A Community Science Approach to Conservation Challenges Posed by Rebounding Marine Mammal Populations: Seal-Fishery Interactions in New England

Between 1880–1962, gray and harbor seals were targeted in legal seal bounty hunts across Maine and Massachusetts due to a perceived competition with commercial fisheries. Following their extirpation 50 years ago, legislative protections allowed seals to recolonize historical grounds along the New England coast. With this conservation success story, conflict has re-emerged as seen in the numerous media articles reflecting a temperament beckoning to the past century, with calls to cull the population and the spread of misinformation. The return of seals after decades of near-absence has created a new ecological and psychological baseline for New Englanders where for three generations, seals were rarely present. Although seals are statutorily protected species, unlike the tools and resources available for depleted, threatened or endangered species, the support needed to increase opportunities for coexistence of humans with rebounding pinnipeds, are comparatively lacking. Even as gray seals have the highest fisheries bycatch levels of any marine mammal in the U.S., resources to address these management challenges are minimal due to limitations and prioritization processes for committing available support. While seal conservation has been a success, the manner in which management is often separately applied to ecosystem elements (e.g., harvested species, protected species) contributes to knowledge gaps, and a disconnect between the goals of conservation to sustainably utilize natural resources while also protecting the intrinsic value of resources for ecosystem health. Solutions to such coexistence challenges could benefit from a more holistic ecosystem conservation approach. To address these disconnects, a two-day workshop was convened to understand seal-fishery interactions where we provided opportunities for community members to meet and learn from one another including, but not limited to, fishermen, natural resource managers, marine mammal stranding response personnel and scientists. A convening that might otherwise result in tumultuous and adversarial engagement, we used as a tool to engage. This community science approach led to long-term relationships that have allowed for successful applied, and community driven, solutions. Here we share the lessons learned and subsequent partnerships. Our intent is to share our approach to address other marine mammal conservation conflict challenges, allowing for collaborative pathways toward long-term coexistence.

Disentangling Natural and Anthropogenic Forms of Mortality and Serious Injury in a Poorly Studied Pelagic Dolphin

Killer whale (Orcinus orca) populations specialize in both prey and prey acquisition tactics around the world and may be a primary evolutionary driver of the habits of small cetaceans. Entanglement in fishing gear is the most significant anthropogenic threat to the survival of cetaceans worldwide. Distinguishing between natural and human-caused sources of mortality and injury is a key task in marine mammal conservation and management. In British Columbia (BC), Canada, mammal-eating killer whales co-occur with Pacific white-sided dolphins (Lagenorhynchus obliquidens). Bycatch mortality rates are unknown here due to lack of systematic fisheries observer coverage. Drawing from more than three decades of first-hand observations of killer whale attacks on Pacific white-sided dolphins, we identify common themes with respect to predatory behavior of killer whales and anti-predatory responses of dolphins. With input from veterinary pathologists, we outline clues to distinguish killer whale rake marks from scars and wounds likely to be caused by fishery interactions. We examined photographs of 415 well-marked Pacific white-side dolphins for evidence of injuries and scars consistent with either killer whale attacks or fishery interactions. In this case study, healed scars from interactions with killer whale predators were ∼8× more common than scars from fishery interactions (3.9 vs. 0.5%), suggesting that predation is a much bigger threat to Pacific white-sided dolphins in the study area than anthropogenic impacts, or that dolphins are much less likely to survive a fishery interaction than a predation attempt. To advance our knowledge on poorly studied species, multiple lines of evidence will be needed.

First records of the megamouth shark Megachasma pelagios (Taylor, Compagno & Struhsaker, 1983) as bycatch in Peruvian small-scale net fisheries

Between October 2018 and October 2019, seven megamouth sharks were reported as bycatch in the small-scale surface and midwater gillnet fisheries operating from the ports of Mancora and Salaverry in northern Peru. Here we present details of these specimens and bycatch events that represent the first documented records of this species in Peruvian waters, confirming their occurrence as fisheries bycatch. We recommend continued monitoring programs in small-scale fisheries toward assessing the extent of this species’ occurrence in Peru and its vulnerability to fishery interactions.