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EFFECTS OF TRAP FUNNEL AND FINGER DESIGN ON SEA LAMPREY ENTRANCE AND RETENTION
†1Peter J. Hrodey, 2Gale Bravener, and 3Scott Miehls
1USFWS, Marquette Biological Station, 3090 Wright Street, Marquette, MI, 49855, USA
2 Fisheries and Oceans Canada, 1219 Queen Street East, Sault Ste. Marie, Ontario, P6A 2E5, Canada
3 USGS, Great Lakes Science Center, Hammond Bay Biological Station, 11188 Ray Road, Millersburg, MI 49759, USA
Traps are used to catch adult Sea Lamprey during their upstream migration, to estimate their abundance in streams, and in turn provide a measure of the Sea Lamprey Control Programís effectiveness.† During 2015 and 2016, we experimentally compared two components of Sea Lamprey trap design: trap entrance funnel type and presence of retention devices, using side by side in-stream test chambers as well as laboratory flumes. We modelled how likelihoods of entrance, retention and capture (the result of entrance and retention) were influenced by funnel type, retention fingers, water temperature, and lamprey sex. Likelihood of entrance was highest with bottom-oriented funnels and no retention fingers. As water temperature increased, the likelihood of entrance generally increased, but funnel type and retention fingers determined the magnitude of the increase. Likelihood of retention was highest with bottom-oriented funnels and retention fingers, and was also influenced by water temperature. The likelihood of capture was highest for bottom-oriented funnels, and varied by water temperature and lamprey sex, but not retention fingers. Further testing on other components of trap design is needed. This type of controlled experimental design can help guide future work to improve trap exploitation rate.