Bionomics of a lesser known goby, Stenogobius gymnopomus (Bleeker, 1853) (Perciformes: Gobiidae) from southern Kerala, India

 

S. Lekshmi 1, G. Prasad2 & S.D. Rita Kumari 3

 

1,2Department of Zoology, University of Kerala, Kariavattom, Thiruvananthapuram, Kerala 695581, India

3Department of Aquatic Biology and Fisheries, University of Kerala, Kariavattom, Thiruvananthapuram, Kerala 695581, India

 Email: 2 probios1@gmail.com (corresponding author)

 

 

 

Date of publication (online): 26 December 2010

Date of publication (print): 26 December 2010

ISSN 0974-7907 (online) | 0974-7893 (print)

 

Editor: Neelesh Dahanukar

 

Manuscript details:

Ms # o2328

Received 09 October 2009

Final received 08 November 2010

Finally accepted 12 November 2010

 

Citation: Lekshmi, S., G. Prasad & S.D.R. Kumari (2010). Bionomics of a lesser known goby, Stenogobius gymnopomus (Bleeker, 1853) (Perciformes: Gobiidae) from southern Kerala, India. Journal of Threatened Taxa2(13): 1359-1364.

 

Copyright: © S. Lekshmi, G. Prasad & S.D. Rita Kumari 2010. Creative Commons Attribution 3.0 UnportedLicense. JoTT allows unrestricted use of this article in any medium for non-profit purposes, reproduction and distribution by providing adequate credit to the authors and the source of publication.

 

Author Details: S. Lekshmi is a research scholar since 2009.  She successfully completed her MSc in Zoology from Mahatma Gandhi University, Kottayam, Kerala in 2003 and MPhil in Aquatic Biology and Fisheries under the guidance of Dr. S.D. Rita Kumari in 2007; from 2008 onwards she is enroled for PhD.  Dr. G. Prasad is assistant professor with experience on fish biology and aquaculture in addition to life history traits of threatened fishes of Western Ghats parts of Kerala. He also studies the Human Wildlife Conflicts and interested in biology, habitat ecology and conservation of threatened fauna of Western Ghats.  Dr. S.D. Rita Kumari is well experienced fish biologist and freshwater fish taxonomist with several papers in fish biology and ecology, and has recently retired as professor from the department after 30 years of service.

 

Author Contribution: SL was involved in the sample collection, data processing, data analysis and writing the paper. GP involved in the identification of specimens, preparation and correction of manuscript. SDR was involved in design and data analysis of the study.

 

Acknowledgements: The authors are thankful to Mr. P.H. Anvar Ali and Dr. N.K   Balasubramanian for their help and assistance during the study.

 

Abstract: The biology of a lesser known goby, Stenogobius gymnopomus was studied from the freshwater systems of southern Kerala. Dietary analysis showed that S. gymnopomus is a euryphagousfeeder and an omnivore. Cladocerans, together with fish eggs and scales, constituted the major food items.  The minimum size at first maturity for male S. gymnopomus is 78mm and for females 72mm.  This species was found to be a batch spawner with a prolonged spawning season extending from August to December. Fecundity ranged from 46,323 to 61,291 eggs.  Sex ratios revealed that local populations of S. gymnopomus are male dominated.

 

Keywords: Food and feeding, goby, reproductive biology, Stenogobius gymnopomus.

 

 

For figures & table  -- click here

 

 

Introduction

 

The family Gobiidae is a perciform taxon represented by several thousand species which underwent extensive adaptive radiation.  Most populations occupy marine, brackish and inland habitats of tropical and temperate regions (Gandolfi et al. 1991).  Gobies were in existence in the Eocene (50 million years ago) (Grzimek 1974) and they are considered the ‘Lilliputians’ of the fish world as most species are under three inches in length and many are under one inch in length.  They are bottom dwellers having worldwide distribution. Most gobies inhabit the shallow coastal waters of warmer seas especially on rocky shores, some being left behind as the tide ebbs and they shelter under stones in rocky pools.  Others live in burrows in sand or mud or shelter among branching corals (Burton & Burton 1975).  A few seek out the brackish water region at the mouth of rivers and only a very few are able to penetrate into absolute freshwaters.  Gobioids are experts in concealing themselves, spending most of their time hidden in mud or sand, or in burrows or bores of mangrove stems.

