Inventory of Reclamation Facilities where Lamprey Species Exist, Issues Confronting Lamprey, and How to Aid Fishways for Passage and Monitoring
* Is Reclamation prepared to address the imminent lamprey issue?
* Can we develop a lamprey data base to know where these species exist and what issues Reclamation will confront pending an Endangered Species Act (ESA) listing?
* Can we develop guidelines for Reclamation on how to effectively pass and monitor lamprey species?
Need and Benefit
Numerous Reclamation facilities in the Mid-Pacific (MP) and Pacific Northwest (PN) regions contain lamprey. Reclamation needs to inventory facilities where lamprey exist and determine what issues are hindering their existence at these facilities. Techniques to pass and monitor lamprey have not been fully developed. Currently, there are very few locations where adult lamprey passage and monitoring is occurring and those locations are where lamprey are incidentally caught or seen in salmonid traps or ladders. There are at least two species of lamprey that pass Reclamation facilities in the MP and PN regions to access vital upstream spawning waters. Reclamation facilities could preclude or hinder upstream lamprey passage affecting their life cycle, thus contributing to the decline of lamprey species.
Lamprey have a remarkable ability to use their sucker mouth to climb natural barriers and penetrate headwater areas that are not available to other anadromous fish. Therefore, it seems surprising that upstream passage barriers would be a problem for lamprey. However, lamprey are unable to cope with many artificial barriers. Lamprey are weak swimmers since they lack paired fins and they have no jumping ability. In order to climb, they must find rough surfaces that they can cling to in areas with low to moderate currents so they will not be washed backwards. Lamprey are excluded, along with other migratory fish, from passing dams that were not intended to pass fish. Lamprey have been observed to have great difficulty traversing fish ladders that are designed to pass migrating fish and are apparently unable to use many of these structures. Areas of the fish ladders that seem most difficult to the lamprey include those areas where lips or gratings have to be crossed, areas where water velocity is higher such as entry ways and over diffuser gratings, and areas that are lighted at night. Any barrier that have a sharp lip, high velocity current, and/or smooth downstream surface, or a hanging downstream drop more than a few inches high will be a passage problem. The need to pass and monitor lamprey through fish ladders is apparent when the fish ladder is the only route where lamprey can access upstream spawning waters.
However, due to the lampreys' strong phototaxic behavior expressed as light avoidance, they often do not approach counting windows as other anadromous fish do. So, alternative passage and monitoring strategies must be employed to facilitate lamprey passage and identify areas where they are unable to pass and also locate areas where the fish hang up in Reclamation managed facilities and fish ladders. Reclamation needs to be proactive and be prepared to address the needs of these species before they become ESA listed.
This information was last updated on January 31, 2015
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