LOS ANGELES (AP) — Three weeks after a huge fish die-off in Southern California, officials have a fish count but still can’t say what drove 175 tons of sardines into a marina.

Dave Caron, professor of biological sciences at the University of Southern California, said Thursday that as many as 2.5 million sardines blanketed the surface and floor of King Harbor Marina.

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After the fish surfaced on March 8, about 700 volunteers and city workers scrambled to remove the remains to ease the threat to other sea life.

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Redondo Beach City Manager Bill Workman says crews may have gotten some unexpected help from the tsunami in Japan, which caused tidal surges and flushed fish out of rocks and crevices.

Workman estimates the cleanup will cost at least $300,000.

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