Direct interactions with fisheries are broadly recognized as the leading conservation threat to small cetaceans. In open-ocean environments, one of the primary gear types implicated in these interactions is the pelagic longline. Unlike accidental entanglement in driftnets or deliberate entrapment by purse-seines, interactions between cetaceans and longlines are often driven by attraction of the animals to feed on bait or fish secured on the gear, a behavior known as depredation. Many small and medium-sized delphinid species have learned to exploit such opportunities, leading to economic costs to fisheries and a risk of mortality to the animals from either retaliation by fishermen or hooking or entanglement in fishing gear. Two pelagic longline fisheries in the United States experience depredation and bycatch by odontocete depredators: the Hawai‘i deep-set longline fishery, which is depredated primarily by false killer whales (Pseudorca crassidens), and the Atlantic pelagic longline fishery depredated primarily by short-finned pilot whales (Globicephala macrorhynchus). These fisheries are among the most intensively documented and managed pelagic longline fisheries in the world, with high levels of observer coverage, and bycatch mitigation measures required to reduce the mortality of seabirds, sea turtles and cetaceans. Both fisheries have active, multi-stakeholder “Take Reduction Teams,” enacted under the U.S. Marine Mammal Protection Act (MMPA), that are tasked to develop measures to reduce the bycatch of cetaceans below statutory reference points. Consequently, these two Teams represent model processes within which to address depredation and bycatch, having access to detailed, high-quality data on the nature and frequency of interactions with cetaceans, meaningful stakeholder involvement, resources to test potential solutions, and the institutional will to improve outcomes. We review how mitigation strategies have been considered, developed, and implemented by both Teams and provide a critical analysis of their effectiveness in addressing these problems. Notably, in the absence of straightforward avoidance or deterrence strategies, both Teams have developed gear and handling strategies that depend critically on comprehensive observer coverage. Lessons offered from these Teams, which have implemented consensus-driven management measures under a statutory framework, provide important insights to managers and scientists addressing other depredation problems.
Bycatch is the leading global threat to cetaceans, with at least 300,000 cetaceans estimated to be killed each year in fisheries. Regional fisheries management organizations (RFMOs) are key actors in global fisheries management, including bycatch reduction, but their role in cetacean bycatch management is often overlooked. The primary mandate of RFMOs is to manage fisheries of target stocks, but many of their Convention Agreements call for addressing bycatch of threatened and protected species in their fisheries, including cetaceans. We reviewed 14 RFMOs to understand their current cetacean bycatch management efforts. We developed twenty-five criteria for best practices in cetacean bycatch management to understand efforts made by each RFMO, grouped into five categories: 1) general bycatch governance; 2) observer coverage; 3) quantitative bycatch limits; 4) data analysis and transparency; and 5) mitigation efforts. Collectively, based on our application of these criteria, RFMOs scored highest in “data analysis and transparency” (average=0.74) and lowest in setting “quantitative bycatch limits” (average=0.15). Overall, RFMOs have passed few binding conservation and management measures focused on cetacean bycatch, particularly compared to those addressing the bycatch of seabirds and sea turtles; the few existing measures are primarily focused on bycatch in purse seines. Notwithstanding the United Nations (UN) large-scale drift gillnet ban (46/215) on the high seas, only one RFMO has passed a management measure specifically focused on cetaceans and gillnets, widely recognized as the gear type posing the highest risk to cetaceans. No measure in any RFMO specifically addresses cetacean bycatch in longlines. We provide recommendations to the RFMO community to encourage progress on this critical issue, including leveraging other recent policy developments such as the adoption of the 2021 UN Food and Agriculture Organization Guidelines to prevent and reduce bycatch of marine mammals in capture fisheries and implementation of the U.S. Marine Mammal Protection Act Import Provisions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.