Integrating biological, ecological and socio-economic indicators to assess data-limited, tropical, small-scale fisheries: the case of the Colombian Pacific


In tropical countries Small-Scale Fisheries (SSF) contribute more than half of the total fisheries catch and provide food security, nutrition, employment and multiplier effects to local coastal economies. The multi-species and multi-gear nature of SSF demands a holistic approach for their assessment and management. Using the Colombian Pacific coast as a case study area of tropical, data-limited SSF, this thesis presents a comprehensive assessment that includes: a) the stock condition of main target species, b) the potential impacts of SSF to the biological communities and ecosystems, and (c) the socio-economic drivers of the gear choices made by small-scale fishers.

Based on government and non-government fisheries data, estimated values of stock indicators converged to suggest a state of heavy to over-exploitation for the three assessed species, although there were differences observed among data sources that were attributed mainly to the fisheries selectivity and sampling design. Taxonomic, size-based, functional and conservation features of the nominal catch vary greatly with geographical location and gear type used. Overall, handlines and longlines tended to select larger sizes and higher trophic level species than nets but they also caught a higher proportion of intrinsically vulnerable species and species of conservation concern. This challenges the idea that more selective gears have overall lower ecological impacts. Fishers' gear choices were influenced by the value of their target species and potential profits but also by access to markets, access to fishing grounds and the local socio-economic conditions. Highly variable catches and profits, coupled with relatively high entry and operational fishing costs, led to an overall low economic income for small-scale fishers, which inevitably increases their already vulnerable socio-economic condition. A set of practical recommendations to transition towards more holistic assessments and management of tropical SSF is drawn from the results of the thesis, taking into account the regional and global contexts.