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Protecting a crop of underwater `crackers'

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One of California's newest farms has no farmyard, fields, or cows -- and it's 15 feet underwater. The experimental sea farm, built by marine biologists in San Francisco Bay, has only one crop -- seaweed covered with fish eggs. But if all goes well, that crop will be worth up to $20,000 a ton, and the farm may help preserve a fishing industry threatened by disappearing seaweed.

Dr. Judith Hansen, a marine biologist at the University of California, Santa Cruz, started the pilot farm in an effort to preserve the Bay Area's valuable kazunoko kombu fishery.

Kazunoko kombu -- a coveted Asian delicacy consisting of herring eggs on seaweed -- is created each winter when millions of fertile herring swim under the Golden Gate Bridge and into the bay to spawn. While herring lay their eggs on almost any surface, many will coat seaweed called kelp with layers of small, rubbery eggs. Within hours, the egg-frosted kelp is harvested, then pickled in brine.

Much of the crop is exported to Japan, where it is viewed as a delicacy. Dr. Hansen says, ``It's a type of caviar,'' selling for $8 to $20 a pound; the kelp serves as a cracker.

Although several tons of kazunoko kombu are harvested each year, this has little effect on future herring populations, Hansen says, because the eggs that are collected are likely to die anyway. Kazunoko kombu harvesters prefer kelp with 10 or more egg layers, and most of the eggs inside such thick masses die before they hatch.

While the herring aren't threatened, however, the kelp is. In the last decade, the ``cracker'' has begun to disappear from California's coastal waters, jeopardizing the kazunoko kombu industry. Although reasons for the kelp decline are not well understood, researchers say that natural cycles, pollution, changing weather patterns, and overharvesting of the state's natural kelp ``forests'' all may contribute to the losses.

Concerned about the decline, state fish and game officials asked Hansen to study ways to cultivate a kelp called Laminaria sinclarii. Particularly prized by kazunoko kombu harvesters, this kelp is scarce in the herring spawning grounds. Eventually, Hansen's research may lead to commercial kazunoko kombu farms, along with domestic seaweed ``nurseries'' that could restock wild populations. Already, officials in Canada and the state of Washington have expressed interest in Hansen's work, which was funded by the California Sea Grant program, a part of the National Oceanographic and Atmospheric Administration.


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