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Selective removal of sea lamprey via behavioral guidance in a model fishway: a proof of concept test
J.B. Hume1, C.M. Wagner1, M.C. Lucas2, U. Reinhardt3, P. Hrodey4, and T. Castro-Santos5
1Room 13, Natural Resources Building, 480 Wilson Road, Michigan State University, East Lansing, MI 48824.
2Durham University, School of Biological & Biomedical Sciences, South Road, Durham, England, United Kingdom DH1 3LE.
3Eastern Michigan University, Biology Department, 403A Mark Jefferson Science Complex, Ypsilanti, MI 48197.
4U.S. Fish & Wildlife Service, Marquette Biological Station, 3090 Wright St, Marquette, MI 49855.
5US Geological Survey, Conte Anadromous Fish Research Center, One Migratory Way, PO Box 796, Turners Falls, MA 01376.
Restoration efforts of native fishes that spawn in Great Lakes tributaries are hampered by the necessity of restricting sea lamprey access to similar spawning habitats with in-stream barriers. Our goal was to establish the feasibility of a “Pass-and-Trap” approach to selective fish passage as a mitigating solution to this problem; by developing criteria whereby sea lamprey upstream movement remains restricted while permitting the passage of native species through a barrier. Previous GLFC-funded research revealed sea lamprey can exploit physical circumstances other fishes cannot (ascending inclined surfaces called eel ladders) and be behaviorally manipulated in such a way as to alter their upstream movement tendencies (application of a putative alarm cue). Together, both features could enable the development of a “Pass-and-Trap” fishway, one which comprises two channels to simultaneously pass native and desirable species while entraining and removing sea lamprey from another. We demonstrated that a large proportion of sea lamprey, when constrained in proximity to an eel ladder, could be removed from a stream mesocosm (total 62.7%, n = 188/300; 97.9% of those approached the eel ladder, n = 188/192). We also demonstrated that white sucker would not be removed by this device (0% trapped). Thus establishing the viability of an eel-ladder trap as a selective sea lamprey removal device. When a low-flow vertical slot fishway was activated with alarm cue, we demonstrated 100% blockage of sea lamprey could be achieved, and this odor did not prevent passage of white sucker through the vertical slot, which achieved 100% passage. Thus, we established the viability of this odor as a selective behavioral deterrent to sea lamprey seeking passage through a fishway. We successfully established several design criteria that should be considered for future implementation. Specifically where positioning ‘Pass’ and ‘Trap’ channels in conjunction with any sea lamprey barrier. 1) A concentration of sea lamprey alarm cue of 1 PPM is sufficient to achieve 100% blockage of the species attempting to pass through an open channel, for a minimum of 4 hours. 2) This odor does not retard or prevent upstream movement tendencies in sea lamprey, which were found to rapidly move upstream in its presence seeking alternate routes past. This should ensure that traps positioned adjacent to areas activated by the cue will remain available to sea lamprey. 3) The alarm cue appears species specific as white sucker passage through an area activated by the cue was 100%. 4) An eel ladder set at 45° and a length above the water surface of > 1 m did not deter sea lamprey ascent, but did prevent ascent of white sucker. 5) Attempts should be made to constrain sea lamprey to areas close to the eel ladder to ensure maximum efficiency, as when constrained capture rate is significantly higher (97.9% vs 14.5%, n = 18/124). When given larger areas to explore sea lamprey will seek alternative routes past a barrier, therefore to improve trap efficiency in Pass-and-Trap designs encounter rate with the removal device should be maximized.