Diet and consumption rates of common dolphinfish, Coryphaena hippurus, in the eastern Arabian Sea

Authors


Author's address: Sijo P. Varghese, Cochin Base of Fishery Survey of India, P.B. No. 853, Kochangadi, Cochin 682005, India.

E-mail: varghesefsi@hotmail.com

Summary

The aim of the study was to identify the diet composition, feeding preferences, size and sex related diet changes, and to calculate the consumption rates of common dolphinfish, Coryphaena hippurus, in the eastern Arabian Sea. Fish were caught using longline gear during the years 2006–2009. Stomachs of 238 specimens with fork lengths ranging from 324 to 1250 mm were analysed; 72 (30.25%) of the stomachs were empty. Epipelagic finfishes were the predominant prey followed by cephalopods and crustaceans. Occurrence of items such as sargassum, sea fans, corals, plastics and pieces of wood in the stomachs indicate an opportunistic and voracious feeding nature. Flyingfishes (family Exocoetidae), especially Exocoetus monocirrhus (%IRI 16.92), dominated the diet. Unidentified filefishes (family Monacanthidae), Sthenoteuthis oualaniensis, Euthynnus affinis, Cheilopogon furcatus and Cubiceps pauciradiatus were other important food items. The diet varied between sexes and different size classes. Juveniles and adults (size classes <75 cm, 75–95 and 95–115 cm) fed mainly on epipelagic finfishes, whereas the large adults (>115 cm) fed preferentially on cephalopods. Food consumption rate was higher in females (6.37% BW day−1) compared to males (4.04% BW day−1), and increased with their increase in size up to 75–95 cm length classes, thereafter decreasing. The daily meal and daily ration was 332.63 g day−1 and 5.25% BW day−1, respectively, and average annual food consumption was 121.41 kg.

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