A newly described species of microsporidium, Kabatana newberryi, (McGourty
et al. 2007) infected the Big Lagoon tidewater goby study population. Infection was
indicated by white globular structures just beneath the epidermal surface; 7 % (105/
1,513 individuals) of the sample population were visibly infected. This represents a
minimum infected rate as individuals are likely infected but the microsporidium are too
small to be visually discerned. Visibly infected individuals were found every month
of the sampling period except February 2005 (Fig. 11). The range in TL of visibly infected
individuals was 19-56 mm and the average TL of visibly infected individuals was 37.3
mm (Fig. 12). This suggests that Kabatana newberryi, at a relatively advanced state
of infection, occurs in settled-out larvae as well as adults at nearly all times of the year
in Big Lagoon.
A similar visible infection of white globular structures just beneath the epidermal
surface has been observed in populations throughout Del Norte, Humboldt, and
Mendocino counties and Rodeo Lagoon, Marin County (G. Goldsmith, unpublished
data; D. Fong, National Park Service, personal communcation). Histopathological
effects of these microsporidia on the tidewater goby are currently unknown. Further
investigation is needed to determine how this microsporidium may impact the long-term
persistence of the endangered tidewater goby.