Length based population characteristics and fishery of skipjack tuna, Katsuwonus pelamis (Linnaeus, 1758) from Tuticorin waters, Tamil Nadu, India.

Abstract

Fishery and population characteristics of skipjack tuna (Katsuwonus pelamis) along Tuticorin coast were studied for the period of one year from June 2016 to May 2017. Population parameters of Katsuwonus pelamis based on the length frequency data collected from fish landing centers of Tuticorin. Lengths ranging from 25 to 80 cm total length were observed and analyzed in current study. The population parameters L∞, K, M, Z and F were estimated as 95.70 cm, 0.40 year-1, 0.73, 1.63 and 0.90 respectively. Virtual Population Analysis (VPA) indicated that noticeable fishing mortality starts from 35-39 cm class interval and continued increasing till 50-54 length class. Afterwards a general decline in fishing mortality was observed with a relatively heavy fishing pressure on penultimate length class. The exploitation ratio (E) of 0.55 was derived from present study which is less than the maximum exploitation ratio (Emax = 0.805) indicating a scope for potential increase in production.