Local Ecological Knowledge and Scientific Data Reveal Overexploitation by Multigear Artisanal Fisheries in the Southwestern Atlantic

Abstract

In the last decades, a number of studies based on historical records revealed the diversity loss in the oceans and human-induced changes to marine ecosystems. These studies have improved our understanding of the human impacts in the oceans. They also drew attention to the shifting baseline syndrome and the importance of assessing appropriate sources of data in order to build the most reliable environmental baseline. Here we amassed information from artisanal fishermen's local ecological knowledge, fisheries landing data and underwater visual census to assess the decline of fish species in Southeastern Brazil. Interviews with 214 fishermen from line, beach seine and spearfishing revealed a sharp decline in abundance of the bluefish Pomatomus saltatrix, the groupers Epinephelus marginatus, Mycteroperca acutirostris, M. bonaci and M. microlepis, and large parrotfishes in the past six decades. Fisheries landing data from a 16-year period support the decline of bluefish as pointed by fishermen's local knowledge, while underwater visual census campaigns show reductions in groupers' abundance and a sharp population decline of the Brazilian endemic parrotfish Scarus trispinosus. Despite the marked decline of these fisheries, younger and less experienced fishermen recognized fewer species as overexploited and fishing sites as depleted than older and more experienced fishermen, indicating the occurrence of the shifting baseline syndrome. Here we show both the decline of multigear fisheries catches – combining anecdotal and scientific data – as well as changes in environmental perceptions over generations of fishermen. Managing ocean resources requires looking into the past, and into traditional knowledge, bringing historical baselines to the present and improving public awareness.

Traditional fisher perceptions on the regional disappearance of the largetooth sawfish Pristis pristis from the central coast of Brazil

“…3). Local knowledge accumulated over generations may provide a valuable source of information on fisheries trends (Bender et al 2014), and insights on species extinctions into local and regional scales (Luiz & Edwards 2011).…”

Flight response of the barber surgeonfish, Acanthurus bahianus Castelnau, 1855 (Teleostei: Acanthuridae), to spearfisher presence

“…are caught by inexperienced spearfishers (Bender et al, 2014) and exported to international markets from northeast Brazil (Lessa & Nóbrega, 2000). Between 1996 and2008, 3,335.49 metric tons of fish were caught and freshly exported for human consumption in the State of Rio Grande do Norte, northeastern Brazil, to the United States and the European Community, where Acanthurus spp.…”

Follower fish of the goldspotted eel Myrichthys ocellatus with a review on anguilliform fish as nuclear species

“…Nevertheless, in Arraial do Cabo, we recorded only one species of grouper (Mycteroperca acutirostris) in a single event. This low frequency of groupers in following associations may be related to the marked decrease in the abundance of groupers in the region during the last three decades as a consequence of overfishing [29,30]. Therefore, changes in the fish community caused by anthropogenic activities can be affecting interspecific associations, thereby influencing the reef trophodynamics.…”