MNR_netting in Mindemoya Lake shows less walleye,new smelt presence

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MNR_netting in Mindemoya Lake shows less walleye,new smelt presence

 

 

October 28, 2009

Jim Moodie / manitoulin.ca

 

 

LAKE MINDEMOYA-Recent netting by the Ministry of Natural Resources (MNR) in Lake Mindemoya suggests that walleye numbers are down while smelt are suddenly present.

 

While the two aren't necessarily connected, and more study is required before an assessment of either trend is possible, each development has piqued the interest of the researchers and leaves room for armchair theorists to wade in while awaiting an official conclusion.

 

Over four days in mid-October, fisheries workers with the ministry's district office set a dozen gill nets at various locations in the lake in order to get "a snapshot of what the lake supports," explained biologist Wayne Selinger, adding that the "site locations were picked randomly, so we weren't targetting a particular habitat."

 

Nor was the catch limited to a certain type of fish. "These are experimental nets, which are not like commercial fishing nets," pointed out Mr. Selinger. "They're designed to catch not just sports fish but the gamut of sizes and species, so you get a picture of the whole fish community."

 

That said, the main focus of the undertaking-as its official name, Fall Index Walleye Netting, would imply-was to gauge the health of the walleye, or pickerel, population. It's an exercise that the MNR carries out every four or five years, with the last study of this type occurring on Lake Mindemoya in 2005. Before that, there were similar net surveys carried out in 2001 and 1995.

 

Lake Mindemoya was getting due for another such sweep, but it was fast-tracked as a result of issues raised. "We could have done this next year," said Mr. Selinger. "But based on a number of concerns that were expressed, we decided to step it up."

 

The sense among many anglers, and their representative voice in the United Fish and Game Clubs of Manitoulin (UFGCM), has been that the number of walleye in Lake Mindemoya has dwindled in recent years, with one theory for that decline being the impact of zebra mussels.

 

"It's one of the concerns," admitted Mr. Selinger. "We know for a fact that they have been introduced within the last decade, and no doubt that will result in changes to the fishery, but we have to get a handle on what that impact is."

 

Walleye are a key part of the Mindemoya fishery, and, unlike Lake Manitou and Lake Kagawong, have never been stocked here. "In my estimation, Mindemoya is the only native walleye population on the Island," said Mr. Selinger.

 

He'd like to see it remain a natural, self-sustaining fishery, believing that "natural recruitment" is preferable to planting fish in the lake.

 

At this point, it is premature to make any firm comment on the state of the walleye fishery, or its main threats, as the information from the index netting remains to be analyzed. "We have to get the fish aged and compare the data to past surveys, as well as to other lakes in the Northeast," said Mr. Selinger. This process, he warned, will take several months.

 

In general, though, "the numbers are down a bit relative to earlier surveys, and we're concerned about that," conceded Mr. Selinger. "Once we get into the data, we'll understand more why this is happening."

 

Fish caught in the gill nets were measured for length and weight, said the biologist, "and for walleye and perch, we also look at sex and maturity." Ovaries have additionally been preserved to study egg production, and age will be determined by analyzing an inner ear bone, known as the otolith, that was removed following the collection of the samples.

 

In case you're trying to picture how the fish are now faring in the lake, minus a few ovaries and inner-ear parts, we might as well state the obvious: none of these scooped-up swimmers actually survived to be returned to their element.

 

"People get concerned about this, but the alternative is trap netting, which is much more labour-intensive and provides less information," said Mr. Selinger. "The number of fish taken is very low compared to what the lake in theory can spare, and the data is used for the betterment of the fishery over time."

 

Over four days, the MNR crew hauled up a total of 500 fish, and that included "all species," stressed Mr. Selinger, not just walleye. White suckers made up a significant portion of the catch, along with lake herring and whitefish. Bass were relatively few, but that's less a statement on their presence in the lake than their body shape. "They don't net very well, which is good," said the biologist.

 

The one surprise was the appearance of rainbow smelts among these other finny kin. The small, non-indigenous fish has been established in both Lake Manitou and Lake Kagawong, but had not previously been thought to inhabit Lake Mindemoya, said Mr. Selinger.

