The catshark Chiloscyllium griseum  belonging to the family Hemiscyllidae is described in detail from

samples collected from both east and west coast of India. Various patterns of growth of individual organs

are described. Analysis of data on length-weight relationship showed no significant difference between

sexes. Hence a common value of Log W= — 4.8378 + 2.7314 log L is obtained. The shark feeds on

bottom fishes and crustaceans. Males mature at 520 mm and females at 530 mm total length. The paired

oviduct contains 4 egg-cases, 2 on either side at a time without any embryonic development taking

place while inside the oviduct. The egg-cases are laid outside for embryonic development and hatching

in the sea water

Devadoss, P

CMFRI Digital Repository

J. mar. biol. Ass. India, 28 (1 & 2) : 192 - 198 STUDIES ON THE CATSHARK CHILOSCYLLWM GRISEUM FROM INDIAN WATERS P. DEVADOSS* Central Marine Fisheries Research Institute. Cochin - 682 031 ABSTRACT Thecatshark Chiloscyllium ^wewm belonging to the family Hemiscyllidae is described in detail from samples collected from both east and west coast of India. Various patterns of growth of individual organs are described. Analysis of data on length-weight relationship showed no significant difference between sexes. Hence a common value of Log W= — 4.8378 + 2.7314 log L is obtained. The shark feeds on bottom fishes and crustaceans. Males mature at 520 mm and females at 530 mm total length. The paired oviduct contains 4 egg-cases, 2 on either side at a time without any embryonic development taking place while inside the oviduct. The egg-cases are laid outside for embryonic development and hatching in the sea water. INTRODUCTION CATSHARK Chiloscyllium griseum MuUer and Henle 1841, is a sluggish, slow moving shark which inhabits the inshore regions of the coastal waters. It is fished by the mechanised trawlers during December to May period and is able to live out of water longer. No com-plete account on the taxonomy and biology of this species is available. Literature on the biology of this shark has been short and patchy. Sundara Raj (1914) described briefly the egg-case, while Setna and Sarangdhar (1948) gave a short account of the structure of the repro-ductive organs and egg-cases. In the present work covering over a period of 4 years, some attempts were made to fill the lacuna in our knowledge on the biology of this shark. Day (1878) recorded the genus Chiloscyllium from Indian waters under the family Scyllidae. Later Jordan (1917) assigned Chiloscyllium under the family Hemiscyllidae. But Fowler (1941) and Berg (1947) classified this under the family Orectolobidae. Compagno (1984) * Present address : Madras Research Centre of CMFRI, 29 Cammander-in-Chief Road, Madras-600 105. dealt Chiloscyllium with the family Hemi-scyllidae. Misra (1959) and Devadoss (1977) treated C. indicum of Day as a junior synonym of C-griseum. MATERIAL AND METHODS Samples for the present work were collect-ed as and when available at Vellayil fish land-ing centre and also from the fish market, Cali-cut. Specimens collected from Porto Novo were analysed for the taxonomic study. For pro-portional dimensions, measurements from 23 sharks were analysed and the results are pre-sented here in a format which indicate the variations and changes, if any of the dimen-sions with the growth of the animal (Fig. 1). Colour pattern, sex and reproductive status were noted. The methods as adopted by Bass et al. (1975) for recording stomach contents and Devadoss (1978) for determining maturity condition were followed. DeSCRIPTION Super-Order: Galeomorphii Order: Orectolobiformes STUDIES ON CATSHARK FROM INDIAN WATERS 193 Family: Hemiscyllidae Gill, 1862 Genus: Chiloscyllium Muller and Henle, 1837 dual organs as the fish grows in total length (Fig. 1). These can be summarised as follows: Chiloscylliuin griseum Muller and Henle, 1841 i. "Korangan" in Malayalam and "Korangu sora" in Tamil. Chiloscyllium griseum Muller and Henle, 1841. Syst. Beschr. Plagiostomen, 19 (type locality, India, Japan); Sundar Raj, 1914, Jiec. Indian Mus., 10: 818-819 (egg-case); Misra, 1959, Rec. Indian Mus., 57: 81; Devadoss, 1977. Ph.D. Thesis, Annamalai Univ. Chiloscyllium indicum (not Gmelin) Day, 1878. Fishes of India pt. 6, 726 fig. 3. Hemiscyllium punctatum (Muller and Henle) Fowler, 