Abstract
Simple SummaryWhales and dolphins in managed-care and wild settings are exposed to human-made, anthropogenic sounds of varying degrees. These sounds can lead to potential negative welfare outcomes if not managed correctly in zoos or in the open ocean. Current wild regulations are based on generally broad taxa-based hearing thresholds, but there is movement to take other contextual factors into account, partially informed by researchers familiar with work in zoological settings. In this spirit, we present more nuanced future directions for the evaluation of acoustic welfare in both wild and managed-care settings, with suggestions for how research in both domains can inform each other as a means to address the paucity of research available on this topic, especially in managed-care environments.Cetaceans are potentially at risk of poor welfare due to the animals’ natural reliance on sound and the persistent nature of anthropogenic noise, especially in the wild. Industrial, commercial, and recreational human activity has expanded across the seas, resulting in a propagation of sound with varying frequency characteristics. In many countries, current regulations are based on the potential to induce hearing loss; however, a more nuanced approach is needed when shaping regulations, due to other non-hearing loss effects including activation of the stress response, acoustic masking, frequency shifts, alterations in behavior, and decreased foraging. Cetaceans in managed-care settings share the same acoustic characteristics as their wild counterparts, but face different environmental parameters. There have been steps to integrate work on welfare in the wild and in managed-care contexts, and the domain of acoustics offers the opportunity to inform and connect information from both managed-care settings and the wild. Studies of subjects in managed-care give controls not available to wild studies, yet because of the conservation implications, wild studies on welfare impacts of the acoustic environment on cetaceans have largely been the focus, rather than those in captive settings. A deep integration of wild and managed-care-based acoustic welfare research can complement discovery in both domains, as captive studies can provide greater experimental control, while the more comprehensive domain of wild noise studies can help determine the gaps in managed-care based acoustic welfare science. We advocate for a new paradigm in anthropogenic noise research, recognizing the value that both wild and managed-care research plays in illustrating how noise pollution affects welfare including physiology, behavior, and cognition.
Highlights
Note to Revision of Guidelines from the DanishEnergy Agency; Aarhus University, DCE—Danish Centre for Environment and Energy: Roskilde, Denmark, 2021.U.S Fish and Wildlife Service
180◦ away with their tail facing the sound source may provide some respite from aversive sounds [55]. This angular sensitivity to sound indicates that potential harm is affected by the incidental position of animals, and may be further complicated by sound that is stemming from multiple sources around whales or dolphins. This complexity presents an additional challenge to assessing anthropogenic noise induced harm among wild individuals, whereas their maintained counterparts in facilities can provide additional insight into this phenomenon through behavioral studies focusing on the way in which cetaceans orient their heads in respect to certain anthropogenic sounds
Because cetacean ears were adapted to conditions that were presumably quieter than current conditions and are quite sensitive, excessive levels of anthropogenic noise can have deleterious consequences, including death, hearing loss, acoustic masking, behavioral changes including acoustic behavior, and cognitive effects
Summary
Cetacean welfare is a topic of concern for the public, scientists, and policymakers. Welfare is defined as the well-being of an individual, which teeters between two opposing states, positive and negative, as the animal responds to its environment [1]. A negative acoustic environment can impact mental states due to chronic negative experiences that can impact the four physical domains by causing a chronic stress response Both wild animals and those housed in managed-care potentially face acoustic welfare concerns. Acoustic welfare concerns across both toothed and baleen cetaceans have included extreme physiologically damaging outcomes, including deafness and death [14,15], and have been studied far more extensively than potential effects in managed-care settings Despite these critical consequences to wild individuals, the discussion of these issues, welfare consequences were more centered around the conservation and preservation of stocks over the experiences of individual animals, with a few exceptions [16,17,18]. We advocate for a synergistic paradigm to evaluate acoustic welfare in cetaceans, both in the wild and under human care such that each can inform the other when considering the acoustic welfare of all cetaceans
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
