Conservation group claims early end to crab season helped reduce whale entanglements off California shores
Reports of whales entangled in fishing gear off the West Coast declined by about half over nearly the first eight months of the year compared with a similar period a year ago, reflecting an early end to the California commercial crab season, according to the Center for Biological Diversity.
The National Oceanic and Atmospheric Administration reported 17 confirmed entanglements and one unconfirmed in California, Oregon and Washington from January through Aug. 23, according to preliminary data released this week.
Last year, from January through August, NOAA logged 42 whale entanglement reports, 34 of them confirmed.
Though impossible to prove, the Center for Biological Diversity credited the improvement to removal of commercial Dungeness crab gear from California coastal waters in mid-April, under a legal settlement reached in its 2017 lawsuit against the California Department of Fish and Wildlife. The season typically has run from Nov. 15 through June 30.
The nonprofit conservation group sued the state wildlife agency after a spike in whale entanglements centered in California, most involving crab gear. The group claimed deficient management of the commercial crab harvest puts endangered marine mammals and sea turtles at risk, particularly endangered humpback whales.
Whale entanglement numbers hit records three years in a row, peaking in 2016 with 71 cases off the West Coast. The group dropped its suit after commercial crabbers agreed in March to painful, costly concessions.
Under terms of the complex settlement, the state closed California’s commercial crab season 2½ months early, ordering removal of all crab pots and lines from the water as the spring migration of humpback whales was starting.
The effect of the settlement remains unclear, with only two of the 10 California entanglement reports this year were known to have involved California commercial Dungeness crab gear. Both were observed in August and involved humpback whales.
Also, there were three humpback whales caught up in Oregon and Washington commercial crab gear, and three gray whales snagged by other fishing gear, including gill nets. Several others found off the California coast and elsewhere were entangled in lines and buoys of unknown origin.
Historically, crab gear has accounted for a large number of whale entanglements, if not “the vast majority,” said Steve Jones, a Center for Biological Diversity spokesman.
“Getting lines out of the water reduces entanglement risk,” Catherine Kilduff, a senior attorney for the group, said in an email. “Off California, we know that’s a problem in the spring, based on the historical presence of whales. So we feel confident that the closure (of commercial crab season) helped whales avoid fishing gear.”
Sonke Mastrup, an environmental program manager for the California Department of Fish and Wildlife, was less willing to make a definitive connection between the truncated commercial crab season and the reduction in entanglements.
His boss, agency director Chuck Bonham, had linked the initial spike in entanglements with environmental factors that in 2016 shifted the location of forage fish and whale feeding grounds at the same time that a toxic algae bloom delayed the start of the commercial crab season by 4 1/2 months. The result was that most of the crab fleet had gear in the water at the same time whales came up the coast to feed near shore, increasing the chances the massive mammals would become ensnared in the heavy lines that connect crab pots on the ocean floors to buoys floating on the surface.