Biology of the Redtail Surfperch (Amphistichus Rhodoterus) from the Central Oregon Coast

by Donald E. Bennett, Richard S. Wydoski

1977

Data on certain aspects of the life history of the redtail surfperch were collected along the central coast of Oregon, from April 1967 through April 1969. Annulus formation occured during February through June, usually earlier in young than in older fish. Mating occurred from late December to early January, and the young were born from July through September. The number of embryos per female ranged from 1 to 39 (mean 13.3) and increased linearly with the length and weight of the females. Food of the fish from the surf zone included crustaceans (by far the most important group in both frequency of occurrence and total volume) and (in order of decreasing importance) fishes, mollusks, and polychaetes. Parasites of the redtail surfperch were immature nematodes (Anisakinae) ; the digenetic trematode Genitocotyle acirra; the monogenetic trematode, Diclidophora sp.; and the copepods, Caligus sp., Clavella sp., and Argulus catostomi.

The Razorback Sucker, Xyrauchen Texanus, in the Upper Colorado River Basin, 1974-76

by Charles W. McAda, Richard S. Wydoski

1980

The razorback sucker, which has declined in abundance in the upper Colorado River primarily because of man's impact on the environment, has been recommended for listing as "threatened" in the U.S. Department of Interior's list of threatened or endangered species. During the present investigation, razorback suckers were nevertheless found in relatively large concentrations at two restricted locations -- the mouth of the Yampa River and a flooded gravel pit connected to the Colorado River near Grand Junction, Colorado.