The splashing sounds from the nearby stream let us know we were getting close.
As we wound our way around the ancient cedars and massive yellow birch that dominate this wetland, our excitement rose as the streambank neared. Big splashes now, accompanied by a flash of spray from the water’s surface.
Peering carefully into the running water we saw them… salmon! Big ones! Fish on migration, on their way to reproduce, on their way to die.
The stream is quite shallow here, between ankle and knee deep as it flows over gravel beds and under fallen tree limbs. As the water is low and the fish are big, their backs are often well exposed as the fish wriggle and twist to gain another couple metres of the stream.
Fall migration is well known as it pertains to birds and to monarch butterflies; the seasonal movement of fish is less understood by those of us who fall outside the realm of being ardent anglers. And so, for me and our hosts of this outing, to bear witness to this event is quite exciting.
The watercourse that these fish have swum runs from Matchedash Bay upstream on the Coldwater River to the quiet reaches within Oro-Medonte Township; measured on a map the distance clocks in at 24 kilometres. And that does not include the many twists and turns of this river bed.
It is known that these fish have returned to the same site from which they were born, having spent two years in Georgian Bay until ready to spawn. How do they find this remote and almost hidden area? Much research has been conducted on this phenomenon, looking at moon charts, water temperatures, flow rates and other sundry factors that fish might notice… and the answer is… smell.
There are well over 100 intersections of tributaries entering the Coldwater River, and each has its own perfume to a fish’s nose. Who knew? Well, fish scientists now think they know. And so, the fish ‘sniff’ their way home to the gravel beds of their youth.
These are Chinook salmon and, like most of their related species, die immediately after laying and fertilizing their eggs. On the day of our visit, a few carcasses were already noted, their white bodies awash on the gravel shores or caught within the branchy embrace of a low leaning cedar.
Well, that’s the romantic side of the salmon story. Are you ready to hear about what’s really going on?
There are several species of salmon in Lake Huron/Georgian Bay, all deliberately introduced to these waters from their natural range of the Pacific coast. Chinook, Pink and Coho were brought here in the 1960s to enhance the fishing rewards of both anglers and commercial fishery operations. Thus began the saga of the rise and fall and rise again of the salmon fishery in Lake Huron.
Fish management has always been on the periphery of my interests, as I know just enough to know that there was a huge amount to be learned about fish management; so I stuck with waterfowl and botany… and am still struggling to take in all that those disciplines demand. I mention this as the following is a summary of what I could glean in my short research.
In the 1950s, the Welland Canal was created and allowed fish to enter into the upper Great Lakes, an aquatic environment that nature had held safe by way of the Niagara Falls (a tad too high for fish to jump over). This carved opening allowed myriad non-native species to flood into the region, including lamprey eels and alewife fish.
The alewives grew into massive schools that ate the abundant plankton found in the Great Lake waters, as well as the eggs and young of smallmouth bass, pickerel, perch and other fish species native to these freshwater lakes. Alewives also change the chemical makeup of the waters where lake trout spawn (on shallow gravel shorelines) and soon these native species were in sharp decline.
Someone realized in the 1960s that salmon eat alewives and the introduction program rolled out. Fewer alewives meant greater populations of bass, pickerel and trout, plus created a new fishery for anglers. Win-win-win.
But the invasion of zebra and quagga mussels in the 1990s soon upset that apple cart. These mussels filtered out most of the plankton from the water, so much so that the alewives all but died out. The salmon soon began to starve and in 2003 their populations crashed by 95-percent.
With these introduced fishes now gone, the native species rebounded in glorious numbers and Georgian Bay became known as one of the world’s best sites for catching bass, perch, lake trout and other swimming culinary delights.
Today the introduction of hatchery raised salmon continues, with the goal of ensuring there are enough salmon to attract anglers (who spend a lot of money pursuing their sport) and the continued control the alewife population. As with any manipulated management plan for wildlife, it is full of risk and challenges… and under much debate.
The dead salmon that lay before us in this quiet stream are a ‘wild version’ salmon whose introduced ancestors somehow adapted to using the streams and river mouths that feed Georgian Bay. In a year that has seen very few acorns or walnuts produced, the black bears and raccoons of the neighbourhood will be feasting well tonight.
Dave’s Notebook: I do hope that you have had the opportunity to get out and take in this fabulous display of fall colours. Best showing since 2008! This week's story is about an overlooked fall migration... unless you are an angler.
© 2022 David J. Hawke