Tiny Coastal Fish May Lose Some Protection

Tidewater goby | Photo: USFWS/Flickr/Creative Commons License

A two-inch fish found only in tidal estuaries along the California coast may get less protection under the law if a proposal by the nation's leading wildlife agency goes through.

The U.S. Fish and Wildlife Service is proposing to remove the tidewater goby (Eucyclogobius newberryi) from its current status as Endangered under the U.S. Endangered Species Act (ESA), placing the fish instead on the Threatened list. That would give the species less stringent protection from management activities that might result in injury to individual fish.

The goby was added to the endangered list in 1994, as the result of an extended drought in the early 1990s that shrunk the species' coastal lagoon habitat. The proposal to downlist comes after what USFWS calls a three-fold increase in populations of the fish, though its main cause would seem to be a petition from ESA opponents the Pacific Legal Foundation.

USFWS's proposal kicks off a public comment period that runs until May 12, 2014.

It's hard to think of a fish more closely tied to the California coast than the tidewater goby, whose total global range historically ran from Tillas Slough, three miles south of the Oregon state line in Del Norte County, to Agua Hedionda Lagoon in San Diego County, just 44 miles north of Mexico. They tend to inhabit lagoons and estuaries where mixing freshwater and seawater provide a wide range of salinities: while the fish can tolerate water significantly saltier than the ocean, they seem to prefer to hang out in water about a third as salty as seawater, given the choice.

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The best breeding habitat for tidewater gobies seems to be the calm, flatwater lagoons that develop behind coastal sandbars, though the fish tend to retreat upstream in summer when those lagoons become stagnant. Winter storms can occasionally flush all the gobies in a stream out into the open ocean when the flood cuts through the protective sandbar. Fortunately, the fishes' tolerance of salinity allows them to seek out other estuaries nearby. That trait has allowed the species to spread up and down the California coast.

The biggest historical threat to the tidewater goby has been human development of its wetland habitat. As much as 90 percent of California's original estuarine wetlands have been damaged or destroyed. San Francisco Bay, once a stronghold for the species, now has no tidewater gobies living in it. Invasive species, such as the killifish and yellowfin and chameleon gobies that likely outcompeted San Francisco Bay's population of tidewater gobies, offer an additional threat. So do pollutants in runoff from urban storm drains and farm fields: The Salinas River's tidewater goby population was probably killed off by sewage discharges into the river.

Sometimes management for other wildlife has been a problem for the goby, as with the Bolsa Chica wetlands in Orange County. Permanent breaching of that estuary's sandbar augmented habitat for shorebirds, but essentially extirpated the tidewater goby from the lagoon.

But USFWS maintains that numbers both of the fish and of its viable populations are higher than they'd thought when the species was listed in 1994 suspected. The agency also says that the gobies bounce back better from drought than had been suspected. Here's hoping they're right, especially this year.

If the USFWS' proposal is implemented, the main effect will be to give the State of California's agencies more latitude in managing the fish. That's certainly less troubling than a complete delisting, but given the political pressure put on California wildlife agencies by the state's increasingly regulation-intolerant governor, it's worth keeping a close eye on the state's Department of Fish and Wildlife should the downlisting happen.

For ongoing environmental coverage in March 2017 and afterward, please visit our show Earth Focus, or browse Redefine for historic material.
KCET's award-winning environment news project Redefine ran from July 2012 through February 2017.

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