Jim Reynolds and I just taught a boat electrofishing course in Redding, California at Whiskeytown Lake. That provided some threshold fishing data for voltage, current and power for each of four electrofishing boats. One can standardize by power using any of the three parameters. Which parameter is less variable among a fleet of boats?
Electrical fields around electrofishing anodes are critical to fish capture effectiveness. The size, shape and intensity of those electrical fields are determined by the anode design and deployment in the water as well as by the electricity applied to them. There were two main questions to answer in this little study: (1) Could accurate electrical measurements be made from approximately ¼ scale model electrodes in a small body of water, and (2) Would those measurements provide useful information about the effect of anode ring size on their electrical fields?
Dr. Alan Temple posted a blog on December 9, 2015 entitled “Setting Doses for Lab Experiments.” He suggested that I submit a blog on other aspects of lab studies in tanks. This blog covers the setup of tank studies for electrofishing research, and I plan to submit a companion blog on procedures for tank studies. Important aspects to consider for lab studies are the test tank, the electrodes, the power supply and the electrical field.
Electrofishing is a primary sampling method for near-shore fish species in lakes and rivers, and for fish species and assemblages in streams. We must admit, however, that it is a sampling technique with inherent risks. People, water and electricity are in close proximity. This blog describes the potential for human injury or death if someone falls into water having an electrical field. It specifically involves boat electrofishing, but the same idea can be used for tow/push barges, shore-based units and backpack electrofishing.Continue Reading..
Overall resistance of an electrofishing system is determined by the combination of ambient water conductivity and the electrodes. The electrode shape, number, length or size, diameter of stock material, configuration and spacing affect both their overall resistance and the profile of the electrical field in the water around the electrodes. Rarely are there data available for assessing the effects of electrode changes on resistance or on fish catch. This blog presents some empirical results from field measurements of electrode resistance before and after some electrode changes.
Of all the environmental variables which affect electrofishing success, the one for which the most is known, and indeed it has been said is the most important, is water conductivity. This article explores the how and why of conductivity in electrofishing.