J. Exp. Zool. India Vol. 22, No. 1, pp. 609-613, 2019 www.connectjournals.com/jez ISSN 0972-0030 FEEDING BIOLOGY AND LENGTH-WEIGHT RELATIONSHIP OF INDIAN ( DUVAUCELI) IN COASTAL WATERS OF GUJARAT

Panja Tehseen*, A. Y. Desai, Jyoti Saroj and Joshi Arti College of Fisheries, Junagadh Agricultural University, Veraval - 362 265, India. *e-mail: [email protected] (Accepted 27 August 2018)

ABSTRACT : are exclusively marine molluscs and there are about 600 species in the world oceans and of these less than a hundred species are of commercial importance. Indian squid (Uroteuthis duvauceli) is the commercially important species of Veraval. The marine fish landing during the year 2013 of the country has been estimated as 3.78 million tonnes. Marine squid landings in India during the year 2013 was 100014 tonnes (CMFRI, 2013). The present study gives a brief information about the feeding biology of . Gujarat is one of the most important maritime state of the nation contributing to the nation’s economy. Cephalopods including squids are one of the most important export commodity from the state. The length-weight relationship study would help to analyse the status of squid fishery off Gujarat mainland and the study about the feeding biology using monthly stomach content data of squid will help to know about the feeding intensity in different seasons and their diet composition. The maximum Dorso–Mantle length encountered during the study was 205 mm, where as the minimum was 56 mm. The food of U. duvaucelli appears to consist of fish, crustaceans and cephalopods. The detailed results of studies on feeding biological aspects such as length composition, length-weight relationship, feeding intensity are presented here in this paper. Key words : Uroteuthis duvauceli, , biology, feeding intensity, FPI.

