What's In Your Watershed?

The Feisty Tidewater Goby

By Jan Steffe

Get out your calendars. May marks the beginning of the tidewater goby breeding season! As you read this article, the mating drama of this small fish is unfolding in the brackish water of lagoons, estuaries, and marshes near you.

It all starts when the male tidewater gobies construct breeding burrows in the sand and mud, shutting off access with a plug of sand and mucus. Sometimes the gobies even use empty oyster shells for their spawning ceremony. Next, the feisty females ferociously fight over the burrowed males, the prize being the opportunity to entice the male to open his burrow. A successful courtship results in the female laying eggs, which the male then protects for nine to ten days.

A tidewater goby lives an average of one year. Feeding on small crustaceans and insect larvae, they grow to be no more than two inches in length. Coloration is connected to the need for camouflage, as these fish are a tasty meal for larger fish and aquatic birds. Both male and female gobies are nearly translucent. The females also have a dappling of dark brown, olive, and black on their bodies and dorsal fins.

Found only in California, the species, Eucyclogobius newberryi, was first described in 1856. Historically, the tidewater goby could be found along the California coast, from the southern end just north of Mexico to the northern end slightly south of Oregon. The range has diminished in size, with populations currently found only on the northern California coast.

While the current Tidewater Goby population is secure, and in some areas even abundant, its need for a brackish water habitat, with a very specific salinity level of less than 10ppt, has landed this fish on many protection lists in California. Coastal development and droughts bear significant threats to Tidewater Goby populations. The introduction of non-native competitors and fish predators puts the population at further risk. However, all hope is not lost for the Goby. Habitat restoration and strict protection measures have rendered reintroduction attempts of the Tidewater Goby successful.