Sturgeon River Strain of Brown Trout Shows Promise in Michigan
December 14, 2010
As most anglers know, brown trout are not native to Michigan. Native to Europe - ever hear someone refer to them as German browns? Brown trout were first stocked in the state back in the 1800s. They have adapted well; in many places in Michigan, brown trout reproduce naturally and provide fine fisheries.
But in many places, where natural reproduction is limited, brown trout fishing in Michigan is dependent on hatchery stocking programs.
Over the years, the Department of Natural Resources and Environment has used a number of different genetic strains of brown trout and as recently as a few years ago, the DNRE maintained three strains in its hatcheries: Wild Rose, Gilchrist Creek and Seeforellen, a strain that was thought to be especially well-suited to lakes.
Having a number of different strains makes good scientific sense; in the event that a strain proves to be a failure, say, prone to a specific malady, the Fisheries Division does not suddenly find itself without viable brood stock.
Department fisheries biologists and hatchery crews regularly evaluates the productivity of the various strains and when it studied the Gilchrist Creek strain, it discovered the fish were almost rock stars.
"We found that the Gilchrist Creek strain survived and grew better than either of the other strains," explained Todd Wills, a fisheries research biologist who works out of the Hunt Creek Fisheries Research Station at Lewiston. "And the Seeforellens did very poorly."
The Seeforellen strain, once thought of as a potential savior of Great Lakes brown trout fisheries, was "genetically running out of steam," Wills explained. "We were seeing problems in the hatchery such as poor fertilization and eye up and physical anomalies things like asymmetry in the gillrakers - different numbers of gillrakers on one side than the other. In addition, growth and survival was poor. So we decided to replace that strain in the hatchery."
The fisheries folks did not have to look too far. They decided to gather brood stock from the Sturgeon River (the one in the northern Lower Peninsula). The strain had two things going for it off the bat: for one thing, it was a local strain of trout so in the event that additional brood stock was needed, they were available nearby and, perhaps just as importantly, biologists believed they would suit lake stocking programs as well.
"They have a lake element to them," Wills explained. "They demonstrate a migratory behavior between the Sturgeon River and Burt Lake. They'll move between the two environments and that was something that appealed to our fisheries managers."
Fisheries crews gathered Sturgeon River strain brown trout for hatchery brood stock in the fall of 2006.
Although the program is still in its infancy, the future looks rosy. Evaluations of Sturgeon River strain brown trout stocked in rivers along with equal numbers of Wild Rose strain have been positive so far.
"I'm encouraged by what we saw from our electro-fishing surveys in the Au Sable River (below Mio Dam) and Manistee River (below Hodenpyl Dam)," Wills said. "You can't make a final determination based on one year's worth of data but from what we saw, the post-stocking survival of Sturgeon River strain brown trout looks good. They far outnumbered the Wild Rose fish in our samples.
Growth of the Sturgeon River strain fish looks promising, too.
"The Sturgeon River fish that we captured were running a little bit smaller than the Wild Roses, but that's not a big surprise because they went in quite a bit smaller," he continued. "I was pleased to see that. They grew quite a bit after stocking and had almost caught up to the Wild Roses in length."
The surveys made in the lakes where the fish were stocked, again, alongside Wild Rose brown trout with different fin clips so they could be identified, were slightly less encouraging. But not enough to raise any red flags, Wills said.
Sturgeon River strain browns were stocked in several northern Lake Huron Watershed lakes that are open to fishing as well as in a pair of research lakes where no fishing is allowed near the Hunt Creek facility.
"Although we found good carry-over of larger unmarked brown trout from previous stockings in the lakes open to fishing in the northern Lake Huron watershed, we only found one marked brown trout, from this year's plant," Wills said. "It was a fin-clipped Sturgeon River strain brown. In the research lakes, we found more Wild Rose strain than Sturgeon River."
But Wills said it's quite possible that, because the Sturgeon River fish were stocked at a smaller size than the Wild Roses, that the fish have not grown large enough to be susceptible to the nets or the electro-fishing gear the fisheries personnel used in the lakes for the study. Or maybe they hadn't started using the same areas as the larger Wild Roses.
"We saw something very similar with two brook trout strains we were testing a number of years ago," Wills explained. "We stocked equal numbers of each strain in our research lakes, but in the first year, we only found one strain which was larger at them time of stocking. But the next year, we found good numbers of the other strain. So the first year they avoided capture, perhaps by using cover we could not sample effectively.
"Hopefully next year the Sturgeon River strain will have grown enough in the lakes to be vulnerable to our equipment and we'll be able to do a better job of sampling them. If so, we'll be able to do a better job of determining their growth and survival compared to the Wild Rose strain when we get four or five years out in the study."