The night shift begins! Electrofishing 16 Michigan lakes

Our team has started conducting nighttime electrofishing surveys of 16 Michigan lakes, meaning long days and lots of excitement!

I mentioned in the previous post that our big research question is, “what habitats are best for Largemouth Bass?” We are using net pens to confine fish to particular habitats and follow their growth, but of course fish can swim from habitat to habitat in many lakes. So, we are complementing the net pen research with a study of Largemouth Bass populations across lakes that provide different habitats. Some lakes have lots of aquatic vegetation while others have only a few spots. How much is enough? How much is too much? These are questions that have been addressed in the fisheries research to some extent, but most studies are from southern lakes choked with vegetation. Not much use up in Michigan! So, we are setting out to study these questions by comparing the Largemouth populations of many lakes to maps of aquatic vegetation and other habitat characteristics.

That means we get to go out and catch thousands of fish. The best way to do that is electrofishing, which I’ve already written about here. Here’s what it looks like from my perspective on the boat.

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Bass research continues at Blue Lake

Hayden (left), Amanda (center), and Ayman (right) with the day's catch: Largemouth Bass for our net pens.

Hayden (left), Amanda (center), and Ayman (right) with the day’s catch: Largemouth Bass for our net pens.

Our big research question is “what habitats do Largemouth Bass survive best in”, but breaking it down scientifically into testable hypotheses is really tough! One way to approach the question is by confining the fish to particular habitats and seeing how they do. Of course, there are some big assumptions confining mobile fish, but more on that later.

On July 2, we began our first experiment of this year. We placed 12 net pens in Blue Lake (near Fountain, MI) and stocked them each with baby Largemouth Bass. The net pens are 10 feet by 10 feet, with an open bottom. We put the pens in areas with 0%, 50%, and 100% vegetation coverage, to see whether the fish grow better or eat differently. Our results from last year suggested that bass in pens with no vegetation grew more slowly. However, we were challenged by a major issue: turtles! Continue reading