Sunday, October 14, 2007

gone fishing

Last week I got to do something completely different for work. I was able to help some biologists do a fish survey. How does one do a fish survey? By using an electrofisher of course. Elecrofishing is used by fish biologists to survey streams and lakes. They make ones for boats as well as a backpack model like the one we used.
Someone is lucky enough to wear the backpack unit and hold the pole with a metal loop on the end. Current is applied to the loop and fish that come into contact are stunned.
The range of the loop is about a few feet. The stunned fish float belly up and are quickly scooped up using a net.
So we find natural pools in a stream surveyed the years before. We string nets across the pools to trap the fish in the pools and do sweeps. All fish are placed into buckets to identify and measure. Measurements include length and weight.

It was a fun time trying to capture fish. I was on bucket duty since I had never done this before. As you can imagine, mixing electricity and water is a bad combination and can be dangerous so we had protective gloves and extensive safety training.

The current is not that strong and is dialed in to stun and not kill the fish. The electricity only stuns the fish and after a few minutes they become active again. I am not sure how they decide how many volts to use but it involves measurements of dissolved oxygen and turbidity and other nerd stuff.

We measured many fish and it was fun to work with them. We kept them in a special cage until we were done and let them go back in their pools. Electrofishing is an easy, fast way to catch fish. I know that some people use this method to fish for sport but is cheating if you ask me. I think someone died using a bug zapper to fish but that may have been in a Simpson's episode.

On the way home I saw a tarantula crossing the road. I guess the males are out and looking for mates. He was crossing the road and he was sooo big!