Stock status indicators for Cobia Rachycentron canadum in the Indian EEZ

stock status of cobia in Indian EEZ

Abstract

Regional fisheries for cobia (Rachycentron canadum) along the Indian coast was assessed
using length-based stock status indicators. Drift gill nets-cum-hook and line fisheries landed
bigger sized cobia as bycatch while multi-day mid-water trawls landed juveniles. Dominant
size groups in the landings along the west coast were 40–160 cm and 60-120 cm on the
east coast. Gear selectivity operating at regional levels because of the multi-gear fisheries
and fishing grounds of the Indian EEZ affects the size distribution of fish caught. Compared
to drift gill net-cum-hooks and line units targeting large pelagics in deeper waters, smaller
size groups of cobia dominated as bycatch in trawls. The length at first capture (Lc50) being
smaller than the estimated length at first maturity of about 60 cm, implementing size-based
output controls such as Minimum Legal Size (MLS) is suggested. The indicators for fishing
mortality rates (Fmax) on the cobia stocks were on the higher side in certain locations only,
but being part of the multi-species bycatch mix, there is little scope to introduce fishing
gear regulations solely for cobia. However, the option of short-term, targeted spatiotemporal
effort regulations with fishers’ participation can be explored, based on the stock
assessments made at local or regional levels.

Keywords:
Cobia, Fishery indicators, Length-based indicators,
Minimum Legal Size, Rachycentron canadum, Stock
status