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The Problem
Severe water quality problems in Upper Klamath Lake, OR have led to concerns about how Lost River and shortnose suckers are distributed during the summer and whether suckers utilize areas of water quality refuge. Previous data collected the Bureau of Reclamation biologists indicate suckers are primarily located in the northern portion of Upper Klamath Lake during the summer months. This work provided good background information on habitat use and water quality parameters associated with fish locations. However, limitations to this data set include 1) tracking was conducted during daylight hours where dissolved oxygen conditions in the lake are typically better than at night, 2) water quality information was only available from fish locations and not available from other locations in the lake making it difficult to determine if fish were seeking out areas of better water quality, and 3) the sample sizes of tagged fish were relatively small year to year making comparisons between species or tagged individuals difficult. In 2001, the U.S. Fish and Wildlife Service identified the need to improve our understanding of how suckers utilize habitats in Upper Klamath Lake, particularly with respect to water quality. In 2002, the USGS initiated a joint study between the Klamath Falls Field Station and the Oregon District, Water Resources Office to examine the movements and behavior of radio-tagged adult suckers with respect to water quality conditions. Objectives Science objectives addressed include: 1) Determine the distribution and general movement patterns of radio-tagged adult Lost River and shortnose suckers in Upper Klamath Lake from June-September; 2) Determine specific movement rates of radio-tagged adult Lost River and shortnose suckers in Upper Klamath Lake from June-September; 3) Establish an array of fixed water quality monitoring stations that will provide the basis for a GIS model of the 1-m off-bottom water quality in the northern part of the lake; 4) Collect water quality profiles associated with individual locations of radio-tagged suckers; and 5) Establish the frequency, duration, spatial extent, and strength of vertical stratification with continuous datasets collected from a profiling buoy. Methodology About 100 adult suckers will be tagged during the first year of study (targeting equal numbers of Lost River and shortnose suckers of each sex) with digitally encoded programmable transmitters that will be turned on from approximately February to October. Because of the extended life of these transmitters, the study is planned to be continued for 3 years, with the possibility that additional tagging will be conducted between years to supplement sample sizes from individuals that may die or leave the study area. The proposed sample size of tagged fish allows for the possibility to randomly select individuals to locate and collect data on a weekly and perhaps daily basis, allowing for stronger statistical comparisons. Fish to be located will be randomly selected to allow greater inference of these results to the overall population. Also, the sampling design allows for the ability to test for individual differences before grouping observations from the tagged population. Boat-tracking surveys will be conducted both during daylight hours and during hours of darkness to determine if differences in behavioral patterns exist between day and night (e.g., depth distribution or distance to shore). Boat tracking surveys will be supplemented by aerial surveys to determine the locations of general congregations of fish.
In addition to implanting radio transmitters in fish, a sub-sample of fish will be tagged with archive tags capable of recording hydrostatic pressure and water temperature. Individual fish implanted with these tags will be recaptured after the summer and the tags will be removed. The information collected will provide a detailed history of the water depth exposure of the fish. Highlights and Key Findings Data collection for 2002 was completed in the end of September 2002. Analyses are still ongoing although preliminary data indicate adult suckers utilized different portions of Upper Klamath Lake during different times of the summer. Water quality information collected from both fixed monitoring stations and RUSS profiling stations are being incorporated into a GIS model to describe water quality conditions in the area of interest. Where Are We Headed In 2003 Work to be completed in FY 2003 will include the completion of the 2002 field season, data entry, proofing and processing of records, report preparation, field season preparation, tagging of additional study fish to supplement sample size in 2003, and continued data collection in 2003 following methodologies outlined in the Summary Narrative. Project Contact Rip Shively Email: rip_shively@usgs.gov Publications |
