Management strategy evaluation case study – joint management of fisheries in South Africa
Plagányi et al. (2007) report on the management of South African sardine and anchovy fisheries. The two species have to be managed jointly as the anchovy harvest is necessarily accompanied by the bycatch of juvenile sardine; however, the latter is more valuable when adult, resulting in a trade-off. A trade-off curve was used in the selection of management goals to show explicitly the inverse relationship between the projected anchovy catch, with its associated juvenile sardine bycatch, and the directed (adult) sardine catch. Individual rights-holders in the fishery sector selected their own anchovy-sardine trade-off, rather than adopting a universal optimum. Recent recruitment estimates are based on an age-structured population model (de Moor, 2014). Early season catch quotas are tested by simulation to ensure robustness in terms of expected catches and uncertainties about the resource dynamics and harvest limits are adaptively adjusted during the year, as catch data are processed (De Oliveira and Butterworth, 2004).