in a typical anabantid manner during breeding seasons. It is a hardy and peaceful fish excepting while breeding. It tolerates a temperature ranging between 65° and 85°F. Higher temperatures of the water induce brilliant colouration and accelerate spawning of the fish. This species is considered to be a perennial breeder (Abraham,

— 83—

1962). The existing reports on its breeding habits are based on the observations made in laboratories. Little is known about its spawning periodicities and breeding habits under natural conditions (Mookerjee and Mazumder, 1960). It builds a bubble nest over bits of plants dead and alive in which operation the female assists her mate. There is a prolonged courtship before and after nest building; and the pair rests for a while after ejaculation and oviposition. The male recovers first and collects the deposited eggs in its mouth and blows them into the nest. Simultaneously the male drives off the female from its vicinity and guards the nest.

SPAWNING:

The fry of C. lalia are available only twice a year i. e., during February-March and July-August. Late  April or September practically no fry  is caught and this indicates that this species possesses two distinct peaks of sexual activity. During late summer i. е., in May adult fishes possess fully mature ovary but they do not spawn; their oocytes get entirely resorbed.

GROWTH:

Fry measuring about 38 mm and below in length do not show any secondary sexual characters. It is only beyond this length the male fry are identified by their secondary sexual colouration. Therefore the growth is estimated up to 38 mm for both sexes combined; and over 38 mm it is estimated for males and females separately (Figs. 1, A-D). It is found that the males grow faster than the females exceeding in their length by 1.6 mm during summer (Fig. 1, A) and 2.6 mm during monson (Fig. 1, B; Table I).

Moreover, the monsoon-born fishes grow rapidly during their adult stage and reach their maximum length in summer while the summer-born fishes though they grow faster during their fry stage, show a lower rate of growth during monsoon and reach their maximum length about four weeks after the normal period required of the monsoon-born fishes for reaching their maximum growth (Figs. 1 C and D).

— 84—

Table I: Mean values of body length (mm) of different
growth stages of Colisa lalia during monsoon and
summer (1961-1962)

Body length of individuals
Period of growth      Before attainment of chromatic sex dimorphism
in bi-weeks              Monsoon (1961)              Summer (1962)

.                                                                              At time of catch

1                    11.8                                13.2
2                    18.0                                19.8
3                    23.5                    Pre-adult 25.0
4       Pre-adult 28.5                                30.4
5                    32,0                                34.6
6                    34.0                         Adult 36.4
7              Adult 35.6                               37.2
8                     36.8                                38.0

___________________________________________

After attainment of chromatic sex dimorphism

Growth during                      Growth during
summer (1962)                      monsoon (1962)

Male        Female                   Male      Female

 9        39.2         38,6                    38.6        38.0
10       41.0         39.2                    40.0        38.8
11       41.8         40.0                    44.8        39.4
12       42.6         40.6                    44.6        41.6
13       43.6         41.4                    46.2        43.4
14       44.0         42.2                    47.6        45.4
15       44.8         42.8                    48.2        46.2
16       45.8         44.0                    48.4        46.6
17       46.8         44.8                    48.6        47.0
18      47.4         45.2                        —           —
19       48.2         45.6                        —           —

— 85—

Fig. 1:  Growth in body length of Colisa lalia during the monsoon and summer seasons of 1961 – 1962

. .. . .. .. . growth before attainment of secondary sex coloration;
— • — • — growth after attainment of secondary sex coloration
mg – monsoon growth; sg – summer growth.

— 86—

MATURITY:

The primordial germ cells appear as a layer between the mesoderm and endoderm and lie ventrolateral to the kidney in fry measuring 6 mm in length (Fig. 2). They multiply, descend as a mass suspended by the mesentery and occupy a positionbesides the intestine. This mass of primordial germ cells along with stroma cells forms the rudiment of the gonad and becomes easily distinguished in fry 12 mm long. The primordial germ cells divide to form primary oogonial cells; and these in turn divide forming the secondary oogonial cells (Figs. 3 and 4). The secondary oogonial cells transform into immature oocytes and this transformation is almost completed at 24 mm stage of the fry. The ovary now is packed with uniform immature oocytes (Fig. 5). The immature oocytes grow and become mature in about 35 mm long fishes.

 Table 2 : Stages of development of the ovary and
the corresponding body growth of female* C. lalia

Stages of growth     Body length     Stage of development of
of the fish              mm               the ovary

Fry or juveniles  8 – 24       Organisation of ovary;
formation of immature oocytes

Pre-adults     24 – 34   Stages of growth of immature
oocytes into mature ones.

Adults          35 and above Ovary in mature and spent
condition; contains also oocytes of
next crop.

*Sex identified from the histology of the gonad, though the external features do not indicate any sex difference in fishes upto 38 mm. in body-length.

