Lilliput: Consultations on down-listing on the List of Wildlife Species at Risk

Information summary and survey for the consultations on potentially down-listing Lilliput on the List of Wildlife Species at Risk from endangered to Special Concern.

Please fill out the survey.

Engagement

Let your opinions be heard

Canada’s Species at Risk Act (SARA) provides legal protection for wildlife species at risk to conserve biological diversity. It also acknowledges that all Canadians have a role to play in the conservation of wildlife species. Before deciding whether Lilliput (Toxolasma parvum) will be down-listed on the List of Wildlife Species at Risk from endangered to Special Concern, we would like to hear your opinion, comments, and suggestions regarding the possible ecological, cultural, and economic impacts of down-listing or not down-listing this species under SARA.

Down-listing a species from endangered to Special Concern on the List of Wildlife Species at Risk

The process of down-listing a species under SARA consists of several steps. It begins with a status reassessment by COSEWIC and ends with a Government of Canada decision on whether or not to down-list a species on the List of Wildlife Species at Risk. Public consultations are conducted to gather the opinions of Canadians and are an important step in this process.

Facts about Lilliput

• The Lilliput is a small freshwater mussel (maximum length of 5.8 cm), and is one of the smallest freshwater mussels in Ontario
• The species can be distinguished from other freshwater mussels by its brown to brownish-black shell and the absence of rays
• It can be found in a broad range of habitats, namely from small to large rivers, wetlands, lakes, ponds, and reservoirs, typically over bottoms with muck, detritus, sand, silt, and clay
• The Lilliput is a filter feeder and requires a host fish to complete its life cycle. Host fishes have not been identified for Lilliput populations in Canada. Six fish species have been identified as host fishes for Lilliput in the United States:
  • Bluegill (Lepomis macrochirus)
  • Green Sunfish (L. cyanellus)
  • Johnny Darter (Etheostoma nigrum)
  • Orangespotted Sunfish (L. humilis)
  • Warmouth (L. macrochirus)
  • White Crappie (Pomoxis annularis)
• In Canada, Lilliput is found only in Ontario within the Lake St. Clair, Detroit River, Like Erie, and Lake Ontario drainages (Figure 1)

Who assigned the Special Concern status to Lilliput?

In 2025, the Committee on the Status of Endangered Wildlife (COSEWIC) re-assessed Lilliput in Canada from endangered to Special Concern. COSEWIC is an independent committee of experts that assesses which wildlife species are in some danger of disappearing from Canada and assigns a status to these species. It conducts its assessments based on the best available information including scientific data, local ecological knowledge, and indigenous traditional knowledge. Under SARA, a Special Concern species is defined a wildlife species that may become threatened or endangered because of a combination of biological characteristics and identified threats.

Why is the Lilliput at risk?

COSEWIC re-assessed the Lilliput from endangered to Special Concern because 18 new subpopulations were discovered as a result of increased sampling effort, and there is no evidence of continuing decline in abundance. However, the species maintains a limited distribution where habitats are highly degraded as a result of urban and agricultural pollution, agricultural dredging, water management activities, and droughts.

If a species is down-listed under the Species at Risk Act

If Lilliput is down-listed as Special Concern, the kill, harm, harass, capture, possess, buy, sell, or trade prohibitions of SARA would no longer apply to the species, and critical habitat would not be identified.  A management plan would be developed to identify conservation measures to address known threats and to identify actions that can be taken to help conserve the species.

Additional information

• PDF format: Recovery strategy and action plan for Lilliput in Canada (PDF, 2.5 MB)
• HTML format: Lilliput (Toxolasma parvum): recovery strategy and action plan 2022
• Lilliput (Toxolasma parvum)