Otters in Our Lake

By:  Jim Fell, Lake Management

Roaming Shores residents have frequently photographed or published sightings of river otters at our lake.  To help evaluate the potential impact of otters on the lake fishery, RRA Lake Management recently attended a presentation on otters hosted by Pymatuning State Park.  Kelly Ashcraft Pearce, PhD, a biology professor at Allegheny College, presented her findings from many years of masters and doctoral study of river otters.  Jared McGary, Pennsylvania Department of Conservation and Natural Resources reported on his research of otters specifically at Pymatuning lake. 

In pioneer times river otters lived in the waterways of our area but were extirpated as a result of  excessive trapping, loss of habitat, and poor farming practices that allowed silt to muddy waterways making it difficult for otters to visualize and catch prey.  Beginning in 1986, the Ohio Division of Wildlife began to reintroduce otters into selected watersheds, including the Grand River.  The otters seen in our lake probably originate from upstream migration of generations of their offspring. 

Dr. Pearce’s doctoral research involved collecting otter scat (feces) and processing it in order to analyze otter food sources.  By examining fish bones and scales, as well as remains of crayfish and other aquatic animals, Dr. Pearce concluded that 80% of otters’ diet consists of crayfish, frogs, salamanders, etc. in the spring and early summer, but then would more heavily rely on fish later in the summer, fall, and winter when crayfish and amphibians were burrowed into the mud. From study of fish scales and bones in otter scat, Dr. Pearce determined the predominant species captured by otters were carp, suckers, bullheads, catfish, and perch.  Dr. Pearch suspects that remains of sport fish, such as trout, were found in less abundance in otter scat because these species are faster and more difficult for otters to catch.  Otters are also an essential part of the original ecosystem of our area because they remove sick and disabled fish from the water.  Mr. McGary utilized trail cameras to study otters at Pymatuning and its watershed.  During the annual shad die-off, otters will feast on these forage fish in Shenango Creek below the dam which can be a good location to observe them.

Otters tend to be very territorial and will mark their territory with their scat and a musky scent called spraint.  They live in low population densities.  The range of an otter can average from 3-12 square miles, and they are constantly on the move.  Typically, otters will not “homestead” in one locale and subsequently will not overly deplete the food supply in any given area.  Dr. Pearce’s master’s thesis research concerned the impact of otters on the many federal, state, and private fish hatcheries in Pennsylvania.  While otters would visit fish hatcheries for food, only one operator reported that otters were a problem with hatchery operations. 

The 2022 fish study at our lake revealed that overall the fishery health was good; however, the RRA and Lake Management will continue to monitor water quality, nutrient, aquatic plant, algae, and fish populations for early detection of any changes impacting the lake ecosystem.