1941. Bull. U.S. natn. Mus., 100 : 85. The proportional morphometric dimensions from 23 specimen are given in Table 1. Head length (snout to first gillslit) 12.49-15.76, snout to anterior margin of eye 5.36-7.60, snout to pectoral 15.37-18.31, snout to pelvic 31.69, 35.60, snout to mouth 4.26-6.34, intemarial distance 3.67-5.63, diameter of eye 1.15-1.97, interorbital distance 4.30-6.43, first dorsal base 7.04-9.36, between dorsal bases 8.09-12.16-pectoral length 11.03 - 13.60, distance from pectoral to pelvic 10.98 - 19.97 and length of upper caudal lobe 24.10-27.60 in percentage of total length. Spiracles and eye equal, the former rather upper than behind the latter, short labial folds at angle of mouth and broad lower lip grooves continuous across chin; teeth in 28 - 30 in each jaw; nostril cirri almost equal orbit; origin of first dorsal behind the base of pelvic origin; (me to three dermal ridges on the back, in some 13 transverse dark brown bands along the length of the body. Distribution: India, Southeast Asia, China and Japan. Pattern of growth Analysis on the proportional dimensions revealed various patterns of growth of indivi-Reduction in the characters of head region both length and breadth; in the size of the eyes, distances from snout to first gill slit, mouth, anterior margin of eye, nostrils, pectoral and pelvic fins and in the inter-narial and interorbital distances. TABLE 1. Summary of the proportional dimensions of C. griseum 136-580 mm Characters Distance from snout to pelvic pectoral I gillslit eye nostrils mouth Length of nostril Between nostrils Eye diameter Interorbital distance Mouth width Orbit to spiracle Length of spiracle Between dorsal bases Second dorsal to origin of caudal Pectoral to pelvic I dorsal base height II dorsal base height Anal base Pectoral base length Pelvic origin to lateral corner Caudal upper lobe lower lobe Length of I gillslit III gillslit Juveniles 34.19 + 0.68 17.34 + 0.39 15.22 + 0.53 7.23 + 0.30 2.80 + 0.98 5.56 + 0.38 J 1.34 + 0.13 ; 4.88 + 0.42 1.80 + 0.21 5.98 -f 0.42 5.61 + 0.34 1.13 + 0.25 1.59 + 0.28 9.18 + 0.72 10.13 + 0.95 11.73 + 1.06 8.54 + 0.83 6.66 + 0.93 8.55 + 0.59 5.75 + 0.80 12.06 + 1.07 6.41 -1- 0.53 12.19 + 0.86 10.70 + 0.97 25.67 4- 1.28 19.45 + 1.07 j 2.18 + 0.42 2.46 + 0.51 Adults 32.64 + 1.13 15.82 + 0.53 13.22 + 0.51 6.14 + 0.37 2.60 + 0.31 4.49 J - 0.20 f 1.09 + 0.06 3.92 + 0 . 1 5 1.38 + 0.12 4.72 + 0.30 5.22 + 0.22 0.80 + 0.07 1.50 + 0.15 11.15 -t-_0.69 15.05 + 0.81 17.74 + 1.36 8.23 + 0.50 6.13 + 0.48 8.84 + 0.70 5.48 -1- 0.44 11.81 + 1.04 6.41 + 0.31 12.49 + 0.34 11.50 + 0.59 25.00 + 0.77 17.33 -1- 0.65 1.85 -h 0.46 2.23 -f 0.37 194 P. DEVADOSS (9 II 9 1.4 I z 6 5 4 16 14 *• 12 18 16 34 32 II D - Caudal origin Between dorsal bases Eye diameter Snout-Mouth SflOut-IGilislit Snout-Pectoral Snout-Pelvic 200 300 400 500 ' 600 LO \ Lower caudal Upper caudal CM 1 D height . CM U O height CM • Pectefttl Itngth Pelvic length LO Between atbWi 21 19 17 27 25 75 14 £ 120 a. 12 10 7 5 100 200 300 400 500 '600 TOTAL LENGTH IN mm Fig. 1. Different types of growth patterns in the proportional dimensions of C. griseum (C- Constant; CM-Curvilinear, rising to a maximum followed by decrease as the shark grows in total length. Ll-linear, increasing and LD - linear, decreasing. 2. Accelerated growth in the trunk and cau- 3 slackening in the growth of dorsal fins dal region and lengthening of pectoral and pelvic fins. and lower caudal lobe. STUDIES ON CATSHARK FROM INDIAN WATERS 195 It is a fact that fast swimming pelagic sharks have much larger first dorsal fin placed over the pectoral region and a distinct lower caudal, whereas the very slow swimming ones which live at the bottom possess small first dorsal fin placed over the pelvic region and a very much reduced or non-existent lower caudal (Bass et al, 1975). So the slackening in the growth of dorsal fins and lower caudal found in the present observation contribute to the charac-ters of lower grade of this shark. • Male a. Femote C* sr-t;—2J ii ij. u iii u u U f . L Fig. 2. Length-weight relationship of C. griseum. Length-weight relationship The length-weight relationship was calcu-lated by the least square method by using the LeCren formula W = aL*' or its logarithmic ; form log W = log a + b log L, where W is weight, L length, and a and b