Opossum shrimp (mysis)
Mysis diluviana · Aquatic life
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Also called Mysis diluviana, Mysis relicta, Freshwater shrimp, Mysis shrimp
How to identify Opossum shrimp (mysis)
- Clear to whitish shrimp about 0.5 to 1 inch long
- Large eyes on short stalks
- Females carry eggs and young in a pouch under the body
- Usually only caught in deep night tows or seen in fish stomachs
Similar species
Scuds (amphipods) are curved and flattened side to side with no stalked eyes; phantom midge larvae have dark air sacs.
Profile
| Season | Present all year. |
|---|---|
| Starts | Cold water, below about 57 F |
| Light | Avoids light; stays near the bottom by day and rises at night |
| Depth | Deep water by day, upper water at night |
| How it spreads or reproduces | Live young carried in a brood pouch; spread only by stocking or water transfers |
| Habitat | Cold, deep, well oxygenated lakes and reservoirs where they were stocked, such as Lake Pend Oreille and Priest Lake in Idaho and Wallowa Lake in Oregon. |
Why it matters in a lake
Stocked decades ago as fish food, but it often eats the Daphnia and other zooplankton that kokanee need and has hurt kokanee fisheries in some lakes. It can grow very large kokanee and lake trout where they are able to feed on it.
Where it is found
- Idaho: Rare
- Oregon: Rare
- Wyoming: Not recorded
Classification
| Kingdom | Animalia |
|---|---|
| Phylum | Arthropoda |
| Class | Malacostraca |
| Order | Mysida |
| Family | Mysidae |
| Scientific name | Mysis diluviana |
Seed shrimp (ostracod)
Phantom midge larva
Daphnia (water flea)
Midge larvae (bloodworms)
Keratella (spined rotifer)
Mosquito larvaeNeed a hand?
Found it in your lake?
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Idaho / Wyoming (208) 501-4531Oregon (541) 280-0596