LOS ANGELES, July 24 (Reuters) - Fresh-caught swordfish will be off the menu in California restaurants for at least the next month, due to a federally imposed temporary ban on drift gillnets in the Pacific to protect endangered sea turtles starting on Friday.
The closure, to remain in effect through Aug. 31, covers 25,000 square miles (62,160 square km) of ocean waters off Southern California that constitute the prime West Coast fishing grounds for swordfish and thresher sharks caught with gillnets.
The mile-long strands of nylon mesh suspended in the water attached to floats pose a hazard to other sea life, including marine mammals and turtles that can become inadvertently snared as "bycatch" in the nets and drown.
The new gillnet ban marks the first time such a restriction has been imposed off California by the National Marine Fisheries Service as a safeguard for loggerhead turtles, an endangered species that normally feeds in more southern waters off Mexico's Baja Peninsula.
The agency's 2003 loggerhead conservation plan calls for closing the waters off San Diego and Los Angeles to gillnet fishing in years when the ocean-warming pattern known as El Nino occurs or is forecast, said Ben Enticknap, a senior scientist with the environmental group Oceana.
The warmer-than-usual water temperatures are expected to draw the loggerhead's preferred prey, pelagic red crabs, and the turtles themselves farther north into harm's way from gillnets, Enticknap said.
The bulk of gillnet fishing off Southern California generally occurs from mid-August through January, and Enticknap said a number of loggerheads have been sighted in regional waters or found stranded on San Diego-area beaches recently.
Two swordfish boat captains who spoke to Reuters said sightings of any sea turtles off Southern California are rare, as are bycatch of the marine reptiles, and they questioned predictions that loggerheads would begin turning up in greater numbers due to El Nino.
"I don't think there's going to be any more turtles up there than there already are," said Dan Krebs, captain and owner of the swordfish boat Goldcoast, based in San Diego, adding that fishermen have been working successfully for years to reduce their bycatch.
The five-week gillnet closure will halt fishing operations for a fleet of 16 boats whose annual swordfish and thresher shark catch is valued at about $1 million on average, a small fraction of California's overall commercial fishery.
The next closest swordfishing grounds to the U.S. West Coast are in Pacific waters far off Hawaii and Samoa, said California-based fisherman Nathan Perez. (Editing by Eric Walsh)