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What's going on with Lake Scugog's walleye?

What’s going on with Lake Scugog’s walleye?

in Environment by

The City of Kawartha Lakes was not idly named. The lakes and rivers that crisscross our landscape are a hub for year-round recreation and chief among these pastimes is fishing.

On Lake Scugog, especially, anglers have long been a common sight from ice through open water, flocking from all around to wet a line in the lake’s tea-stained waters. In 2016, however, this story changed after the Ministry of Natural Resources and Forestry (MNRF) placed a year-round closure on Lake Scugog’s walleye fishery.

Since then, the future has looked uncertain for local anglers. In fact, four years later, there remains a lot of confusion surrounding the initial closure itself. So, what exactly is going on with Lake Scugog’s walleye? Before any notions of future fishing adventures can be explored, it’s important to clear this up.

For the last several decades, the MNRF has been conducting a number of programs which monitor fishery health across the Kawarthas. The Kawartha Lakes Fisheries Assessment Unit’s trap netting program and the province-wide Broad-scale Monitoring program are among the most substantial of these projects, gathering data on population size, growth, maturity, contaminant levels and other biological details of local fish species.

In conjunction with the MNRF, Scugog Lake Stewards Inc (SLSI) has also conducted a number of important research projects over the years. Ranging from work on shoreline management to more broad habitat studies, these programs have not only furthered our understanding of how Scugog’s ecosystems function, but how they have changed.

Over time, however, data collected from these programs has begun to paint a worrying picture for the lake’s walleye. Not only has their overall population been in a steady decline but the number of new fish which are being naturally added to the lake’s stock each year (otherwise known as annual recruitment) is also falling rapidly.

Unsurprisingly, causation is difficult to establish. For one thing, Lake Scugog has a history of extremely heavy fishing pressure. In fact, fisheries management zone 17, which encompasses Kawartha Lakes, is the heaviest-fished region in the entire province. Add to this a nearly universal love for walleye meat among anglers and it becomes easy to see how recreational fishing has played a role in their decline.

Popular though it may be, sport fishing is far from the only threat to this species. Like many Kawartha Lakes waterways, Scugog has been through a number of serious changes over the years. For one thing, its waterfront is considered prime real-estate, which has meant the development and destruction of a great many shoreline ecosystems. Walleye rely on shallow water for their spawning habitat, which makes close-to-shore projects like stone retaining walls and dredging a serious detriment to their reproduction.

The lake has also seen the introduction of a number of non-native species over the years, likely the most recognized of which is the zebra mussel. Mussels are filter feeders, which means they cycle particulate like algae out of the surrounding water and, ultimately, increase water clarity.

According to MNRF fisheries biologist Margaret Bérubé, “This can decrease the amount of nutrients available to lower trophic levels, decrease the overall productive capacity of lakes, and create conditions that are more favourable for some species (e.g. smallmouth bass, muskellunge) and less favourable for others (e.g. walleye).” In fact, because walleye are an extremely light-sensitive fish, improved water clarity not only makes them less effective predators, but more vulnerable to predation themselves.

The list goes on. Rising water temperatures are creating better conditions for warm water species like bass, while impeding fish like walleye that prefer cool water. The introduction and growth of several other popular sport fish, namely black crappie and bluegill, has also meant more competition for the already struggling walleye.

Additional influencers may include invasive plants like starry stonewort, which leeches oxygen from the surrounding water, and increased algal blooms caused by fertilizer and septic runoff.

With all of this in mind, the question remains. Where do we stand at present?

The unfortunate reality is that ecological recovery is often a slow and arduous process. This is a highly nuanced issue and, with only four years since its inception, Lake Scugog’s walleye moratorium is still considered to be in the early stages. It is also worth noting that, since the landscape in and around the lake has been altered so dramatically, it may not be realistic to ever expect an exact return to historical walleye numbers.

Despite a lack of certainty, the future does not have to be a grim one for this quintessential Kawartha Lakes species. We need only look at the recovering population of walleye in Rice Lake to see that situations like this can, if acted upon, be turned around.

Outside of the season closure, there are a number of projects aiming at doing just that through continued research, habitat recovery and more. In fact, in 2016 the Scugog Lake Stewards began a three-year comprehensive study of the lake’s declining walleye, funded by the Ontario Trillium Foundation. The complete results of this study, which has been conducted in partnership with University of Ontario Institute of Technology, Kawartha Conservation and York University, will be available in spring, 2020.

In the meantime, members of the public are being called upon to help.

The “Walleye Watch” program, run jointly by SLSI and the MNRF, aims to engage waterfront property owners who are willing to monitor the waters around their own property, or allow others to do so, during the months of March to April. Information gained from this program will help to develop a better understanding of walleye spawning distribution across the lake.

Outside of community-based research, waterfront owners can have an impact through mindful property management strategies. Allowing a shoreline to naturalize, for instance, can be very helpful to local fish populations. Residents are encouraged to allow a buffer zone of natural vegetation between their lawn and the waterway, and should avoid the use of hard retaining walls, which create erosion and sedimentation issues.

Runoff is also an important consideration in the maintenance of waterfront, as it can cause a host of aquatic ailments. Eliminating the use of chemicals around a property, as well as being up to date on septic maintenance, are both extremely effective ways of minimizing the impact that you have on sensitive species like walleye.

Lastly, it’s important to be vigilant when it comes to invasive species. Taking time to learn about species identification and the means by which these harmful waterway hitchhikers get around is a small action that could have a substantial impact.

In the end, we can’t overlook the fact that walleye are themselves an introduced species to Lake Scugog. Once only a jumble of river, marsh and flooded farmland, the lake we recognize today is largely the product of Lindsay’s multiple damming projects throughout the 1800s. Between the years 1920 and 1940, walleye were deliberately introduced to the new waterbody, where they spread and, eventually, became part of the region’s complex and ever changing ecology. Ironic though it may be, this arguably “non-native” species has long since become an important part of the Kawartha landscape, both in terms of biodiversity and of human value. Native or not, that’s worth protecting.

If you’d like to learn more about the state of Lake Scugog’s walleye and the surrounding ecosystems, or to help with the many local projects aimed at fixing this problem, visit https://scugoglakestewards.com/. The Lake Scugog Stewards also have a number of free informational videos on this and other important subjects available on YouTube. Additional resources include the official websites of Kawartha Conservation and the Ministry of Natural Resources and Forestry.

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