Evaluation of Artisanal Fishing Gear Selectivity and Its Conservation Implications in Cross River

Fishing gear selectivity determines the size and species composition of catches in artisanal fisheries and is a critical factor in the sustainability of freshwater fish populations. This study evaluates the selectivity characteristics of four commonly used artisanal fishing gears in the Cross River fishery, Cross River State, South South Nigeria: monofilament gill nets of varying mesh sizes, cast nets, hook and line with varied hook sizes, and basket traps. Selectivity experiments are conducted through comparative fishing trials at six river stations between November 2023 and June 2024. For gill nets, SELECT model analyses of length frequency data from catch samples are used to estimate retention probability curves and select length at full retention for key target species including Chrysichthys nigrodigitatus and Labeo parvus. Minimum legal size assessments compare the observed size distributions of landed catches against the minimum legal fishing sizes prescribed under the Cross River State Fisheries Regulations. Length-weight relationships and maturation length data inform evaluation of juvenile capture rates. Observer data on by-catch composition, including protected species and undersized fish, are recorded for each gear type. Findings are expected to reveal high levels of juvenile and undersized fish capture by monofilament gill nets with small mesh sizes (25 to 35 millimetres), representing a significant sustainability concern. Gear-specific recommendations for mesh size regulations and the introduction of biodegradable escape vents in basket traps are proposed for adoption by the Cross River State Ministry of Agriculture. Keywords: gear selectivity, artisanal fisheries, Cross River, sustainability, mesh size regulations