An account on the emerging gastropod shell-trap fishery of short-armed octopus Amphioctopus aegina (J. E. Gray, 1849) in Palk Bay, Southeast coast of India

Abstract

Octopuses are bottom-dwelling molluscan species that inhabit both surface and deep waters. Octopuses exhibit camouflaging behaviour and usually hide in the crevices of reefs and rocks. This paper reports the re-emergence of the shell trap fishery for short-armed octopus, Amphioctopus aegina, after four decades in the Palk Bay region, following traditional fishing practices and Fiberglass-Reinforced Plastic (FRP) boats with outboard engines. Fishermen use gastropod shells as their base material. About 3000 – 3500 gastropod shells were tied at one-metre intervals on a 2 mm-thin Polypropylene rope. Amphioctopus Aegina formed 97 % of the landings with an estimated average catch per unit effort ranging from 40 to 50 kg/unit, followed by A. marginatus (2 %), and A. neglectus (1 %). The estimated profit margin is 61.3 %, and the labour efficiency is 20 kg.