Tracking interactions: Shifting baseline and fisheries networks in the largest Southwestern Atlantic reef system

Abstract

Increasing evidence has revealed that different fisheries have collapsed around the world. This is generally more evident in countries that can maintain long‐term research and fisheries monitoring. When monitoring data are not available, alternative approaches to assess fisheries trends can be used, such as the local ecological knowledge of fishers. To investigate decadal changes in fisheries the local ecological knowledge of small‐scale fishers' was evaluated at four sites in Brazil: Porto Seguro, Prado, Alcobaça, and Caravelas. A fisher–fish network weighted by interaction strength was built to indicate the most relevant resources among fishers. The results suggest the occurrence of the shifting baseline syndrome among generations of fishers regarding commercially important fishes such as groupers and snappers. Handline fishers indicated a decline in catch per unit effort over 5 decades. Fisher–fish networks from Caravelas showed greater stability with stronger interaction strength, while Porto Seguro and Alcobaça networks were more fragile, and Prado network showed intermediate characteristics. Overfishing has affected high trophic level species that act as module hubs across the majority of sites. The fisher–fish network approach can be applied in data limited cases, improving the assessments of fisheries' dynamics (in space and time) and declining species.

Complementary Role of Fishers’ Experiential Knowledge to Conventional Science in Terms of Species-Specific Biological Traits and Population Changes in Azorean Waters

“…Fishers from different generations may have different perspectives on resource conservation status and may use biased information to judge changes in the environment (shifting baseline syndrome; [56]). Studies have documented this phenomenon in SSF [57], although some fishing communities may have attenuated potential patterns related to shifting baselines [19,21]. Low statistical representativity prevented assessing this effect in the Azores during the present study, but future research should strive to do so.…”

Functional biogeography of marine vertebrates in Atlantic Ocean reefs

“…In the Caribbean, the most diverse vertebrate reef assemblage in the Atlantic, changes in reefs have been associated with the absence of mesopredator species as groupers and sharks, caused by fishing pressure, habitat degradation and pollution (Cheung et al., 2010; Ward‐Paige et al., 2010). In the Southwestern Atlantic coast, groupers have suffered marked population declines in recent decades (Bender et al., 2014; Zapelini et al., 2019). Overall, the rarity and limited distribution of sharks and large‐bodied groupers to few reefs suggests that their ecological function as mesopredators may be compromised in the Brazilian province (Morais et al., 2017).…”

Local Ecological Knowledge Networks in Tropical Artisanal Shrimp Fisheries

“…To test the signi cance of the NODF, random matrices (n = 1000) were generated from the original binary matrix, in which the probability of interactions between shers and CEL was proportional to the total number of interactions [63]. The proportion of random matrices with NODF values equal to or greater than the observed values indicated a degree (signi cantly) greater than the expected nested pattern [64]. Observed and null NODF values the matrices were calculated using the software Aninhado v.3.0 [63].…”