Marine Mammal Interactions With Fisheries: Review of Research and Management Trends Across Commercial and Small-Scale Fisheries

Abstract

Marine mammal interactions with fisheries, such as bycatch and depredation, are a common occurrence across commercial and small-scale fisheries. We conducted a systematic review to assess the management responses to marine mammal interactions with fisheries. We analyzed literature between 1995 and 2021 to measure research trends in studies on direct and indirect interactions for: (i) high and low to middle-income countries, (ii) fishery operations (commercial and small-scale), and (iii) taxonomic groups. Management responses were categorized using the framework described previously in peer-reviewed studies. Marine mammal bycatch remains a major conservation concern, followed by marine mammal depredation of fishing gear. A high proportion of studies concentrated on commercial fisheries in high-income countries, with an increase in small-scale fisheries in low to middle-income countries between 1999 and 2020. The insufficient understanding of the social dimensions of interactions and the inevitable uncertainties concerning animal and human behaviors are major challenges to effective management. Despite the key role of human behavior and socioeconomics, we found only eight articles that incorporate human dimensions in the management context. Integrating social dimensions of marine mammal interactions with fisheries could help in setting pragmatic conservation priorities based on enhanced understanding of critical knowledge gaps. An area-specific adaptive management framework could be an effective tool in reducing the risk to marine mammals from fisheries by coupling technical solutions with socio-economic and political interventions. We conclude that despite the vast body of literature on this subject, a “silver bullet” management solution to marine mammal interactions with fisheries does not yet exist.

Assessment of the interactions between cetaceans and fisheries at the south of the Cetacean Migration Corridor and neighboring waters (Western Mediterranean)

“…Valencia fishers are still very collaborative with conservation workers and aware of conservation issues; however, management actions are needed for both keeping the fishing activity sustainable and preserving the dolphin populations in the area. Future work must focus on updating extant knowledge in cetacean species abundance, distribution, behavior, and habitat use in order to assess spatial risk (Jog et al, 2022), but it is also necessary to implement management actions for reducing cetacean-fisheries interactions, such as the use of visual deterrent devices, acoustic deterrent devices, and gear modifications, also contributing with compensation funds to fishers in order to reduce these interactions (Jog et al, 2022). participated in the interviews.…”

“…The opposite situation seems to happen at Valencia province, where low engine power contribution values do not explain the clusters of striped dolphin strandings, probably associated with the proximity to the preferred area of distribution for striped dolphin in the region. Therefore, fishing capacity alone does not seem to explain the stranding distribution throughout the region The effect of other variables such as species distribution (Leeney et al, 2008), abundance of cetacean species and/or of their prey, or drifting conditions and migration of carcasses due to sea currents and winds (Peltier et al, 2014;Saavedra et al, 2017;Jog et al, 2022) should be also considered to explain cetacean distribution. In fact, at the study area, the stranding clusters of both dolphin species found at the south of the Valencia province could be explained by the existence of a main north-south surface coastal current, already described as a potential factor explaining loggerhead sea turtle stranding distribution in the area (Tomaś et al, 2008).…”

Opportunistic gillnet depredation by common bottlenose dolphins in the southwestern Gulf of Mexico: Testing the relationship with ecological, trophic, and nutritional characteristics of their prey

“…Expansion of human populations and local fisheries have led to increasing opportunities for competition with coastal marine predators. A recen review by Jog et al (2022) shows that the number of published studies of marine mammal interactions with fisheries is rising and is largely dominated by cetaceans in both commercial and small-scale fisheries. Depredation of catches in at least 214 fisheries covering almost all of FAO's (Food and Agriculture Administration) fishing areas has been reported since 1979 (Northridge, 1991;Tixier et al, 2020).…”

“…Depredation of catches in at least 214 fisheries covering almost all of FAO's (Food and Agriculture Administration) fishing areas has been reported since 1979 (Northridge, 1991;Tixier et al, 2020). Marine mammals such as cetaceans and pinnipeds are the most frequently reported taxonomic groups that exhibit this behavior (Tixier et al, 2020;Jog et al, 2022). Depredation of small-scale fisheries is less frequently reported for pinnipeds due to the distributions of this type of fisheries; within the odontocetes, killer whales (Orcinus orca) and common bottlenose dolphins (Tursiops truncatus, hereafter referred to as "bottlenose dolphin"), possess the highest number of depredation reports, but only bottlenose dolphin has been documented to interact with different types of fishing gear used by the recreational, commercial, and artisanal sectors (Northridge, 1984;Tixier et al, 2020).…”

“…Competition has been recognized by FAO as one of the most relevant conflicts faced by coastal bottlenose dolphins at a global level, given the socioeconomic and ecological importance for man and marine predators, respectively (Northridge, 1984;Northridge, 1991;Bearzi, 2002;Read, 2008;Tixier et al, 2020;Jog et al, 2022). Socioeconomic impacts include damage to fishing equipment and reduction of the catch, threatening the economic security and food acquisition for fishers, especially those that operate at subsistence level (Bearzi, 2002;Bearzi et al, 2019;Guerra, 2019).…”