Stock status and some biological aspects of Lethrinus lentjan (Lacapede, 1802) from the south coast of Kenya

Abstract

The Pinkear Emperor (Lethrinus lentjan, Laćepède, 1802) is among the three demersal species dominating fish catches in the artisanal fishery on the Kenyan coast. Available data indicate that total landings of L. lentjan have declined over the past decade due to possible over-exploitation. This paper provides a brief account of the stock status of this species and biological aspects including length-weight relationship, body condition, and reproduction from a total of 575 fish specimens sampled. Sampling was done at Msambweni, Shimoni, Majoreni and Vanga fish landing sites on the south coast of Kenya from September 2016 to February 2017. Individual total length (TL, cm) and body weight (BW, g) was measured on site while some specimens were dissected for sex and gonad maturity analysis. Mortality, exploitation rate, length-weight relationship, condition factor, fecundity, and size at maturity (L₅₀) were determined. Length frequency analysis indicated that L. lentjan was exploited above the optimum level, at E = 0.55 (exploitation rate). Growth was allometric with the length exponent (b = 2.95) being significantly <3. Mean fecundity was 89,573 ± 9,841 eggs/female/year. Gonadosomatic index was highest in January (2.08 ± 0.20) suggesting a possible peak spawning period at this time. The study provides a brief scientific overview of L. lentjan as a baseline for future in-depth biological studies of this species along the Kenyan coast.