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  • Shannon Carnevale & Hanley Renney

What Otters Can Teach Us About Our Lakes

July is National Lake Appreciation Month, a fitting designation for one of the busiest times of year for water sports and recreation here in Central Florida.

With so many people using the lakes, there are bound to be concerns about the health of our waterways. However, we can actually address many of these concerns by observing just one species: the North American river otter (Lontra canadensis).

These semi-aquatic animals are plentiful both in and out of the water and can often be spotted on docks or in waterfront backyards. Most of the time, they are found splashing and rolling around with one another, as if they don’t have a care in the world! Otters are incredibly social animals and playing with one another is one of the main ways they interact.

Happy otters are typically healthy otters, and healthy otters often mean healthy lakes. This is because otters are an important ecosystem indicator species. Their presence or absence from an area can be a sign of environmental health, water quality, and the effects of pollution. One primary reason that otters function as an indicator species is a process called biomagnification, or the build-up of pollutants as they ascend the food chain.

Because otters consume so much prey, the process of biomagnification is rapidly advanced. Their primary source of food is fish, but they can also be found munching on other aquatic creatures, including frogs, crayfish, turtles, and invertebrates. Otters are voracious predators, and they may consume up to 20% of their body weight in a single day, which can add up to over five pounds of meat. Over time, pollutants that have built up in their food sources can also build up in the tissues of an otter’s body, leading to poor health or reproductive problems.

If a certain pollutant is present at a high enough concentration that it affects the otter population, there is likely cause to be worried about the health of the environment, the water, and even the humans living nearby. As the old saying goes, “the poison is in the dose.” While a small amount of that pollutant may not be an issue for a smaller organism, a large amount of it could be for the otter.

Otters also reflect the health of larger systems, such as watersheds, which channel water into lakes, creeks, and rivers. On a smaller scale, each lake here in Polk County has its own watershed, sometimes referred to as a lakeshed, just like our springs further north; you may be more familiar with the term springshed.

The connections created by these systems mean that even if you don’t live directly on the water, the landscape around your house or apartment also impacts the health of our watersheds and ultimately, the lakes.

Here in Polk County, there are certainly aspects of our lake health in need of improvement; however, the thriving otter population in the central Florida region is a testament to the overall health of our water bodies, which bodes well for many years of outdoor and water recreation to come!

We can all play a role in maintaining healthy watersheds and supporting our otter populations by adopting these practices:

· Trash your trash and pick up poop: Make sure litter, trash, and other items are properly disposed of. Dog poop can introduce parasites, elevated protein levels, and bacteria to our lakes, ponds, and rivers, so please pick up after your dog… even in your backyard.

· Reduce use of broadcast herbicides and insecticides in yard care: If you’ve got a pest or weed issue, use a targeted product rather than a multi-tasker. Plants and insects are important parts of the ecosystem and food web.

· If you have questions, you can call the UF/IFAS Extension Plant Clinic at 863-519-1057 or email them at

· Install a rain garden or redirect gutters to your yard, rather than down your driveway: We can all contribute to watershed health by keeping the rain that falls on our property, on our property. When rain collects pollutants from yards, sidewalks, and roads, it flows into our stormwater drains and then flows straight to our lakes! Let that water seep into the green areas of your neighborhood or yard instead.

When you see otters or other wildlife while boating or spending time near the water, remember to practice safe wildlife viewing techniques. These animals are fun to watch from a safe distance but getting too close or harassing them may disrupt their natural behavior—we wouldn’t want to interrupt otter playtime or harm this indicator species. And, for our waterfront residents, we know otters can make a mighty big mess. We can practice a little tolerance towards their messy play and eating habits by keeping a hose nearby to clean off docks or seawalls after the otters leave.

Regardless of how you enjoy the water this summer, keep an eye out for our otters from a safe distance, and keep in mind that happy, healthy otters mean healthy lakes and watersheds!

This article was written by Natural Resources Extension Program Intern, Ms. Hanley Renney, under supervision by Natural Resources and Conservation Extension Agent, Mrs. Shannon Carnevale.


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