Louisiana Pearlshell
A federally threatened mussel survives only in narrow central-Louisiana headwaters, where clean flowing sand and a fish host must remain connected for its life cycle to close.
Artwork inspired by Caroline Dormon
Louisiana pearlshells are dark, oblong mussels with a rounded buried front and pointed exposed rear. They occupy shallow riffles in clear, moderately swift headwater streams, usually over loose fine sand rather than deep silty pools. Adults filter food from the water; buried juveniles feed within the streambed.
Reproduction links mussel, fish, and current. Females release microscopic glochidia that must quickly attach to a suitable host; Grass Pickerel has produced juveniles in captivity. After about a month the transformed mussels drop to the streambed. Sediment, channel alteration, pollution, and barriers can therefore interrupt the species long before an adult bed visibly disappears.
- Entire range
- Four watersheds in Grant and Rapides parishes
- Federal status
- Threatened
- Confirmed captive host
- Grass Pickerel
Quick guide
- Protect the evidence
- Never lift living, dead, or tagged shells
- Protect the system
- Keep clean sand, current, and fish movement connected
Understand the pearlshell without disturbing its bed
- Read habitat from the bank
- Look for a narrow, clear headwater stream with shallow current over stable fine sand and occasional gravel.
- Follow the life cycle
- Follow a Louisiana Pearlshell from released glochidia to a temporary Grass Pickerel host and then to a juvenile settling into the streambed.
- Leave all evidence placed
- Look without moving a living mussel, empty shell, tag, marker, or surrounding sediment.
- Report discreetly
- Use photographs and a broad locality when contacting the U.S.
Good to know
Grass Pickerel is a demonstrated host in captivity: larvae attach to the fish’s gills, transform for about a month, then release and settle into the streambed. The fish is part of the mussel’s recovery habitat.
Notice these
- Dark kidney-shaped shell
- Rounded buried front and pointed rear
- Shallow fine-sand headwater riffle
- Fish-host larval stage