Variation in Population Characteristics and Harvesting Pressure Influencing Recruitment Pattern of an Economically Important Fish, Osteomugil cunnesius of Indian Sundarbans

Population characteristics of Osteomugil cunnesius (Longarm mullet) are significant in Indian Sundarbans as the species has high commercial demand in local market. But research work on population dynamics and stock assessment of this mullet species is very limited. The present work aims to determine some of the key management parameters of growth, mortalities, recruitment pattern and exploitation for Osteomugil cunnesius in Sundarbans, India, a world heritage site. The sampling was performed between 2015 and 2017 from the Sundarbans estuary. The parameters of growth, mortalities, exploitation, recruitment pattern, probability of survival, probability of capture, virtual population analysis were recorded. The population dynamics were analysed by FiSAT II (Version 1.2.2) software. The recruitment patterns occurred more or less continuously with one major pulse between May and July. We observed that natural mortality was higher than fishing mortality in 2015 and 2016, whereas, the fishing mortality was higher than the natural mortality in 2017. The result indicated that the fishing pressure increased gradually, which reflected overexploitation of O. cunnesius in 2017. Fishing pressure was increasing over the available stock in the particular Sundarbans area, necessitating appropriate steps to control the fishing pressure. The overall rising impulse of fishing mortality in respective years would be highly alarming to the fish stocks in near future. The present study may be further explored to establish a better fisheries management.