Studies on food and feeding of marine Demersal finfishes with special Reference to trophic interactions

Abdurahiman, K P (2006) Studies on food and feeding of marine Demersal finfishes with special Reference to trophic interactions. PhD thesis, Cochin University of Science and Technology, Cochin.

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Abstract

Food and feeding habits of fourteen demersal finfishes exploited off the Karnataka coast were studied to investigate trophic interactions within the marine food web. The demersal finfi shes selected for the present study are Epinephelus diacanthus (rockcod), Grammopli/es suppasitus (spotfin flathead), Priacan/hus hamrur (bulls eye), Johnieops sina (drab jew fish), O/oli/hes cuvieri (lesser tigertooth croaker), Nempilerus japanicus (threadfin bream), Nemipterus mesoprion (thread fin bream), Leiognathus bindlls (si lvcrbclly), CYlloglosslIS macros/om liS (tongue sole), PUII/PIIS argenteus (silver pomfret), Lactarill.v lactarill.r (bigjawed jumper), Pseudorhombus arsius (Iargetooth flounder), Carcharhinus Iimba/us (blacktip shark) and Rhync'loba/us djiddensis (guitar fish). • For understanding the importance of various diet components, the widely accepted diet index, the Index of Relative Importance (IRI), which integrates large data on three diet indices such as number, volume or weight and frequency of occurrence, was used to quantify diet components of each predator. Ontogenetic, seasonal (pre-monsoon, monsoon and post-monsoon) variation in feeding and prey-predator relationship studies were conducted. Prey-spece fi c abundance plots (Amundson plot) and Electivity index were drawn to interpret each predators feeding strategy and prey se lectivity respectively. • The resu lts showed that the rockcod, E. diacanthus is a demersal carnivore and preferred to feed largely on benthic crustaceans. Crustaceans followed by fishes and molluscs were the most important food components of E. diacanti1l1s. Of all the stomachs analysed, 73% were empty and 27% contained food items. The most important crustaceans were benthic crabs (69.4%) followed by Acetes indicus (15.9%) and Oratosquilla nepa (6. 1%). Dietary breadth had great seasonal variations. The mean trophic level was 4.11 ± 0.26. There was a significant ontogenetic shift toward larger benthic crabs in larger rock cods (P<0.05). Electivity study showed strong positive selection to all crustaceans in all the seasons.

Item Type:Thesis (PhD)
Supervisor(s):Mohamed, K S
Uncontrolled Keywords:food and feeding; Demersal fisheries; finfishes; trophic interactions
Subjects:Theses
Demersal Fishes
Food and Feeding
Divisions:CMFRI-Cochin > Marine Capture > Demersal Fisheries
CMFRI-Cochin > Physiology and Nutrition Pathology
ID Code:7595
Deposited By:Dr. V Mohan
Deposited On:17 Feb 2011 16:57
Last Modified:20 Jan 2014 12:13

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