Although Lake Manitou shows spiny water flea infestation, biologist says lake ‘reasonably healthy’

by Alicia McCutcheon

LAKE MANITOU—Preliminary results are out from last summer’s broad scale monitoring study on Manitoulin’s largest body of water, Lake Manitou, showing the lake is “reasonably” healthy, but has a new and not-so-welcome addition.

The presence of the invasive spiny water flea has been confirmed, Wayne Selinger, Ministry of Natural Resources (MNR) biologist, told The Expositor, “but the really good news is there is no sign of zebra mussels.”

“The true value of this survey will become clearer in time,” he added. “The good news is the baseline has been set. A study will be done every five years and as the database builds, we will have other lakes to compare it to. Not every lake has this kind of commitment.”

“These are just preliminary results, as this is a long-term study,” Jeff Amos, fisheries population specialist with the MNR, reiterated.

He explained that Lake Manitou was selected as a “fixed lake” as part of the provincial study and will be revisited every five years, with the next monitoring process occurring in four years. “They will duplicate the same survey in four years,” he continued. “It’s not just index netting (netting fish with small and large mesh nets), but water quality sampling for the Ministry of Environment for major/minor nutrients and aerial angler counts (winter and summer).”

“The idea (behind broad scale monitoring) is to move away from individual lake management to fishery management zones (FMZ),” Mr. Amos explained of the provincial plan, noting Lake Manitou is in FMZ 10. “We’re still plugging away on a lot of the science, meaning how to use the data for scientific diagnosis. We would need to compare Lake Manitou to other lakes in the area of similar size and with similar species,” he continued, noting Lake Wahnapitae and Lake Panache as similarly sized lakes which could be compared to the Island lake.

“These are promising results, such as decent amounts of brook trout netted thanks to stocking efforts,” Mr. Amos said. “They caught decent amount of lake trout as well and there was a range in lake trout ages, which is a good indication that the population is healthy. Lake Manitou looks to be in pretty good shape.”

“It’s a reasonable catch of lake trout,” Mr. Seligner added, “considering they would have run deep by the time the survey was done.”

The biologist was very pleased with the brook trout numbers, which was approximately one-third of the lake trout catch, and attributed it to both the work of the MNR’s stocking efforts and Manitoulin Streams rehabilitation work.

“The walleye catch was on the low side, but it’s not truly a walleye lake,” he continued. “The low nutrient count, and cold deep lake is more favourable to lake trout.”

The fisheries crew also netted a great deal of yellow perch, which is also important to Lake Manitou’s fishery. The high numbers of yellow perch didn’t have “super strong showings in the size anglers want to catch,” Mr. Selinger added, but the large count should be a good thing for the future when the young fish get to be ‘a size.’

Second of the 16 species caught was rock bass, followed by bluenose minnow, cisco, white sucker, smallmouth bass, lake trout, rainbow smelt, whitefish, walleye, trout perch, ling, brown bullhead and log perch.

The largest lake trout caught was 9.2 pounds and 27.9 inches (fork length) while the oldest lake trout caught was 24-years-old. The largest walleye netted was 8.3 pounds and 27.2 inches long. The oldest walleye captured was 16-years-old.

The largest brook trout netted was 3.5 pounds and 18.8 inches and the oldest captured was three-years-old. The largest smallmouth bass caught was 3.7 pounds, 17.7 inches long while the oldest smallmouth was 12-years-old.

“There’s nothing in this study that particularly alarms me, it’s a reasonably healthy lake,” Mr. Selinger concluded.

The water quality and aerial angler search results are not yet available.