The following notes, necessarily imperfect, on the habits, spawning season and early stages of sorne of the Madras freshwater fish, are based mainly on investigations made during 1910-11, the results of which were embodied in a dissertation which was submitted to the University of Madras in 1912. The enquiry, however, was continued in subsequent years amidst other work, and consequently the original paper has been considerably modifed as the result of additions and corrections made in the light of further research and study.
Though a number of notes on the habits of Indian freshwater fish have appeared from very early times, they are comparatively few and most of them are at best random observations. In the following pages an attempt has been made to combine all that is known regarding the habits and early stages of the fish in question (by a fairly exhaustive though by no means complete reference to previous literature) with facts personally observed and recorded for the first time in this paper. Only such observations from previously published accounts as are likely to be of general interest have been included and duly acknowledged. They have been gathered for the most part from the writings of Hamilton Buchanan , Sir E. Tennent , Cantor , Jerdon , Day , Thomas and especially Dr. Willey , whose observations on the breeding habits of Ophiocephalus striatus and accounts of the nests, eggs and fry of some other species in his report on the inland fisheries of Ceylon are substantial contributions to our knowledge of the spawning habits of Indian freshwater fish.
The local limits of my collection and obseivation are defined by the title of this paper, my examination being confined to the rivers Cooum and Adyar and to the ponds within the municipal limits of the city of Madras, and in a few cases being extended to some large outlying tanks such as Sembarambakkam and Red Hills. The Red Hills, some seven miles west of Madras, is a large perennial tank, while Sernbarambakkam, about ten miles from the City, is the largest irrigation tank in this neighbourhood, but runs dry during the hot weather. The ponds within the city limits are of the usual type and require no special consideration; nearly all of them contain fresh water excepting a few on the sea-coast in which the water is brackish. The rivers Cooum and Advar, like most rivers of the Coromandel coast, are almost dry for several months of the year; the season of their chief flow is usuall during the N. E. monsoon (November and December). When in flood they are raging torrents and the water is brick-red owing to the mixture of a red deposit of light specific gravity: at other times the water is clear and collects in pools on the bed. Near the mouth for a distance of over two miles from the sea both rivers form estuaries, and the embouchures of both are encumbered by natural bars. Since the construction of the Buckingham Canal it has been found necessary to keep the mouths of both rivers closed throughout the year in order to regulate and confine their spill so as to contract the waterway for boat traffic: in the case of Cooum a high level in estuary is further necessary for sanitary purposes, in order to submerged its sewage-laden banks and shoals. Hence the estuary is not subject to ticel action and the percentage of salt is not very variable. A sample of water contained from the Cooum estuary in August, when the river was at its lowest, had 3.576 per cent of dissolved salts and a specific gravity of 1.0164. 1
The Cooum estuary is always highly contaminated with sewage except during the freshets.
The flora of the ponds and the rivers of Madras is more or less the same and consists chiefly of many filamentous and unicellular algae notably species species of Chara and Spirogya ; the former abounds in brackish water. A few species of Phanerogams, principally Elodea and Vallisneria , occur; the former is the commonest and the most abundant water-weed in Madras, while the latter is found in clumps in a few places in the rivers.
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. - A very common species in ponds, ditches and rivers. In the Cooum it occasionally occurs within tidal influence. In its natural surroundings O. striatus often resorts to the margin of the water overgrown with weeds. It frequents shallow water probably because air is easy of access and so suits its amphibious habits. The air-breathing habit of this fish is well-known: in consequence it lives hours, sometitnes days, out of water, especially when kept among moist water-plants. Like most other air-breathers it is never seen to perforM the usual respiratory movements of fish. During the rains in Madras young Ophiocephali are often caught on land in the course of their migrations: out of water they progress in a serpentine manner, by means of their pectoral fins and the alternate contractions of the lateral muscles of the body. During periods of drought they are known to bury themselves in the soft bottom mud of ponds. 2
All the species of Opiocephalus are monogamous and build nests 3 for depositing their eggs. Under favourable conditions O. striatus breeds twice a year, about January 4 and February and again in June and July; but the same pair do not seem to breed twice in the year. The nest consists of a circular clearing in grassy swamps or in the weedy edges of ponds and rivers. Both parents, the male in particular, keep guard. The eggs, which are large (1.25 mm.) and float at the surface, are never numerous but vary from a few hundredls to a few thousands according to the size of the fish. Dr. A. Willey gives a full description of the nest, egg and young of this species in Spolia Zeylanica, Vol. VI, pp. 108-123 . The following is a brief summary of facts observed by him.
