In 2014, the Responsible Fisheries Alliance (RFA) commissioned the University of Cape Town (UCT) to identify significant endangered, threatened and protected (ETP) species caught, mostly as bycatch, in five major South African commercial fisheries. These include the hake inshore trawl, the hake offshore trawl, the hake longline, the horse mackerel midwater trawl, and the tuna and swordfish longline fisheries.
Associate Professor Colin Attwood and Laura Weston were tasked with undertaking this study. To achieve this, a review of scientific literature, governmental reports and other grey literature, and onboard observer data was conducted, and an assessment of the target and bycatch species reportedly caught in each of the five fisheries was made. The conservation and protection status of each species caught was reviewed, and any ETP species caught in each of the five fisheries were identified. A review of international literature is presented, detailing previous approaches used in assessing bycatch species that may be vulnerable to overfishing.
The impacts of fishing on bycatch populations are difficult to assess, owing to the large number and diversity of different species caught in some fisheries, as well as the corresponding lack of data on these species. To overcome this, several risk-based approaches have been applied in the assessment of bycatch populations globally. Productivity susceptibility analysis (PSA) is one such approach that has proven to be effective in assessing bycatch populations, and thus far has been one of the most extensively used methods to assess the risk of these species to overfishing.
Criteria to determine significant ETP teleost, chondrichthyan, mammal and turtle species caught as bycatch in the five fisheries assessed here, were therefore developed through the application of a PSA. The PSA methodology has been adopted by the Marine Stewardship Council (MSC) as a part of the assessment of fisheries for MSC certification. The productivity and susceptibility criteria used in this report were therefore based on those criteria stipulated by the MSC. Seven productivity criteria and four susceptibility criteria were scored. Total PSA scores were calculated and then ranked to determine those ETP species at higher risk of becoming overfished compared to the other ETP species caught in the fishery in question. For the results of this study, please see the attached project report below: