Muskoka’s Lakes Should Offer Good Homes for Fish

We all know fish live in water. Anglers know that fish, just like us, have their real estate preferences, and don’t hang out just anywhere in a lake. The sandy beach with a westerly outlook is great for you to enjoy the sunset, but not for them; they prefer the sheltered inlet full of lily pads that create a dappled pattern of light and shade, or the boulder shore with a couple of fallen trees, now submerged, creating golden arches and sheltered hidey holes.

The 2014 Muskoka Watershed Report Card used four criteria to assess the health of the waters of Muskoka, and one of these four was Fish Habitat.

While the larger fish spend most of their time in the deeper waters, venturing close to shore only where the waters are shady, not too shallow, and offer lots of cover, young fish spend most of their lives in the narrow strip of water fringing the shoreline. Here the water is warmer, promoting rapid growth, and they are away from the mouths of larger fish that seldom turn down the opportunity to grab a tasty fish dinner.

Of course, this is the same part of a lake in which we spend most of our time when we are in the water, swimming, playing, or getting ready to go out skiing, tubing, canoeing or sailing over the deeper water. While baby fish crave the cover provided by aquatic plants, branches, small boulders and undercut ledges, we prefer sandy shores, easy on the feet, and free of “debris” or other “icky things”.

And so, we “improve” our shallow shores, removing rocks and debris, raking the sand, clearing out “weeds”, installing docks, retaining walls, slides, and large inflated plastic castles. I think you can see where I am going…  Our notion of a desirable waterfront is not quite what baby fish would choose.

There is a simple solution, of course: share the waterfront by leaving most of it in as natural a condition as possible while “improving” a small portion so we will be comfortable inviting our friends to come wading in the lake. That is why every municipality in Muskoka includes a requirement that shoreline alteration not be undertaken on more than 25% of a lot’s frontage – a specification that originally comes from Fisheries and Oceans Canada’s recommendations for preserving habitat for young fish and other creatures vital to the health of a lake. (Yes, there is valid science behind those rules we must follow in developing our Muskoka property!)

Using measurements of the extent of shoreline modification around lakes, the Report Card classifies each subwatershed in terms of the proportion of fish habitat available. A watershed with heavily developed lakes, in which owners have extensively modified their waterfront areas, is less able to provide the conditions young fish need to survive and grow up. That lowers watershed quality because if little fish cannot grow up, there will be fewer big fish around for us or the loons or the osprey to enjoy.

Think about this next time you are “tidying up” at the edge of a lake – you are probably destroying somebody’s watery home.

Past articles are available in this blog under the Watershed Notes Articles category or under Past Articles in the Resources section.