Translucent golden-yellow or amber-coloured. They are spread like a sheet, flush with the surface in a sub-circular area in tlie centre of the nest. Diameter of egg 1.25 mm.
«The floating eggs owe their buoyancy to the presence of a sincle large oil-globule which occupoes the greater part of the ovum, and is immersed in the golden-yellow yoke. It is adjacent to the upper pole of the egg, and in surface view under a low power of the microscope is seen to be surrounded by a narrow zone of the yolk. The whole being contained within a space bounded by the viteline membrane.»
The subjoined table gives a summary of the chronological data ascertained by him regarding the external features of the development of O. striatus .
|Days after hatching||Total length||Principal events|
|1||3.5 mm.||Yolk-sac circulation established; pigment cells develop their black colouration; pigment begins to appear in eyes.|
|2 and 3||4.5 to 5 mm.||Pectoral fins arise; mouth opens, and respiratory movements commence.|
|4||6.75 mm.||Larvae leaving the surface and swimming freely at all levels. Bright yellow spots over eyes.|
|7||7 mm.||Larvae swarming and turning in unison at the slightest concussion. Caudal cartilages appear.|
|12 - 15||6. 75 mm.||Posterior end of notochord bends up.|
|28||8 to 10 mm.||Caudal rays jointed and articulated with the basal cartilages. Larvae rise to surface to take air.|
|37||10 mm.||Primordia of dorsal and anal rays.|
|40||10.25 to 13 mm.||Rudiments of ventral fins appear. Dorsal and anal fins separating from caudal. End of larval development.|
|63||17 mm.||Fry now hide in the mud|
|73||25 mm.||Fry now hide in the mud.|
On either side of the body there is a broad reddish-orange band occupying almost the entire height of the myotomes, commeneing from the eye on each side, and ending behind with a rounded edge at the base of the caudal fins. The iris is golden with a red flush; there is a bright golden occipital, point, and the base of the anal and dorsal fins is black along their whole length. This characteristic livery is retained by the fry till they reach a length of about 40 mm. (nearly for 3 months after hatching); after which period the definitive markings begin to appear, in the form of 9 dark vertical half-stripes on either side descending from the base of the dorsal fin. 5
From the fifth dav after hatching, when the larvae begin to feed independently, the daily growth begins to vary. Some young O. striatus kept by Dr. Willey in Colombo had an average total length of about 35 mm. in February 1908, 45 mm. in July 1908, 96 mm. in April 1909 ; the series last measured consisted of six individuals ranging from 85 mm. to 115 mm. The average measurements of a brood hatched in the central pond of the Marine Aquarium, Madras, was as follows: -
|April 1913||hatched from eggs|
|April 1914||6 inches|
|April 1915||over a foot in length|
In nature growth is even more rapid and the young under favourable conditions begin to breed in about two years.
O. striatus is one of the largest and most valuable food fishes of our inland waters, Being an air-breather it is transported with ease 6 ; and is admirably adapted for pisciculture. Care, however, should be excreised in introducing it into preserved waters 7 as it is very voracious and destructive to fry. The young are susceptible to attacks from internal parasites ( ? Schistocephalus larvae). 8
A very common species everywhere in ponds, ditches and rivers. In the last it is known to occur in Brackish water when it is said to acquire a purplish colour. 9 It is a mud-burrowing fish 10 and prefers stagnant and muddy to running water. 11 It is one of the fish Day saw exhumed from the mud of a dried-up tank. 12
The breeding habits are very similar to those of O. striatus . O. punctatus is monogamous, and breeds twice in the year, about January and February and again about July and August; occasionally nests are met with at other times. 13 At these seasons the fish come together in pairs and construct a nest among the rushes in the shallows of ponds and rivers. I have never seen the nest in water deeper than a foot and a half, as a rule it is built in water only a foot in depth. The nest is the usual roundish clearing measuring 8 or 9 inches in diameter. The nests of O. striatus differ in being larger(about 12 to 14 inches in diameter) and are found in water at least 2 feet, frequently 3 or 4 feet deep. At the surface the nests of both species appear as circular areas of clear water with the eggs floating in the centre. Both parents tend the nest; while the male keeps a vigorous guard, aggressively protecting the spawn from intruders, the female is found in the neighbourhood.
