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Counting Fish, Probing Habitats

Daniel Hayes, a MSU AgBioResearch fisheries scientist and a professor in the MSU Department of Fisheries and Wildlife, studies dams and dam removals, as well as habitat conditions such as water temperature, plant cover and food resources, and their effects on fish populations.

Hayes sqThough his work is focused on the field, it remains quantitative in nature. “My approach is statistical — that’s the quantitative part,” said Hayes, a Quantitative Fisheries Center researcher. “In science, sometimes you find things and nobody uses them, but we help discover how things work through statistical modeling that has real impacts in the world. It’s very applied.”

Hayes and his colleagues have increasingly found that variance among individual fish in a population is an important element in the success of that species, and they have developed a new statistical model to incorporate that. The individual-based model allows researchers to examine how the differences between individuals in a population affect the whole. For example, though most fish in a population spawn within the same time period, not all fish spawn at exactly the same time.

“If the water is warm when they spawn, the young develop too fast and hatch in the winter; if it’s cold, they might develop slower and hatch in more favorable conditions,” Hayes said. “We use the individual model to understand this better.

“If you look at young fish, the average fish dies,” Hayes said. “With this model, we’re trying to determine what makes that small percentage of survivors more fit. The average doesn’t always tell us what’s going to happen in the long run, so we need to look more closely.”

Photo: Michigan Department of Natural Resources

Caption: Since 1998, Dr. Dan Hayes at Michigan State University has led research efforts on the environmental impacts of Stronach Dam on the Pine River before and after removal. This research will be used to provide guidance for similar efforts across the nation.

– from Futures, James Dau, AgBioResearch

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