constants. The logarithmic regression equations obtain-ed are as follows: Males log W = -4.8674 + 2.7390 log L Females log W = -4.7941 + 2.7205 log L The corresponding parabolic equations are: Males W = 0.00001357 X L Females W = 0.00001607 X L 2.7390 2.7205 jr-Fig. 3. Female reproductive organs with 4 egg - cases (O - Ovary with yolked ova; ODF-Oviducal funnel; NG - Nidamental gland and OD -Oviduct - enclosing egg - cases). The significance between the regression coefficients for males and females was tested by the methods of analysis of covariance (Snede-cor, 1956) and it was found that difference between male and female regression coeffici-ents was not significant at 5% level. Hence sexes were combined and a length-weight relationship obtained as follows. logW = - 4.8378 2.7314 log L and its parabolic equation is: W = 0.00001453 X L" 2.7314 196 P. DEVADOSS The logarithmic values of observed weights and length are plotted in Fig. 2. With the regression line fitted based on the above equation. Analysis of covariance is given in Table 2. on the bottom fishes and crustaceans. Fishes like soles, juvenile Psettodes erumei small sciae-nids and leiognathids formed the main item. Prawns and crabs constituted the crustacean TABLE ^2. Analysis of covariance With in males With in females pooled with in DF 36 21 57 2 "' 2.270066 1.612253 3.882319 2 xy 6.217865 4.386329 10.604194 2 y» 17.182675 12.220130 29.192904 B 2.739068 2.720621 2.731407 Differences between slopes Deviation from i DF SS 35 20 55 56 1 0.000321 F — — 0.004149 0.151520 0.076691 0.228211 0.428532 0.000321 0.077369 NS regression MS 0.004329 0.003834 0.004149 0.004081 0.000321 TABLE 3. Summary of the stomach contertts of 43 sharlcs Type of food No of items present / o Remarks Teleost fish Crustaceans Molluscs 24 19 7 55.8 44.2 16.3 includes mostly soles, juvenile Psettodes erumei. sciaenids and leiognathids. prawns and crabs, mainly Sepia spp. Food and feeding The stomachs were classified based on the degree of their distension due to food content, ftf the 43 stomachs analysed 2.33% of them were gorged (1+), 20.93% in full condition (1), 62.79% in half full (0.5) and 13.95% of them were empty (0). The food items were in various stages of digestion. Summary of the stomach contents is given in Table 3. This shark has got a definite feeding habit. It feeds diet. Molluscs mainly Sepia spp. formed a smaller portion of the feed. Breeding Sex is differentiated by the appearance of the claspers at the relatively early stage of em-bryonic development. In the case of ScoUodon laticaudus the appearance of claspers was noti-ced at the early stage when the embryo attains STUDIES ON CATSHARK FROM INDIAN WATERS 197 the size of 30 mm (Devadoss, 1979). The sex differentiation by the development of gonads occurs later when the individual reach puberty. Gonads appears at the anterior end of the epigonal organs. Fig. 3. shows the female reproductive organs of C. griseum. As in most sharks the overy on the right side was functional. The structure of uterus is same as that of S. laticaudus des-cribed by Devadoss (1979) earlier. As the shark is oviparous, the nidamental glands are relati-vely bigger in size than those of the viviparous observed. As the embryo in the egg-case starts developing, the next capsule comes down into the oviduct above the earlier one. Like wise a number of capsules are contained in the oviduct arranged one above the other and in various stages of embryonic development before they are laid out side. But in the present case even-though there are more than one capsule pre-sent in the oviduct at a given time, no develop-ment of embryos inside the capsule was obser-ved which implies that the period of stay in the oviduct may be only for a short time. As the first one is laid out side the third one may i l 6 0 40-3 20-OW ISO 250 350 A50 TOTAL LENGTH IN mm 550 650 750 Fig. 4. Relationship between the length of claspers and the total length of shark. Species where the function of the nidamental gland i.e. secretion of the egg-case is the minimum. As the fertilized ova pass through nidamental glands, they are enclosed in albu-men with thick brownish yellow egg-case. At a time 4 egg-cases two on either side are present. This observation corroborates with the find-ings of Stena and sarangdhar (1948). The development