Striped Bass on the coast of California: a review

Abstract

Striped Bass (Morone saxatilis), a non-native, anadromous fish introduced to California in 1879, is a popular sport fish and piscivorous predator in the San Francisco Bay/Delta ecosystem, but comparatively little is known about its distribution and ecology in estuaries and rivers of the California coast. Here we review recent scientific papers, consultant reports, and correspondence to evaluate its distribution in coastal estuaries and rivers, evidence for local reproduction, and scope for impacts on native fishes, especially salmonids. Striped Bass is extremely rare in the ocean along the north coast, and has not turned up in extensive surveys of Humboldt Bay, the Eel River estuary, or the Russian River estuary. It is, however, a perennial feature of seining surveys in estuaries south of the Golden Gate and along Monterey Bay, usually sporadically and as a very small proportion of total catch. It has become quite common in the Carmel River estuary, and is occasionally caught in the ocean further south. Small upstream migrations, possibly for spawning, have been observed in the Salinas River and Carmel River, but no evidence of eggs or larvae has been found—perhaps due to a lack of ichthyplankton surveys anywhere except in Elkhorn Slough. However, the species’ reproductive ecology is not a good match to the hydrologic structure of most coastal stream systems, requiring a large long river where adults can spawn, in combination with an extensive, ramifying estuarine system where larvae can accumulate. One potential good match is the Salinas River system, especially in its historic form as the Salinas River/Old Salinas River Channel/Elkhorn Slough complex of the 19th century. Despite the modest presence of the species on the coast between the Golden Gate and Carmel, it still has scope for large impacts on emigrating salmonids, due to its extreme piscivory at larger size-classes and its ability to exploit migration bottlenecks as feeding grounds. Most likely the individuals observed in coastal estuaries originated in the San Francisco Bay/Delta system and use local systems opportunistically for foraging, but the hypothesis of local reproduction cannot be ruled out without further study.