Masters Thesis

Spawning time, fecundity, habitat utilization, and parasites of Eucyclogobius newberryi in Humboldt County, Big Lagoon, CA

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. We conducted a 14-month study (November 2004-December 2005) to determine spawning time, fecundity, habitat utilization, and parasites of a tidewater goby population in Big Lagoon, Humboldt County, CA. Spawning time was determined by monthly length-frequency data and by the presence of gravid females. Spawning occurred throughout the year. Two distinct age classes were observed in June-August 2005. Gravid females were collected in March and May-July 2005. Goby habitat utilization was evaluated using a stratified random sampling technique on a seasonal basis. High goby densities were commonly associated with vegetation in silt and sand substrates. A previously unrecognized microsporidian is described from the musculature of Eucyclogobius newberryi. Spores are ovid with mean length=2.8 um and mean width=1.9 um. The polar tube has 9 or 10 coils in 1 or 2 rows. Development occurs in direct contact with muscle host cell cytoplasm, without xenoma or sporophorous vessicle formation. Phylogenetic analysis of the new species and of 35 other microsporidians known to infect fish using 1115 bp of aligned 16S rRNA gene indicate the new species is most closely related to Kabatana takedai, with 11% sequence divergence. Divergence in morphology and genetic data supports recognition of a new species of microsporidia, Kabatana newberryi n.sp., presently known only from Eucyclogobius newberryi.

Relationships

Items