Risks to biodiversity and coastal livelihoods from artisanal elasmobranch fsheries in a Least Developed Country: The Gambia (West Africa)

Abstract

Developing nations in tropical regions harbour rich biological resources on which humans depend for food, income and employment, yet data to aid their management is often lacking. In West Africa, the diversity and fsheries of elasmobranchs are poorly documented, despite them being known to be economically important and vulnerable to overexploitation. Rapid qualitative surveys of fsh processing and landing sites in The Gambia from 2010-2018 revealed valuable new data on species composition, biology, relative abundance, fsheries and utilisation by humans. Diversity and abundance was dominated by batoids, with a major component comprising a large guitarfsh (Glaucostegus cemiculus) that was apparently targeted, and a small whipray (Fontitrygon margaritella). Nearly all taxa recorded are classifed by the IUCN Red List as Critically Endangered (angel sharks Squatina spp.), Endangered, Data Defcient, or Not Evaluated; several were endemic, of exceptional evolutionary distinctness, cryptic, possibly undescribed, and rare (including stingray Hypanus rudis not apparently recorded since description in 1870). Signifcant threats to biodiversity, coastal livelihoods and possibly food security are identifed based on the apparent importance of elasmobranch fsheries and processing; the known inability of key taxa to withstand intensive fsheries; ‘fshing down the food web’ by intensive utilisation of F. margaritella; and the absence or rarity of previously common elasmobranch species that may be severely depleted in the region. This study provides data that may act as a starting point to aid sustainability accreditation of local fn-fsheries, and demonstrates the value of inexpensive and low-resolution data collection in developing countries.