— 87—

   Discussion

SPAWNING:

In most of the tropical freshwater fishes spawning takes place principally at the beginning and end of monsoon seasons as a result of the profound physical, chemical and biotic changes taking place in connection with monsoon rains and inundations (Forselius, 1957). Hermes (quoted by Forselius, 1957) during his field studies in central Thailand has observed nests of anabantids mainly Trichogaster species and Trichopsis vittatus specially in the beginning and end of rainy season.

Only a little is known about the breeding habits and spawning of C. lalia under natural conditions. Based on ova diameter, Abraham (1962) has reported that this species is a perennial breeder. In the present study spawning periodicity is determined from the availability of fry. It was referred earlier on that the fry of C. lalia are available only twice a year i. e., during February- March and July-August, and by the close of each season no fry is caught. Further it was observed that after fortyfive days from the time of catch the monsoon-fry grow into pre-adults; while the summer-fry attain the pre-adult stage after a month. From these it is evident that this fish spawns only twice a year, with the result its fry occur only during the periods mentioned above. The absence of these fry during other parts of the year as observed in the present study seems to contradict the observations of Abraham (1962) who reports that this species is a perennial spawner. However, her observation that majority of these fishes spawn around December and again during June-July partly conforms with the two spawning seasons observed in the present investigation.

Mellen and Lainer (quoted by Jones, 1946) have stated that C. lalia spawns several times during summer at 75°F. It is quite robable that higher temperature of the water has accelerated the

— 88—

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??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????

— 89—

oocytes transform into mature oocytes. The ‚adult’ refers to the stage when the first crop of oocytes attains maturity.

 Summary

Spawning periodicity of Colisa lalia has been determined from the availability of fry under natural conditions.

The growth of fry and adults during summer and monsoon seasons has been critically examined. The growth of this species is interpreted in terms of the growth of the gonad.

Acknowledgment

One of us (V.G.K.) is grateful to the Ministry of Education, Government of India for the financial assistance.

References

Abraham, J. G., 1962. Studies on Colisa lalius (Cuv. and Val.). Fisheries Station Reports and Year Book, April 1957-March 1958. Department of Fisheries, Government of Madras.

 Axelrod, H. R., 1956. Tropical fish as a hobby, A guide to selection, care and breeding. George Allen and Unwin Ltd, London.

Axelrod, H. R., and Schultz L. P. 1955. Handbook of tropical aquarium fishes. McGraw-Hill Book Co., New York.

Brody, S., 1945. Bioenergetics and growth. Reinhold, New York.

Das, K. N., and Das Gupta, B. N., 1945. Factors influencing the spawning of Indian carps. Froc. Nat. Inst. Sei. India, 11, 324-327.

Day, F., 1958. The Fishes India. William Dawson and Sons Ltd., London. s. a.

  — 90—

Forselius, Sien., 1957. Studies of Anabantid fishes I. II and III. Zool. Bidrag Uppsala, 32, 97-597.

Hussain, A., 1945. Factors influencing the spawning of Indian carps. Proc. Nat. Inst. Sci.
India, 11, 320-324.

Jones, S , 1946. Breeding and development of Indian freshwater and brackish water fishes II. J. Bombay Nat- Hist. Soc., 46, 453-472.

Krishnamurthy, V. G., 1964. Corpuscles of Stannius in Colisa lalia (Hamilton – Buchanan). Naturwiss., 51, 344-345.

Krishnamurthy, V. G., 1967. Development of the Corpuscles of Stannius in the Anabantid teleost, Colisa lalia. J. Morph., 123(2), 109-120.

Krishnamurthy, V. G., 1968. Histochemical and biochemical studies of the corpuscles of Stannius of the teleost fish, Colisa lalia. Gen. Comp. Endocrinol., 11, 92-103.

Merriman, D., and Schedl, H. P., 1941. The effects of light and temperature on  gametogenesis in four-spined stickleback, Apeltes quadrants (Mitchill). J. exp. Zool., 88, 413-449.

Mookerjee, H. K., and Mazumder., 1960. On the life history of Colisa lalius (Hamilton). Proc. Zool. Soc., 13, 29-38.

Pickford, G. E., and Atz, J. W., 1957. The physiology of the pituitary gland of fishes. New York Zoological Society, New York.

 

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______________________
____________

The review of applied entomology. Series B. Medical and veterinary, Vol, 33, 1945 ,  p. 144

 Hamid Khan. On the relative Value of certain larvivorous Fishes from the Punjab, with Notes on their Habits and Habitats.— Indian J. vet. Sci. 13 pt. 4 pp. 315-325, 23 refs. Delhi, 1944.

The following is mainly based on the author’s summary.

