CR

Suwannee Moccasinshell

Medionidus walkeri

Declining

Overview

Medionidus walkeri, the Suwannee moccasinshell is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.

Medionidus walkeri faces severe population decline primarily due to habitat degradation from dam construction and water diversions that have altered natural flow regimes in its river systems. Sedimentation from agricultural runoff and urban development has degraded water quality and buried suitable substrate for reproduction. The species' dependence on specific fish hosts for larval development makes it particularly vulnerable to declining fish populations caused by habitat fragmentation and water quality deterioration.

Threat summary

Habitat

This freshwater mussel inhabits clean, flowing waters of medium to large rivers with stable gravel and sand substrates. It requires well-oxygenated water with minimal sedimentation and depends on specific fish species as hosts for its larval stage.

FRESHWATER· major

Conservation measures underway

Site/area protectionResource & habitat protectionHabitat & natural process restorationSpecies recovery

Other threatened species in UNIONIDAE

VU

Brazzaea anceyi

Unknown
Lampsilis higginsiiEN

Lampsilis higginsii

Unknown
EN

Triangle Pigtoe

Fusconaia lananensis

Declining
VU

Lampsilis dolabraeformis

Unknown

Threatened in United States

VU

Lepiota echinella

Unknown
VU

Paddlefish

Polyodon spathula

Unknown
VU

Copper Shark

Carcharhinus brachyurus

Declining
EN

Lyophyllum deliberatum

Unknown

Frequently asked questions

Why is Suwannee Moccasinshell classified as Critically Endangered?
Suwannee Moccasinshell is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. Medionidus walkeri faces severe population decline primarily due to habitat degradation from dam construction and water diversions that have altered natural flow regimes in its river systems. Sedimentation from agricultural runoff and urban development has degraded water quality and buried suitable substrate for reproduction. The species' dependence on specific fish hosts for larval development makes it particularly vulnerable to declining fish populations caused by habitat fragmentation and water quality deterioration.
Where does Suwannee Moccasinshell live?
Suwannee Moccasinshell occurs in United States. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Suwannee Moccasinshell?
The main threats to Suwannee Moccasinshell are 1.1, 2.1, 3.2, and 9.2. The full IUCN-classified threat record for this species is detailed on the species page.

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