A total of 2,830 whales, dolphins and seals of 25 different species will be harassed — but not injured or killed — by high-energy seismic surveys planned by PG&E offshore of Diablo Canyon nuclear power plant, federal officials have determined.
For most of the species, the percentage of the animals affected will be less than 1 percent. However, the Morro Bay population of harbor porpoises will bear the brunt of the impacts.
Nearly three-quarters of the population, or 1,513 animals, will be affected. These porpoises are especially vulnerable to the surveys because they could be driven from their preferred feeding and habitat areas.
“This small-bodied species has a high metabolic rate requiring regular caloric intake to maintain fitness and health; therefore there is a potential for adverse health effects if an animal were forced into an area offering suboptimal habitat for an extended period of time,” said Helen Golde, acting director of the Office of Protected Resources of the National Marine Fisheries Service.
The agency has issued a proposed Incidental Harassment Authorization to cover the biological impacts of the surveys that was recently published in the Federal Register.
The authorization does not cover southern sea otters, which are handled by a different federal agency, the U.S. Fish and Wildlife Service. An estimated 600 otters will be affected by the surveys, or about 21 percent of the animal’s total population.
Starting in mid-November, PG&E proposes using a research vessel to emit very loud blasts of sound —250 decibels — into the ocean from air guns that will help the utility better understand the earthquake faults surrounding the nuclear plant.
The sound blasts will be emitted every 15 seconds almost continuously for much of November and possibly into December along a 50-mile stretch of ocean from Cayucos to Guadalupe. If needed, PG&E can apply to conduct more surveying next year during November and December.
The surveys were prompted by a state law written by state Sen. Sam Blakeslee, R-San Luis Obispo, and the March 2011 Fukushima earthquake and nuclear disaster in Japan. They are intended to yield new geologic information. The California Energy and Public Utilities commissions support the survey work.
No marine mammals are expected to be injured or killed as a result of the surveys, the Fisheries Service and other agencies have concluded. However, the sonic blasts will result in what the federal government calls Level B harassment.
This kind of harassment is defined as any human activity “causing disruption of behavioral patterns, including but not limited to migration, breathing, nursing, breeding, feeding or sheltering.”
PG&E will pay the Fisheries Service and other agencies $8 million to conduct a series of measures intended to monitor the effects of the sonic blasts on marine life and minimize them. These include:
Ramping up the loudness of the sound blasts in order to give marine mammals a chance to swim away and maintaining sound emissions at lower levels when the research vessel is turning and not actively surveying.
Observing protocols for shutting the survey work down if marine mammals are close to the research vessel or if there is evidence that marine life is being injured or killed. Trained observers will be on the research vessel and support boats to watch for and alert the survey vessel if marine mammals are in the vicinity.
Conducting aerial, acoustic and beach monitoring before, during and after the survey work to find out where marine mammals are and detect behavior modifications that would indicate stress or the possibility of animals beaching themselves.
Limiting the survey work to November and December, when biologists say the impacts would be minimized.
In addition to protecting the marine mammals, the mitigation measures will give biologists new information about the biology and behavior of those mammals and how they react to seismic surveys, particularly the harbor porpoise and sea otter, said Jearl Strickland, PG&E’s nuclear projects manager.
“It’s a very detailed program,” he said. “This is the first time this type of monitoring has been put in place for high-energy seismic surveys even though they are done regularly in the Gulf of Mexico and other places.”
The measures to protect harbor porpoises were developed by Karin Forney, a wildlife biologist from Santa Cruz, who determined that harbor porpoises living along the Central Coast are a distinct population.
The Morro Bay stock of harbor porpoises ranges from Point Sur to Point Conception with its core habitat area around Morro Bay. The animal is primarily found in shallow water. Its estimated population is 2,044 animals.
The U.S. Geological Survey is planning an extensive monitoring plan to gauge the impact of the sonic blasts on sea otters. In October, the agency plans to capture 60 otters, with 40 coming from within the survey area and 20 outside the area to act as a control population.
Each otter will have blood samples taken and each will be implanted with devices that record their location and diving activity. The monitoring devices will reveal how the otters react to the sonic blasts. The same otters will be recaptured after the surveys and more biological samples will be taken.
Comparing the samples should allow biologists to determine how stressed the otters were by the surveys, Strickland said.
In spite of these mitigation efforts, opposition to the seismic surveys is steadfast among environmentalists, fishermen and county residents, who fear the surveys could harm the local economy. A common theme among opponents is the belief that the damage the sonic blasts will do to the ocean outweighs whatever new earthquake fault information the process will generate.
“This section of coast offers expansive stretches of beach and reef breaks,” said Brad Snook, chairman of the Surfrider Foundation’s San Luis Obispo chapter.
“This proposed high-energy seismic testing project threatens the sporting experience and biodiversity of the Central Coast.”
PG&E has already obtained a crucial permit to do the studies from the State Lands Commission.
The utility still needs permits from about 10 other federal, state and local agencies. Another crucial permit will go before the state Coastal Commission for a hearing Nov. 14 in Santa Monica.