Tons of dead fish pulled from California marinaMarch 10, 2011 By ROBERT JABLON , Associated Press in Biology / Ecology
It could take a week - and the smell could get pretty bad - before crews manage to scoop and vacuum up tons of dead sardines from a Southern California marina.
Net-wielding crews in rowboats and firefighting vessels began work Wednesday, hoping to remove the estimated one million fish before they rot and possibly poison remaining sea life in the harbor.
The cleanup came after the enormous school of sardines apparently suffocated in the confines of King Harbor, possibly while seeking shelter from a predator or simply becoming lost near a breakwater late Monday.
Instead of leaving, the fish crowded toward the back of the Redondo Beach marina and used all the oxygen in the water, marine experts have said.
A fire boat experimented with possible ways of retrieving the silvery corpses carpeting the bottom of the marina, including blasting them with a fire hose so they popped to the surface, police Sgt. Phil Keenan said.
"Some places, we have upward of 2 feet of dead fish on the bottom," he said.
State Department of Fish and Game officials sent samples of the fish to a lab to determine why they died, and strongly suggested the fish just got lost before landing in the marina.
But that didn't stop speculation about what drove the sardines.
An initial theory had them moving away from a toxic algae bloom outside the harbor - a so-called red tide such as one responsible for killing millions of fish in Redondo Beach in 2005.
However, fish and game experts said no red tide was detected.
Others suggested high winds and rough seas drove the sardines to seek shelter, while waves washing over the breakwater flushed seagull excrement into the harbor that further depleted the oxygen.
Larry Derr, 55, owner of In-Seine Bait Co., scoffed at that idea, saying he has fished in rough water and gotten fine catches.
"These fish don't care about weather. They're not walking on the water," he said. "Fish can handle the wind."
In rough seas the sardines simply go into deep water, Deer said, "they're not going to go running to the harbor."
Derr believes the unlucky sardines were trapped by predator fish.
A few days ago, he saw the channel between the breakwater and marina filled with sardines, and behind them were large Pacific mackerel that love dining on the smaller sardines.
There were so many mackerel, "guys were able to scoop them by hand," Derr said.
Derr believes the sardines were chased into the marina and suffocated sometime after midnight, when the tide began going out, reducing water in the marina.
"Chances are, between the mackerel and the seals, the kind of got cornered," Derr said. "And when the tide started going out - end of story."
Twenty-two tons of dead fish were collected Tuesday on the surface, Keenan said.
Nearly 300 city workers and volunteers were busy Wednesday, scooping sardines from the surface to be sent to a composting facility. Redondo Beach is seeking volunteers to help with the rest of the cleanup, saying no experience is necessary and offering water, food and sunscreen.
City officials said it could cost up to $100,000 to clean up the 10-acre harbor.
Bill Smythe, 51, of Monrovia said he spent Sunday night on his moored 35-foot sailboat and heard a flapping sound from the huge number of fish around his boat.
He wasn't at the marina Monday night but later talked to neighbors who slept on their vessels and reported the sound of fish slapping around, desperately seeking oxygen in the depleted water.
"Everybody said it sounded like hail - all of the fish gasping for air," Smythe said.
Oxygen levels remained low in the stagnant water of the marina, and there was concern that unless the fish were collected within a few days, they would begin to decompose and release ammonia that could poison fish, crustaceans and other sea life, Keenan said.
Additionally, bacteria feeding on the bloated fish corpses could multiply and further deplete the oxygen.
A big concern would be the death of mussels that act as water filters and keep the marina clear, Deer said.
"The smell in three days is going to be horrendous," he said.
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"Tons of dead fish pulled from California marina" March 10, 2011 https://phys.org/news/2011-03-tons-dead-fish-california-marina.html