Margaritifera hembeli
Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Louisiana_pearlshell
Overview
The Louisiana pearlshell, Margaritifera hembeli, is a rare species of bivalve mollusk in the family Margaritiferidae. This freshwater mussel is native to Louisiana in the United States, and was previously present also in Arkansas. It grows to a length of about 10 cm (4 in) and lives on the sand or gravel stream-bed in riffles and fast flowing stretches of small streams.
Its life cycle involves a stage where it lives parasitically inside a fish. This mollusk is sensitive to increased sedimentation and cannot tolerate impoundments. Because of its limited range and its population decline, the International Union for Conservation of Nature has rated this mollusk as being critically endangered.
Margaritifera hembeli faces severe population decline due to habitat degradation from agricultural runoff and sedimentation in its freshwater mussel beds. Dam construction and water diversions have altered natural flow regimes essential for its reproductive cycle, while invasive species compete for resources and disrupt established ecological relationships. The species' extremely limited range makes it particularly vulnerable to localized environmental changes.
Habitat
This freshwater pearl mussel inhabits clean, well-oxygenated streams and rivers with sandy or gravelly substrates. It requires stable water conditions and specific host fish species for its larval development stage.
