Incidental catches of franciscana in coastal gillnet fisheries in the Franciscana Management Area III: period 1999-2000

Abstract

Bycatch of franciscanas in fishing operations along the western South Atlantic Ocean has been observed for approximately 60 years. Reports on bycatch in shark gillnet fisheries off Uruguay date back to the early 1940s. A decade later, gillnet fisheries for bottom-dwelling fish became the major conservation concern for franciscanas in both Brazil and Argentina. A small portion (c. 10%), of the coastal gillnet fleet which operate from the port of Rio Grande (southern Rio Grande do Sul, Brazil) was monitored in 1999-2000. The total annual bycatch was estimated to be 946 franciscanas (non-parametric CI = 467 - 1525) for the year 1999 and 719 (non-parametric CI = CI: 248 - 1413) dolphins for 2000. The total bycatch for the whole FMA III was 1106 (CI: 578 - 1915) for 1999 and 992 (CI: 475 - 1832) for 2000. Since data were not normally distributed confidence intervals were estimated by non-parametric bootstrap. Despite strong evidence of decline for the stock from FMA III, no mitigation strategy has been established or designed. Instead, fishing effort is still very high, it is increasing and bycatch is uncontrolled. Thus, prompt management action is required. Regulation of gillnet fishing effort might be the only suitable immediate action to mitigate the bycatch.