Colisa lalia, Ambassis baculis and Barbus sophore, three larvivorous fish of the Punjab, were observed in captivity to devour 148, 136 and 90 mosquito larvae per fish per day, respectively. A study of their gut contents indicated that  C. lalia and A. baculis invariably feed on mosquito larvae when put into a reservoir where these are present. In the absence of mosquito larvae, they feed on Crustacea, rotifers and the larvae of aquatic insects. Though B. sophore fed actively on mosquito larvae in the laboratory, in ponds it mostly feeds on mud, decayed vegetation, algae and aquatic weeds, and thus reduces the food-supply of mosquito larvae. All three species bred successfully in  reservoir water. Only C. lalia survived in a mixture of equal parts of reservoir water and sewage water, but all could thrive in such stagnant waters as lie near towns and villages. Notes are given on their breeding habits. All need sub-surface vegetation, especially in July and August, to enable them to lay eggs. The investigations made have demonstrated the effectiveness of C. lalia and A. baculis in destroying mosquito larvae in reservoirs and ponds, and their use is recommended. It is calculated that to free water of mosquito larvae as quickly as possible, a population of 2,500 fish per acre of water is necessary.

 

Links:

http://archive.org/stream/annualrecordofsc1876bair#page/320/mode/2up

http://quod.lib.umich.edu/m/moajrnl/acw8433.1-15.360?node=acw8433.1-15.360:1&view=text&seq=226

http://www.jstor.org/stable/10.2307/1435496

http://archive.org/stream/fishesofindiabei01dayf#page/374/mode/2up

http://archive.org/stream/fishesofindoaust04weberich#page/342/mode/2up

http://www.seriouslyfish.com/species/trichogaster-lalius/

http://link.springer.com/article/10.1007%2Fs10228-009-0121-2?LI=true

http://www.nzaquaculture.co.nz/AHI/AQUACULTUREHEATH%2008.pdf#page=38

http://www.sciencedirect.com/science/article/pii/S004484860300512X

http://digilib.litbang.depkes.go.id/files/disk1/28/jkpkbppk-gdl-grey-1995-wahyuni-1359-fish-vol23-2-2.pdf

http://en.bdfish.org/2010/02/dwarf-gourami-colisa-lalius/

http://archive.org/stream/annalsmagazineof4171876lond#page/172/mode/2up

2012/11/25 | Supplementum

Suplement XXVII

Kaj J. (1958b): Przebieg tarła ryb w dolnym odcinku rzeki Wełny. Pol. Arch. Hydrobiol., Warszawa, pp. 183 – 192.

J. Kaj.

Przebieg tarła ryb w dolnym odcinku rzeki Wełny

Maszynopis otrzymano 5.II.1956

W wysuniętym w 1954 roku projekcie utworzenia rezerwatu rybnego w dolnym odcinku rzeki Wełny, prawobrzeżnym dopływie Warty w jej środkowym biegu, podane zostały powody natury przyrodniczej i rybackiej tej inicjatywy. W skrócie przedstawiają się one następująco: Odcinek о mozaice biotopów, o ogólnym charakterze wartkiej rzeki i znamionach rybackich, tzw. krainy brzany, jest miejscem rozrodu cennych gospodarczo gatunków, takich jak certa, brzana, kleń, świnka, przede wszystkim zaś szczytowym warciańskim tarliskiem wędrownych ryb łososiowatych — łososia i troci.

Z dwóch ostatnich gatunków notowany jest na tym odcinku regularniejszy pojaw troci, podczas gdy obecność tarliskowa łososia właściwego jest zjawiskiem raczej sporadycznym i dotyczy jedynie pojedynczych osobników, pochodzących z względnie jeszcze licznego pogłowia tej ryby biorącego udział w tarle w dopływach Noteci (Drawa, Głda) i w dolnej Warcie po rejon miasta Wronki. Omawiany odcinek jest według dotychczasowych mych obserwacji miejscem pobytu stałego lub okresowego 20 gatunków ryb, do których dołączają się zstępujące z góry rzeki gatunki wprowadzone ostatnio przez człowieka w akcjach zarybieniowych, mających podnieść atrakcyjność wędkarską rzeki Wełny, a więc pstrąg potokowy, pstrąg tęczowy i lipień.

О charakterze rzeki świadczy między innymi obecność rzadkiego w dorzeczu Warty gatunku, jakim jest głowacz białopłetwy (Cottus gobio). Postępujący zanik tarlisk naturalnych szeregu ryb w samej Warcie w wyniku nasilonej regulacji tej rzeki i zwiększających się zanieczyszczeń ściekami przemysłowymi zmusza do otoczenia specjalną opieką nielicznych już fragmentów dorzecza o stosunkowo mało zmienionych przez człowieka warunkach przyrodniczych. Groźny dla ichtiofauny stan pogarsza panujący już od szeregu lat niski poziom wody w rzece. Zmasowanie tarła kilku gatunków ryb na dolnej Wełnie czyni obiekt ten tym godniejszy ochrony. Wysunięcie ochrony rezerwatowej przyniosło, jak dotąd, efekt częściowy w postaci ustanowienia na omawianym odcinku obrębu ochronnego, a więc wprowadzenie ochrony czasowej w okresie ustawowych czasów ochronnych (wiosennych) dla ryb. Rozwiązanie takie trzeba uznać za połowiczne choćby z tego względu, że poza ochroną czasową ustaloną dla obrębu ochronnego znalazła się część gatunków ryb tarła wiosennego, wobec stwierdzenia odbywania przez nie tarła aż po drugą połowę czerwca włącznie, to jest poza obowiązujący okres ochronny ograniczony końcem maja.

