Scientists and Fishermen Discuss Solutions to Whale Entanglements

right whale entangled in fishing line
A North Atlantic right whale entangled in fishing line.

When the New England Aquarium set up the Consortium for Wildlife Bycatch Reduction a decade ago, one of its objectives was to create opportunities for sharing experience internationally on what is often the most immediate threat to many marine mammals, seabirds, sea turtles, sharks, and other groups of animals. After all, bycatch, the term used to describe the animals generally not targeted by fishermen that nonetheless become snagged in fishing gear, occurs in all fisheries and all fishing nations. Promoting exchange on what is working and what isn’t helps us become more efficient in finding viable solutions that work for fishermen and endangered marine species alike.

Last week, we organized a workshop sponsored by NOAA and the International Whaling Commission to review research on preventing large whale entanglements. Every species of the group known popularly as the “Great Whales” (14 species of whales that feed with baleen and the sperm whale) have been documented as becoming entangled in fishing gear, and there are even records of some species becoming tied up in lines used in mussel aquaculture and fish aggregating devices (FADs). In some cases, such as that of the North Atlantic right whale that occurs along the eastern coastlines of the US and Canada, it is the single most immediate threat to a population that now numbers only around 500 individuals. Whaling, once the scourge of the planet’s great whales, has been replaced by collateral damage from our desire for seafood.

This and similar workshops that the Consortium for Wildlife Bycatch Reduction organizes create productive exchanges among scientists and fishermen from different parts of the world facing common challenges. In this case, our objective was to examine various techniques for continuing to fish without entangling whales. Australian lobster fishermen shared their several years of experience using submerged ropes with their New England counterparts, which involves keeping buoy lines close to the seafloor except when hauling their catch. Might this work in the more crowded fishing grounds of the Gulf of Maine? If we remove ropes in the path of whales, then the entanglement risk would be largely eliminated. Plans are underway to continue sharing ideas on this fishing technique between these nations. Engineers and marine mammalogists also explored the potential of using sounds that might startle animals just long enough to stay away from entanglement hazards, especially nets. We understand far less about the hearing of large whales than we do of dolphins and porpoises, and while some studies have shown an area deterrent effect for some species of these smaller marine mammals, no such study has shown that these devices work for large whales. Meanwhile, some governments and fisheries consider it a possible option to manage whale entanglements, and constructive dialogues among participants identified some suitable test beds for advancing our understanding about the true potential of acoustic bycatch deterrents.