Size composition of small-scale demersal catches in a multispecies multi-gear fishery along the Kenyan coast

Effective gear management is essential for sustaining small-scale demersal fisheries in diverse habitats such as seagrass beds and coral reefs, which are vital for food security among poor coastal communities. Multispecies fisheries typically target species and sizes that maximize profitability, driven by their high abundance, using a range of fishing gears. The main objective of this study was to assess the size composition of catches across a series of fishing gears to evaluate the role and importance of the different fishing gears for the exploitation of the different species and sizes in the small-scale demersal fisheries along the Kenyan coast. The small-scale demersal catch comprised many species, however, Siganus sutor, Lethrinus lentjan, and Lutjanus fulviflamma predominated across five main gear types. Basket traps, handlines, and monofilament gillnets primarily captured mature S. sutor, supporting sustainability, while reef seines and multifilament gillnets disproportionately harvested juveniles. Mature L. lentjan were mainly targeted by handlines, whereas gillnets caught both juveniles and adults, and basket traps and reef seines focused on juveniles. For L. fulviflamma, monofilament and multifilament gillnets targeted mature individuals, but other gears caught mostly juveniles, raising concerns about growth overfishing. Habitat differences further shaped population dynamics: seagrass areas supported more mature S. sutor and L. fulviflamma, while coral reefs and mixed habitats showed varied juvenile-to-adult ratios. The south coast exhibited a high proportion of juveniles, highlighting the need for conservation, especially in coral reef zones. Findings indicate that current fishing practices exploit a wide size range, increasing pressure on stocks and contributing to fishing mortality. Existing gear regulations are inadequate, as fishers employ diverse methods to target entire populations. To promote sustainability, regulations should prioritize reducing juvenile catch while ensuring mature individuals reproduce before harvest. Revising gear-based rules to address gear-specific impacts is crucial for alleviating overfishing, guiding recovery, and ensuring long-term sustainability of small-scale demersal fisheries.