Aby zdać sobie sprawę z wartości omawianego odcinka jako tarliska naturalnego, wartości mierzonej liczebnością biorącego udział w tarle pogłowia poszczególnych gatunków ryb oraz efektem tarła, dokonałem w okresie wiosennym szeregu obserwacji całodziennych,  dobierając terminy tak, by uchwycić istnienie związku między warunkami hydrologicznymi i klimatycznymi a nasileniem tarła. Względy technicznej natury nie pozwoliły niestety na przeprowadzenie spostrzeżeń w sposób ciągły.

Próba liczbowego ujęcia ryb biorących udział w tarle nasuwała szczególnie duże trudności zważywszy ruchliwość stada rybnego, stosunkowo rozlegle i jednocześnie rozproszone tarliska, jak i pojaw poszczególnych zespołów ryb na tym samym tarlisku w kilku nawrotach. Liczby podane niżej obarczone są więc błędem, w większości jednak wypadków są one raczej nieco niższe od rzeczywistych. Ze względów metodycznych obserwacje dokonywane były głównie na jednym tarlisku, poniżej jazu piętrzącego wodę na potrzeby młyna turbinowego. Czynnikami ułatwiającymi obserwacje była stosunkowa płytkość rzeki i przeźroczystość wody, widoczność do dna oraz względnie mała szerokość rzeki w granicach 8 — 14 m. Liczbę ryb na tarle uzyskiwano przez zsumowanie liczb ustalonych jednocześnie przez kilku współpracowników, obserwujących z obu brzegów poszczególne z góry wyznaczone sektory tarliska. Obserwacje nad przebiegiem tarła połączone były z pomiarem termiki powietrza i wody oraz poziomu wody zmieniającego się tak z powodu opadów, zresztą nieznacznych, jak głównie wskutek okresowego otwierania upustów w jazie regulującym poziom zbiornika retencyjnego powyżej spiętrzenia.

Czas obserwacji objął okres między 5 maja a 3 lipca 1955 r. z przerwami parodniowymi. Sygnałem rozpoczęcia spostrzeżeń było pierwsze wiosenne zwiększenie się ilości ryb na całym omawianym odcinku rzeki, przy czym ciąg tarliskowy rozpoczęła świnka (Chondrostoma nasus).

Niżej podany raptularz spostrzeżeń obejmuje najtypowsze dla omawianego okresu momenty.

1. 8.V.1955. Temperatura powietrza 17°C; temperatura wody 13°C. Głębokość wody na tarlisku 50 cm. W ujściowej partii rzeki pojawiają się liczniejsze kilkugatunkowe zespoły ryb, ciągnące z Warty w górę rzeki. Przeważa świnka. Kontrolny połów wykazuje IV stadium dojrzałości płciowej u tego gatunku. Tarło nie odbywa się.

2. 10.V.1955. Temperatura powietrza 18°C. Temperatura wody 13,6°C, poziom wody 50 cm. Na tarlisku dojrzała świnka (Chondrostoma nasus). W odbywającym się tarle bierze udział około 300 sztuk tego gatunku. Pojawiły się nieliczne certy (Vimba vimba) i brzany (Barbus barbus).

3. 21.V.1955. Temperatura powietrza 16°C. Temperatura wody 11,2°C. Poziom wody 50 cm. Całkowity brak ryb na tarlisku w związku z obniżką temperatury wody i powietrza, spływ ryb już w dniach poprzednich na głębsze wody rzeki w kierunku Warty.

4. 22.V.1955. Temperatura powietrza 16°C. Temperatura wody 10,8°C. Poziom wody na tarlisku wzrósł do 60 cm w związku z otwarciem jednego upustu śluzy. Złowiono 1 brzanę w IV stadium dojrzałości płciowej, próbującą pokonać prąd przy upuście dla przebycia zapory.

5. 30.V.1955. Temperatura powietrza 18°C. Temperatura wody 15°C. Spadek poziomu wody do 45 cm. W pobliżu spiętrzenia skaczące brzany. Pojaw pojedynczych okazów innych gatunków, głównie klenia (Leuciscus cephalus) i certy.

6. 4.VI.1955. Temperatura powietrza 18°C. Temperatura wody 15,2°C. Dalszy spadek wody do poziomu 40 cm. Na tarliskach trące się klenie (około 100 sztuk) i małe grupki brzany. Odłowiono kilka brzan w stadium V dojrzałości płciowej i kilka w IV stadium według skali Maiera.

7. 7.VI.1955. Temperatura powietrza 28°C, słonecznie. Temperatura wody 18,6°C. Poziom wody osiąga minimum wynoszące 30 cm. Tarło masowe klenia (około 300 sztuk) i certy (około 2500 sztuk). W peryferyjnych partiach tarliska i wokół wyspy bardzo dużo uklei dojrzałej nie odbywającej jednak jeszcze tarła.

