Killer Whale Fence Initiative

Killer whales forage near fishing vessels in the Bering Sea. While entanglements in trawl gear are rare, an unprecedented increase occurred in recent years. This was likely related to a change in how killer whales were foraging. Although the affected killer whale stock is healthy, entanglements threaten crew safety, animal welfare, and fishery sustainability. Killer whales also hold social and cultural value, making their protection critical. Fishermen recognized the need for proactive mitigation. Because operational changes had limited success, fishermen focused on gear-based solutions.

Fishermen, gear manufacturers, and marine mammal experts collaborated to develop the “Killer Whale Fence”. The concept originated in 2023, when a captain and net manufacturer co-developed a prototype. Simultaneously, a killer whale expert studied the animals’ behavior around vessels to identify peak entanglement risk. The fence design was refined through flume tank testing with input from additional fishers and scientists.

The fence consists of a large mesh panel secured to the headrope and wings. It expands and contracts with the net maintaining coverage across all fishing stages. The mesh is scaled to allow target fish to pass while deterring whales, and its materials are detectable via echolocation, ensuring effectiveness in dark or turbid conditions. Additional dropper-lines increase coverage and allow marine debris to pass freely. Though its development required substantial collaborative investment, the result is straightforward and cost-accessible, enabling adoption across a wide variety of fleets.

By 2024, all vessels in the Bering Sea deepwater flatfish fishery adopted the fence, corresponding with a substantial reduction in entanglements. Ongoing refinements and behavioural research in 2025 are expanding its versatility and demonstrate a model of collaborative, science-based innovation.