Extensive studies on gobiod fishes are available from many regions of the world (Morawski 1978; Miller 1989; Bouchereau & Guelorget 1997; Horackiewicz & Skora 1998; Chesalin et al. 2004; Borek &Sapota 2005; La Mesa et al. 2005).  Studies on Indian gobioidfishes are very few, and those available are restricted mostly to the Large Indian Goby Glossogobius giuris, a commercially important fish growing to considerable size.  Tandon (1962) studied the feeding biology of the species in the river Ganga.  Bhowmick (1963) made a preliminary study of the food and feeding habits of G.giurisfrom Hoogly estuary.  Geevarghese (1976) carried out a detailed study of G. giurisfrom Lake Veli, Kerala, India.

 As Smith (1959) pointed out, gobioid fishes are not a favouriteof most ichthyologists; largely because of their small size and the trouble involved in their collection.  Very little is known about this group from Kerala.  The present study reports the food and feeding habits and breeding biology of Stenogobius gymnopomus from Thiruvananthapuram, Kerala.

 

 

Materials and Methods

 

Samples of Stenogobius gymnopomus were collected on a monthly basis from the different regions of Pallichal Canal near Arattukadavu, Vellayani, Thiruvananthapuram District (located 11km south of Thiruvananthapuram City) Pallichalcanal originates from Neyyar River and joins the Vellayani Lake at the northern border.  It has a width of 1.5m and an average depth of 1.75m (Fig. 1).  The collection site located between 76058’30’’-76059’30’’E & 8027’-8025’30’’N.  Samples (n = 108) were collected using a cast net over a period of 10 months from July 2006 to April 2007.  Samples were anaesthetized at the collection site itself and preserved in 5% neutral formalin for further examination in the laboratory.  The length of whole fish was measured to the nearest millimeter and weighed to the nearest gram.  The fish was dissected and the gut taken out for dietary analysis. The ratio of gut length to the total length of fish in different size groups was determined.  The food composition in each gut was determined using a points and occurrence method as described by Hyslop (1980).  Of the 108 specimens, 65 males ranged in length from 61-150 mm and 40 females ranged from 41-130 mm in total length and the remaining three which ranged in length from 30-40.1 mm were too small to determine the sex.

From the intact gut the intensity of feeding was assessed (Geevarghese1976). Guts were classified as:

Empty - the gut contained practically nothing and its wall was least distended.

Poor - the gut contained little food but no distension of the wall was evident.

Medium - the gut was nearly half full and the wall was slightly distended.

Good - the gut was almost full and the distension of the wall was clearly evident.

Heavy - the gut was gorged with food and the wall was fully distended.

Depending upon the degree of fullness of gut, points were allotted.  Subsequently each category of food was sorted out and points were awarded for each food item. The total points thus allotted in a food category in a sample for a particular month were summed and expressed as the percentage of the total points.  Combining percentage of occurrence and points, the index of preponderance (li) was calculated following Natarajan & Jhingran (1961).

ViOi

Ii =    ---------  x 100

∑ViOi

 Where Ii is the index of preponderance, Vi and Oi represent the percentage volume and occurrence of particular food (i) respectively.

The gonads were carefully dissected and colour, shape and weight of each gonad recorded.  A few ripe stage ovaries were preserved in 5% formalin.  The percentage occurrence of different maturity stages (males and females separately) were noted and grouped into 10mm interval length groups to indicate the minimum size at maturity.  A quantitative assessment of the condition of the gonad, employing the technique of gonado somatic index (GSI), expressing the gonad weight in terms of the percentage of the body weight, was worked out.

 Gonad weight

GSI = -------------------- x 100

 Body weight

Sex ratio was calculated as the percentage of males and females in each monthly collection.  From the samples of ovaries, sub samples were taken and the eggs counted, and then the fecundity determined (Clark 1934; Prabhu 1956).

 

 

Results

 

Major food items and index of preponderance of S.gymnopomus is presented in Table 1.  S. gymnopomusis predominantly an omnivorous fish feeding mainly on cladoceransand fish eggs and scales which are being supplemented with other food materials such as green algae, blue green algae, diatoms, crustaceans, aquatic insects, bivalves, nematodes, polychaetes and detritus.

It was observed that fishes with heavy guts (gorged and full) constituted an annual average of 9.48%.  Fishes with heavy guts exceeded the annual average in the months of August, October, November and December and reached its maximum incidence in December.  The relation between relative gut length and weight of fish was represented in Fig. 2.

The reproductive parameters of the fish are given in Table 2.  Female S.gymnopomusless than 60mm were all immature while all fish were matured, when they were 71mm.  Fish ≥ 111mm were all in ripe condition.  The minimum size for the attainment of maturity for at least 50% of females and males of S. gymnopomus is around 72mm (TL) and 78mm (TL) respectively.  Therefore females mature at a length smaller than that of males.  Size at first maturity of males and females are showed in Figs. 3 and 4 respectively.