INTRODUCTION as Tamil Nadu, Gujarat, Kerala and Maharashtra. They Cephalopods are exclusively marine molluscs and constitute 4-5% of the total marine fish production in there are about 600 species in the world oceans, which India. Among the molluscan Cephalopods, squid has been are diverse in form, size and nature. Of these less than a catch in high quantity (Meiyappan et al, 2000). (Write hundred species are of commercial importance (Mohamed, new data regarding production of cepahlopods). 2012). The life expectancy of cephalopods is about one Cephalopods represent one of the most important to two years in most forms, but larger species of squids exploited marine fishery resources of Veraval. Cephalopod and octopus, live for several years. Many species are landings formed 56,092 tonnes 7.95% of the total marine known to die after spawning (Anusha et al, 2014). production in Gujarat, with contribution of 52% landings Among the diversity of Intertidal area, the molluscs of squids (CMFRI, 2013). Cephalopod landing was 1.73 are highly successful group in terms of ecological lakh tonnes in 2014 and in that the total squid landing adaptation and they are found in nearly all habitats ranging was 83223 tonnes (CMFRI, 2014). Cephalopods were from deepest ocean trenches to the intertidal zone, one of the major fish resources landed at various landing freshwater and land where they occupy a wide range of centers in India and the state, which contributed the habitats (Vaghela and Kundu, 2011). are very maximum in cephalopod landing was Gujarat with 33% abundant and form an important link in the food chains of the total landing in year 2014 (CMFRI, 2014). (Vaghela et al, 2013). Kore and Joshi (1975) studied that squid is Cephalopods, which have gained great grandness in carnivorous, cannibalistic and shows seasonal variation recent years due to the increasing, demand in the export in the intensity of feeding; they also reported in trade. It is mainly due to their abundance and high L.duvauceli an increase in cannibalism and decrease in nutritional quality. Bulk amount of cephalopods were crustacean feeding for larger squid. Silas et al (1985) exploited in India, mainly in the four maritime states such also reported that Prawns and fishes form the chief item of food of this species. Other items like crabs, stomatopods 610 Panja Tehseen et al and euphausids also form the diet of this squid. 21.06 mm) and September (134.4 + 30.8mm) were higher, Cannibalism has been often noticed. Meiyappan et al while those caught in the month of March (102.5 + (2000) also noticed that adult cephalopods are voracious 30.2mm) and October (100.75 + 9.43mm) were smaller. and active carnivores feeding mainly on fishes and The mode length of the species caught was higher in the crustaceans. Anusha et al (2014) reported about the month of September (115mm) and February (118mm) feeding strategy of squid that it is entirely different from while it was lower in March (72mm) and January (94mm). other fishes. They use their tentacles and oral arms for The smallest specimen (i.e., 56mm) was observed in prey capture. The toxic saliva termed ‘cephalotoxin’ cause March 2015 and the specimen with highest length (i.e., paralyzing and respiratory distress sometimes even kill 205 mm) was observed in February 2016. The length was their prey. within the range 40 to 365 mm that has been reported in Here, in this work some biological aspects of earlier times from Mangalore waters (Rao, 1988). Uroteuthis duvauceli are studied and the results obtained Length – weight relationship are presented below. A total of 340 specimens in the length range of 56 – MATERIALS AND METHODS 205 (138 males and 202 female) were used for determining The present study was conducted off the Veraval coast the length weight relationship separately for males and of Gujarat. The specimens for biological analysis were females. The equation arrived at was: collected from the identified trawlers operated basing the Male: BW = 0.002478 X (DML) 2.11 (r = 0.91) Veraval fishing grounds (Lat- 20°54' N Long - 79°22'E) Female: BW = 0.000654 X (DML) 2.42 (r = 0.89) situated in the Gir-Somnath district of Gujarat, India. There was significant difference between the slopes Materials used for the collection, preservation and at 5% level (Table 1). This study established that the slope observations of the study were the measuring scale, of the regression equation for U.duvaucelli indicates electronic balances, sampling container and the common allometric growth in males and females of the species. laboratory equipment. Similar results were reported by Silas et al (1985) and The samples of squid collected from the trawler were Mohammed et al (1997) from the coast of Mangalore, cleaned and prepared for the biological analysis in the Cochin and Madras. laboratory. Each squid was measured and weighed in the Feeding intensity fresh condition. Total Dorso – Mantle length of the squid A total of 348 stomachs of U. duvaucelli ranging its together with the total length including dorso mantle length size from 56 to 205 mm Dorso - Mantle length (DML) and tentacles length was measured to the nearest 1 mm were examined during the one year period of this study. from the tip of the mantle cavity to the tip of the tentacles Ontogenetic shifts in diet are widespread among fish, (Fig. 1). Weight was recorded to the nearest 1 g on an which are a function of an increase in the sizes of body electronic weighing balance with gonads and viscera and mouth; permitting the individuals to capture of preys intact. Length-weight relationship was determined by broader ranges of size and types (Labropoulou et al, allometric formula separately for both the sexes and 1997). Most of the examined specimens were with empty significant differences in the slopes of regression lines stomachs. Full filled stomach were only found in squids for males and females were confirmed by ANCOVA ranging from in 70-90 mm DML group. The highest (Snedecor and Cochran, 1967). proportion of empty stomachs, 100%, was observed in To analyze the stomach content in squid the gut 190 – 210 mm DML group. The percentage of stomach portion from the dissected squid is removed and examined. with three fourth and full stomach contents were very As the gut in squids is relatively very small compared to low. other fishes, the contents cannot be distinguished to The percentage of empty stomachs was the highest particular taxa. (78.26%) in September and the lowest (46%) in RESULTS AND DISCUSSION November. Stomach with three fourth and full contents Length composition were very low in all the month. Since the breeding started A total of 348 U. duvaucelli specimens ranging its by April, the squids must be feeding voraciously for energy dorso mantle length from 56 to 205 mm were collected reserves in the preceding month of breeding, i.e., March, from multi day trawlers during the study period for resulting into lesser percentage of fishes with empty studying their biology. The mean DML of the species in stomachs and higher percentages of fishes with more the month February (130.3 + 35.8 mm), April (125.05 + stomach distension. The percentage of full stomachs was Feeding biology and length-weight relationship of Indian squid 611

Fig. 1 : Morphometric study of squid.

