Dwarf Wedgemussel

Species Name: Alasmidonta heterodon

Species Distribution in Massachusetts


Federal Rank: Endangered

Massachusetts State Rank: Endangered

Habitat Description

Historically, the Dwarf Wedgemussel’s habitat ranged from Atlantic coastal watersheds in North Carolina to New Brunswick. Dwarf Wedgemussel can be found in Massachusetts’ Connecticut River watershed, which contains the largest population of Dwarf Wedgemussel. It inhabits both small streams and large rivers of many substrate types, generally living in shallow waters. Dwarf Wedgemussel prefers areas with large amounts of silt and is patchily distributed throughout rivers.

Threats to Survival

Many reasons are attributed to the endangerment of Dwarf Wedgemussel: overall short lifespans, low fertility, low population density, and host specificity result in limited Dwarf Wedgemussel populations. As stationary filter feeders, Dwarf Wedgemussels are unable to move from their endangered environments and are vulnerable to waterway alterations as well as many other threats caused to their habitats.

Actions Recommended to Ensure Survival

Collection of Dwarf wedgemussel population data and the discovery of Wedgemussel populations is instrumental to the overall protection of freshwater mussels. Monitoring Dwarf Wedgemussel populations and habitat can help effectively target conservation and restoration efforts. Surveys are critical to restoring Dwarf Wedgemussel populations, as they help ensure understanding of their behaviors and affinity for life in different habitats. Eliminating sources of pollution, maintaining river flow and river vegetation, limiting water withdrawals, and identifying barriers are also ways to improve the population density of Dwarf Wedgemussels.