Stock Assessment of the Pink ear emperor, Lethrinus lentjan (Lacapede, 1802)

Kenya’s artisanal demersal reef fishery is an important component of the coastal economy, contributing significantly to food security, employment, livelihoods, and marine fish production. The fishery is highly diverse, targeting over 200 species using various artisanal gears. However, increasing fishing pressure, expanding effort, and the use of non-selective gears have raised concerns about over-exploitation, declining catches, reduced biodiversity and the capture of juvenile fish. Among the key target species is Lethrinus lentjan, a commercially valuable reef-associated fish widely distributed in coral reefs, seagrass meadows and mangrove ecosystems. Despite its ecological and economic importance, information on its stock status remains limited. This study therefore assessed the biological stock characteristics, stock status and sustainability of L. lentjan to support science-based management. Data were collected from artisanal fisheries along the Kenyan coast, extending from the Somali to Tanzanian border. Landed catches were sampled using standardized protocols that recorded date, vessel and gear type, fishing ground and crew size. Fish were identified to species level, measured for total length and weights. Stock status was evaluated using length-based methods, yield-per-recruit analyses, biological reference points and yield isopleths to determine the effects of fishing mortality and size at first capture. Results showed variations in gear selectivity. Beach seines (4%), basket traps (31%) and ringnets (13%) principally captured immature individuals, while handlines (68%), monofilament nets (67%) and gillnets (59%) mainly retained mature one. The length-weight relationship indicated negative allometric growth (b = 2.897). Growth and mortality estimates showed moderate growth rates, while total mortality (Z) consistently exceeded natural mortality (M), indicating that fishing mortality (F) was the primary source of stock removal. Exploitation rates (E) were generally above the optimum level of 0.5, demonstrating persistent overexploitation. Fishing mortality ranged from 0.44 to 7.82 year⁻¹, with the highest pressure recorded in 2021. Although F/Fmax remained below 1, elevated F/F0.1 ratios, extremely high F/F0.5 values, low Length-Based Spawning Potential Ratio (LBSPR) estimates, and the premature capture of immature fish all indicated growth and recruitment overfishing. In conclusion, L. lentjan is overexploited along the Kenyan coast, with reduced stock productivity and compromised reproductive capacity. Management should focus on increasing mesh sizes and promoting more selective fishing gears to allow fish to mature and spawn before capture. Such measures would enhance recruitment, rebuild spawning biomass, and improve the long-term sustainability of the fishery.