Proposed rules boost coaster brook trout
MARQUETTE – New restrictions on trout fishing along the lower reaches of eight streams in Marquette and Baraga counties are being proposed to try to help revitalize coaster brook trout populations in Lake Superior tributaries.
Coaster brook trout live in Lake Superior and spawn in tributaries. The large fish once occurred in more than 100 Lake Superior tributaries, but were highly vulnerable to overfishing.
One source said streams within 30 miles of Marquette were fished out by the end of the Civil War. Today, the Salmon Trout River in Marquette County is often cited as the only remaining stream on the south shore of Lake Superior with a significant population of coasters. Those fish are protected with a shortened season, 18-inch minimum size limit and single fish daily bag limit.
The new regulations would be part of an effort to develop populations in tributaries elsewhere along the Lake Superior shoreline over the two-county area.
“The coaster rehabilitation initiative has received a lot of support when presented to sportfishing groups and the public,” said Phil Schneeberger, Michigan Department of Natural Resources Lake Superior Basin Coordinator in Marquette. “The recommendation will be to impose special regulations conducive to coaster rehabilitation on eight stream segments.”
The special regulation would limit anglers to a one fish daily bag limit, with a 20-inch minimum size requirement for brook trout.
“Similar efforts in Minnesota and Ontario tributaries to Lake Superior have resulted in rehabilitation of coaster numbers, and we think this approach has the best chance for successfully rehabilitating coaster brook trout populations in Michigan,” said Troy Zorn, a fisheries research biologist at the Marquette Fisheries Research Station.
The Michigan streams expected to be included in the recommendation are the Iron, Big Huron, Little Huron and Big Garlic rivers in Marquette County and the Silver, Slate, Big Huron, Ravine and Pilgrim rivers in Baraga County.
Only specifically defined segments of the streams would have the special regulations. Those segments would be in the lower portions of streams, protecting fish that venture into the streams near river mouths. Currently, regulations dictate a 7-inch minimum size requirement for brook trout in those streams, with a five-fish per day bag limit.
“Our assumption is that fishing mortality in streams may be hindering rehabilitation of coaster brook trout in Michigan tributaries to Lake Superior,” Zorn said.
That assumption is based on spawning migrations of brook trout into the Salmon Trout River and Ontario tributaries begins in mid-July; minimum size limits on most Michigan tributaries to Lake Superior are 7 or 8 inches and because brook trout are aggressive and readily caught by anglers.
The DNR is proposing to put the regulations in place for 10 years. The recommendation is expected to be presented at the March 2015 meeting of the Michigan Natural Resources Commission.
“After 10 years, I hope to see age 4 or older brook trout in our fall stream surveys, and/or receive increased reports from anglers catching coaster-sized brook trout in these streams or nearby areas of Lake Superior,” Zorn said. “Large, old brook trout are rarely encountered in Michigan streams, if at all, so increased occurrence of them would likely indicate a positive response of populations to the protective regulations.”
Efforts to restore coaster brook trout in several areas by stocking supposed “coaster” strains of brook trout have largely failed. However, restoration of the trophy fish has been a longstanding priority of U.S, states, Canadian provinces and Native American tribes situated around Lake Superior, Zorn said.
After a decade of regulations in place to protect coaster brook trout in downstream portions of Minnesota tributaries to Lake Superior, coasters were found in fall electrofishing surveys and by anglers fishing for steelhead.
“Coaster numbers in Minnesota are still fairly low, but biologists think Minnesota’s coaster populations historically were low due to a limited shallow water habitat offshore from river mouths and dense lake trout populations in the area,” Zorn said.
Genetic analysis of rehabilitated Minnesota coaster brook trout has shown that they originated from native brook trout stocks rather than “coaster” strains previously stocked in Minnesota waters.
“These findings suggest that the potential for the migratory (coaster) life history form of brook trout resides within the genetics of our existing populations, and a low mortality environment (in the lake and stream) is needed for that coaster life history to be expressed and flourish,” Zorn said. “It is notable that the only coaster populations in Michigan are in relatively inaccessible waters (Salmon Trout River and Isle Royale). Both populations persist under protective regulations.”