8. 10.VI.55. Temperatura powietrza 24°C, pogodnie z  przejściowymi zachmurzeniami. Temperatura wody 14°C. Poziom wody utrzymuje się nadal na 30 cm. Tarło certy przerwane, ryba spływa w dół rzeki. Odbywa się jednak tarło uklei. Kamienie tarliska usiane ikrą certy. Próby pobrane wykazują brak niezapłodnionych ziaren.

9. 18.VI.55. Temperatura powietrza po okresie ochłodzeń i deszczów spada do 11°C. Temperatura wody 13,6°C. Wzrost poziomu wody do 60 cm. Całkowity brak ryb na tarlisku.

10. 20.VI.55. Gwałtowne ocieplenie. Temperatura powietrza 26°C. Temperatura wody podnosi się do 18,2°C. Ponowny spadek poziomu wody do 40 cm. Z Warty ciągną duże ilości certy. W tarle bierze udział około 1700 osobników tego gatunku.

11. 22.VI.55. Temperatura powietrza wzrasta do 28°C. Temperatura wody osiąga 19,6°C. Wzrasta również poziom wody do 50 cm. Tarło certy w pełni. Szacunkowa ilość osobników tego gatunku 3000 — 3500 sztuk. Takie nasilenie tarła powoduje,  że odbywa się ono mniejszymi grupkami również w innych partiach rzeki, szczególnie w rejonie mostu kołowego w obrębie miasta Oborniki. Prócz certy trze się ukleja i kleń. Próbne połowy uklei pozwalają na szacunkowe ustalenie liczby osobników tego gatunku w granicach 5 — 6000 sztuk. Liczba kleni około 200.

12. 24.VI. — 3.VII 55. Krótkotrwałe obserwacje w odstępach dwudniowych wykazują utrzymywanie się temperatury wody w granicach 19 — 20°C przy małych wahaniach temperatury powietrza w zakresie 28 — 29,5°C. Wahania poziomu wody w granicach 55 — 60 cm  wywołane są zwiększeniem przepływu wody przez upusty jazu. Ilość ryb na tarlisku maleje gwałtownie, chociaż aż do 3.VII. następuje sporadyczne tarło małych grup certy. Jako element stały obserwuje się pojedyncze sztuki wytartych brzan.

Obserwacje przedstawione w skrócie powyżej pozwoliły na zgromadzenie danych dotyczących przebiegu tarła poszczególnych gatunków, wyboru przez nie pewnych specyficznych partii rozległego tarliska, pory dnia i przybliżonego stosunku płci w poszczególnych jednogatunkowych zgrupowaniach. Так więc tarło certy i klenia odbywało się w pełnym świetle, w dobrze nasłonecznionych partiach tarliska, przy czym trące się certy gromadziły się z reguły wokół większych głazów, wywołujących swą obecnością w łożysku rzeki znaczne lokalne różnice nasilenia na krawędziach i w „cieniu” przeszkody. Akt tarła kleni wykazywał mniejsze powiązania z jakością dna, rozciągając się tak na partie żwirowe i piaszczyste, jak i na partie dna usiane głazami. Największe nasilenie tarła dwóch tych gatunków przypadało zawsze na godziny  południowe, przeciągając się czasem do godziny 18. Tarło świnki rozciągało się na partie rzeki o dnie piaszczystym z kępkami roślinności. Obecność dużej ilości  Fontinalis antipyretica na kamieniach dna sprzyjała wybitnie zlokalizowaniu ikry, dając dobre warunki przyczepu dla kleistych w pierwszym okresie ziaren ikry wymienionych gatunków.

Miejscem masowego przyczepu ikry uklei były prawie wyłącznie drobne korzenie wierzb i olch w płytkiej wodzie przybrzeżnej. Ikra brzany zlokalizowana była najczęściej na małych kamieniach dna. Uderza zmasowanie certy w trące się grupy dochodzące do 30 sztuk, przy czym na jedną samicę przypadało siedem do dziesięciu samców. Obserwacje te ułatwiała wybitna i znana różnica w ubarwieniu obu płci tego gatunku. Tarło kleni odbywało się w małych grupkach po trzy do sześciu osobników.

Przebieg tarła wiosennego na dolnej Wełnie w roku 1955 i jego zależność od termiki i poziomu wody ujmuje graficznie rys. 1.

