Matching Fishers' Knowledge and Landing Data to Overcome Data Missing in Small-Scale Fisheries.

Background: In small-scale fishery, information provided by fishers has been useful to complement current and past lack of knowledge on species and environment.

Methodology: Through interviews, 82 fishers from the largest fishing communities on the north and south borders of a Brazilian northeastern coastal state provided estimates of the catch per unit effort (CPUE) and rank of species abundance of their main target fishes for three time points: current year (2013 at the time of the research), 10, and 20 years past. This information was contrasted to other available data sources: scientific sampling of fish landing (2013), governmental statistics (2003), and information provided by expert fishers (1993), respectively.

Principal Findings: Fishers were more accurate when reporting information about their maximum CPUE for 2013, but except for three species, which they estimated accurately, fishers overestimated their mean CPUE per species. Fishers were also accurate at establishing ranks of abundance of their main target species for all periods. Fishers' beliefs that fish abundance has not changed over the last 10 years (2003-2013) were corroborated by governmental and scientific landing data.

Conclusions: The comparison between official and formal landing records and fishers' perceptions revealed that fishers are accurate when reporting maximum CPUE, but not when reporting mean CPUE. Moreover, fishers are less precise the less common a species is in their catches, suggesting that they could provide better information for management purposes on their current target species.