Abalone divers are in for a shock this year, likely more uncomfortable than the first surge of cold ocean water inside a wetsuit.
In the wake of an unprecedented abalone die-off in 2011, new regulations for the 2014 season have curbed the annual catch limit and closed the North Coast's most popular abalone dive site at Fort Ross State Park.
Also new is a later daily starting time for the sport fishing season that draws thousands of people who pry about 260,000 of the tasty sea snails a year off rocks along the scenic coast.
Forty-five sites in Sonoma and Mendocino counties account for 96 percent of the catch, according to state records.
California Department of Fish and Wildlife officials say the rules are based on dive surveys that found a 60 percent decline in Sonoma County abalone population density following the die-off in August 2011 that littered the shore with dead white abalone carcasses, detached from their shells.
"We want to ratchet back the whole fishery," said Laura Rogers-Bennett, a Fish and Wildlife environmental scientist based at Bodega Marine Laboratory.
The season-long closure at Fort Ross and the nearby Reef Campground, by far the most popular site with an average catch of more than 41,000 abalone a year, is intended to "give it a rest," Rogers-Bennett said.
Some abalone divers are chafing at the restrictions and challenging the rationale for them.
"We have a very healthy abalone population," said Roger Rude of Windsor, a veteran abalone diver who is making a documentary movie on the sport.
Rude, who said he has seen "abalone stacked upon abalone" in places, contends that state officials are "overstating" the damage from the 2011 die-off.
A retired Sonoma County sheriff's lieutenant, Rude was especially critical of the new annual catch limit of 18 abalone and the provision that only nine can be taken from Sonoma and Marin counties.
The previous annual limit was 24. The daily catch limit remains at three abalone, along with the minimum size of seven inches.
Also new for the season opening April 1 is an 8 a.m. start time, nearly three hours later in midsummer than the previous start time of half an hour before sunrise.
"It's a little too much over-regulation," said Ben Dougherty, co-owner of a Bodega surf shop who described himself as an "occasional" ab diver.
Dougherty said he expected some reaction to the die-off and acknowledged that it takes a long time - biologists say up to a dozen years - for abalone to grow seven-inch shells.
"It's a touchy topic," he said. But the annual limit of nine from Sonoma County waters seems "a little too strict."
California's only sport abalone fishery is for red abalone, one of seven
species in the state, taken north of the Golden Gate Bridge.
The season runs from April through November except for a closure in July.
Rude faulted the annual abalone surveys by Fish and Wildlife, contending that divers swim over the bottom and note the visible abalone, resulting in a significant undercount.
Rogers-Bennett said the survey divers, using scuba tanks that are prohibited in sport fishing, check the rocky cracks and crevices where many abalone rest.
Working in pairs, the divers stretch a 30-meter tape along the bottom and each diver surveys a meter-wide band along the tape, she said. It takes three years to complete the surveys at four sites in Sonoma County and four in Mendocino County.
"We have very accurate density estimates," Rogers-Bennett said.
Surveys showed abalone density in Sonoma County declined 60 percent from the 2003-07 period to the 2009-12 period, a Fish and Wildlife report said.
The density at Fort Ross dropped below 0.25 abalone per square meter, requiring site closure under the state's Abalone Recovery and Management Plan, the report said.
Mendocino County's abalone population density was unchanged between the two periods, it said.
The sudden die-off in 2011 was "a Sonoma County phenomenon," occurring from just south of Bodega Bay up nearly to the Mendocino County line, Rogers-Bennett said.
Population density is critical to the species because abalone, which live firmly fixed to rocks, shed eggs and sperm into the ocean and must be close together to achieve fertilization, she said.
Biologists were initially stumped by the die-off, which stunned local divers and was erroneously attributed to a red tide.
The cause has since been identified as a bloom of microscopic algae called Gonyaulax membranacea, which produce a toxin called yessotoxin that was found in abalone gut tissue.
No similar algae bloom has occurred since 2011, Rogers-Bennett said.
You can reach Staff Writer Guy Kovner at 521-5457 or guy.kovner@pressdemocrat.com.
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