Testing assumptions required to estimate lake-wide parasitic sea lamprey abundance

LEPSL

October 2015 - December 2018

Sea lamprey population control and assessment could be improved by increased understanding of ecology and population dynamics between parasitic and spawning phases. For example, understanding factors that influence timing of entry into spawning streams could guide development of interception trapping. Further, accurate estimates of lake-wide parasitic sea lamprey abundance could an objective evaluation of control-program effectiveness. Previous attempts to estimate the number of parasitic sea lampreys in a lake resulted in estimates that were biased (inaccurate) because key assumptions were violated. We consider each assumption as a research question to be evaluated prior to implementing lake-wide mark-recapture (e.g., using coded-wire tagged sea lampreys). If assumptions are supported, mark-recapture methods may provide estimates of lake-wide adult sea lamprey abundance. Acoustic telemetry will be used at two life stages (parasitic juvenile and adult) to address the determine if: (1) timing of stream entry is related to stream water level, stream water temperature, lake water temperature, or photoperiod; (2) survival to stream entry is related to release location; (3) spawning stream selection is related to release location; and (4) acoustic tagging affects survival. Acoustic receivers (Vemco VR2W; 69 and 180 kHz) in 15 Lake Erie tributaries, incl. Detroit R., will provide time and direction of tributary entry and exit. Lampreys (n=140 per life stage per year) will be implanted with coded wire and acoustic tags and released at 7 locations in L. Erie in early winter (parasitic juveniles) and early spring (adults) 2015-16, 2016-17, and 2017-18.

• Determine if stream entry timing is related to stream water level, stream temperature, lake temperature, or photoperiod. Determine if survival is dependent upon release location. Determine if spawning stream location is dependent on release locati
• Determine if survival is dependent upon release location.
• Determine if spawning stream location is dependent on release location.
• Determine if probability of recovery in traps is related to acoustic-tagging.

• Results from this project are expected to (1) show if lake-wide parasitic sea lamprey abundance estimates can be obtained using relatively simple mark-recapture methods; (2) direct new capture methods (e.g., interception traps or nets) to tributaries and times when sea lampreys are most likely to be caught; and (3) show the proportion of adult sea lampreys in Lake Erie that enter each tributary to spawn, including the Detroit-St. Clair River System.

• Christopher Holbrook (United States Geological Survey - Hammond Bay Biological Station) - cholbrook@usgs.gov
• Michael Hansen (United States Geological Survey)
• Nicholas Johnson (United States Geological Survey)
• Scott Miehls (United States Geological Survey)
• Gale Bravener (Fisheries And Oceans Canada)
• Jessica Barber (United States Fish And Wildlife Service)

• United States Geological Survey
• United States Fish and Wildlife Service
• Department of Fisheries and Oceans Canada

• Great Lakes Restoration Initiative
• Great Lakes Fishery Commission