Aberrations in the feeding behaviour of the Indian Mackerel, Rastrelliger kanagurta

The food and feeding habits of the mackerel have been studied extensively, which suggest that mackerel generally adopts either filter feeding or preying on the individual animals. Plankton consisting of copepods, diatoms and dino-flagellates and small crustaceans such as the Acetes sp. are reported in their feed. However, a deviation from the normal feeding habit was observed in the gut analysis of mackerel collected on 8th October 2013 from trawlers at Mangalore Fisheries Harbour. Among the 50 stomachs analysed 4% contained oil sardines juveniles and 2% had digested squid remains as a food item. The specimens which ranged from 192 mm to 285 mm in total length and weighed 67 g to 224 g were mature with their gonad in spent or spent recovery stages. The semi-digested oil sardine present in the gut of mackerel ranged in size from 36 to 81 mm