Lampsilis cariosa

Adults can grow to 75-155 mm (approx. 3-4 inches). They display sexual dimorphism. Adult females are rounder shaped and adult males more elongated. The shells are glossy, yellow to reddish-brown, and have greenish colored growth rings. L. cariosa can be mistaken for other Unionidae like Atlanticoncha ochracea and Lampsilis cardium. in Medway, Maine == Distribution and Habitat ==

This species is currently believed to occupy 124 watersheds in Canada and the United States. == Ecology and Life History ==

Lifespan L. cariosa can live up to 15 years and reaches sexual maturity around 2-4 years. The glochidia are typically fertilized in late summer or fall and mature as the female overwinter. Females are gravid from March to October, making them bradytictic. Reproduction L. cariosa and other Lampsilis utilize a parasitic reproductive strategy. Lampsilis sp. display a mantle-flap that resembles a small bait fish that attracts larger predatory fish. These fish bite down on the mussel, which then releases the glochidia and they embed themselves into the fish's gills. They remain until they detach after 14-55 days as juveniles. Host Fish Relationships The habitat range of L. cariosa depends greatly on the presence and abundance of host fish species. Confirmed host fish species include Morone americana and Perca flavescens. Researches have successfully used Micropterus salmoides, Pomoxis nigromaculatus, Morone chrysops, and Morone saxtilis as host species in lab settings. == Conservation Status and Threats ==

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has listed it as a species of special concern. The Canadian Species at Risk Act listed it in the List of Wildlife Species at Risk as being a species of special concern in Canada. It is believed to be extirpated in Rhode Island and Vermont. It is listed as endangered in four U.S. states (Massachusetts, Connecticut, Delaware, and North Carolina) and is listed as a special status in 10 other states. L. cariosa faces many serious threats. Warming waters due to climate change are affecting that habitability of aquatic systems for many of the host fish species, leading to a decrease in L. cariosa. Habitat fragmentation caused primarily by the construction of dams have also led to the decrease in host fish species. Competition from other invasive bivalve species like Zebra mussels (Dreissena polymorpha) and Asian clams (Corbicula fluminea) also threaten the status of L. cariosa and other native freshwater bivalves. == Restoration Efforts ==

Captive propagation is a very effective tool for rebuilding freshwater mussel populations. A multi-state restoration effort led by the Virginia Department of Wildlife Resources Aquatic Wildlife Conservation Center uses this method and as of 2025, has released over 72,000 L. cariosa into Virginia watersheds. == See Also ==