The original project boat has since been converted into a smaller utility boat, but its main function now serves as an electrofishing boat (albeit on the small side). One of Dr. Cooke's other grad students, Chris Pullen, was able to fabricate a safety cage and all the associated rigging for the anodes. It came out looking very professionally done and I've been eager to get out and use it.
Today was my chance to see if we could electrofish a few muskies. There is a project being conducted by another member of Dr. Cooke's lab, Alison Colotelo, which involves heavy sampling across many different sites looking for four species of concern. Although most of the sampling has been completed, Alison agreed to help me try to shock a few muskies.
For those not familiar with electrofishing it involves sending rapid pulses of electricity into the water to temporarily stun fish. It is a very safe method of sampling when done properly, and is extremely efficient.
Why are we trying to electrofish muskies? We are interested in getting controls and "baseline" physiology from muskies NOT captured via hook-and-line. It is impossible to get true control fish as any method of capturing fish causes some deviation from homeostasis (normal resting physiology).
We decided to sample a smaller stretch of the Rideau River with a good population of muskies. Most of the morning was spent sifting through lots of different species - including walleye, bluegill, pumpkinseed, smallmouth bass, largemouth bass, yellow perch, rock bass, and smaller minnow species. However, the muskies evaded us... for a bit. Finally, after switching to our third location, a nice 34 inch male was shocked and quickly brought aboard. Within 15 more minutes we had another smaller muskie at 30 inches. These were the only two we took blood from, but we did manage to shock a small YOY (young-of-the-year) and another about 20 inches in length.
So how did these control fish compare to those C&Red? Their glucose and lactate levels were much lower than those that were angled. This shows that the angling event does impose some degree of stress on the fish, but the magnitude is still unclear and will require more controls to compare.
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Very interesting! Are you at all surprised by the numbers you shocked - or didn't shock? :-o Planning on doing more electrofishing? BTW - how long are they "out" after you stun them? If they have been subject to less stress, are they more frisky and difficult to handle when they come to?? ;-)
ReplyDeleteI'm neither pleasantly surprised nor disappointed. I'd expect to get a couple muskies from the Eccolands since the population appears to be pretty good, but at the same time you can't expect too many since overall muskies are fairly low density.
ReplyDeleteThe duration they are "out" for depends on the amount of electricity they're received. We had one that was out for a little under five minutes yesterday and the other was super green immediately after I scooped it and let off on the electricity. Sometimes they will be stunned for longer regardless of how long you apply the electricity. It's more fish-to-fish than anything else I suppose.