Fig. 2 : Length–weight relationship of male and female U.duvaucelli. very low in all the months except April, when there were 2). Fish formed the chief food item occurring in more no individuals with full filled stomach which means the than 55% of the stomachs of both the sexes. Crustacean squids avoid feeding at the time of breeding and spawning. remains in the form of chitinous exoskeleton, appendages Kore and Joshi (1975) has observed higher number with setae and eye stalks occurred in the stomachs of of three fourth filled and full filled stomach among U. squids. The frequency of stomachs containing the fish duvaucelli throughout the year. The high percentage of was maximum in September and minimum in October. empty stomach was in months of October and November The fish remains include semidigested flesh attached to indicating lower feeding intensity. Hertling (1938) states spines and vertebrae, scales and eye-balls of clupeid fishes. that among fishes the species in which fish forms an The skin scrapings containing chromatophores and important item of food, tend to have a higher proportion cylindrical bits of tentacles were suggestive of cephalopod of empty stomachs, the main reason for it being that the food present in the stomachs of squid. These reveals that calorific value of fish is, weight for weight, higher than adult squids feed on young squid thus practicing other items like crustaceans. canabalism. Canabalism was found prevalent in the month of March, October and January. Food Preference Index Kore and Joshi (1975) observed the percentage of The food of U. duvaucelli appears to consist of fish, crustacean, fish and squid to be 39.08, 56.89 and 40.22 crustaceans and cephalopods. The FPI for fish, % respectively in the total stomachs with food. The crustaceans and cephalopods occurred in 55, 31.69 and predominance of crustaceans and fish in the diet and a 36% respectively in the total stomachs with food (Table 612 Panja Tehseen et al Table 2 : Monthly variations of FPI in the dietary components of U.duvaucelli. Month No of stomach Fish Cephalopods P value 1.83 0.0002 with food March 32 56.5 9.375 April 18 66.7 % NA NA F value NA NA September 11 81.8 % October 7 28.5 28.5 e November 22 40.9 % December 19 42.1 % January 17 52.94 17.64 February 7 71.4 % 0.042 Mean Squar Annual 133 55.105 36.18 ession egr e tendency towards cannibalism, as observed in L.

om r duvauceli, also characterise the feeding habits of L. pealei (Williams, 1909), L. opalescens (Fields, 1965), Illexillecebrosus illecebrosus (Squires, 1957), 5.79 Sum of Squar 10.85 0.032 0.945 0.945 28.35 12.25 5.060 0.025 0.457 0.457 13.70 Ommastrephess loanipacificus (Soeda, 1956) and Sepioteuthis arctiphmis (Rao 1954). Hertling (1938) states that fast rate of digestion may also be the reason for empty condition of stomach. The study on food items ee of Deviations fr

eedom indicates that L. duvauceli of all sizes eat fish. The 137 Degr fr 338 1 340 201 1 preference to crustacean meal declines with the increase in size. Dietary change with growth is also present in squids, Illexillecebrosus illecebrosus (Squires, 1957) and

ession Loligoopalescens (Fields, 1965). 1 2.1 coefficient Regr 2.42 CONCLUSION A. U. duvaucelli is one of the major fishery resource as it has got great export value by itself in the marine fish ANCOV

spxy 52.14 export sector of Gujarat. The smaller mean and mode If Prob<0.05 then significant at 5% level if Prob<0.01 then significanrt at 1% level by length of U.duvaucelli during the present study indicated e

Note: the growth overfishing on the stock of the species along inshore waters off Veraval coast. Acetes spp. were one of

U.duvaucelli the favorite food items and the adults exhibited variable

Y cannibalism.Size selectivity factor must be taken care of of Sum of Squar 49.59 18.38 131.25 while designing gears for cephalopods as well as other species in order to manage the important fisheries at Rsqr 0.913191 e sustainable level. Till date there is no targeted fishing operation for squids or cephalopods, it has been caught in trawlers as bycatch for this many years. And this is the

ference between slopes reason that major portion of the cephalopods onboard 15854 of X variable Sum of Squar 13.607.59 66.6922.84 28.78 Dif Between adjusted means are deteriorated as they are kept with the other bycatch B 2.1 and no proper chilling of it has been done, which is not at all cost effective so steps must be taken to keep the squids

ee of in good condition until they reach their final destination. eedom fr Degr 138 202 NA341 NA NA NA NA NA NA NA NA NA NA NA NA NA NAACKNOWLEDGEMENT NA NA NA NA NA A 0.000654 2.422178 0.897965 0.002478 I hereby take the opportunity to thank my major guide,

