(Clarifies purpose of bycatch permits, other details, paragraphs 3-4 and 14)
By Steve Gorman
LOS ANGELES, March 1 (Reuters) - Great white sharks off the coast of California gained new protection on Friday as regulations took effect designating them candidates for listing under the state's Endangered Species Act.
The world's largest predatory fish, whose fossil record by some estimates dates back some 16 million years, has been off-limits to commercial and sport fishing under California law since 1994.
But great whites, particularly as juveniles, are still snared as unintentional "bycatch" in gill-net fishing for halibut, swordfish and white sea bass off California and Mexico's Baja Peninsula. Such bycatch, or also known as incidental taking, has been unrestricted.
Under the sharks' new status, gill-net fishermen will be required to obtain special state permits to allow bycatch of great whites but on a restricted basis.
The permits are likely to entail limits on the amount of time gill-nets can be in the water, where they can be placed and how many sharks can be caught before fishing is ordered halted, state Fish and Wildlife Department biologist Traci Larinto said.
Violations would be treated as criminal misdemeanors, but it was not yet clear what penalties such an offense would carry.
Before Wednesday, there were no limits on bycatch and no penalties for incidental killing of great whites, though fishermen were supposed to throw surviving sharks back or turn them over to scientists studying the species.
The five-member California Fish and Game Commission voted unanimously on Feb. 6 to name the great white shark as the first marine animal granted candidate designation under the state Endangered Species Act.
If formally listed, fishery management bodies would be required to develop measures to minimize bycatch. In the meantime, candidate status carries the same legal force as an actual listing.
BALANCED MARINE ENVIRONMENT
The panel acted after environmental groups presented data collected in 2011 and 2012 showing adults and sub-adults of the species numbering fewer than 340 in two principal feeding grounds off central California and Baja.
The survey, the first tally of great whites along the U.S. Pacific Coast, provided no comparison numbers.
Commercial fishing industry groups have questioned whether the tally, which may seem small, might actually reflect a healthy number for an apex marine predator, and whether it represents a growing or shrinking population.
Larinto cited recent data suggesting that more than half of young great whites snared in gill-nets survive. Of 94 caught inadvertently and turned over to scientists between 2006 and 2011, 55 were later released alive, most with research tags.
She said those figures probably represent the majority of great white bycatch off California south of Santa Barbara.
Zeke Grader, a spokesman for the Pacific Coast Federation of Fishermen's Associations, said fishermen and environmentalists share an interest in keeping great white populations healthy since they are vital to maintaining a balanced marine environment.
For instance, great whites are important in controlling the population of sea lions and other marine mammals that prey on salmon and other commercially valuable fish, Grader said.
Scientists consider the West Coast population of the shark to be genetically distinct and isolated from other great whites worldwide, thought to number several thousand off Australia, South Africa, New Zealand and in the Atlantic Ocean. Australia and South Africa have listed their great whites as endangered.
The Fish and Wildlife Department will recommend by next February whether great whites warrant formal listing, with the Fish and Game Commission making the final decision. Environmental groups also seek to list California's great whites under the U.S. Endangered Species Act.
While the great white is among three shark species most associated with attacks on humans - along with bull sharks and tiger sharks - such encounters are exceedingly rare. But great whites hold a special place in the popular imagination due mainly to their size, with some specimens known to have reached 20 feet (6 meters) in length and 5,000 pounds (2,268 kilograms).
(Editing by Cynthia Johnston and Xavier Briand)