THE OUTDOORS : Research Programs at Redondo Beach and San Diego Raise Saltwater Offspring to Restock Ocean : Halibut, Sea Bass Are Fish for the Future
Qualifying on the merits of popularity and decline, two groups of fish have for the last four years starred in a program to help assure the future of their species.
One group, white sea bass, a member of the croaker family, is kept comfortable in a large tank here on the water’s edge at Mission Bay. Farther north, a school of California halibut does its thing in a marine laboratory behind the locked doors of the Edison Power Plant in Redondo Beach.
Both are induced to spawn as productively and as often as possible, and together they could become forerunners of a new strategy in fisheries management, whereby adult game fish act as broodstock for a “raise and release” policy for declining species of saltwater fish.
The ultimate goal of the researchers involved in the two projects, cumulatively known as the Ocean Resources Enhancement and Hatchery Program, is to enhance populations of marine fish for sport and commercial values, starting with the capture of adults for broodstock and ending with the release of juvenile fish into the ocean.
“I want to see the oceans of the world filled and brimming over with fish,” State Sen. Larry Stirling (R-San Diego) said after watching the release of 9,000 white sea bass fingerlings into Mission Bay last September, while he was still a state assemblyman. “I am looking forward to the day when we have marine fish hatcheries which will positively impact our marine resources and significantly add to the food supply and economy of the world.”
In 1984, Stirling sponsored the legislation that resulted in the program. And although his dream may be far from reality, specialists here at the Sea World Research Institute-Hubbs Marine Research Center and at the Edison marine laboratory have made what they call significant strides in the last four years--proving that it is possible to raise saltwater fish in a hatchery environment.
Dr. Robert Lavenberg of the Los Angeles County Museum of Natural History, who heads the halibut project in a makeshift hatchery on Edison property adjacent to King Harbor’s boat yard, said that since the program began, his staff has turned loose about 50,000 small halibut into Anaheim Bay and Marina del Rey.
Donald Kent, who heads the white sea bass project, said that after a series of smaller releases, his project in 1987 expanded from an experimental to what he called a pilot stage with the completion of a culture system designed to produce 15,000 juvenile fish per crop. The next release, of 15,000 fish, is scheduled for later this month.
Such releases are aimed at gaining more information about the fishes’ habitat, feeding habits and ability to survive.
“The basic premise is to see if it makes sense to restore the fisheries,” said biologist Steve Crooke of the Department of Fish and Game.
The primary concern among officials is whether such a program can be carried out on a much larger scale and be cost-effective in the bargain.
Initial results of a model program suggest that it would cost 25 cents to produce a juvenile white sea bass, 78 cents to raise a fish to release size and $4 to raise a “legal” fish of 28 inches. Studies show that largely because of the halibut’s higher natural mortality rate, a legal-sized fish of 22 inches could cost up to $8.
Even so, Kent believes that a full-scale hatchery capable of producing up to 2 million juvenile fish a year would be worthwhile in the long run because such facilities “could help reduce the billions that American pay each year for foreign fish imports.”
Said Crooke, citing the need for further field investigations and releases: “I think we need the program to continue for about three more years to get the answers. There’s still a lot we don’t know.”
Funding, which for the most part has come from the sale of fishing stamps that accompany sport and commercial fishing licenses, is scheduled to run out at the end of 1989, but Stirling is expected to introduce additional legislation that would extend the stamp for three more years.
White sea bass and California halibut were picked because, Crooke said, “we had to have species that are caught by both commercial and recreational fishermen, and species that looked like they were in trouble.”
The white sea bass, prized for its fighting ability and taste, certainly fits those requirements. Catches of white sea bass, once a primary target of Southern California sportfishermen, have been mostly incidental in recent years.
According to the most recent marine recreational fisheries statistical survey, sportsmen caught just 616 fish in 1987, down from the 1,604 caught in 1980. Kent said that locally in the 1940s, about 70,000 were being caught annually, adding: “And the effort has gone up since.” Commercial catches off the California coast dropped from 294,691 pounds in 1978 to 110,000 pounds last year.
Kent said that increased fishing pressure and destruction of habitat--primarily in and around coastal estuaries--were primary factors for the species’ growing scarcity.
On the far corner of Sea World’s 135-acre marine park, Kent has 20 adult white sea bass that he uses as broodstock. Temperature and light conditions are monitored and kept at optimum levels to induce spawning, which Kent said occurs three to five times a season.
The fertilized eggs--a single spawn may produce more than a million--float and are filtered out of the tank and collected in a basket and put in another tank. The fish spend about four days feeding on their own yolk sacks, then begin eating microorganisms called rotifers and algae, also cultured in large test-tube-like cylinders at the facility.
“We had to learn how to grow algae by reading available literature, and now we’re presenting papers on it,” Kent said. “We’ve learned how to grow fish, all the way down to the organisms they eat.”
Young white sea bass are kept in a greenhouse and range from less than an inch to 3 or 4 inches and are “graded” according to size for their own protection.
“They’re cannibalistic,” Kent said, pointing to one fish with another halfway down its gullet. “We learned the hard way that you have to separate them according to size as best as possible.”
After about three months in captivity, the fish are released into Mission Bay.
The California halibut, also a favorite among Southland fishermen, is in much better shape than the sea bass, although stocks have declined.
“Right now, halibut don’t need enhancing,” Crooke said. He said its selection was based on the poor catch rates in the years just before the program began.
Crooke said the decline was most likely caused by the warm-water El Nino current that wreaked havoc on several fisheries in 1982 and 1983. Recreational fishermen in 1983 caught just 30,000 halibut, but catches increased to 120,000 in 1986, a number that has remained fairly constant since.
“We still don’t know if the fish moved north (during El Nino) or what,” Crooke said.
Though the halibut project, which includes 12 adult halibut as broodstock, has received less attention and much less funding--one of its biggest fund-raisers has been the annual Santa Monica Bay Halibut Derby, which contributed more than $7,000 last year--it has been moving along at about the same pace.
“We are able to produce large quantities of 2-month-old halibut, which are about three-quarters of an inch long,” project manager Dena Gadomski said. “We released 20,000 last year and will probably release many more this year.”
Through the program, a great deal has been learned about the species.
“In the last four years, we’ve developed the know-how to spawn halibut in captivity,” Lavenberg said. “This year we have also learned where to release them.”
Lavenberg, who says juvenile halibut prefer near-shore areas and therefore are extremely vulnerable to coastal development and pollution, has ruled out Marina del Rey for future releases because it’s too polluted.
The survival rate of the young halibut in captivity has improved from about 10% in 1986 to between 50% and 75% in 1988, Gadomski said.
Considering the shape of most marine fisheries--the number of fish of various species caught off the California coast aboard party boats between 1975 and 1985 declined 58%, while commercial fishing dropped 44% in the same period--the program, if nothing else, appears a step in the right direction.
“It’s time to take pressure off the ocean and to (restore the fisheries) directly,” Kent said. “(Marine hatchery programs) hold tremendous promise for the future.”
