The 4 Bad Effects Of Motorboats On Lakes And Rivers

Who doesn’t love a day at the lake or river?

There is nothing like being on the water in a kayak, canoe, or raft. Paddling is a wonderful experience. Many even fish from kayaks and canoes (and at one point in my life, even from an inflatable raft…). It is mostly harmless to the environment and can be enjoyed with a clear conscience.

Some, in order to free up their hands to fish, and still move, use silent, non-polluting electric trolling motors. Of course, in modern times, people are always pushing to move faster, no matter what the activity, so to that effect, many use hydrocarbon-burning, loud motorboats. Last year, it was estimated that there are over 12 million motorboats in use in the United States.  Sales of motorboats in 2018 totaled well over 20 billion dollars¹.

Every day, millions of people use motorboats to fish, ski, Jet Ski, or just ride around for pleasure. It’s next to impossible to go to any lake or large river and not see some motorboats.  Of course, no one wants to dowse anyone’s fun, but we need to ask..

Do all these hydrocarbon fuel-burning boats have an impact on the ecosystem of the water?

The 4 Effects Of Motorboats On Lakes And Rivers

According to most studies, the effects of motorboats fall into four major categories:

1. Chemical Pollution

Boat engines are not very efficient. Outboard engines are worse than inboards, and two-stroke engines are by far the worse. Many lower-powered boat motors are two-strokers. If you look behind any motorized boat (except one using an electric motor) you will see a beautiful rainbow on the water.

But like the beautiful but dangerous Zebra Fish, appearances can be deceiving. That rainbow is unburned fuel and oil polluting the water. Sure, it looks like just a little bit, but the engine keeps spewing unburned fuel and oil as long as it is running. And there are mostly like several hundred other boats on that water doing the same thing every day. This fuel and oil never goes away. It is not biodegradable. This introduces metals and harmful chemicals which can affect the water PH and oxygen levels adversely. This does have a bad effect on the local wildlife and vegetation.

2. Sedimentation

All boats must go through some shallow water to launch and land. The propellors stir up sediment which becomes suspended in the water column. This creates turbidity, which affects the amount of light that can penetrate the water and can harm certain aquatic vegetation. It can also destroy spawning areas that many fish require to reproduce.

And possibly the worst effect is that it can suspend many times more nutrients that should be on the bottom, which can cause massive algae blooms. Algae blooms can be devastating to fish populations, which can affect all the other aquatic and semi-aquatic life, including ducks, geese, beavers, otters, turtles, snakes, etc…

3. Shoreline Erosion

When underway, boats generate a wake, or bow wave on each side of the boat, which will eventually hit the shore somewhere. Its impact will depend on the speed of the boat, and the distance to the shore.

Even small waves can have a significant effect on the erosion of the shoreline. This can damage nesting areas for many birds, waterfowl, reptiles, and amphibians. It can adversely affect the habitats for beavers, muskrats, otters, turtles, alligators, etc… It can damage or even kill shoreline vegetation and change the ecosystem completely, over time.

4. Noise Pollution

Boats make a tremendous noise underwater, as any diver can tell you. And it travels very far underwater and faster than through air. Also, the propellors make serious vibrations in the water. Fish are designed to rely on both sound and vibrations to find food, and avoid predators. They have a lateral line to detect vibrations and a sense of hearing far better than humans, but neither of these were designed to operate at the volumes and frequencies that boat motors generate.

A recent study published last year shows a severely detrimental effect on fish survival, as much as a 70% reduction, due to the noise and vibrations from boat motors. It’s been known for a long time that natural fish populations have been declining since the late 19th century, both in numbers and size. It was commonly accepted that it was from over-fishing, but the decline mirrors the use of motorboats pretty close. New studies indicate that noise from boat motors may affect the survival of young fish to a significant extent, which could explain the overall decline since the 1890s.

Boating is fun and is a very profitable industry, but perhaps it is time to enact at least some restrictions on it in order to protect our irreplaceable ecosystems so that our future generations will be able to enjoy the same aquatic activities we currently cherish.

Happy fishing…

Leave a Comment