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Concentration of CO2 in the Atmosphere

Time to Go Fishin’

Fishing in a stream in Vermont. Tim McCabe, USDA Natural Resources Conservation Service.

George Harvey

We have over ninety species of fish in the Northeast, and many of them are abundant, fun to catch, and tasty. With climate change and pollution, we have some cautionary notes, but the opportunities abound for sport fishing all through the year. In fact, fresh water fishing may be one of the outdoor activities that has been so far least changed by warming weather.

True, the ice fishing season may suffer with warmer winters. But the biggest threats to fish species are still in the future, rather than the present. Invasive species that threaten aquatic environments exist, but their impacts are not as difficult as those felt by moose, for example, which are suffering declining populations due to invasive ticks.

It is true that fishing is under pressures that all anglers should be aware of. While climate change has not yet altered fresh water fishing terribly, pollution problems have been around a long time. We can think back to the nineteenth century, when there was a thriving commercial fishing fleet in Lake Champlain. Overfishing and pollution did their work on that. But even here, the pollution is not as bad as it could be. PFAs are found in our food and water, but have not been shown to be bioaccumulating in our fish, as yet. Microplastics have also appeared in the news. But they have not appeared in any alarming way in our fresh water fish, as yet.

There are some contaminants anglers should be aware of. Historically, our waters were polluted by mercury emitted by coal fires, largely in the Midwest, and the methylmercury it produced is still in our waters. More modern pollutants include PCBs and others. Levels of these contaminants vary widely among species of fish and different bodies of water. Some pollutants tend to accumulate in fish that are higher on the food chain, and bigger fish are likely to have more contaminants than smaller ones. Also, effects of methylmercury are much worse problems for the youngest children, so extra care should be taken by those who are six or younger and by women of child-bearing age.

The states have advisories, and it is good to review these for your state. NH: http://bit.ly/eat-fish-safely-nh, NY: http://bit.ly/eat-fish-safely-ny, and VT: http://bit.ly/eat-fish-safely-vt.

Other pollutants are also of high concern today. One is PFAs, which seem to be everywhere. Another is from agricultural runoff, which often contains phosphates which can lead to algae blooms and large amounts of cyanobacteria in the water. And there are such toxins as glyphosate (the active ingredient in products like Roundup).

Having said all that, fishing is definitely alive and well in the region. And locally caught fish can be an important part of a healthy diet.

Eric Palmer, Vermont’s Director of Fisheries, told us a few things we did not know about fish in Vermont waters, including Lake Champlain. “When folks think of climate change, they think of warming and the effects of warmer water on fish. It is true that warmer winters produce less ice cover and earlier ice-outs. But when I think of climate change, I think of higher precipitation, including its impacts.”

While higher precipitation can produce devastating impacts, especially for such fish as brook trout, so can drought. These fish need cool water, where the levels of oxygen are high and their metabolisms are not unduly increased. With heavy rain, they can be washed down to water too warm for them. But in a drought situation, they may not be able to get to cool water at all. “Being able to move is one factor of climate change,” Palmer said.

When we asked about dams, he said they are only part of the problem. “In Vermont, one of the main barriers to fish movement is road crossings and culverts. They have to be built correctly, with the right slope, orientation, and width, to accommodate sediment. Too steep or too shallow and they block fish movement entirely. Size, slope, and orientation are the issues.”

He also put focus on an issue most people might not think about. A lot of the food fish eat actually comes from the forest. He said there is a saying, “Fish grow on trees.” The trees are habitat-forming features, especially when they die and fall into the river. Having good habitat and especially good vegetative buffers make it easier for trout to survive. But with a decline in the health of forests and a changing climate, there will be effects that will be harder to predict on fishing.

As for the future of fresh water fishing in the Northeast, the changes brought about by a warming climate are far more obvious for land-dwelling animals, such as moose, than for fish. Climate change is here, and it is getting worse.

In the broader picture, salt water fishing is definitely changing as the seas warm. While declines in global catches of salmon may suffer from habitat destruction and cod may suffer from overfishing, there are definitely changes relating to carbon emissions and changing climate. Ocean acidification due to dissolved carbon dioxide is reducing the ability of shellfish to produce shells. Lobster harvests are reduced in southern areas as the location of densest population is moving farther north. Some ocean fish are also on the move, creating another set of environmental problems.

But fresh-water fishing is still a great opportunity to get outdoors, spend some time in nature – and maybe have a good meal.

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