Prathibha Rohit

First Record of the Keeltail Pomfret Taractes rubescens (Jordan & Evermann, 1887) (Teleostei: Perciformes: Bramidae) from the South-Eastern Arabian Sea

Present study reports the first record of the keeltail pomfret, Taractes rubescens (Jordan & Evermann 1887) in the south-eastern Arabian Sea based on four specimens collected from the Cochin Fisheries Harbour, Kerala, India. The results of the comparative morphometric and meristic analysis of the present and previous records are presented here. This study revealed the first record of T. rubescens in south-eastern Arabian Sea extending its known geographical range by more than 2000 km in southward direction from the Oman Coast. Further, it is an addition to the deep sea ichthyofaunal biodiversity of the west coast of India.

New Distributional Record of Flat Needlefish Ablennes hians (Valenciennes, 1846) (Beloniformes: Belonidae) in the North-Eastern Indian Ocean with Taxonomic Details

Present study is based on five specimens of flat needlefish Ablenneshians collected from Puri North (Lat. 19047′43.062″N, Long. 85049′38.5788″E), Odisha, India on 7 January 2018. Based on morphometric and meristic characters, the specimens were identified as Ablenneshians (family Belonidae), having laterally compressed body with a series of vertical bars, 26 to 27 anal fin rays, 24–25 dorsal fin rays, 13–14 pectoral fin rays, and single lobe of gonad. A.hians can be distinguished from other three species of needlefishes reported from northeast coast of India based on body shape (body strongly compressed laterally in A. hians vs. rounded in cross section in other three species), number of anal fin rays (24–28 in A. hians vs. 15–25), vertical bars on body (a series of vertical bars in A. hians vs. no vertical bars in others except for S. leiura where few vertical bars are present on anterior half of the body). The occurrence of flat needlefish along Odisha Coast revealed the extension of its known geographical distributional range i.e. from noth of Andhra Pradesh in the North-eastern Indian Ocean. Further, it is an addition to the ichthyofaunal biodiversity of northeast coast of India.

Extending Geographical Distribution Range of Reef Needlefish Strongylura incisa (Valenciennes, 1846) (Teleostei: Beloniformes: Belonidae) in the Eastern Indian Ocean with a Key to the Species of Needlefish Occurring in the Area

Present study deals with new distributional records of Strongylura incisa (Belonidae) based on five specimens collected from the Andaman Islands and Tuticorin Coast (Tamil Nadu), India during 2016–17. Specimens were identified by absence of scales at bases of dorsal and anal fins, 19–20 dorsal fin rays, 21–23 anal fin rays, 102–113 predorsal scales, dorsal fin origin over 4–5 anal fin rays, prominent elongate spot on cheek between opercle and preopercle, and double lobe of gonad. Strongylura incisa can be distinguished from its most similar congener S. leiura based on number of predorsal scales (100–125 in S. incisa versus 130–180 in S. leiura), dorsal fin origin over anal fin rays (4–6 in S. incisa versus 7–10 in S. leiura), number of gonad lobes (2 in S. incisa versus 1 in S. leiura) and colour characteristics (prominent elongate spot on cheek between opercle and preopercle in S. incisa versus black bar on cheek between opercle and preopercle and anterior region of the body in S. leiura). Present study provides the first documented record of S. incisa from the Andaman and Nicobar Islands and East Coast of India with an updated key for Strongylura species. Further, it is an addition to the ichthyofaunal biodiversity of the Andaman and Nicobar Islands and East Coast of India.

Diet composition and feeding dynamics of Trichiurus lepturus Linnaeus, 1758 off Gujarat, north-west coast of India

The largehead ribbonfish, Trichiurus lepturus Linnaeus, 1758 forms a major fishery along north-west coast of India comprising the two coastal states of Gujarat and Maharashtra. Diet composition was analysed for five years (2010-2014) to understand shifts if any in the prey items. Seasonal changes in the prey items were studied for three years (2012-2014) to explore the temporal dynamics of prey availability in the ecosystem and in largehead ribbonfish guts. Feeding indices viz., Stomach fullness index (SFI), empty stomach ratio (ESR), gastrosomatic index (GaSI) and relative gut length (RLG) explained the feeding behaviour, seasonal dynamics and ontogenetic shifts in prey items. The Vacuity Index (VI) was estimated as 37.56%, indicating that T. lepturus is a carnivore and relatively edacious. Diet of T. lepturus comprised of fishes (47.16%), crustaceans (45.22%), molluscs (4.33%) and miscellaneous items (3.28%). Acetes sp. was the most dominant prey item during the study period. Feeding intensity was found to be high during the post-monsoon months which coincided with the period of gonadal maturation of the fish. Significant variations (p<0.05) were seen in the feeding indices during different months, different sizes and between sexes due to the availability of prey items, physiological changes and ontogenetic shifts. A detailed knowledge on diet composition, temporal dynamics in diet patterns and feeding indices can reveal the trophic interaction of prey-predator, resource abundance and fluctuations which are important inputs in ecology-based fishery management models/tools.

