Interactions between cetaceans and artisanal fishermen from Ilhéus, Bahia - Brazil

Abstract

Ethnobiological studies are necessary to understand the relationships between fishers and cetaceans. The aim of this study was to describe the interactions between cetaceans and artisanal fishers and the possible conflicts that can arise as a result. Semi-structured interviews were conducted from February to September 2017 with 35 fishermen from the municipality of Ilhéus, Brazil. All fishermen reported both positive and negative interactions with Megaptera novaeangliae, Tursiops truncatus and Sotalia guianensis and only negative interactions with Balaenoptera acutorostrata (n=14) and Stenella frontalis (n=4). The positive interactions consisted of playful relationships and collaborative fishing. Negative interactions (bycatch, entanglement, collisions) affect both the fishermen and cetaceans. S. guianensis is the species most affected by bycatch in fishing nets and M. novaeangliae by entanglement and collision with vessels. The results of this study highlight the value of bringing together scientific and fishing communities to understand conflicts by monitoring interactions in order to assess the impact of fishing activity on cetacean populations. Fishers have a positive perception of cetaceans, know the areas where accidents occur and would like to avoid them. They can contribute to research on these animals and to the development of management plans appropriate to the local reality. This points out the need to integrate scientific and local knowledge for the conservation of cetaceans and for the sustainability of fishing practices.

When large marine predators feed on fisheries catches: Global patterns of the depredation conflict and directions for coexistence

“…Studies of spatiotemporal factors have identified peak areas of depredation associated with strong overlaps between natural foraging grounds of predators and fishing operations (González et al, 2015;Nitta & Henderson, 1993;Seminara, Barbosa-Filho, & Pendu, 2019;Stepanuk et al, 2018;Wickens, 1995) and/or distances from haul-out sites for pinnipeds (Cronin, Jessopp, Houle, & Reid, 2014;Hückstädt & Antezana, 2003). Similarly, peak in depredation were associated with seasonal variation in species co-occurrence with fisheries due to their phenology (reproduction or migrations) (Bombau & Szteren, 2017;De María, Barboza, & Szteren, 2014;Janc et al, 2018).…”

“…For instance, multi‐variate statistical analyses highlighted times of year or areas of high probability of depredation for pinnipeds (e.g. Cosgrove et al, 2015; González, Vega, & Yáñez, 2015; Pon et al, 2012), for odontocetes (e.g. Cruz, Menezes, Machete, & Silva, 2016; Goetz, Laporta, Martinez Portela, Santos, & Pierce, 2011; Hernandez‐Milian et al, 2008; Muñoz‐Lechuga, Rosa, & Coelho, 2016; Passadore, Domingo, & Secchi, 2015; Pennino, Rotta, Pierce, & Bellido, 2015; Rocklin et al, 2009; Söffker et al, 2015; Tixier, Burch, et al, 2019; Tixier, Giménez, et al, 2019) and for sharks (e.g.…”

“…Some publications did reflect the emergence of interdisciplinary approaches, at both the individual (researcher) and collective (collaborations across researchers of diverse expertise/background) levels. Biologists are starting to incorporate aspects of the behaviour of fishers driving depredation through methods derived from Animal Ecology and Human Sciences (Dalla Rosa & Secchi, 2007; Hückstädt & Krautz, 2004; Mitchell, McLean, Collin, Taylor, et al, 2018; Passadore et al, 2015; Powell & Wells, 2011; Richard et al, 2018; Pon et al, 2012). Instances of collective interdisciplinary research were highlighted in scientific programs on depredation involving biologists and fishery scientists, but also cross‐sectoral (transdisciplinary) collaborations with industry representatives (fishers, companies, gear suppliers, etc.).…”

Fishers and whales in Iceland

“…Using these methods to engage with fishers can improve the relationship between fisheries and research institutes and can therefore lead to increased data and better fisheries management (Johnson and Densen, 2007). This method has been used to study experiences and effects of whale depredation on fisheries in Alaska, USA (Peterson and Carothers, 2013), seal-fisheries interactions in Greece and Cornwall, England (Glain et al, 2001), gear damage caused by whales and sharks in Newfoundland and Labrador, Canada (Lien and Aldrich, 1982), fisher knowledge of marine megafauna bycatch off Mayotte Island, Mozambique (Pusineri and Quillard, 2008), cetacean-fisheries interaction in Galicia, Spain (Goetz et al, 2014) and Bahia, Brazil (Seminara et al, 2019) and marine mammal bycatch in the South China Sea (Liu et al, 2016), Victoria, Australia (Norman, 2000), Northwest Spain (López et al, 2003), artisanal fisheries in African, Asian and Caribbean countries (Moore et al, 2010) and Iceland (Ólafsdóttir, 2010). Surveys of fishers and onboard observation can be useful tools to collect eye-witness accounts of whale-gear interactions and specific details of these incidents that cannot be inferred using conventional methods of studying whale entanglements (Knowlton et al, 2005).…”