Inventory of Reclamation facilities where lamprey species exist, issues confronting lamprey, and how to aid fishways for passage and monitoring.
Can upstream adult lamprey passage be monitored using infrared video surveillance equipment?
Need and Benefit
Techniques to monitor adult lamprey passage are not fully developed. Currently, there are very few locations where adult lamprey 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 Upper and Lower Columbia Area Office regions to access upstream spawning waters. Reclamation facilities could hinder upstream lamprey passage affecting their life cycle thus, contributing to the decline of lamprey species.
Lampreys 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 has 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 monitor lamprey passage 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, an alternative monitoring strategy must be employed to enumerate adult passage and to identify areas where they are unable to pass and also locate areas where the fish hang up in Reclamation managed facilities and fish ladders.