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

Abstract

BackgroundIn small-scale fishery, information provided by fishers has been useful to complement current and past lack of knowledge on species and environment.MethodologyThrough 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 FindingsFishers 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.ConclusionsThe 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.

Fishers’ knowledge indicates short-term temporal changes in the amount and composition of catches in the southwestern Atlantic

“…This agrees with previous studies indicating decreases in catches over time and even local extinctions, according to fishers' knowledge [18,22,31,35,39,59,67]. Nevertheless, a recent study has not evidenced a decline in the biomass of fish caught in the northeastern Brazilian coast during the last 10 years [21]. The observed decrease in the biomass of fish caught also agree with concerns of coastal fishers regarding intense fishing pressure by large scale fishers [3,15,65].…”

“…Recent studies have successfully applied fishers' knowledge to investigate temporal trends in abundance of fishing resources and changes in ecological conditions in a range of freshwater and coastal Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/marpol ecosystems [18,22,35,39,61]. Nevertheless, most of these studies address particular fish species more susceptible to fishing pressure, such as reef fish or sharks [31,59], while fewer studies investigate temporal changes in the amount and composition of fish catches by comparing distinct data-bases, such as governmental landing statistics and fishers' knowledge [21]. Information on temporal trends in fish catches are required to support management interventions and policy measures better suited to the needs and concerns of Brazilian small-scale coastal fishers [6,7].…”

“…Information on temporal trends in fish catches are required to support management interventions and policy measures better suited to the needs and concerns of Brazilian small-scale coastal fishers [6,7]. In Brazil, previous studies analyzed fishers' knowledge to reconstruct temporal changes in abundance of some target fish species in the tropical northeastern coast [18,21,31], but fewer studies have addressed changes in fish abundances in the more populated and potentially more heavily impacted southeastern coast [42]. Moreover, studies usually concentrate in particular fishing communities and few studies analyze a large amount of interviews with fishers from a broad geographic area [10].…”

First record of Batrachoides surinamensis (Bloch & Schneider, 1801) and Canthidermis maculata (Bloch, 1786) (Pisces: Teleostei) from Rio Grande do Norte, northeastern coast of Brazil

“…Therefore, their actual conservation status might have been unknown to researchers, fisheries managers, and younger fishers before such species were first assessed. This seems to be the case, for example, for C. maculata; in data collected from fishers (see Damasio et al 2015), elderly fishers reported high catches of triggerfishes prior to 2003 and the complete disappearance of current landings. However, fishers used just common names (cangulo) and grouped together several species such as Bali stes vetula, B. capriscus, and Cantherhines macrocerus.…”

“…In the conservation status may not represent historical declines. In Rio Grande do Norte, fishing activities are considerably unregulated, unreported, and to some extent also illegal (Ross et al 2015;Damasio et al 2015;Bevilacqua et al 2016). Some fisheries and target species are poorly assessed or not assessed at all, and the presence, abundance, and availability for fisheries of some species might be misreported.…”