The Great Lakes fish populations are in trouble.
If you’ve spent your summer fishing in the Great Lakes, you may have noticed that fewer fish than usual are biting. This isn’t because the Great Lakes fish have decided your lures are sub-par, or because you’re doing something wrong. On the contrary, your lower fishing haul is probably the result of the dwindling Great Lakes fish populations. Quite simply, there are fewer fish biting your hook because there are fewer fish period. The alarming decline in fish populations is the result of climate change, and unless something is done, the decline will continue over the next few years and decades to the point where the Great Lakes fish population could be almost entirely decimated.
Part of the problem is warmer and shorter winter seasons. Since 1956, the number of days below freezing around lakes such as Erie and Superior has decreased by almost an entire month. Long and bitterly cold Midwest winters have largely given way to a preponderance of freeze-thaw weather patterns—something that may be nice for land-dwelling residents, but which is putting a damper on species reproduction among Great Lakes fish such as the walleye and yellow perch. These are fish that thrive in more normal winters, where a thick layer of ice forms across the water and where the spring season brings a gradual warming period rather than a sudden and dramatic temperature shift.
Unfortunately, the winters in Michigan and the surrounding Great Lakes region have been anything but normal over the past few years. 2011 saw unseasonably winterish conditions in April and May, which are the months where most Great Lakes fish spawn and hatch, while 2012 experienced such a dramatic heat wave in March that the fish populations weren’t the only things affected. Michigan, usually a hot bed for fruit growth – cherries especially – lost the vast majority of its local crops when the March heat wave was followed by freezing temperatures mere weeks later. Fish species that decided to spawn early likely experienced the same destruction.
What does this mean for fishermen, beyond the obvious consequence of fewer fish to catch? For one thing, the dominant fish populations in the Great Lakes could begin to shift, a process of natural selection that would likely choose an adaptable species such as the white perch over a more delicate population like the yellow perch or walleye. Currently, Lake Erie is especially famous for yellow perch, but if that population begins to disappear, the lake’s reputation could begin to change too. The same goes for the rest of the Great Lakes: they could all be in for major upheaval if the irregular winters continue.