DETERMINING ADULT PACIFIC LAMPREY ABUNDANCE AND SPAWNING HABITAT IN THE LOWER DESCHUTES RIVER SUB-BASIN, OREGON
Citation
Matt Fox, Jennifer C. Graham, Department of Natural Resources Confederated Tribes of the Warm Springs Reservation, Oregon. 2008. DETERMINING LAMPREY SPECIES COMPOSITION, LARVAL DISTRIBUTION AND ADULT
ABUNDANCE IN THE DESCHUTES RIVER SUBBASIN, OREGON
Summary
An adult Pacific lamprey (Lampetra tridentata) escapement estimate was generated in the lower Deschutes River during run year 2008. This included a mark-recapture study to determine adult abundance and a tribal subsistence creel. Fish measuring less than 10.5 cm received two marks for the mark-recapture estimate while those measuring greater than 10.5 cm were surgically implanted with radio transmitters to monitor migration upstream of Sherars Falls (rkm 70.4). Radio telemetry was used to determine habitat, focal spawning areas and spawn timing. All fish were collected at the Sherars Falls fish ladder from July – October 2008 using a long handled dip-net. Escapement was generated using a two event mark-recapture experiment. Adult lamprey [...]
Summary
An adult Pacific lamprey (Lampetra tridentata) escapement estimate was generated in the lower
Deschutes River during run year 2008. This included a mark-recapture study to determine adult
abundance and a tribal subsistence creel. Fish measuring less than 10.5 cm received two marks for
the mark-recapture estimate while those measuring greater than 10.5 cm were surgically implanted
with radio transmitters to monitor migration upstream of Sherars Falls (rkm 70.4). Radio telemetry
was used to determine habitat, focal spawning areas and spawn timing. All fish were collected at
the Sherars Falls fish ladder from July – October 2008 using a long handled dip-net. Escapement
was generated using a two event mark-recapture experiment. Adult lamprey populations were
estimated at 3,471 (95% CI = 2,384-5,041; M = 101; C = 885 R = 25) using Chapman’s
modification of the Peterson estimate. The relative precision around the estimate was 31.42. Tribal
harvest was approximately 806 adult lamprey (95% CI= +/- 74) with a total escapement of 2,669.
Fourteen lamprey received radio tags and were released at Lower Blue Hole recreation site (rkm
77.3). Movement was recorded by mobile, fixed site and aerial telemetry methods. Upstream
movements of lamprey were documented from July through December 2008 with most lamprey
over-wintering in the mainstem Deschutes River.
