Mangrove mudwhelk (Terebralia palustris, Linnaeus, 1767) harvesting and subsequent use in basket trap fishery, at the Mida creek Biosphere reserve, Kenya

Abstract

Abstract Traditionally basket traps, baited with gastropods, seagrass, among others, deployed in nearshore fishery, are typical to tropical coastlines. Although fish landings from such fishery are documented, bait utilized remains sketchy. The Indo-Pacific Mangrove mudwhelk (Terebralia palustris) are keystone species, threatened by habitat degradation but also the poorly documented human harvesting. Forest bait harvesting is comparable to tropical forest hunting but has received scant attention in spite of potential impacts. This study elucidates mudwhelk baited trap harvest and subsequent use in basket trap fishery at the Mida creek. Bait and fish landings and effort, and habitat attributes at sites at the Mida creek, are determined and variations described. Results show 0.64 kg.m-2 of mudwhelk occur at Mida creek, with higher biomass (P<0.05) at the more complex Dabaso forest. Harvesters targeted larger individuals (10.38 cm), extracting 9.26 kg.harvest-1 at a rate of 0.12 kg.min-1, with higher harvest (P<0.001), at the less complex Kirepwe forest. The mudwhelk bait, were used to land 0.69 kg.fisher-1 of fish with relatively low landing efficiency (>1.0 kg fish.kg-1 bait), but higher (P<0.001) landings at Kirepwe. We tentatively estimate Mida creek mudwhelk harvest of 5.9 t.yr-1, corresponding to 5.2% of stock (115.2 t), but may mask localized overharvesting at sites with higher trap fishery participation and require more testing to guide sustainable management.