A large (~50mm) adult tidewater goby (Eucyclogobius newberryi)

postlarval juvenile tidewater goby (Eucyclogobius newberryi)

Biologist Greg Goldsmith surveys isolated pool habitat containing tidewater goby (Eucyclogobius newberryi)

Greg Goldsmith
Arcata Fish and Wildlife Office
A parasite not previously known in the federally-endangered tidewater goby (Eucyclogobius newberryi) was recently described in a scientific paper co-authored by Arcata Fish and Wildlife Office (FWO) Biologist Greg Goldsmith. Published in the June issue of the Journal of Parasitology, the paper describes the life cycle, morphological features, phylogenetic relationships and genetic divergence of the parasite Kabatana newberryi. The paper also indicates that scientists are uncertain what range of impacts may be caused by this parasite and that more research is needed to determine if it is contributing to declines in tidewater goby throughout its range.

The tidewater goby is a species endemic to California coastal lagoons and estuaries. It ranges from Tillas Slough (mouth of Smith River, Del Norte County) south to Agua Hedionda Lagoon (San Diego County). Historic records suggest that the tidewater goby once occurred in as many as 134 locations. There are currently 96 known populations, of which 23 are thought to be unstable. The tidewater goby was first considered threatened by the State of California in 1987. By 1994, the tidewater goby was classified as an endangered species under the U.S. Endangered Species Act.

K. newberryi was first discovered in Big Lagoon, Humboldt County, by Greg Goldsmith during routine presence/absence surveys for the tidewater goby. Very little is known regarding organisms that parasitize the species. There is only one other documented parasite that infects the tidewater goby (a trematode, Cryptocotyle lingua), which has also been documented by Greg during surveys of tidewater gobies in the north coast region of California.

K. newberryi is a microsporidian, which is a primitive single-celled type of fungi. These organisms are obligate parasites with diverse life cycles that are very host-specific. In this case, the parasite infects the muscle cytoplasm of the host, eventually weakening the host animal, and eventually causing its death.

The Arcata FWO has an as yet unfunded proposal from another of the co-authors to conduct research into the prevalence of K. newberryi throughout the range of the tidewater goby. We also continue to watch for visible evidence of the parasite while conducting tidewater goby surveys.

The full journal article is available for viewing at  http://www.bioone.org/archive/0022-3395/93/3/pdf/i0022-3395-93-3-655.pdf