High GSI values were obtained for female S.gymnopomusfrom August to October, and December and March months while the lowest GSI values were during November, January to February and April months.  From the above mentioned observations it appears that the species is a multiple spawner and spawning season of the species could be from August to December and March months. The eggs represented by different modes and these modes represent distinct stock of ripe ova.  This is the ripe stock to be immediately spawned.  The next stage of ova represented by a mode was the ripening stock that undergoes rapid maturation and takes the position of first mode as the ripe stock of eggs is eliminated by spawning.  Subsequently, the newly ripe ova are extruded during the next spawning process which occurs within a very short period.  The occurrence of large number of ova of intermediate size between the immature and fully ripe sets of ova in the mature fish itself also indicates the prolonged spawning period of the species.  It has been observed that the male to female ratio is around 1.62:1 indicating the dominance of males.  From November to February, females dominated over males and in October, males and females were in equal ratio i.e. 1:1.  In all other months the sex ratio was skewed in favour of males.  Fecundity ranged between 46,323 to 61,291 eggs.  The relation between fecundity and weight of fish is represented as Fig. 5.  The fecundity and weight of fish was positively correlated. The monthly average GSI against months of male and female are represented as Figs. 6 and 7 respectively.

 

 

Discussion

 

The growth of fish is determined by the combined effects of food quality and quantity.  The present study revealed that the main constituents of gut content are filamentous algae, molluscs and worms.  This mixed diet composition revealed that the fish is an omnivore. According to Menon & Chacko(1956) fishes feeding on filamentous algae, molluscs, worms, and whose guts contain sand grains in fair proportions are benthic feeders.  If this characterization is to be relied upon, S.gymnopomusis also a bottom feeder as with most of the gobioidfishes.  Sunil (1994) reported that Stigmatogobius javanicus and Eleotris fuscafrom Veli Lake in Kerala are also benthic feeders.

Since the food and feeding habits of this species has not been reported previously, a comparison with earlier results becomes difficult.  But details are available on the feeding habits of other species of gobioids.  Such information shows that they may range from near herbivorous to purely carnivorous, feeding on a wide variety of ingestible organisms from its habitat.  It has even been noticed that the same species may consume a variety of food from different localities which means that, some of the gobioid species have no food specificity.  Marquez (1960) found G. giuris from Philippines to be predominantly herbivorous, feeding mainly on algae. Tandon (1962) found the same species in Varanasi (India) to be carnivorous, feeding mainly on fishes and insects.  Geevarghese(1976) recorded the same species in Veli Lake as carnivorous, feeding mainly on fishes and crustaceans.  These observations suggest that availability of food in the habitat is the main factor that determines the feeding habits of some gobioids, and that such species have no food specificity. From the observations, it is clear that there is a linear relationship exists between weight of the fish and relative gut length of fish (Kharat et al. 2008).

Breeding in teleosts is characterized by unique specialization, which permits the successful adaptation to diverse environmental conditions.  From the data on GSI and monthly distribution of maturity stages it can be assumed that spawning is a continuous process in S. gymnopomusand extends for nearly 7 to 8 months in a year.  For the period of investigation (July 2006 - April 2007) the peak spawning lasted from August to December.  A total absence of mature males and females was noticed in January and February and ripe specimens started appearing from March-April onwards.  Other gobioidfishes like Chasmichthys dolicognathus and Peteragobius esapoides (Nakamura 1936), Chaenogobius urotaenia (Dotu 1955), Gobius cobitis (Gibson 1970), Gillichthys mirabilis (Barlow & DeVlaming1972), Leseurigobius friesii (Gibson & Ezzi1978) and a majority of the Pacific species (Barlow & DeVlaming1972) also have a protracted breeding season.  Another gobioid Aphia minuta was noticed to spawn at least twice (Caputo et al. 2000). Gobius niger (De Casabianca &Kiener 1969) seemed to be an exception for the absence of an extended breeding season.

Results of the ova diameter frequency indicated that the ovary contained two distinctly separated definite batches of eggs and hence the same individual may spawn more than once during a season. Considering the above characters S.gymnopomuscan be placed in Group IV of Karekar & Bal’s (1960) classification (fishes which spawn intermittently over a prolonged period, with ovaries containing batches of eggs which cannot be differentiated from each other) and in category II of Qasim & Qayyum(1961) (fishes having a longer breeding season, with more than one batch of maturing eggs).  Tandon (1962), Marquez (1960), Saksena(1976 a,b) and Geevarghese (1976) after studying the reproductive biology of G. giurisconcluded that the species has an extended breeding season and breeds throughout the year.  Saksena (1976 a,b) reported that the spawning period of the species extends from June to September and that this difference in the breeding habit may be ascribed to geographical and environmental variations.  In the present observation it is clear that the species is characterizes with prolonged breeding season.

