Fin clipping of brown trout to be stocked in Au Sable River (below Mio)

The last time the DNR conducted a large electrofishing effort below the Mio dam to look at the relative survival of different strains of clipped brown trout, we noticed a large percentage of fish were not clipped. In the past, the information we had allowed us to assume natural reproduction of brown trout in this reach was generally negligible. Those results caused us, and anglers who noticed the same thing, to wonder if that assumption was correct.

We talked to anglers and angling groups and decided to see if we could take a closer look at the situation. The trouble is, fin clipping fish takes time and we couldn't muster the funds to clip all the fish necessary.

That is where the anglers who fish the Au Sable stepped up. They asked, "How can we help?" and did so by driving over to Harrietta State Fish Hatchery to help clip adipose fins of brown trout. Because of their assistance, we stocked fin clipped fish this year, and hopefully in the years to come.

We will follow-up with fall electrofishing to check the ratio of fin clipped fish to non-clipped brown trout. If natural reproduction makes up a large portion of the population, we could consider changes in our stocking allocations to the river. We always hope for our trout populations to sustain themselves. Stay tuned for the results in a few years.

See below for photos of the fin clipping activities.

net full of brown trout

adult hands holding a brown trout while clipping fin