Atlantic Mud-Piddock

Barnea truncata

SARA Status
No Status
NS
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

SARA Status

  • No Status NS
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX
COSEWIC Status
Not at Risk
NR
Special Concern
SC
Threatened
TH
Endangered
EN
Extirpated
EX

COSEWIC Status

  • Not at Risk NR
  • Special Concern SC
  • Threatened TH
  • Endangered EN
  • Extirpated EX

Description

The Atlantic Mud-Piddock (Barnea truncata) is an intertidal bivalve mollusc. One of only two species in its family in Atlantic Canada, this unique species has the following features:

  • A thin delicate ridged shell that is greyish-white in color and is 3-5 cm long;
  • Sometimes referred to as an “angel wing” because of its appearance;
  • There is no noticeable difference between male and female Atlantic Mud-Piddock

Habitat

The Atlantic Mud-Piddock is found in the intertidal zone, meaning it is above water at low tide and under water at high tide. They burrow into marine substrates such as marine peats and firm mud for protection. They become entrapped as they grow, thus remaining there for their lifetime. When it dies, the resulting tunnelled hole can provide habitat for other marine species.

The Atlantic Mud-Piddock is found along the east and west coast of the Atlantic Ocean, primarily inhabiting coastal areas from Florida to southern Maine, USA. In Canada, the only population is found in the red-mudstone of the Minas Basin in the Bay of Fundy, approximately 350 km from the nearest population found in Maine. The Minas Basin habitat is extremely limited, less than 0.6 km². The high tides of the Bay of Fundy and large temperature fluctuations provide highly oxygenated waters with lots of particulate matter for the molluscs to feed on.

Atlantic Mud-Piddock live separately in their burrows, releasing their eggs and sperm into the surrounding water. Fertilized eggs grow into larvae which then settle to the bottom and begin burrowing. Population trends and sizes are unknown due to the restrictions of accessing the species habitat.

Threats

The main threat to the Atlantic Mud-Piddock is changes to the ocean bottom, particularly increases in sediment over their limited habitat. Increases in sediment can smother the animals and render their limited habitat unusable. These changes may occur as a result of natural processes such as tidal erosion, ice scouring, and major storm events, and there is concern that increased storm activity and sea-level rise due to climate change may negatively impact the species. In addition, dredging, turbine installations, and oil spillage from tankers in the Gulf of Maine and Bay of Fundy may also pose potential threats.

Further Information

In Canada, the Atlantic Mud-Piddock has been designated as threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) due to its limited distribution.

There is no commercial or food, social and ceremonial (FSC) fishery for the Bay of Fundy population

Visit the Species at Risk (SARA) Public Registry.

Atlantic Mud-Piddock

Atlantic Mud-Piddock. Illustration by Jeff Domm.

Illustration by Jeff Domm

Scientific name: Barnea truncata
SARA Status: Threatened
COSEWIC Status: Threatened
Region: Atlantic Canada
Taxonomy: Molluscs

Distribution of the Anticosti Island population

Distribution of the Atlantic Mud-Piddock in Canada. This map was adapted from the Fisheries and Oceans Canada Canadian Science Advisory Report: Recovery Potential Assessment for the Atlantic Mud-Piddock, Barnea truncate, published in 2010. The Atlantic Mud-Piddock population in Canada is limited to the Minas Basin which is located in Nova Scotia at the north-east end of the Bay of Fundy. The map indicates the 14 discrete sites in the Minas Basin where the species is found. These locations are in the intertidal areas of the Northern and Eastern portions of the Minas Basin with one additional site found in the South West at Evangeline Beach.

Did You Know?

After a brief (35 days) planktonic stage of floating in the water, the larvae settle down and begin burrowing. They become trapped in their burrow as they grow inside and depend on the water for food, respiration and physiological functions, making the quality of water where they live a crucial part to their survival. The body of the Atlantic Mud-Piddock cannot be completely withdrawn into the shell, which is why burrowing is crucial for further protection for the mollusc.

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