The sex ratio of S. gymnopomus in the present study was 1.6:1 favouring males. The ideal sex ratio in natural adult populations of fish is close to 1:1 (Nikolsky 1980).  The deviation in sex ratio from the ideal one with a distinct predominance of males may be a contributing factor to the endangered status of S. gymnopomus.(Nikolsky 1980).  Geevarghese(1976) in G. giurisand Gibson & Ezzi (1978) in L. friesii also reported similar skewed sex ratios. In G. giuris, the male: female ratio was 5:1 and in L. friesii it was 1.2:1.  The reduction in number of females may be attributed to the fact that the females of S.gymnopomusare less hardy and more liable to death due to the dynamics of breeding and also due to their peculiar parental care (Sunil 1994).

Fecundity of similar sized gobies may differ between different species (Miller 1989).  In Sicyopterus japonicus of 105mm, the fecundity was reported as 224960 eggs whereas in Neogobius melanostomus of the same length, the number of eggs produced was 1600.  According to Borek & Sapota (2005), fishes which are more vulnerable to predation produce more number of eggs.  Fecundity shows a linear relationship with weight of fish. This shows ovary grow in proportion to the body growth.  According to Kharatet al. (2008) the non-isometric growth of ovary as compared to somatic tissues can have evolutionary significance. In the present study, it is clear that during spawning period the stomach of a gravid female is normally empty.  This arrangement suggests that the fish devotes its entire abdominal space for the growing ovary. On conclusion it can be stated that the S. gymnopomus collected from the canals of Thiruvananthapuram area of Kerala, India is an omnivorous, bottom feeder with a skewed sex ratio favouringmales.  The fish has got a prolonged breeding season and peaks from August to December.

 

 

References

 

Barlow, G.W. & V.L De Vlaming (1972). Ovarian cycling in long jaw gobies Gillichthys mirabilis from Salton Sea. California Fish and Game 58(11): 50-53.

Burton, M. & R. Burton (1975). Encyclopedia of Fish.Octopus Books, London, 88pp.

Bhowmick, R.M. (1963). Studies on some aspects of the biology of Glossogobius giuris(Ham.) with notes on its fishery in the Hoogly estuary. Proceedings of Indo-Pacific Fishery Commission 11: 99-115.

Borek, K.W. & M.R. Sapota (2005). Breeding characteristics of the sand goby (Pomatoschistus minutus) one of the most abundant goby species in the coastal waters of the Gulf of Gdansla region (Southern Baltic Sea). Oceanological and HydrobiologicalStudies 34: 47-55.

Bouchereau, J.L. & O. Guelorget (1997). Biodiversity of tactics used by three gobiidae (Pisces: Teleostei), Pomatoschistus minutus (Pallas, 1770), P. microps (Kroyer, 1838) Gobius niger Linnaeus, 1758, to survive in a Mediterranean Lagoon environment. Oceanological andHydrobiological Studies 2-3pp.

Caputo, V, G. Candi, M. La Mesa & B. Arneri (2000). Pattern of gonad maturation and the question ofsemelparity in the paedomorphicgoby Aphia minuta. Journal of Fish Biology 58: 656-669.

Chesalin, M.N, G.V. Zuev& T.L. Chesalin (2004).Transparent goby Aphia minuta (Gobiidae) in the pelagic zone of the Black Sea. Journal of Ichthyology 44(8): 587-591

Clark, F.N. (1934). Maturity of California sardine (Sardina caerulea) determined by ova diameter measurements. Fish Bulletin 42: 1-49.

De Casabianca, M.L. & A. Kiener (1969). Gobiides des etangscorses. Systematique ecologie, regime alimentare et position dans les chairnestrophiques – Vie Milieu 34: 611-634.

Dotu, Y. (1955). The life history of a goby, Chaenogobius urotaenia (Hilgendorf). Science Bulletin of the Faculty of Agriculture (Kyushu University) 15: 367-374.

Gandolfi,G, S. Zerunian, P. Torricelli & A. Marconato (1991). Pesci delle acqueinterne italiane. Istituto Poligrafico e Zecca dello stato, Rome,Italy, 616pp.

Geevarghese, C. (1976). Studies on some aspects of the biology of Glossogobius giuris (Ham.) with a taxonomic note on six gobioid fishes occurring in and around Trivandrum. M.PhilDissertation, Department of Aquatic Biology and Fisheries, Kerala University, 90pp.

