California will expand the commercial Dungeness crab season and reopen the central and southern coasts on Jan. 18.

Crab vessels will be allowed to set traps beginning at 8 a.m. Jan. 15, according to a California Department of Fish and Wildlife declaration published Jan. 11.

Recreational crab fishing was opened along the coast on Nov. 4, 2023, but was restricted from the Sonoma and Mendocino county line to Lopez Point in Monterey County.

The commercial crab season, which usually starts Nov. 15, was delayed for a third time last year, to protect migrating humpback whales. The delays were based on excessive humpback whale entanglements in leftover crab gear over the last three years, and a high number of humpback whale sightings off the central coast of California, according to the fish and wildlife department.

This year, the coastal region open to crabbing will be expanded to allow commercial operations south of the Sonoma and Mendocino county lines with a 50-percent reduction in the number of crab traps that can be deployed.

The department’s director, Charlton Bonham, said he evaluated the fishery’s management considerations and opened up the season with restrictions on crab traps.

“I have determined that the management action ... protects humpback whales based on the best available science,” Mr. Bonham wrote in the Jan. 11 determination.

The gear limitations are a direct result of high numbers of entangled whales and a shift in the location of crabs, which are concentrated off the central coast this year, according to Oceana, an international advocacy organization focused on ocean conservation.

Dr. Geoff Shester, Oceana’s California campaign director and senior scientist, and a member of the California Dungeness Crab Fishing Gear Working Group, said the state’s Dungeness crab fishery has injured and killed endangered whales.

“California’s Dungeness crab fishery is in a state of crisis due to wildlife entanglements and its future is on the line,” Mr. Shester said in a statement Jan. 11. “Sadly, this popular and economically important fishery has injured and killed endangered humpback whales at an unsustainable rate that may impede recovery of the species.”

Last month, a critically endangered Pacific leatherback sea turtle was also entangled and drowned in commercial gear that was lost in a previous fishing season, according to Mr. Shester.