Oviposition usually takes place at night; a few thousand eggs 14 are deposited by the female in a single night. The eggs measure about 1.25 mm. in diameter and are of a pale amber colour. In size and appearance they are hardly to be distinguished from those of O. striatus and like the latter contain a large oil-globule and float flush with the surface of the water 15 (figs. 17 and 18 ).
The rapidity of the embryonic development seems to depend on the strength of the sun. On all occasions when I obtained collections of eggs they invariably hatched during the night following, i.e., on the average in 24 hours after procuring them. This corroborates the statement of fishermen that the eggs of O. punctatus usually hatch on the night following that on which they are laid.
The embryonic and larval development of this species closely resembles that of O. striatus , 16 but is more rapid. In fresh eggs the outline of the embryo encircling the yolk becomes evident in about 8 hours; the eyes and auditory sacs are developed in 16 hours ; and the heart begins to beat and the curious yolk-sac circulation also starts soon after this (figs. 19 and 20 ). At the time of hatching the embryo violently twitches its tail, which is now free of the yolk-sac, and performs rotations within the egg membrane.
On hatching the fry measure 3-25 mm. in length and are almost identical in general appearance with the first day hatchlings of O. striatus (fig. 21 ). They, however, do not remain at the surface for 3 days like the latter fry but begin to descend down even at the close of the first day, though this is accomplished with considerable effort.
On the second day, the pigment cells are well developed; the eyes being quite black; the length increases to 4.5 mm.; the mouth opens and respiratory movements begin; and the pectoral fins develop. The larvae move in unison and effect their descent from the surface in a long procession, swimming slowly close to the bottom sand of the aquarium. Most of the above changes are those of the 3rd day in the developinent of O. striatus .
On the third day, the fry swim at all levels, with ease. On the sides of the body the mid-lateral line is clear of pigment, but pigment is intense along the root of the dorsal and ventral portions of the median embryonic fin. During the second and third days the capillary network formed by the caudal vein in joining the subintestinal vein, and the «marvellous yolk-sac circulation» described by Dr. Willey, arise in the same way as in O. striatus .
On the fourth day (fig. 22 ), the length is 5 mm. The characteristic black and yellow colour of the fry, which distinguishes it from the brown and pilik fry of O. striatus , now begins to appear.
It will be seen from the above observations that the larval development in this species, while it closely resembles that of O. striatus , goes forward more rapidly. This is true of most of the subsequent stages, such as the formation of the network of vessels at the root of the caudal fin (which happens about the eighth or ninth day instead of on the twelfth as in O. striatus 17 ); the deflection of the end of the notochord, the commencement of aerial respiration, etc.
The characteristic larval colouration begins to appear as early as the fourth day after hatching (fig. 22 ). On the sides of the body, as noticed above, pigment is intense along the root of the dorsal and ventral portions of the median embryonic fin, but the mid-lateral line is free of pigment and is consequently traversed by a pale longitudinal band, which later on acquires a bright golden yellow hue. There is also a more or less uninterrupted pale longitudinal band in the mid-dorsal line of the head and fore-body. 18
The larval colours when fully assumed are as follows: - The body is dark olive along the back and sides, becoming slightly pale or whitish along the abdomen. This dark ground colour is resolvable into close-set longitudinal stripes along the seales, clearly seen in specimens preserved in spirit. Three longitudinal golden-yellow bands pass from the snout to the caudal fin; a mid-lateral band on each side which becomes narrow as it passes over the opercle and the upper portion of the eye to meet its fellow on the tip of the snout, and a narrow median dorsal band extending from the junction of the above two bands on the tip of the snout, along the base of the dorsal fin to the root of the caudal. These three bands are of a brilliant golden-yellow colour and stand out clearly on the dark ground colour; while the two lateral bands extend on the caudal fin to the extent of nearly one-third the length of that fin; the dorsal band, which is comparatively narrow and is more distinct in younger than in older stages, has two spindle- shaped enlargements in front of the dorsal fin (fig. 22 ). Thus the fry of O. punctatus are easily distinguished from the fry of O. striatus after they assume their characteristic larval colour.