Wielokrotnie ponawiane pobieranie prób kontrolnych dna tarliska w końcu czerwca i w początkach lipca wykazało masową obecność ikry wszystkich wymienionych gatunków ryb. Niektóre z prób wykazywały ikrę o różnym stopniu rozwoju zarodka jako wynik kilkakrotnie powtarzanego tarła w tym samym miejscu. Uderzający byt wysoki udział ikry zapłodnionej, z reguły przekraczający 80% ziaren na badanych kamieniach czy innych przedmiotach zanurzonych. Próbki włoczkiem narybkowym dokonywane w połowie lipca

Rys. 1. Przebieg wiosennego tarła ryb w dolnej części rzeki Wełny

Próbki włoczkiem narybkowym dokonywane w połowie lipca wykazały obecność bardzo licznego wylęgu. Ilość jego z dnia na dzień malała, zapewne wskutek znoszenia wylęgu z prądem wody w dół rzeki. Trudno ustalić, w jakim stopniu do zmniejszania się ilości wylęgu przyczyniło się żerowanie ryb drapieżnych czy nawet niedrapieżnych. Obecność szczupaka na płytkiej wodzie tarliska była zjawiskiem wyjątkowym, wzrosły za to połowy zarówno drapieżnych, jak i niedrapieżnych ryb w Warcie w pobliżu ujścia do niej rzeki Wełny.  Omawiany odcinek rzeki Wełny został w sierpniu całkowicie „spłukany” z drobnych ryb przez otwarcie jazu dla spuszczenia wody ze zbiornika powyżej młyna turbinowego. Dokonano tego dla oczyszczenia młynówki ï kilkuletnich osadów dennych. Akcja ta, niezgodna z interesami rybactwa, spowodowała pokrycie nie tylko tarlisk, ale prawie całego odcinka aż po ujście grubą warstwą mułu i piasku. Potrzeba było dopiero kilku miesięcy, by znów normalny przepływ wody w rzece oczyścił koryto z naniesionych osadów i by w częściach rzeki z bujniejszą wegetacja roślin zanurzonych nastąpić mogła jej regeneracja. Wygląd w przybliżeniu normalny odzyskała rzeka dopiero w początkach października.

Z kolei należy zdać sobie sprawę z efektu naturalnego tarła wyrażonego liczbą złożonej ikry. Wydaje się to ważne szczególnie w odniesieniu do certy — z uwagi na specyfikę jej tarlisk i mala ilość miejsc jej naturalnego rozrodu w dorzeczu Warty. Przyjmując raczej niekorzystny stosunek procentowy płci w populacjach biorących udział w tarle 1 : 3 na niekorzyść samic — w rozrodzie w roku 1955 brało udział na omawianym odcinku Wełny со najmniej 2000 ikrzyc tego tego gatunku. Połowy kontrolne wykazały obecność okazów 200 — 1000-gramowych z dominacją osobników 400 — 600-gramowych. Bez większego błędu przyjąć możemy płodność ryb tej wielkości na 80 000 ziaren ikry na osobnika żeńskiego. Efektem tarła było więc złożenie со najmniej 160 000 000 ziaren ikry. Jest to cyfra ogromna, zważywszy, że ikra ta złożona została na stumetrowym odcinku poniżej jazu oraz w rozproszonych skupiskach na 200 m odcinku powyżej i poniżej mostu drogowego na linii Oborniki — Czarnków.  Jest możliwe, że liczbę w ten sposób obliczonej ikry należałoby nieco obniżyć z uwagi na udział w końcowej fazie tarła osobników małych, około 300-gramowych, zwanych tu „jakubówkami”. Ocena ilości złożonej ikry klenia nasuwa więcej trudności, zważywszy większe jej rozproszenie. Biorąc pod uwagę obecność na tarle со najmniej 150 ikrzyc tego gatunku o średniej wadze osobniczej około 0,5 kg i płodności względnej 40 000 ziaren na 1 kg ciała ilość złożonej ikry była nie mniejsza niż 3 000 000 ziaren.

Na tle wysokich cyfr ikry certy i klenia ilość złożonej ikry brzany wydawała się dość niska. W przeciwieństwie np. do roku 1951, kiedy obserwowałem w dniu 18 maja jednorazowe tarło со najmniej 200 sztuk w jednym miejscu, jej pojaw tarliskowy w roku 1955 ograniczył się szacunkowo do około 150 sztuk we wszystkich dniach przeprowadzanych obserwacji. Możliwe, że stan ten jest odzwierciedleniem obserwowanego w latach powojennych zaniku brzany w dorzeczu Warty,со znajduje swój wyraz w zmniejszającym się udziale brzany w połowach przeprowadzanych przez rybactwo spółdzielcze w Poznaniu. Dodać tu należy, że w okresie tarła certy i klenia obserwowano na tarlisku pojedyncze okazy jelca (Leuciscus leuciscus). Czy odbywało się tarło tego gatunku trudno ustalić, choć jest to prawdopodobne.

Z obserwacji z lat ubiegłych zdaje się wynikać, że dominacja jednego lub drugiego gatunku na tarliskach dolnej Wełny zależy od ilości toczonej przez rzekę wody. W latach о poziomie wyższym, a więc przy głębszej wodzie, słabsze jest nasilenie pogłowia certy przy jednoczesnym wzroście liczbowym dużej brzany i klenia. Jednocześnie wzrastają ilości okonia i szczupaka w zagłębieniu pod śluzą, w ujściowej zaś partii pojawia się leszcz i płoć.

