SAN LUIS OBISPO -- 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 Pacific Gas & Electric 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. But 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. Harbor porpoises would be 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
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 nearly 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 the same November and December period.
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 spend $8 million to monitor the effects of the blasts on marine life and minimize them.