of embryos inside the egg-case does not commence during its journey down along the uterus, in closely related Japanese cat-shark Cephaloscyllium, Scyliorhinus, Apristurus and Japanese Galeus as Nakaya (1975) descend down in quick succession to take the place of the second one which in turn move down to number one place. So much so there are two capsules present at a time inside an oviduct. In addition to four egg-cases on their way to be laid out, currently present inside the ovi-duct, there are 18 fully yolked, mature eggs measuring 20-25 mm in diameter present in the ovary along with numerous smaller ones in various degree of maturity. So breeding in this species appears to be a continuous process. 198 P. DEVADOSS Sexsual maturity Maturity in males is determined based on the enlarged testes and the collection of milt in the seminal sac. This fluid flows out if the sac is pressed gently. With out dissecting the fish sexual maturity can be determined by measurement of clasper length. Claspers are measured from the cloaca to the tip of clasper (Devadoss, 1978). Young claspers are short and flexible reaching barely the tip of pelvic fin. But during the onset of maturity the growth of claspers accelerated and become very stiff. The relationship between the length of claspers and the total length of males is shown in Fig. 4. After reaching sexual maturity the growth rate of claspers slackens. At this stage the males measure 520 mm which may be taken as the length at which males attain sexual maturity. The determination of maturity of females is based on the development of internal organs like the development of ovary, enlargement of lower part of oviduct to function as uterus and the presence of egg-case in the oviduct. Females of C. griseum from 530 mm onwards were observed to possess these characters. So it is possible that females reach maturity when they attain a size of 530 mm. REFERENCES BASS, A. J., J. D. D'AUBREY AND N . KISTNASAMY 1975. Sharks of the east coast of southern Africa. II. The families scyliorhinidae and Pseudotriakidae. Invest. Rep. Ocemogr. Res. Inst,, 37: 1-74. BERG, L. S. 1947. Classification of fishes, both re-cent and fossil (Trans.). Univ. Michigan, MiMgan. pp. 380. COMPAGNO, L. J. V. 1984. Interrelationsihps of living elasmobranchs. In: P. H. Greenwood et al. (Ed.) Interrelationsliips of fisfies. Academic press, London; pp. 15-61. DAY, F . 1878. (Reprinted 1958) The fishes of India William Dawsons & Sons, London. DEVADOSS, P. 1977. Studies on the elasmobranchs of Porto Novo Coast (South India), ffi. D. Tliesis, Annamalai Univ., Chidambaram, pp. 1-210. 1978. Maturation and breeding habit of Dasyatis imbricatus (Schneider) at Porto Novo. Indian J. Fish., 25: 29-34. 1979. Observations on the maturity, breeding and development of Scoliodon laticaudus MuUer & Henle off Calicut Coast. / . mar. biol. Ass. India, 21 (1 & 2): 103-110. FOWLER, H . W . 1941. Contribution to the biology of the Philippine Archipelago and adjacent regions. Bull. U. S. natn. Mus., (100) 13: 1-879. JORDAN, D . S. 1923. A classification of fishes includ-ing families and genera as far as known. Standford Univ. Publication Biolog. Sci., 3: 80-243. MISRA, K . S. 1959. An aid to the identification o. the common commercial fishes of India and Pakistan. Rec. Indian Mus., SI: 1-111. NAKAYA, K. 1975. Taxonomy, Comparative anatomy and Phylogeny of Japanese catsharks Scyliorhinidae. Mem. Fac. Fish. Hoklcaido. Univ., 23 (1): 1-94. SETNA, S. B . AND P. N . SARANODHAR 1948. Obser-vations on the development of Chiloscyllium griseum M. & H., Pristis cuspidatus Lath and Rhynchobatus djeddensis (Forsskal). Rec. Indian Mus., 46: 1-24 SNEDECOR, G . W. 1956. Statistical methods, applied to experiments in agriculture and biology. The Iowa State College Press, Ames, Iowa, U. S. A. {Indian Edn. 1961, Allied Pacific Private Ltd., Bombay). SPRINGER, S. 1960. Natural history of the sandbar shark Eulamia milberti. Fish Wildl. Serv. Fish. Bull., 61, SuNDARA RAJ, B . 1914. Note on the breeding of Chiloscyllium griseum M. & H. Rec. Indian Mus., 10: 317-319. 

Studies on the catshark Chiloscyllium griseum from Indian waters

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Studies on the catshark Chiloscyllium griseum from Indian waters

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