by Alicia McCutcheon
LAKE MANITOU—Over the course of 10 days in July, technicians with the Ministry of Natural Resources (MNR) have been busy on Lake Manitou, setting and hauling nets, analyzing fish and checking for invasive species as part of the Ministry’s broad scale monitoring (BSM) program.
After just three days, technicians Josh Woods and Roque Giroux had caught a wide variety of fish, from whitefish, pickerel, and bass to lake trout, different varieties of perch and brook trout, to name a few.
“It’s a great sign that they’re catching so much variety out there,” said Keith Scott, Fish and Wildlife Technical Specialist with the MNR’s Sudbury District. “Brook trout is important to see too because it’s stocked—we’ve caught seven so far. Wayne Sellinger was here (MNR district biologist) and was very encouraged to see some—it proves that they’re surviving.”
Nets had also pulled up vast quantities of rock bass (one lift garnered 171) and plenty of perch and suckers.
“There’s good whitefish here too—the ones we’ve been catching are up to six and seven pounds,” he added.
Mr. Scott also noted that he was told that pickerel in Lake Manitou grow at a fast rate. This can be attributed to an abundance of their favourite food, lake herring (cisco).
The technicians—the two most experienced technicians in the province—from last Monday until today (Wednesday), followed a routine of placing four small mesh nets and four large mesh nets at random spots throughout the lake, at various depths, each day. The nets are marked with buoys, claiming them as property of the MNR and warning interested boaters off with fears of fines and trouble from the police.
Every morning these nets are removed with the contents placed in a Rubbermaid container—one for each net—to be taken back to the Blue Jay Creek hatchery for hours of painstaking work to size, sex, weigh and sample each fish. The data from these studies is what determines slot sizes and allowable catch with flesh samples going to the Ministry of Environment, providing the data for the ‘Guide to Eating Ontario Sport Fish.’ The net assessments are lethal kill, which means all the fish caught must be killed to garner the results needed by the study.
Not everyone, however, feels that killing all the fish caught is necessary.
“I’m certainly not in favour of the way the netting surveys are being done,” stated Jim Sloss, chair of the United Fish and Game Clubs of Manitoulin (UFGCM). “It’s unbelievable that the MNR doesn’t have an automatic policy for live release, they could be using impoundment nets to catch the fish, tag them and do what they need to and then release them.”
“It’s a common question we have from people, ‘why kill?’; it’s because we need to get at the otolith (calcium structures in the neck of the fish) to determine the age of the fish,” Mr. Scott said. He likened the otoliths (fish have two) to the trunk of a tree—both have rings that are counted to find out the age.
There’s a lot of work involved in this,” he said. “And fish aging is critical to the information needed.”
“The research project is excellent news for Lake Manitou because it puts it on a schedule to be surveyed every five years,” said Mr. Scott, noting that lakes participating in BSM are randomly chosen based on size and location. There are 1,000 lakes across Ontario undergoing BSM, 500 of which are in Northeastern Ontario.
“We’re also looking at invasive species and water quality,” he added. “Manitou is recognized as a significant water body.”
While the technicians are out on the lake every day, they also haul nets of plankton for further analysis, work on mapping and check for cormorant nests.
Mr. Scott noted the many signs he had seen on Manitoulin urging boaters to be invasive species aware and that the nets are thoroughly cleaned and dried before heading to another lake. Three days in (when The Expositor had a chance to sit in on the process), he added, without the help of a microscope for such invasive critters as the spiny water flea, Lake Manitou was invasive free.
Last week, the technicians were sampling from the eastern basis, leaving from Turtle Creek, and have been working with Blue Jay Creek Hatchery and with cooperation of the Lake Manitou and Area Association (LMAA).
“We notified interested individuals before the process and we’ve had great support from the LMAA—they’re great people and have been very positive,” said Mr. Scott.
Kevin Leblond, senior aquatics operations technician with the MNR Northeast region, explained that for 2011, BSM is made up of three different components: netting, aerial angler counts (to see what the fishing efforts are on the lakes) and spring water samples to check for phosphorous levels and water chemistry.
Mr. Lebond noted that while invasive species have not been found in Manitou, the spiny water flea has appeared in Northern lakes such as Larder Lake.
“We’re trying to find out the fish abundancies across fisheries management zones 1, 3, 7, 8, 10 and 11,” he continued. “Lake Manitou is in Zone 10. The lakes are randomly chosen by three different fish species: walleye, lake trout and brook trout.”
“Lake Manitou was also chosen because it’s greater than 10,000 hectares—there’s not many lakes that fit into that class,” Mr. Leblond said.
Results of the BSM will not be released until next summer, Mr. Scott explained, assuring that there would be “full disclosure” with a presentation, perhaps through a meeting of the LMAA with the findings, likely.