Exotic fish species and their impacts on small coastal lagoons in Southern California. (Abstracts).
Both freshwater and estuarine exotic (non-native) fish species
impact small souther California coastal lagoons. In the seven small
lagoons (0.5-50 hectares) on Marine Corps Base Camp Pendleton, the
larger of these lagoons are more impacted by exotics because they have
larger drainages upstream that support freshwater exotic, primarily
mosquitofish, sunfishes and black basses, and catfishes. The smaller of
these lagoons have fewer upstream sources and more seasonal drying
upstream that impede downstream movement by exotics. Marine invasion has
been documented for two exotic species, yellowfin goby and striped bass,
both particularly facilitated by the latest El Nino-La Nina cycle. The
El Nino coincided with a large increase in yellowfin goby recruitment in
the Santa Margarita estuary and the only occurrence of this goby in
several smaller systems. Increased numbers of striped bass arrived later
during the following La Nina. There appears to be a strong negative
correlation of mosquitofish with tidewater goby s uccess at some sites.
The federally endangered tidewater goby appears to do best in the
smallest sites without mosquitofish. The striped bass were few in number
and apparently had little impact and the increase of yellowfin gobies
was relatively short lived, as the influx of other southern native
forms, that their effect was relatively fleeting.
Camm C. Swift (1) and Dan C. Holland (2)