Lake Ontario, Niagara, St. Lawrence River Smallmouth Declining?

Lake Ontario, Niagara River and St. Lawrence River smallmouth bass are declining in numbers even as the size of the bass being caught is increasing.

This is a common pattern that is being seen in other areas of the US and Canada, home to the smallmouth bass. The bass that survive can thrive due to less competition and the ability to eat large numbers of gobies, a favorite food. Less bass are surviving however due to disease and invasive species.

The possible causes are discussed thoroughly in the article published recently in the Oneida Dispatch.

Guides who know the river, the smallmouth’s preferred locations, and the habits of the fish can also catch fish. A decade or two ago they could usually take a couple clients out and catch 50 fish in a day. Now they have to work hard to catch a dozen. Fishing guides from Niagara Falls to Ogdensburg have told me the same thing.

Creel surveys and general comments of the average angler have said they have similar experiences of declining numbers. This does not count the problems of viral hemorrhagic septicemia (VHS) that occurred a few years ago the central area of the Lake Ontario shoreline. Net surveys taken by the DEC each year show much smaller numbers of smallmouth in most areas.

In the past couple decades the habitat has changed due to invasive species like zebra mussels. There has been the well known predation on small bass by cormorants, and now the infestation of round gobies (another invasive species).


Gobies are believed to heavily prey on the eggs of smallmouth bass as they spawn. Studies in Ontario and Wisconsin show this. Northern pike and perch are less subject to this problem because they spawn earlier when the gobies are less active.

One study using underwater cameras focused on bass nests. They showed catching, landing and subsequently releasing the male bass who was guarding the nest. In just that short time lapse, gobies rushed in and consumed 40% of the eggs on the nest. This is a main reason why anglers and guides in northern waters are dead set against a pre-season catch and release season.

Those eggs that hatch into small bass face the usual obstacles to survival, but none greater than cormorants. These fish eating birds consumer prodigious amounts of fingerlings and small bass. Studies and examination of the crops of cormorants show that they eat a pound of fish a day, and a great deal of that is small bass.

The small percentage of smallmouth bass that survive have less competition for food. In fact mature bass feed on gobies, thus growing large from the abundant supply. This is why you are likely to catch larger, bragging sized bass these days in the waters of many Lake Ontario bays and the Niagara and St. Lawrence Rivers. Source

There is a fine balance in nature sometimes and it seems some fisheries are able to tolerate insults to this balance more than others. In a recent post about Maine smallmouth bass, the old timers that remember the rivers last century spoke of water so polluted that no fish were able to survive and now these waterways are prime fishing locations.

Let’s hope that the Lake Ontario, Niagara River and St. Lawrence smallmouth bass are able to thrive despite these challenges and stop their decline.

If you have experience fishing these areas, please let me know and comment below or on our Facebook page.

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