Sporadic Events

Anchovy Die-Off in Santa Cruz Harbor (2013)

Northern Anchovy. Photo credit: Dr. Steve Lonhart, NOAA MBNMS.

September 2013 was a busy month in Monterey Bay — whales and birds have been flocking to the waters just off Santa Cruz, chasing an abundance of forage fish. Very large schools of anchovies have been in close to shore, and these bait fish are in important part of the marine food chain.

Unfortunately for several thousand anchovies, in October 2013 they made a wrong turn and headed into the Santa Cruz Small Craft Harbor, triggering a widespread die-off when they could not leave the oxygen poor waters of the harbor. Numbers of dead fishes were so high that it briefly halted harbor paddling and boating activity.

“It was a die-off and it was an inconvenience, and it could have been much worse,” Port Director Lisa Ekers said.

Four massive anchovy kills have been documented in harbor history: in 1964, 1974, 1980 and 1984. Each one forced the removal of 1,000 to 2,000 tons of stinky fish, and the Port District has been after solutions for more than a decade.

The harbor installed 30 aerators to replenish closely monitored oxygen levels in the water. And Ekers noted conditions have to be right — large numbers of fish, little tidal action or wind and a hot sun — for the population to collapse.

“Normally fish can swim in and out of here,” Ekers said. “This one was unusual in that it wasn’t that large of a school, and it died off suddenly.”

The harbor was briefly closed to paddlers, and the boat launch was closed for a spell while Port officials assessed the problem. It was opened a short time later. Most of the carcasses were taken to a landfill.

To see the original newspaper article, click here.