Moss Landing >> A mysterious neurotoxin that can poison Monterey Bay marine life has returned with a vengeance.

Scientists working on an ongoing study of toxic algae blooms have detected very high levels of domoic acid, which can accumulate in small fish and eventually sea lions, birds and even humans. Anchovies found on the beach in Moss Landing were showed to have excessive amounts, and levels have spiked in mussels on the Santa Cruz Municipal Wharf.

“This is an unusual one,” said Raphael Kudela, a UC Santa Cruz ecologist who is leading the study. “We haven”t seen a bloom this big in 15 years.”



Domoic acid is produced by a naturally occurring algae called pseudo-nitzschia, but why the toxin periodically blooms in Monterey Bay is still a marine mystery. Conditions that the algae seem to like — warmer overall water temperatures and a slight upwelling of deeper waters in Monterey Bay — are in place.

But Kudela said scientists are getting closer to pinning down the reason for the blooms, with human impacts among the range of possibilities.

One reason scientists are close is because of instruments like the Environmental Sample Processors, a 55-gallon drum-sized floating laboratory that analyzes microbes in the water. The devices were developed by Chris Scholin, the head of the Monterey Bay Aquarium Research Institute, and barely a dozen are in place around the world at any given time.



Two of the so-called ESPs are currently positioned in the bay: one south of Soquel and the other near Monterey. They take in water samples and perform DNA-level analysis of microbes, giving near continuous feedback (at least until the 360 D-cell batteries used to power them run out of juice).

The ongoing study is led by UCSC, MBARI, the National Oceanic and Atmospheric Administration and more. The ESPs are anchored and rest about seven to 10 meters below the surface, transmitting data through a cellular modem that sits in a buoy on the surface.



“If you know the IP address you can tunnel in from anywhere and see what”s going on,” said Jim Birch, director of MBARI”s Director of the Sensors Underwater Research of the Future (SURF) Center.

Kudela said the ESPs should help answer the mystery behind the blooms, especially since scientists were able to track the growth of this year”s bloom, which began after the processors were placed in the water.

“We really think that this year we”ve got the perfect data set to start answering some of those questions,” Kudela said.



The Moss Landing anchovies tested recently had exceedingly high domoic acid levels, and mussels in Santa Cruz had doubled in toxicity. Domoic acid is also suspected in a recent spate of bird deaths.

In addition, Sausalito”s Marine Mammal Center — which is already handling an influx of starving sea lions — is seeing a few cases of domoic acid poisoning, which can cause obvious neurological symptoms. Once treated, the sea lions are being released into cooler waters there, a representative of the center said.



By itself, domoic acid poses almost no threat to humans. But the toxins accumulate in shellfish and small forage fish and on up the food chain, concentrating in larger fish, marine mammals and sea birds.

While it can be harmful to human who eat poisoned fish, an annual quarantine of sport-harvested mussels went into effect May 1, and federal fishery regulators closed the sardine fishery in April due to low numbers.

Jason Hoppin can be reached at 726-4363.

