The threatened (yet potentially plentiful) eastern musk turtle

Posted by Sarah Larocque

Few have seen the eastern musk turtle (Sternotherus odoratus), more commonly known as the stinkpot turtle. This might seem logical because of its current status as a threatened species both provincially and nationally. Perhaps just as likely is the possibility that this turtle goes relatively unnoticed because of its small size and highly aquatic lifestyle.

With a carapace length of up to 137 mm, the stinkpot is one of North America’s smallest turtles, inhabiting shallow water bodies with muddy bottoms. Stinkpots crawl along the bottom and probe in the mud, sand, and vegetation for food of almost any type. Being bimodal breathers (able to exchange gas in both air and water), stinkpots remain submerged for long periods of time. As a result, the stinkpot often has algae growth on its shell, further camouflaging it from human eyes. Instead of basking out of water, stinkpots bask at the water’s surface with their carapace exposed or floating in among aquatic vegetation, and thereby go unnoticed unlike typical basking turtles.

Rarely leaving the water’s edge, stinkpots are hard to detect, let alone quantify their population size. Fortunately, my work involving hoop nets allowed me to come across the stinkpot on numerous occasions. For example, from my spring sampling of 105 net sets in 2010, we captured 111 stinkpots (74 males; 37 females). In comparison, we only captured 101 painted turtles (Chrysemys picta; 67 males; 34 females), a species that appears quite common. Similarly, in fall with 60 net sets, we captured 48 stinkpots (45 males; 3 females) which was nearly twice as many as the 26 painted turtles (21 males; 5 females).

Lake Opinicon is known to have healthy turtle populations; however, it is surprising to find that a threatened turtle like the stinkpot has higher catch rates than the commonly found painted turtle. There have also been reports of large numbers of stinkpots in nearby Lower Beverly Lake. For a threatened species, this is good news. Unfortunately, we only have number of captures and neither the actual population size nor data on whether populations are increasing/decreasing/status quo.

The stinkpots threatened status is in part from attributable to such factors as shoreline development and boat collisions.  Yet perhaps in part its status is due to it being difficult to detect … maybe these small critters are more plentiful than once thought (at least in Lake Opinicon)!