Na tle efektów tarła ryb karpiowatych sprawa ryb wędrownych (łosoś, troć) przedstawia się słabo. Nie dysponując obserwacjami z roku bieżącego przytoczyć mogę jedynie dane oparte na posiadanym materiale z lat ubiegłych i informacjach rybaków. Z wypowiedzi miejscowego kierownika brygady rybackiej pracującego na przyległych terenach warciańskich od 30 lat, regularny, choć niezbyt liczny połów łososia względnie troci odbywał się w okresie międzywojennym w czasie poprzedzającym ochronę tarliskową, w samej Warcie, w pobliżu ujścia Wełny. Ilość złowionych okazów (głównie troci) nie przekraczała z reguły 1O sztuk na sezon. W okresie tarliskowym nieliczne okazy wpływały do Wełny, pojawiając się pod młynem Słonawy, poniżej ujścia wody z turbin. Do rąk mych doszły okazy troci z roku 1952, a mianowicie samica wagi 5 kilogramów, długości 84 cm, złowiona 16.VIII w ujściu Wełny, oraz złowiony 23.XII w niedalekim sąsiedztwie samiec wagi 3,8 kg i 77,5 cm długości. Szczególnie ważne wydaje się złowienie na Wełnie w dniu 20.V.1953 roku smolta troci о długości 28 cm.

Niepokojące zmniejszanie się ilości wędrownych ryb łososiowatych w środkowej Warcie ma swą przyczynę niewątpliwie w antysanitarnym stanie rzeki, wywołanym ściekami przemysłowymi. Barierą biologiczną dla łososia czy troci w  dojściu tych ryb na tarliska w ujście Wełny jest przede wszystkim zanieczyszczenie rzeki Warty w rejonie Wronek, siedzibie dużych zakładów przemysłu ziemniaczanego. Znamienny jest fakt połowów w roku 1945, tuż po unieruchomieniu przemysłu szeregu miast nad środkowa Wartą (również i przemysłu miasta Poznania) w następstwie działań wojennych, znacznych ilości łososi właściwych i troci na Warcie w obrębie Poznania, a pojedynczych sztuk nawet kilkadziesiąt kilometrów w górę rzeki po rejon Śremu. Uzdrowienie stosunków sanitarnych na Warcie poprzez unieszkodliwienie ścieków przemysłowych przed wlaniem się ich do rzeki jest sprawą palącą nie tylko ze względów rybackich.Ochrona pozostałych jeszcze tarlisk naturalnych traci sens, jeśli uniemożliwi się rybom dotarcie do tych miejsc rozrodu. Usunięcie bariery biologicznej pod Wronkami w decydującym stopniu przyczynić się powinno do restytuowania stanu i przełomu XIX i XX wieku, kiedy to ichtiolog niemiecki Grotrian mówił o tarle ryb łososiowatych na Wełnie jako o zjawisku normalnym.

Przedstawione wyżej obserwacje z jednego wiosennego okresu tarliskowego posłużyć powinny jako rybacki materiał dowodowy w akcji utworzenia na omawianym odcinku ochrony rezerwatowej. Miarą zrozumienia ważności zagadnienia jest fakt, że sprawa pełnej ochrony posiada najgorętszych orędowników w użytkownikach rybackich tego odcinka, Spółdzielni Rybackiej i licznych rzeszach wędkarzy.

Streszczenie

Wysunięto projekt utworzenia rezerwatu rybnego w dorzeczu rzeki Warty na dolnym odcinku rzeki Wełny, znanym jako miejsce masowego tarła szeregu gatunków ryb karpiowatych oraz szczytowego, sporadycznego tarliska troci lub łososia.  W roku 1955 przeprowadzone zostały obserwacje nad przebiegiem tarła wiosennego ryb dla ustalenia czasu jego trwania oraz zależności nasilenia tarła od czynników hydrologicznych i klimatycznych. Podjęto próbę ustalenia liczebności populacji poszczególnych gatunków biorących udział w tarle.

Z kolei przeprowadzona została szacunkowa ocena efektu naturalnego tarła, wyrażającego się ilością złożonej ikry i stopniem jej zapłodnienia. Obserwacje dotyczyły certy (Vimba vimba L.), klenia (Leuciscus cephalus L.), brzany (Barbus barbus L.), świnki (Chondrostoma nasus L.) i uklei (Alburnus alburnus L.).

Ilość ryb poszczególnych gatunków obecnych na tarlisku w okresie 5.V. — 3.VII.55 ustalono w przybliżeniu na 7000 sztuk certy, 600 sztuk klenia, 150 sztuk brzany, 300 sztuk świnki i ponad 6000 sztuk uklei.

Tarło certy nastąpiło przy temp. wody wynoszącej 15,2°C, ulegając przerwaniu przy spadku temperatury do 14°C. Największe nasilenie tarła tego gatunku zanotowano przy 19,6°C. Podobnie kształtowała się zależność przebiegu tarła od temperatury wody u brzany i klenia. Tarło świnki odbywało się jeszcze przy temp. 13,6°C, uklei zaś przy 14°C.

