Point Reyes Light - August 26, 1999
Tide more brown than red
Expansive burgundy-colored plankton blooms - a so-called red tide - have appeared recently in the waters around Point Reyes. The blooms, however, have not produced any significant level of toxins.
Signs at access points to the Point Reyes National Seashore warn the public of the dangers of collecting shellfish to eat. Such warnings, said park biologist Sarah Allen, are part of an "annual event." A state ban on the "sport" harvesting of mussels along all California coasts and bays remains in effect until October 31.
Gregg Langlois, a State Health Department biologist, said that only very low levels of toxin have been found in Tomales Bay, and that the commercial oyster industry remains unaffected.
"The blooms that we have seen in the past few months are fairly routine," Langlois said. "It's more of a brown tide."
He explained that the chances for finding toxigenic plankton species increases during blooms that are more reddish-brown in color, and that more elevated counts were recorded in the region a few weeks ago.
Local oyster farmers work in conjunction with State Health to test the waters for potentially harmful red tides. According to Langlois, the department provides oyster companies, such as Johnson's and Hog Island, with a microscope, field scope, and net, so that producers can read sample results more frequently.
John Finger, co-owner of Hog Island Oyster Company, confirmed that blooms like the current "brown tide" pose no threat, but added that they can occasionally be a problem for oyster seed.