North Atlantic right whales - the threat from entanglement
After vessel strikes, entanglement in fishing gear is the next biggest threat to the continued survival of the North Atlantic right whale. Their entire habitat along the East Coast of the US and Canada is shared with productive fishing areas where fixed gear is set to catch lobsters, crabs, cod, haddock and other commercially valuable fish. Literally millions of miles of rope are in use all along the U.S. east coast, connecting fishing gear that is set on the ocean floor to buoys at the surface, leaving a labyrinth of gear through which whales must try to navigate. Studies have found that each year between one and three right whales are found dead as a result of entanglement and many who die never wash into shore to be counted. Seventy-two percent of North Atlantic right whales have been entangled at least once, with many individuals becoming entangled more than once. Even those whales that survive entanglements are impacted as research shows that the reproductive rates of entangled females’ declines.
Very little is known about how whales become entangled in gear, though they are most likely to be seen with rope or netting around their flukes, pectoral flippers, or caught through the mouth in their baleen. It appears that the whales may initially roll into the gear when they contact it, exacerbating the entanglement. What we know of these cases are a minimum as, unlike ship strikes, entangled whales do not die immediately. Ropes will slowly cut into tissue and bone, causing infections and chronic pain, often leaving the whale to starve to death. On average, a lethally entangled whale will suffer for six months before succumbing to the resulting infection.
Some whales live in chronic pain as result of the gear wrapped around a part of their bodies for years. In 2004, “Kingfisher”, a male right whale was sighted off the Georgia coast entangled in fishing gear that had originated in Maine. When researchers looked at their most recent previous sighting of Kingfisher, they discovered that he had been seen off Georgia only six weeks earlier without gear. Kingfisher was now towing several feet of rope and attached buoys that wrapped around his right flipper and over his body. A disentanglement effort was attempted with the assistance of the United States Coast Guard cutter Kingfisher (the whale’s namesake) where much of the lines around the body were removed, but was unsuccessful in retrieving the rope wrapped tightly around the flipper. Today, Kingfisher still lives with his right flipper entangled, and the gear continues to tighten, cutting into flesh and bone and causing chronic injury and pain.
Kingfisher’s story demonstrates that entanglements present not only a threat to survival of the species, but also to the welfare of the individuals that do remain.
To help mitigate the potential for entanglement, modifications to fishing gear, as well as seasonal closures have been implemented, but there is still much work to do.
As part of the Atlantic Large Whale Take Reduction Team, WDC worked with fishermen, conservation groups, scientists and state and federal agency representatives to develop a rule requiring the use of sinking ground line for most fixed fishing gear along the East Coast of the US. These ground lines, connecting the traps at the ocean bottom, no longer float and create 20 foot arcs in the water column. By reducing the profile, the risk of a whale encountering a line is greatly reduced. However, the vertical lines connecting the series of traps to a surface buoy for retrieval, continues to pose a significant threat.
In February of 2012, WDC along with The Humane Society of the United States, Defenders of Wildlife, Center for Biological Diversity, International Fund for Animal Welfare, and Duke University put forward a proposal to the National Marine Fisheries Service, the federal agency responsible for overseeing the protection of right whales. We asked the Service to expedite a rule that would reduce the risk of entanglement in vertical line, to include additional areas and gear types not currently considered, and to ensure a viable monitoring and enforcement plan is developed.