I run The Nature Conservancy's Delaware River Basin program in NY. Last year our program removed a low head dam on the Neversink River, a large tributary to the Delaware, in Cuddebackville, NY. The primary objective of the dam removal was to remove a passage barrier for migratory fish as well as host fish for the endangered dwarf wedgemussel.
The two questions that we are trying to answer with our monitoring are: Are shad now moving past the dam? And, are they spawning in newly available habitats upstream of the former dam? I've been investigating several possible monitoring techniques...radio tags, gill netting, electroshocking, and egg surveys (we've done a few years of larval fish sampling and although we documented a blueback herring spawning in the Neversink we have been unable to document shad spawning). Has anyone done egg surveys? My concern with radio tags is the percentage of shad likely to exhibit "fall back" behavior. I'm curious to know more about gill netting. Does anyone have any experience using gill nets on American shad and, if so, what is the mortality associated with this technique? The NeversinkRiver can be challenging to electroshock at summer base flows and during the spring may be impossible much of the time. I'll appreciate ANY suggestions from the group. Thanks. George