Comparison of regression lines male and female principal & dean of my college. I extend my gratitude to

ce my friends and family, without their support and guidance ithin able 1 : Sour W Males Females Between B W+B this would not have been possible. Females Males T L-W relationship Feeding biology and length-weight relationship of Indian squid 613 REFERENCES Mohamed K S and Nagaraja D (1997) Cephalopod fisheries of Karnataka State - An Overview. Fishing Chimes. 16(11), 33- Anusha J R and Albin T Fleming (2014) Cephalopod: Squid Biology, 35. Ecology and Fisheries in Indian waters. Int. J.Fisheries and Aquatic Studies 1(4), 41-50 Mohamed K S (2012) Indian Cephalopod: resources commerical exploitation utilization and trade. World trade agreement and Central Marine Fisheries Research Institute (2013) Annual Report Indian Fisheries paradigms published by Central Marine of CMFRI; 2012-13. Central Marine Fisheries Research Fisheries Research Institute. pp.105-110. Institute. Cochin, 36 p. Rao K V (1954) Biology and fishery of the Palk bay squid, Central Marine Fisheries Research Institute (2014) Annual Report Sepioteuthis arctipinnis Gould. Indian J. Fish. 37-66 . of CMFRI; 2013-14. Central Marine Fisheries Research Institute. Cochin. Rao G S (1988) Biology of inshore squid LoligoduvauceliOrbigny with a note on its fishery off Mangalore. Indian J. Fish. 35(3), Cren E D L (1951) The length weight relationship and seasonal cycle 121-130. in gonad weight and condition in the perch (Percafluvia tilis). J. Anim. Ecol. 20, 201-219. Silas E G, Rao K S, Sarvesan R, Nalr K P, Vidyasagar K, Meiyappan M M, Sastry Y A and Rao B N (1985) Some aspects of the Fields W G (1965) The structure, development, food relations, biology of squids. Cephalopod bionomics, fisheries and reproduction and life history of the squid Loligoopalescens resources of the EEZ of India. C.M.F.R.I. Bulletin 37, 38-48. Berry. Calif. Dept. Fish and Game Bull. 131 1-108 . Snedecor G W and Cochran W G (1967) Statistical methods. Sixth Hertling H (1938) Untersuchungen Uber die Ernahrung von Edition, Oxford and IBM publication Co., New Delhi. Meerfishen. Ber. disch. Komm. Meeresforsch 9, 1-274 . Soeda J (1956) Studies on the ecology and breeding habits of the Kore B A and Joshl M C (1975) Food of the squid Loligoduvauceli. squid, Ommastrephessloani pacificus (Steenstrup). Bull. Proc. Indian Acad. Sci. 81b(1), 20-28. Ifokkaido Regional Fish. Lab. 14, 1-24. Labropoulou M, Machias A, Tsimenides N and Eleftheriou A (1997) Squires H J (1957) Squid Illexillecebrosus (Lesueur) in the New Feeding habits and ontogenetic diet shift of the striped red found land fishing area. J. Fish. Res. Bd. Canada 14, 693-728. mullet, Mullus surmuletus Linnaeus, 1758. Fish. Res. 31, 257- 267. Vaghela A and Kundu R (2011) Spatiotemporal variations of hermit crab (crustacea :decapoda) inhabiting rocky shore along Meiyappan M M, Mohamed K S, Vidyasagar K, Nair K P, Saurashtra coast, western part of India. Indian J. Marine Science Ramachandran N, Lipton A P, Rao G S, Kripa V, Joshi K K, 41(2), 146-151. Abdussamad E M, Sarvesan R and Achary G P K (2000) A review on cephalopod resources, biology and stock assessment Vaghela A K, Bhadja P and Kundu R (2013) Diversity and in Indian seas. Marine Research and Management. pp. 552- Distribution Of Interitidal Mollusca at Saurashtra Coast of 557. Arabian Sea, India. Global J. Biosci. Biotechnol. 2(2), 154- 158.