Present Status of the Sustainable Fishing Limits for Hilsa Shad in the northern Bay of Bengal, India

Abstract

The hilsa, Tenualosa ilisha fishery in the northern Bay of Bengal (nBoB) is passing through a crisis manifested by the persistent decline of fish catch in spite of increasing efforts. During the period 2002–2015, the number of boats engaged in the fishery increased by 25% while the hilsa catch decreased by 13%. The exponential value (b) and condition factor (K) of hilsa has also decreased by 46% and 28% respectively. The value of fishing mortality (F = 2.34 year-1) has considerably exceeded the natural mortality (M = 0.56 year-1) during the study period. It is observed that in place of maximum exploitation rate (Emax) of 0.78, the current exploitation rate (E) of hilsa is 0.81 which is above the sustainable limit. It is a matter of serious concern that with 75% probability the first spawners of the population are being targeted by the present fishing practice. The present study observes that the hilsa population of nBoB are being significantly overexploited in the present level of fishing pressure. The maximum sustainable yield (MSY) limit for hilsa is estimated to be around 25,440 tons per year with the corresponding effort (fMSY) that may be deployed to achieve the above mentioned catch ranged from 3571 to 3987 (number of boats). It can be inferred that the hilsa fishery in the nBoB is being unsustainably exploited.