Stwierdzano z reguły wysoką skuteczność naturalnego zapłodnienia ikry — przekraczającą 80%. Pobrane próby złożonej ikry w zestawieniu z obszarem tarliska i liczebnością samic poszczególnych gatunków ryb były podstawą dla oceny liczebności złożonej ikry. Określono w przybliżeniu ilość złożonej ikry certy na 160 000 000 ziaren, klenia na 3 000 000. Konieczność utworzenia rezerwatu na oznaczonym odcinku rzeki nawet w świetle obserwacji jednego sezonu tarliskowego, przy niedoskonałości metod pracy — wydaje się w pełni uzasadniona.

И. Кай

Ход нереста рыб в низовиях реки Велны

Резюме

Проект образовать рыбный резерват в низовиях реки Велны, вызвал необходимость провести исследования этого массового нерестилища многих видов карповых рыб и  одновременно спорадического нерестилища кумжи и лососей.

В 1955 году проводились наблюдения хода весеннего нереста рыб для того, чтобы определить продолжительность его сроков и степень его зависимости и интенсивности от гидрологических и климатических факторов Были сделаны тоже попытки определить численность популяций отдельных видов, участвующих в нересте.

Затем была проведена оценка результатов естественного нереста, определяющихся по количеству отложенной икры и степени ее оплодотворения. Наблюдения касались сырти (Vimba vimba L.), голавля (Leuciscus cephalus L.), усача (Barbus barbus L.), подуста (Chondrostroma nasus L.) и уклейки (Alburnus alburnus L.).

Численность рыб, принадлежащих к отдельным видам и нерестующих в период с 5.V по 3.VII.55 г., приблизительно определялась на 7000 штук сырти, 600 шт. голавля, 150 шт. усача, 300 шт. подуста и свыше 6000 уклейки.

Нерест сырти начинался при температуре воды — 15,2°Ц и приостанавливался при падении температуры до 14°Ц. Самый большой разгар нереста у этого вида наблюдался при 19,6°Ц. Подобным образом сложилась также зависимость хода нереста от температуры воды у усача и голавля. Подуст нерестовал еще при температуре 13,6°Ц, а уклейка при 14°Ц.

Обыкновенно подтверждалась высокая эффективность естественного оплодотворения икры — превышающая 80%. Отобранные пробы отложенной икры в сопоставлении с нерестной площадью и численностью самок отдельных видов рыбы послужили основанием оценки количества отложенной икры.

Количество отложенной сыртью икры определялось приблизительно на 160 000 000 икринок, икры отложенной голавлем — на три миллиона. Необходимость образовать в данном отрезке реки резерват (даже в свете односезонных наблюдений и при их недостаточном методе)кажется вполне узаконенной.

Список рисунков

Рис. 1. Ход и интенсивность весеннего нереста рыб в нижней части реки Велны.

J. Kaj

Spawning of Fish in the Lower Stretch of the Wełna River

Summary

It is proposed to establish a fish reservation in the lower stretch of the Wełna River (Warta river basin), known from mass spawning of a number of fish species belonging to the Cyprinidae family, and as a sporadic and peak spawning place of sea trout resp. salmon. Observations were conducted in 1955 on spring spawning of fish for the purpose of determining the time of its duration, and the correlation between spawning intensity, and hydrological and climatic factors. Efforts have been made to determine the number of different fish species taking part in spawning. Further the natural effect of spawning was estimated, expressed as the quantity of eggs layed and the degree of fertilization. These observations were conducted on the following fish species: Vimba vimba L., Leuciscus cephalus L., Barbus barbus L., Chondrostoma nasus L. and Alburnus alburnus L.

The number of fish of each of the species present in the spawinng place during the the period May 5-th to July 3.1955 was determined approximately at 7000 Vimba vimba, 600 Leuciscus cephalus, 150 Barbus barbus, 300 Chondrostoma nasus and 6000 Alburnus alburnus.

Spawning of Vimba vimba took place at a water temperature of 15,2°C. stopping with a decline of the water temperature to 14°C. Greatest intensity of spawning was noted at 19.6°C. A similar interrelation between spawning intensity and water temperature was noted in the case of Barbus barbus and Leuciscus cephalus. Spawning of Chondrostoma nasus was still observed at a temperature of 13.6°C, of Alburnus alburnus — at 14°C.

As a rule the effect of natural spawning was high, exceeding 80%. Samples of spawn taken, and confronted with the area of the of the spawning place and number of females of different species, served as a basis for estimating the amount of spawn layed. This amount was estimated at 160 million eggs for Vimba vimba, 3 million for Leuciscus cephalus. The necessity of establishing a reservation in the mentioned stretch of river — even in the light of observations conducted over one season only and of the imperfect methods of study — seems to be obvious.

List of Figures

Fig. 1. The course and intensity of spring spawning of fish in the lower stretch of Wełna river in 1955

2012/11/16 | Supplementum