In growth the dorsal median band is the first to disappear. In specimens above two inches in length the dark olive brown of the back and sides changes to a dirty brown, and a double row of ill-defined brown blotches appear on either side of the body one above the other, the blotches of the upper row alternating with those of the lower. These blotches encroach on the lateral golden bands and disfigure and destroy it in growth; the three golden bands are, however, retained for some considerable time on the head.
The parents guard the young till they reach two inches in length, i.e., till they lose their larval colours. It is quite a sight to see the parents leading their brood of brightly coloured fry in bright sunlight in shallow water in fields, 19 where they usually come out to feed.
O. punctatus is extensively eaten.
This very common species is found in ponds but much more abundantly in rivers, where it often frequents brackish water within tidal influence.
In habits it closely resembles O. punctatus . The breeding season is December and January in Madras (June and July in South Canara). I have not seen the nest of this species; from the accounts of fishermen it does not appear to be among weeds but in sheltered crevices in the bank. A brood of young with the parents were brought to me on the 15th February, 1911, from the river Coourn near Chetput. The adults refused to feed and died after a few days, but the fry continued to live. In habits and appearance the fry were very different to those of the previous two species. The entire brood consisted of some 300 individuals, a comparatively small number.
The average length of the young was 7 mm. (fig. 23); traces of the yolk-sac and the continuous embryonic median fin devoid of fin-rays were present. The colour was dark brown, due to a very considerable development of pigment cells, which were arranged on the sides of the body chiefly in two horizontal rows, one dorsal and one ventral, with a more or less unpigmented area between them along the mid-lateral line. Of the two the ventral band was the more conspicuous, being very broad on the abdomen and tapering gradually into a streak posteriorly. A number of pigment spots are also found on the head; a concentration of them occurs behind each eye. Scattered spots are found on the continuous median fin.
Later on, some much older fry were brought to me from the same locality. These measured on an average 48 mm. long and had the following characteristic colour. The body was of a pale olive-brown, and the sides were crossed by ten or twelve >-shaped light bands with their apices on the lateral line pointing forwards. I have not seen the large ocellus on the dorsal fin mentioned by Day 6 and doubt if it ever occurs in this species. It is frequently present in the young of some larger species of Ophiocephalus
A small fish not much in demand as food.
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1 I am indebted to Mr. Ramaswami, B.A. of the Madras Fisheries, for this information. Back
2 Day, Fishes of India, p. 363 ; Fauna of Brit. India, II, p. 359 . Back
3 Thomas, Rep. Pisc. South Canara, p. 74 (1870) ; Day, Freshwater Fish and Fisheries of India and Burma , p. 23 (Calcutta, 1873). Back
4 Col. Puckle (quoted by Day), Fishes of India, p. 362 ; Thomas, Rep. Pisc. South Canara, p. 37 (1870) . Back
5 Willey, Spol. Zeylan. , V, p. 145 (1908) ; VII, p. 116 (1910). Back
6 Day, Freshwater Fish and Fisheries of India and Burma , p. 2 (Calcutta, 1873). Back
7 Thomas, Rod in India , p. 234 (1897); Willey, Spol. Zeylan. V, p. 146 (1908) . Back
8 Willey, l.c. Back
9 Day, Fishes of India, p. 368 . Back
10 Willey, Spol. Zeylan. , V, p. 149 . Back
11 Day, Fishes of India, p. 368 ; Fauna of Brit. India, II, p. 359 . Back
12 Day, Freshwater Fish and Fisheries of India and Burma , p. 28 (1873). Back
13 Willey records finding a nest in October. Spol. Zeylan. , VII, p. 101 (1911) , and I have seen nests in the Cooum in December. Back
14 Day, Fishes of India, p. 368 (records finding 4702 eggs in a female in February). Back
15 Willey, Spol. Zeylan. , VII, p. 101 . Back
16 Willey, «Nests, eggs and larvae of Ophiocephalus striatus.» Spol. Zeylan. , VI, pp. 108-118 (1909) . Back
17 Willey, Spol. Zeylan. , VI, p. 112 (1909) . Back
18 Willey, Spol. Zeylan. , V, p. 150 ; VI, pp. 116 . Back
19 Willey, Spol. Zeylan. , V, p. 149 . Back
These passages were originally published under the above title in: Records of the Indian Museum . Vol. 12, no. 4, pp. 249 - 294, 1916. The copyright owner Zoological Survey of India has granted snakeheads.org the right to publish it on the org's site. The copyright of the text is still with the copyright in full amount.
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