Geevarghese, C. (1981). Studies on Gobioidsfishes of South-west coast of India. Ph.D Thesis, Department of Aquatic Biology and Fisheries, Kerala University.

Gibson, R.N. (1970). Observations on the biology of the giant goby. Gobius coloitis Pallas. Journal of Fish Biology2: 281-288.

Gibson, R.N. & I.A. Ezzi (1978). The biology of a Scottish population of fries goby, Lesueurigobiuss friesii. Journal of Fish Biology12: 371-389.

Grzimek, B. (1974). Blennies and Gobies, Grzimek’s Animala Life Encyclopedia pp. 176-185. In: Grzimek, B (ed.).Fishes II and amphibians. Vol - 5. VonNostrand Reinholdcompany, New York.

Horackiewicz, J. & K.E. Iskora (1998). A seasonal pattern of occurrence of gobiid fish (Gobiiae) in shallow littoral zone (0-1m depth) of Puck Bay, Instytut Oceanografii, UniwersytetGdansk.

Hyslop, E.J. (1980). Stomach contents analysis – a review of methods and their application. Journal of Fish Biology 17: 411-429.

Karekar, P.S & D.V. Bal (1960). A study of the maturity and spawning of Polydactylus indicus (Shaw). Indian Journal of Fisheries 7(1): 147-165.

Kharat, S.S, Y.K. Khillare& N. Dahanukar (2008). Allometric scaling in growth and reproduction of a freshwater loach Nemacheilus mooreh (Sykes). Electronic Journal of Ichthyology 4(1): 8-17

La Mesa, E. Arneri, V. Caputo & M. Lylesias (2005). The transparent goby, Aphia minuta. Review of Biology and fisheries of a paedomorphicEuropean fish. Reviews in Fish Biology and Fisheries15: 89-109.

Marquez, J.R.S. (1960). Age and size at sexual maturity of white goby (Glossogobius giuris) a common species of fish of Laguna de Bay, with notes on its food habits. Philippine Journal of Fisheries 8(1): 71-101.

Menon, M.D. & P.I. Chacko(1956). Food and feeding habits of freshwater fishes of Madras state, India. Proceedings of Indopacific Fish Communication, Section II and III.

Miller, P.J. (1989). The tokology of gobioid fishes, pp. 118-153. In: Potts, G.W. & R.J. Wootton (eds.). Fish Reproduction: Strategies and Tactics. Academic Press, New York.

Morawski, M. (1978). Winter feeding of the sand goby (Pomatoschistus minutus Pallas) in the relation to the depth in Gdan’sk Bay, Kieler Meeresforschungen, Sonderheft 4, Kiel.

Nakamura, S. (1936). Larvae and young fishes found in the vicinity of Kominato. Journal of the Imperial Fisheries Institute (Tokyo) 30: 131-166.

Natarajan, A.V. & A.G. Jhingran (1961). Index of preponderance – a method of grading the food elements in the stomach analysis of fishes. Indian Journal of Fisheries 8(1): 54-59.

Nikolsky, G.V. (1980). Theory of Fish Population Dynamics. Otto Koetz Science Publishers, Koenigstein, 323pp.

Prabhu, M.S. (1956). Maturation of intra ovariana eggs and spawning periodicities in some fishes. Indian Journal of Fisheries  3: 59-90.

Qasim, S.Z. & A. Qayyum (1961). Spawning frequencies and breeding seasons of some freshwater fishes with special reference to those occurring in the plains of northern India. Indian Journal of Fisheries 8: 24-43.

Saksena, D.N. (1976a). On the reproductive organs and reproductive cycle of male Indian freshwater goby Glossogobius giuris (Ham.) Zool.Jahrb. Abt. Anat.u. Ontog. Tiere 95(1): 121-146.

Saksena, D.N. (1976b). Reproductive organs and reproductive cycle of female Indian freshwater goby, Glossogobius giuris (Ham.)Zool. Jahrb. Abt. Anat.u. Ontog. Tiere 96: 45-73.

Smith, J.L.B. (1959). Gobioid fishes of the families Gobiidae,Periophthalmidae, Trypanchenidae;Tarnioidae and Kraemeridaeof the Western Indian Ocean. Ichthyology Bulletin (Rhodes University) 13 : 185-225.

Sunil, M.S. (1994). Biology of certain gobioid fishes of south west coast of India. Ph.D Thesis, Department of Aquatic Biology and Fisheries, University of Kerala, India.

Tandon, K.K. (1962). Biology of Channa punctatus (Bloch) and Glossogobius giuris (Ham.) Research Bulletin. Punjab University. New Series: Science 13: 263-268.