Mollusc larvae (glochidia)
also known as: Glochidium, freshwater mussel, Margaritifera , Western Pearlshell, Oregon Floater, Western Floater, Winged Floater, Yukon Floater, California Floater, Western Ridged Mussel, Anodonta, Gonidea
The larval stage of mussels and clams are called glochidia and are a temporary parasitic inhabitant of fish. Some molluscs can lure fish close by exposing a piece of their mantle in the water and dose the fish with spawn when it strikes. Glochidia then encyst in the gill epithelium and grow, before dropping off within 10-30 days. In this manner the mussel can extend it's range using the fish for transportation. All but 1 (the Yukon Floater, Anodonta beringiana) of the 7 native species of mussels found west of the Continental Divide are found in Oregon; with an additional ~7 species that have been introduced. Glochidia can resemble trematode metacercarial cysts, and can (rarely) cause mortality when a fish is heavily infested. Mussels are a good indicator of ecosystem health and are one of the longest lived animals.
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Distribution:
Hosts: Freshwater fish
Oregon has 6 native species, plus some 7 introduced species.
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Detection Method:
gross pathology / gross clinical signs Target tissue:
gills |
Species: |