 

"Frankly when I first saw them I didn't twig to it right away, until one of the local gentlemen reminded me that they're not supposed to be here," said the biologist.

 

He can't say categorically that the species was never in Lake Mindemoya in the past, but it appears that they have arrived recently. "They weren't present in 2005 (when the last index netting occurred)," noted Mr. Selinger. "And I've talked to other folks in the Mindemoya area who say they weren't there before."

 

He suspects the smelts found their way into the lake through a careless use of bait or perhaps someone washing a catch from another spot, and losing (or deliberately dumping) a few in the process. "Smelt are harvested during the spawning run, and the eggs and milk will remain viable for days," noted the fisheries expert.

 

The smelt run on Manitoulin makes for a popular angling (well, scooping) activity each spring, and these sardine-like swimmers make good eating not just for people, but pickerel, Mr. Selinger admitted. Still, "it's an addition to the lake that will carry an effect, and the consequences are rarely beneficial."

 

As edible as the silvery little newcomers may be, "I don't think people would trade walleye for smelt," suggested the biologist. Still, he said he has to "dig deeper on this" before he can assess how recent, and widespread, the smelt invasion might be.

 

Reaching a determination on the size and health of the walleye population will also take some time. But while numbers of the sport fish are likely to prove fewer than in the past, this doesn't necessarily mean a crisis.

 

"There are still lots of walleye," said Mr. Selinger, adding that, based on the ones observed in the recent netting, they "are in excellent health, and good-sized fish." His hunch is that growth rates are, in fact, improving, although he stressed that "this is speculation at this point."

 

Fall is the best time to conduct walleye netting since, due to the drop in surface temperature, "they are distributed across the lake instead of clumped up," he explained.

 

The nets "fish the bottom" of the lake, he noted, but the MNR crew didn't focus on the deepest-or shallowest, for that matter-part of the water body. Of the 12 nets set at mid-month, a third were placed in shallow water, another third in deep water, and the remaining four "at mid range," he said.

 

The work was done in consultation with the UFGCM, and with notification provided to the M'Chigeeng First Nation, while use of the Pirate's Cove resort was granted to the MNR crew for docking and fish-cleaning purposes.

 

Mr. Selinger said the three-person MNR team put in long days of 12-14 hours, and had to haul up the nets by hand, in rather grim weather at times, yet he didn't characterize this as arduous work. "It's nice to be working outside," he said.

 

The trio made a point of staying clear of the area where the usual perch anglers were congregated, and in general, felt the project proceeded without ruffling any feathers, or fins. "I think folks understood why we were out there," said Mr. Selinger.

 

Of the fish caught, and sacrificed in the name of science, a lot were provided as food to the M'Chigeeng First Nation, while others were doled out among "some of the local folks" inhabiting the rest of the lake, said Mr. Selinger. Unfortunately, federal health legislation prevents the donation of such a harvest to an organization like Manitoulin Family Resources or Community Living Manitoulin, as has occurred in the past.

 

Still, most of the take ended up on a plate, or in a freezer for future consumption, which is the MNR's preference, as "we don't want to see it go to waste," said Mr. Selinger.

 

He acknowledges that some observers might still question the need for fish to be sacrificed en masse, but in his view "it's a drop in the bucket compared to what the lake should sustain and what recreational fishing takes," and will ultimately assist in the preservation of the resource.

 

Aerial surveys of angling activity, along with creel censuses, can provide some useful information, but neither yields the sort of specific, biological data that is required to properly evaluate the fishery and plan its future. "I'm convinced this is the best tool," said Mr. Selinger.

 

He noted that, apart from gaining a clearer picture of walleye dynamics, "we will have some good information on perch as well, which is another bread-and-butter fishery." And samples from the netting will additionally be shared with the Ministry of the Environment for analysis of contaminants, for its Guide to Eating Ontario Sports Fish program.

 

The downside of such a thorough assessment is that an immediate prognosis on the pickerel situation will not be possible. It takes time to sift through the data, crunch the numbers, and come up with a report.

 

Mr. Selinger said it will take three-six months before all the information is compiled and properly analyzed.