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ThesisItem Open Access “STUDIES ON SOME BIOLOGICAL ASPECTS OF THE BLACK BANDED TREVALLY, SERIOLINA NIGROFASCIATA (RUPPELL, 1982) ALONG THE MANGALURU COAST”(KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2018) KALAVATHI N.R.,; MANSING NAIK)The black-banded trevally, Seriolina nigrofasciata found In indo-west pacific, from eastern coast of Africa to Australia, north to southern Japan. Seriolina nigrofasciata (order: perciformes, family : Carangidae ) is a non-schooling carangid fish which occurs at the depth from 20-150 m and is commonly found in offshore reefs over the continental shelf on rocky bottom. This species is also called as “black banded king fish or butter fish” and locally called as “Neyyi meenu”. The present study is based on the observation of a total 627 individuals ranging in size from 15 to 63 cm total length (TL) comprising 280 males and 347 females. The length-weight relationship for male was W= 0.0179L2.9596 and for female W=0.0186L2.9156 . The relative condition factor (Kn) values for male and female varied from 0.9727 and 1.3307 respectively. Analysis of the gut content indicated that fish is carnivore and the diet was composed of Semi-digested matter 68.04 %, teleost 20.80 %, molluscans 16.66 %, crustaceans 3.49 %. The size at the first maturity for male and female appeared at a length of 36 cm and 39 cm TL respectively. The sex-ratio of male:female was found to be 1:1.23 in the commercial catches, showing dominance of female in the population. The Ganado-Somatic Index values ranged from 0.2149 to 2.1769 in male and in case of female, it fluctuated between 0.2342 to 3.9696. The fecundity ranged from 1,92,295 to 7,60,248 eggs with an average 5,02,906 eggs per individual . The ova diameter ranged from 0.01 to 0.5mm. The maturity stages of Seriolina nigrofasciata indicated that this species is a annual single spawner during November to febraury. Proximate composition revealed that fish muscle has 74.03 % to 83.12 % moisture, 14.58 % to 21.87 %. protein, 0.57 % to 3.66 % fat, and 0.86 % to 1.64 %. of ash.ThesisItem Open Access TROPHIC INTERACTION IN COMMERCIALLY EXPLOITED DEMERSAL FINFISHES WITH EMPHASIS ON ONTOGENIC DIET SHIFTS(KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2018) BHAVANJALI M.R; MRIDULA RAJESHTrophic interactions in seven commercially exploited marine demersal finfishes of Karnataka were studied to understand the trophic organization with an emphasis on ontogenic diet shifts and trophic overlap. In total, 4723 stomachs were examined of which 73 prey items were identified. Crustaceans and fishes formed the major prey item. Based on cluster analysis of predator feeding similarities and ontogenic diet shift within each predator, two major trophic guilds were identified. The first guild of ‘crustacean feeders’ included all size groups of Nemipterus japonicus, N. randalli, O. cuvieri and Priacanthus hamrur. The second trophic guild, ‘piscivores’, was mainly made up of larger size groups of all predators and all size groups of Saurida tumbil and S. undosquamis. The mean diet breadth and mean trophic level showed a strong correlation with ontogenic diet shift. TROPH values ranged from 3.4-4.6 for species indicating carnivorous diet pattern of the species. All the species were carnivores and the extent of carnivory increased with ontogeny. It is clear from the present study that most of the species when they were young preferred crustaceans, other invertebrates and smaller fishes but the preference changed for teleosts and other carnivores as they grew in size and age. A seasonal variation in the diet pattern observed was due to variations in prey abundance. Trophic network analysis showed maximum prey in Trophic level III and any alterations due to ecological or anthropogenic activities affecting the prey would result in alterations in community dynamics of the predators.
