Kerry Griffin of the Pacific Fishery Management Council, which voted unanimously on Friday in favor of the closure, said sardines and similar species like anchovy and herring can experience large population booms and busts.
“So when the sardine population is on the decline,” Griffin said, “you want to protect the core spawning population to protect the stock.”
The latest surveys estimate the abundance of northern Pacific sardines at roughly 28,000 metric tons, well-below the 150,000 metric ton threshold required for commercial fishermen to start dropping nets. In 2006, there were nearly 1.8 million metric tons of sardine swimming off the Pacific U.S., according to NOAA’s estimates.
Griffin said the current decline is “largely environmentally driven.” Changing ocean temperatures, weather extremes like El Niño and predator-prey relationships, he said, have an impact on sardine populations.
“Typically when the conditions are right, these stocks will rebound," Griffin said. "That’s what we’re waiting for.”
Geoff Shester, a marine biologist with the environmental group Oceana, said sardines play a major role in the ocean off California because so much marine life — Brown Pelicans, dolphins, salmon and shark — rely on them for food.
“These are the engines, or the heartbeat of the ocean, that is really supplying our entire ecosystem with the fuel it needs to be productive,” Shester said. “So when sardines collapse, the collapse just pulls the rug out from the entire ecosystem.”
Shester said over-fishing is a threat to the fragile states of Pacific sardines and that keeping the fishery closed could give it a chance to recover.
“Sardines have traditionally been one of California's most important and valuable fisheries,” Shester said. “So this is millions and millions of dollars of lost income.”
Not all fishermen agree with the decision to keep the sardine fishery shuttered.
Diane Pleschner-Steele, executive director of the California Wetfish Producers Association, said NOAA’s sardine survey under-counts the fish, and that the fishermen she hears from are noticing a comeback.
“They are so frustrated because they drive by school after school after school and they can't fish,” Pleschner-Steele said. “This is their livelihood and they have families and they are losing their jobs.”
Pleschner-Steele’s group has been working with the California Department of Fish and Wildlife on different ways to count sardines, including aerial and shallow water surveys that she says may account for fish missed by NOAA's deep ocean boats.
In the meantime, limited sardine catch for use as live bait will be allowed in Southern California to service the region's sportfishing industry. Commercial fishermen may keep a small amount of sardines as incidental catch — below 20 percent — when fishing for other types of fish.
“You have to make decisions to protect the stock," said Griffin. "But also do what you can to protect these small fishing dependent communities."