Eucyclogobius newberryi, the tidewater goby, is a Federally
Endangered species endemic to coastal lagoons and estuaries in California.
Little is known about the biology of this species in northern California; thus
we conducted a 14- month study (November 2004-December 2005) to
assess spawning time, fecundity, habitat utilization, and parasites of a
northern California tidewater goby population in Big Lagoon, Humboldt
County, CA. The presence of individuals less than 20 mm indicated that
spawning occurred every month except March and April. Gravid females
were observed in March and May-July 2005; fecundity ranged from 190 to
531 eggs. Goby habitat utilization was evaluated on a seasonal basis using
a stratified random sampling technique. High goby densities were
associated with vegetation in silt and sand substrates. Minimum population
estimates of tidewater gobies in the southern end of Big Lagoon were
highest in winter 2005 (N=2714) and lowest in fall 2005 (N=163).
Parasitological analysis revealed the presence of a newly described
microsporidian species infecting muscle tissue of the tidewater goby. A
total of 105 of 1513 fish were visibly infected. Visibly infected gobies
ranged in total length between 19 and 56 mm and were observed in every
month except February 2005.