Comparative assessment of population biology of three popular pomfret species, Pampus argenteus, Pampus chinensis and Parastromateus niger in the Bay of Bengal, Bangladesh

Pomfrets are one of the most ample high priced fisheries of the Bay of Bengal, Bangladesh. The present study featuring the comparison of the life history parameters of three Pomfrets i.e. Silver (Pampus argenteus), Chinese (P. chinensis) and Black (Parastromateus niger) is based on the monthly length frequency data from the commercial landings from July 2015 through June 2016. The length (TL) of all three Pomfrets ranged from 8 to 55cm and weight (W) varied from 24 to 1302g. An allometric growth pattern was found in all cases when estimating LWR. The VBGF parameters for silver pomfret was L∞= 54.6cm, K= 0.39yr-1 while it was 54.6cm, 0.62yr-1, 57.75cm, and 0.94yr-1 for both Chinese and black pomfrets, respectively. Based on LCCC analysis the total mortality (Z), natural mortality (M) and fishing mortality (F) for silver and Chinese pomfrets were found to be the lowest compared with some previous studies related to the Indian Ocean, whereas black pomfret showed higher mortality rates to some extent. The exploitation ratio (E=F/Z) of silver and Chinese pomfrets were lower than the Gulland (1971) criterion of demarcation point of 0.5 and was higher for black pomfret which showed over-exploited stocks.  The YPR analysis also showed the heavily exploited state of black pomfret fishery, therefore, immediate management approach should be required to maintain sustainable stocks.