Aquatic Species at Risk

The northern riffleshell is a small, colorful freshwater mussel that lives in highly oxygenated riffle areas of rivers and streams. This subspecies has suffered dramatic declines throughout its range in North America and is now globally endangered. The Sydenham River population still appears relatively healthy and is one of only three reproducing populations left on the continent. The northern riffleshell occurs only in the middle to lower reaches of the East Sydenham River.

In propagating, Northern riffleshell females gape widely allowing fish to be caught well behind the head, or even completely engulfed if small, so that glochidia (mussel babies) can be attached to the fish. What happens next is cruel and unusual... In this video clip (5 MB), a lightly anaesthetized darter is caught, the mussel then inflates the mantle pads, which nearly suffocate the fish. When the fish ceases struggling, the mussel retracts the pads and cradles the fish while it recovers, gasping and inhaling glochidia. Such finesse! This capture strategy may facilitate use of a wider range of hosts than the “snout-grabbing” of snuffbox. (from http://unionid.missouristate.edu/gallery/Epioblasma/default.htm)

Sydenham Species At Risk
c/o St. Clair Region Conservation Authority
205 Mill Pond Cres., Strathroy, ON N7G 3P9
2001 Sydenham River Recovery Team