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Wavy-rayed Lampmussel
SARA Status: Special Concern (March 2013)
COSEWIC Status: Special Concern (April 2010)
Region: Central and Arctic (Ontario)
Did You Know?
Freshwater mussels are molluscs, soft-bodied animals without a skeleton (invertebrates), that live on the bottom of streams, rivers, lakes and ponds. They use a muscular foot to burrow and crawl and have a pair of hinged shells. Mussels are filter feeders — nature’s water purifiers — and are food for other wildlife like fishes, otters, mink, muskrats and some birds. They are also among the most endangered creatures in the world.
Mussel species aren’t just at risk due to direct threats such as habitat destruction. Because they depend on host species for the development of their young, they’re also vulnerable to the effects of declines in host populations. This is the case with the Wavy-rayed Lampmussel, whose host fish—the Smallmouth bass—has declined in the Grand River due to fishing.
Photo: Shawn Staton, DFO
Photo: Todd Morris, DFO
Related Information
COSEWIC Assessment and Status Report on the Wavy-rayed Lampmussel Lampsilis fasciola in Canada (2010)
Recovery Strategy for the Wavyrayed Lampmussel (Lampsilis fasciola) in Canada (2007)
SARA Registry – Wavy-rayed Lampmussel
Aquatic Species at Risk - The Wavy-rayed Lampmussel
Description
Habitat
Threats
Scientific Information
Further Information
Lampsilis fasciola (Rafinesque, 1820)
Male (left) | Female (right)
Photos by National Water Research Institute
The Wavy-rayed Lampmussel (Lampsilis fasciola) is one of five species of the genus Lampsilis that occur in Canada and has the following characteristics:
- Yellow or yellowish-green in colour with numerous thin, wavy rays;
- Rays may be narrow and individual, or thin and coalesced into wide rays, but they are always wavy with numerous interruptions;
- Inside of shell may be white or bluish-white;
- Shells are rounded at both ends, while top and bottom are nearly parallel; Males are quadrate-ovate and females are ovate in shape;
- Shells are usually less than 75 mm long, but may reach 90-100 mm in length;
- Shells are heavy and strong, moderately inflated, with a mid-anterior shell-wall thickness of about 7.5 mm;
- Smooth shell surface, except for concentric wrinkles and growth rests;
- Posterior ridge is indistinct;
- The beak (raised part at the top of the shell) is elevated and beak cavities are moderately excavated; and
- Triangular teeth at the front edge of the hinge are short and divergent, and there are two in each half of the shell.
Wavy-rayed Lampmussels have historically been found in 13 U.S. states and the Great Lakes southern drainage of Ontario. Currently in Ontario, they are found in one lake and its associated river system (Lake St. Clair delta and the St. Clair River), and four other watersheds: the Ausable, Grand, Maitland, and Thames rivers, and their associated tributaries. Recent population estimates suggest that the Wavy-rayed Lampmussel populations are gradually improving in southern Ontario, with the exception of the St. Clair population.
The Wavy-rayed Lampmussel lives mainly in gravel or sand bottoms of riffle areas in clear, medium-sized streams. As it usually burrows into the substrate, it may be particularly sensitive to siltation. The Wavy-rayed Lampmussel is a moderately long-lived, sexually-dimorphic species with a lifespan of at least 10 years, but rarely more than 20 years. Spawning likely occurs in late summer and the glochidia (larvae) are released the following May-August. In females of the genus Lampsilis, the edge of the mantle has evolved into a minnow-shaped lure that is used to attract potential fish hosts when glochidia are ready to be released.
Two hosts for this species have been identified in Ontario: the Smallmouth Bass (Micropterus dolomieu) and the Largemouth Bass (Micropterus salmoides). Like all freshwater mussels, the Wavy-rayed Lampmussel uses bacteria and algae as its primary food source.
The dominant threats to most of the Wavy-rayed Lampmussel populations are declining habitat quality and overall habitat loss resulting from agricultural and urban activities. Water quality is a primary threat to the Wavy-rayed Lampmussel. Similar to most freshwater mussels, the Wavy-rayed Lampmussel is extremely sensitive to a number of chemical contaminants, including copper and ammonia, particularly during their glochidial (larval) and juvenile life phases. Water quality is further degraded by runoff of sediment, pesticides, herbicides and fertilizers into nearby watersheds, along with manure and trampled riparian vegetation. An estimated 15 per cent of the Wavy-rayed Lampmussels traditional habitat is also overlapped by the invasive Zebra Mussel, primarily in the St. Clair River and delta. Due to the Zebra Mussels’ ability to attach themselves directly to hard surfaces (such as other freshwater mussels), the Zebra Mussels directly impair the Wavy-rayed Lampmussels’ ability to feed, respire, reproduce and even move.
For further information, visit the SARA Registry Website.
Scientific Name: Lampsilis fasciola
SARA Status: Reclassified as Special Concern from Endangered (March 2013)
COSEWIC Status: Special Concern (April 2010)