Effect of partial replacement of marine protein and oil sources in presence of lyso-lecithin in the diet of tiger shrimp Penaeus monodon Fabricius, 1978

A 42-days growth trail was performed to evaluate the effect of lyso-lecithin in Penaeus monodon (5.08±0.08 g) in terms of growth and carcass fatty acid composition. Three iso-nitrogenous and iso-lipidic diets were prepared by partially replacing both marine protein and oil sources using plant based ingredients in the presence of soy-lecithin or lyso-lecithin. Each experimental diet was randomly allotted to three tanks with fifteen shrimps per tank and all the tanks were equipped with the flow-through system. Results revealed that shrimp fed diet with lyso-lecithin had significantly (p<0.05) higher specific growth rate, SGR (2.15) and daily growth coefficient, DGC (1.44) than those fed soy-lecithin (1.91 and 1.25 respectively). The growth pattern, feed and protein efficiency measures were not only better with lyso-lecithin compared to soy-lecithin and also on par with the control group. However, there was no significant difference in survival (82.22 to 84.44%) between the dietary treatments. The fatty acid composition of diets to a certain extent was reflected in the carcass composition of shrimp. The most essential fatty acids viz., eicosapentaenoic and docosahexaenoic acids were significantly (p<0.05) higher in shrimp fed lyso-lecithin supplemented diet. Present results suggest that lyso-lecithin enhances growth performance of P. monodon and carcass fatty acid composition compared to soy-lecithin due to its high emulsification properties with partial replacement of marine sources.

Food and feeding habits of the narrow barred Spanish mackerel Scomberomorus commerson (Lacepede, 1800) off Karnataka,south-west coast of India

Scomberomorus commerson were collected on weekly basis during January 2012 to December 2014 at Mangalore Fishing Harbour. Stomach of 214 narrow barred Spanish mackerel measuring from 48 to 105 cm fork length (FL) for males and 45.5 to 115 cm FL for females were analysed to study their feeding habits. Fish with empty stomach were prevalent in almost all the months. Prey mainly comprised of fishes and crustaceans, with the fish component forming 99.9%. The index of relative importance (IRI) showed that the dominant prey were semi-digested fish remains (44.6%) of Sardinella longiceps (30.1%), Decapterus sp. (18.7%), whitebaits (2.5%), Rastrelliger kanagurta (1.5%) and Epinephelus spp. (1.1%), while Saurida sp. (0.7%), Megalaspis cordyla (0.5%), Scombroides sp. (0.2%) and shrimps (0.1%) were found occasionally in the gut. Index of stomach fullness (SFI) was 0.11 in August and 0.65 in January. Generally, SFI was higher during September to January and lower during February to August. The empty stomach ratio (ESR) ranged from 33.3% (August) to 92.3% (April).

Fishery, reproductive biology and stock status of the Indian mackerel Rastrelliger kanagurta (Cuvier, 1817), landed along the north-east coastof India

The fishery, biology and stock status of Indian mackerel, Rastrelliger kanagurta (Cuvier, 1817), landed along the north-east coast was studied during 2011-2014. The average annual catch was 52,206 t. Catch was more or less equally contributed by trawlers, gillnetters and seiners with average catch rates of 3.05 kg h-1, 22.74 kg unit-1 and 140.09 kg unit-1 respectively. Catch was positively influenced by wind speed and negatively by sea surface temperature and precipitation. Growth in males was isometric, while it was allometric in females and indeterminates. Females outnumbered males in the commercial catches. Length at first maturity varied between 18.32 and 18.86 cm. Peak spawning season was during July - October and February - April. Relative fecundity was 567.51 ova per gram body weight. von Bertalanffy growth equation obtained was: Lt = 27.72 [1-e -1.2 (t + 0.023)]. Length at first capture and life span estimated were 12.78 cm and 2.48 years respectively. Natural mortality, fishing mortality and total mortality were 2.06, 3.69 and 5.75, respectively with an exploitation rate of 0.64. Peak recruitment was found to be during September-October. Maximum sustainable yield and yield per recruit were 40,675 t and 14.74 g respectively which were obtained by increasing the present fishing effort by 20%, but at the increased fishing effort, the increase in yield was a meager 0.53%, which indicates that the present level of fishing can be continued.

Fishery, diet composition and reproductive biology of the dolphinfish Coryphaena hippurus (Linnaeus, 1758) off Karnataka, south-west coast of India

Fishery, diet composition and reproductive biology of the dolphinfish Coryphaena hippurus (Linnaeus, 1758) landed along Karnataka Coast during 2013-15 were studied. The estimated average landing of the species in India during the study period was 7975 t of which Karnataka contributed 2.73% (218 t). The fish is mainly exploited by gillnet and also by troll lines operated from trawlers. A few stray specimens were also landed by purse seines. The fork length (FL) was in the range of 32-128 cm and fishes in the length range (FL) of 55-90 cm dominated the catch, contributing 79.8% of the total landings. The most dominant prey item, in terms of occurrence (70.57%) and weight (83.18%) were finfishes followed by cephalopods (19.62% by occurrence and 13.66% by weight) and crustaceans (7.01% occurrence and 1.32% by weight). The index of relative importance (IRI ) values were 85.3, 13.39 and 0.68% respectively for fish, cephalopods and crustaceans respectively. Sex ratio (1:2.05) indicated dominance of females in the fishery. Presence of mature and spent specimens throughout the year suggests that the species spawns all through the year. Peak spawning period was from June to September. This coincided with gradual increase in gonadosomatic index (GSI) values ahead of May which reached a peak during August-September.