Background: The BMNHC covers for the work of Aleta Karstad and Frederick W. Schueler, seeking to explore, conserve, and communicate understanding of landscapes, their living communities, and their natural history and biotic diversity, through art, scientific research, conservation of populations, data, & specimens, publication, and collaboration with individuals & organizations with similar goals. Research Curator Dr. Fred Schueler is a member of the Canadian Freshwater Mussel Working Group, and the BMNHC holds the fourth largest collection of freshwater mussels (Unionoidea) in Canada. You can learn about contributing to the study of freshwater mussels by.downloading "Send Me a Bag Full of Clams" and "the Clam Study Data Sheet" from the South Nation Conservation website.
The Bishops Mills Natural History Centre is pleased to report the discovery of the imperilled Eastern Pond Mussel or Pointed Sand-shell, Ligumia nasuta, in the Lyn Creek watershed near Brockville. Old shells of this species were found last summer, but now living individuals have been found, and it is suspected that the small, naturally muddy, Lyn and Golden creeks between Lyn and Sherwood Springs support a healthy population of the species.
Until the introduction of Zebra mussels, Ligumia nasuta was not uncommon in Lake Erie and Lake Ontario and their tributaries, including the lower Rideau Canal, but it is one of the species of native mussel that has suffered the most from Zebra Mussels (Dreissena polymorpha). The "Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has commissioned a Status Report on Ligumia nasuta, and the Status Report is due for completion early next year. COSEWIC is planning to assess the conservation status of the species at its May 2007 Species Assessment Meeting.
On 9 August 2006, Fred Schueler and Ryan Hawke, of the BMNHC, found L. nasuta in Lyn Creek at Murphy Road, in mud so deep and soft that it was hard for the investigators to move without a great struggle. They surveyed only 25 square metres of the bottom, but found 4 living L. nasuta, and collected 6 shells, the largest 85 mm in length. About 5 km downstream, where the stream loops close to West Hallecks Road, they found one L. nasuta shell among many shells and living individuals of commoner species of native mussels. There are no bridges or settlements between the two sites, and the habitat is as undisturbed as anywhere in eastern Ontario, so there is no reason to think L. nasuta is not present all along this stretch of the creek, and perhaps also in the lower reaches of Jones Creek, which Lyn Creek joins just above its outlet into the St Lawrence River.
(continued with more background discussion below photographs -- all photographs by Aleta Karstad)
August 2006. Green algae cover the posterior portion of the shell that usually protrudes from the substrate.
August 2006. The largest shell is 85 mm long.
September 2005. The largest shell is 60 mm long.
Before the invasion of Zebra Mussels, Ligumia nasuta was found in protected areas of lakes, backwaters of slow rivers, and in canals. It had not been found as far downstream along the Saint Lawrence as Brockville, but was known from the Lake Ontario drainage of the Rideau Canal. Zebra Mussels, introduced from Europe in 1986, kill the native Unionid mussels by clustering around their water siphons and starving or suffocating them. They have eliminated the much larger native mussels from lakes Erie and Ontario, the Saint Lawrence River, and the lower Rideau and South Nation rivers.
Ligumia nasuta can be recognized by its slender shape, combined with the notch on the posterior shell, giving the end of the shell the appearance of a protruding snout (this effect is stronger in males, which have a more slender shell shape than females). There's a sketchy account of L. nasuta in the New York Metropolitan Region and New Jersey Freshwater Mussel Identification Handbook and downloadable accounts of the species from state agencies in South Carolina, and Massachussetts. Please advise the BMNHC or André Martel at the Canadian Museum of Nature of any shells matching this description.
The most general treatment of Ontario Unionids is the 1997 Biodiversity of freshwater mussels in the lower Great Lakes Drainage Basin by J.L. Metcalfe-Smith, S.K. Staton, G.L. Mackie and N.M. Lane. This report found that L. nasuta was "once a major component of the mussel community (5th largest number of records prior to 1960)," and expressed hope that "If L. nasuta is officially designated by COSEWIC, then funds will be accessible under the RENEW strategy for developing a recovery plan that could include protecting... [a healthy population in a small lake in Prince Edward County] as a refuge for this species." Unfortunately, the populations in Prince Edward County lakes, as well as one found by Fred Schueler and Anita Miles in 1996 in Beaver Lake, at Erinsville , have now all apparently been eliminated by Zebra Mussels.
It seems that Zebra Mussels will be introduced into any lake where boats are launched from trailers, so the only hope for Ligumia nasuta may be populations in streams without lakes. The only standing waterbodies in the Lyn Creek drainage are wetland-surrounded ponds only about 1 km long: Lambs Pond, south of New Dublin, and Lees Pond, north of Lillies. Since these are both surrounded by wetlands and without public access, there's as much hope that Zebra Mussels won't be introduced to them as there is anyplace, possibly giving the Lyn Creek Ligumia the chance to persist for the foreseeable future.
The BMNHC's aquatic surveys are supported through the Canadian River Management Society; the BMNHC is seeking funding to support a detailed survey of the Ligumia nasuta they have dicovered in Lyn Creek, and to continue their survey of the mussels of the Jones/Lyn/Golden Creek drainage, Hoasic Creek, and similar tributaries of the St. Lawrence.
Both Zebra mussels and L. nasuta are depicted in Aleta Karstad's drifted painting of the first onslaught of Zebra Mussels in Lake Erie.
This is a detail of the larger Drifted!! painting.