Salmon Feeding In San Pablo Bay
by Alastair Bland, May 13, 2010
Each week during the spring along the shores of San Pablo Bay, tanker trucks hired by the Department of Fish and Game (DFG) deliver thousands of Chinook salmon smolts, born in hatcheries upstream, to strategic sites where the fish are released into the murky waters and, hopefully, into a future that includes a spawning run up the Sacramento River.
While the release effort, conducted in collaboration between the DFG and an organization called the Fishery Foundation of California might otherwise be applauded by fishermen, its critics say the annual juvenile salmon releases, which began this year on April 5, are sabotaged week after week by rapacious striped bass and ravenous sea birds. For years, in fact, appalled fishermen have denounced the effort as one of wasted salmon smolts and the tax dollars used to breed them.
“It seems such a shame to spend all this time and energy raising these fish and then just feed them to the bass and birds,” said Gordon Hough, a party boat captain who keeps his vessel Morning Star at the Crockett marina just yards from one of Fishery Foundation’s three salmon smolt release sites. Hough says on April 20 he watched as scores of two-foot striped bass and swarming gulls devoured freshly released three-inch Chinook salmon inside the harbor just yards from his vessel.
But Fishery Foundation’s executive director Trevor Kennedy, who participates onsite in receiving and releasing the salmon smolts, says the bird and bass activity that sometimes occurs around the release sites looks more devastating than it is.
“The birds are crashing all over the water, but they’re mainly lunging at shadows,” said Kennedy. He said that striped bass predation can be a problem when the smolt releases take place several days in a row at the same place — which happened at Crockett the week of April 12. That week, Kennedy said, difficult tidal and weather conditions prohibited him and his two assistants from receiving and releasing the fish at Fishery Foundation’s two alternate sites, one across the Carquinez Straits near Mare Island and one just north of the Antioch bridge.
Hough says he saw the action that accompanied the smolt releases.
“They let the fish go in the same spot at the same time each day,” he said. “It took the bass and gulls about one day to figure this out, and the rest of the days they were waiting.”
Prior to their release, the juvenile salmon spend up to two hours in floating acclimation net pens — a concept innovated by Fishery Foundation in 1993 and used ever since — where they adjust to the saltwater and recover from the truck ride. The time spent in the pens allows the fish to regain their mobility and capacity to evade predators before they enter open water.
“When you release these fish when they’re acclimated, it minimizes predation,” said Kennedy.
Yet bass feeding frenzies do occur as the fish leave the pens, which Kennedy and his crew slowly tow behind a boat into deeper waters away from the shore before opening. In fact, fishermen have known for years that smolt release days can mean excellent striper fishing. Mike Andrews, skipper of the party boat Predator in Vallejo, regularly zeroes in on the action with boatloads of paying clients.
“Last week when they released them it was very good striper fishing,” said Andrews. “You can often limit out in just minutes. The fish get really active at around 11 o’clock when the trucks show up.”
When cleaning and filleting his customers’ fish after recent days of fishing near Crockett, said Andrews, most of the stripers’ stomachs contained from one to six salmon smolts.
Until 2007, Fishery Foundation used just the Crockett site for releasing the fish, which are hatched at several state and federal facilities upstream of the Delta. Beginning in 2007, in response to criticism, Fishery Foundation adopted the use of the Mare Island site and this year the Antioch location was incorporated into the rotation. The three-site switch-up works well at foiling ambushes from predators, said Kennedy.
In past years, Fishery Foundation has released as many as 21 million smolts — and, amidst the criticism of Fishery Foundation’s program, some sources believe that a great many of these baby salmon survive and eventually spawn, ultimately providing a tremendous boon to the abundance of the species. A positive correlation between the numbers of smolts released by Fishery Foundation and the numbers of salmon that return three years later to spawn in the Sacramento River lends credibility to this belief, they say. In 2006, for example, Fishery Foundation, lacking funding and equipment, acclimated and released zero smolts. Three years later, in 2009, the fewest fall run Chinook salmon ever recorded returned to spawn in the Sacramento. In 2004 and 2005, as well, the underfunded program essentially failed, said Kennedy. Three years later — in 2007 and in 2008 — salmon spawning returns were poor.
Ernie Koepf, a commercial fisherman who operates out of Berkeley, feels that Fishery Foundation’s program has been tremendously successful.
“There have been more salmon in modern times than in the 1950s and 1960s, and it’s because of these acclimation pens and hatchery fish,” said Koepf, who has accompanied the Fishery Foundation crew as they handle the baby Chinooks.
In past seasons, Fishery Foundation has released as many as 21 million salmon smolts into San Pablo Bay. This year, the team will be releasing truckloads of the fish until June, by which time Kennedy expects to have sent 14 million baby Chinooks into the Bay, and to a fate unknown.
(Special thanks to the East Bay Express.)