Reducing the number of crab traps in the sea may be more protective of humpback whales than deploying the most advanced safeguards, including real-time population monitoring. This finding comes from researchers at the University of California, Santa Barbara, and was published in the journal Biological Conservation (BioCon).
The researchers sought strategies to lower whale entanglements while keeping the crab fishery viable. They tested a range of management options and found that simpler changes could outperform more complex interventions. One key takeaway: reducing the total number of crab gear devices can have a pronounced positive effect on whale safety without crippling the crab industry (BioCon).
Humpback whales face entanglement not because crabs themselves pose a direct danger, but because the heavy cables and lines used to haul gear to the surface can wrap around the massive whales. Large whales do not threaten the traps; they are drawn into the gear by the lines used by fishermen, which can lead to dangerous entanglements in busy fishing zones (BioCon).
To reach their conclusions, the team built a computer simulation that modeled how changes in crab abundance, whale behavior, and crabbing practices influence the likelihood of entanglements. After running multiple scenarios, a 30 percent reduction in the number of traps emerged as a highly effective way to minimize interactions between whales and fishing gear, with manageable impacts on the crab harvest (BioCon).
In addition to reducing trap numbers, scientists discussed practical alternatives that could offer a balance between seabird safety, whale protection, and fishermen’s livelihoods. One such option is the use of ropeless traps, which eliminate the surface lines that often entangle whales. These technologies exist today but come at a higher upfront cost than traditional mesh-and-frame structures. Another feasible measure would be to add more than one trap to a single line only when appropriate, or to vary the spacing of gear to reduce entanglement risk without slowing the overall harvest (BioCon).
Researchers emphasize that the North American coastline — including breeding, feeding, and migratory corridors in both Canadian and American waters — presents diverse fishing practices and whale movements. The study’s insights aim to guide policy and best practices that protect whales while supporting coastal crabbing communities, a balance that remains essential for stakeholders on both sides of the border (BioCon).
While prior studies have highlighted concerning levels of mutations and other health indicators in whale populations, the new work focuses specifically on actionable management strategies that can prevent entanglements in real-world fishing operations. The authors note that even modest adjustments in gear usage, when applied broadly and consistently, can yield meaningful improvements for whale safety and ecosystem health (BioCon).