Recent stream surveys on Minnesota's North Shore show that so-called "coaster" brook trout are increasing in size and age, and state fisheries biologists believe restrictive regulations are helping the fish.
Coasters are brook trout that spend a portion of their life in streams and a portion in Lake Superior. Brook trout that spend part of their year in Lake Superior may exceed 22 inches in length and grow to 3 or 4 pounds, while resident brook trout in inland streams rarely reach 12 inches.
Lakewide, these coaster brook trout are faring well in the Nipigon River area in Ontario and near Isle Royale and are thought to be increasing slowly in Wisconsin, according to provincial, state and federal biologists.
Minnesota's survey results from the lower reaches of Lake Superior tributaries this fall are encouraging to Don Schreiner, Department of Natural Resources Lake Superior area fisheries supervisor at French River.
"We're cautiously optimistic," Schreiner said. "We're certainly on a positive trend."
But anglers shouldn't get their hopes up for an expanded recreational fishery anytime soon, fisheries biologists caution. These historically numerous fish still exist at remnant levels, and a complete recovery will be years in the making.
"It takes multiple generations for a fish to respond to restored habitat," said Dennis Pratt, Lake Superior fish manager for the Wisconsin DNR in Superior. "They have to build their populations over time and have to expand into other habitat and reconnect with the lake."
The largest fish found with electro-fishing techniques on 16 streams in Minnesota this fall was 18½ inches long, but DNR employees saw larger fish escaping, said Matt Ward, DNR anadromous fisheries specialist for Lake Superior. A total of 319 fish were sampled, with age ranges from 1 through 4. Average size of the brookies was 8 to 12 inches, Ward said. Surveys are conducted about every five years on Minnesota's streams.
In 1997, the first year of brook trout surveys on Minnesota's North Shore, a total of 327 fish were found, Ward said. In 2002, just 104 brook trout were captured, but not as much effort was put into the survey that fall, he said.
Wisconsin biologists monitor brook trout production at about 60 spots on Lake Superior tributary streams. The number of young brook trout being produced on waters such as the Brule River has increased, Pratt said.
The Wisconsin DNR also counts brook trout bound upstream on the Brule River at a viewing window on the river's lamprey barrier. Over the past eight years, from one to eight brook trout have passed the barrier each fall, Pratt said. Some of those fish have been up to 22 inches long.
"We're beginning to see larger brook trout return at a higher rate," Pratt said. "But it's not very many."
State and provincial agencies tightened brook trout regulations on Lake Superior and lower reaches of tributary streams beginning in the late 1990s to protect the fish. Minnesota has a limit of one brook trout and a minimum size of 20 inches, with an open season from mid-April to Labor Day.
Wisconsin has a one-brook-trout limit on Lake Superior with a minimum size of 20 inches. On Lake Superior streams, Wisconsin has a five-brook-trout limit and a minimum size of 8 inches. Ontario's Lake Superior regulation allows anglers just one brook trout, and it must be 22 inches long.
With those regulations in effect for about 10 years, prospects are improving for coasters.
"We're confident we've protected these fish," Minnesota's Schreiner said.
Wisconsin fisheries officials also have been working to improve brook trout spawning habitat on about 20 miles of tributaries in seven watersheds, Pratt said. Workers are clearing debris to let streams flow faster and uncover the gravel that brook trout require for spawning.
A few remnant brook trout have always inhabited the shore of Lake Superior and its tributaries after the population was decimated by overfishing and logging practices in the late 1800s. In addition, several agencies have stocked the fish, starting in the early 1990s. The Grand Portage Band of Lake Superior Chippewa, in cooperation with the U.S. Fish and Wildlife Service, began stocking brook trout eggs in reservation streams in 1992 and continue stocking young brook trout annually. The Red Cliff Band of Lake Superior Chippewa near Bayfield stocks brook trout in tributaries there. The Ontario Ministry of Natural Resources has stocked brook trout in the Nipigon River watershed.
No natural reproduction has yet been documented at Grand Portage, said Seth Moore, tribal biologist for the Grand Portage band.
"As far as coaster brook trout restoration, something is having an effect," Moore said. "Whether we can document natural reproduction of those fish is still a giant question mark for Grand Portage."
Using genetic analysis from samples taken this fall, Minnesota DNR fisheries officials hope to determine where Minnesota's "coaster" brook trout are coming from. Are they from natural reproduction in Minnesota streams, or are they strays from the Grand Portage stocking?
"If they're truly hatchery fish, we'll have to look at that as a management strategy," Schreiner said.
Meanwhile, anglers fishing North Shore streams near Lake Superior in the fall are catching the occasional coaster brook trout. Most are releasing them according to regulations.
"Salmon anglers have called or e-mailed me stating they have caught 18- to 20-inch brook trout on six different streams along the shore so far this fall," Ward said.
Those big brookies are held in awe by anglers. Ward knows what that experience is like.
"Whether you catch an 18-inch brookie on hook and line or electro-fishing, holding it gives me a rush of adrenaline equivalent to holding a 50-inch muskie or a 20-inch smallmouth," he said. "You just have to respect fish of any species that large."