I'm currently reviewing a report and work plan of another consultant that calls for some methods for electrofishing that I am unfamiliar with. I would like to find out if others have used similar methods or find the indicated methods as strange as I do.
The work plan calls for a seine to be stretched across the river immediately downstream of a riffle to capture all floating fish. Shocking is to commence 9 meters above the riffle break and sweep the entire riffle habitat downstream to the seine. No dip nets are to be used unless required by poor water clarity. The report indicated that many fish were lost at the seine before being captured. Fortunately, no mortalities were reported.
In my experience working with salmonids in Oregon and Washington, fish hit hard enough to be captured by floating down to a seine are essentially dead fish. Whenever I have shocked warmwater or coldwater species I have always used dip nets to facilitate capture and reduce the potential harm to the fish. In addition, I have always worked upstream rather than downstream as indicated in the work plan.
I should mention that the river being sampled is easily wadable during low flows but carries as much as several thousand cfs during high flows. I don't have any measured widths but I estimate that channel widths range from 6 to 30+ meters.
Has anyone else used this type of method or something similar?
Applied Ecosystem Services
[log in to unmask]