Yes, size matters…and that includes fish size when electrofishing. Large fish are immobilized with less field intensity or power density than are small fish. Large fish sustain a higher total dose of electrical energy than do small fish; this is sometimes referred to as whole body voltage. An excellent paper on this topic is Dolan, C.R. and L.E. Miranda. 2003. Immobilization thresholds of electrofishing relative to fish size. Transactions of the American Fisheries Society 132:969-976. This short blog provides results of a simple study with various sizes of alligator gar.
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.
Here’s a few pics of electrofishing porn from the American Fisheries Society meeting in Portland, OR, 2015. Lots of new goodies. Enjoy!
Most boat electrofishing pulsators (control boxes) are powered with portable generators that provide 240-V, single-phase AC. These generators are available from common commercial sources such as hardware stores or electrical supply houses. (Note: a notable exception is the GPP pulsator made by Smith-Root, Inc., that requires a specially-constructed generator; it will not be discussed further here.) This short blog explains the electrical outlet of a generator, how to test for the safety of a generator if used for boat electrofishing, and what to do if the test indicates that a generator is not safe for electrofishing.