A crappie suffering from Black crappie sarcoma
Black crappie sarcoma (BCS) is a skin and muscle condition affecting black crappie (Pomoxis nigromaculatus). The condition causes raised sores and tumor-like growths on the fish’s body and fins. It was first observed in 1980 in Staples Lake, Wisconsin, and is periodically seen in certain lake systems, primarily in western Wisconsin.
There is no evidence that Black crappie sarcoma causes mass fish mortalities. Observations tend to be intermittent or ephemeral, with cases appearing and disappearing over time within the same waterbodies. Black crappies with sores/lesions are generally found behaving normally and actively feeding.
- What causes this disease?
- The cause of Black crappie sarcoma is currently unknown. Testing has so far not revealed any infectious agent though research is ongoing.
- What does it look like?
- Raised, red sores on the body, operculum (gill cover), and fins.
- Lesions may be fragile, bloody, and extend deep into muscle tissue.
- Lab studies indicate that these sores are sarcomas - a type of fish skin cancer that originates in the scales and dermal tissues.
Select to enlarge
Select to enlarge
Select to enlarge
- What fish species are affected?
Black crappie (Pomoxis nigromaculatus)
- Where has the disease been found?
Black crappie sarcoma has been reported in over 35 lakes in western and northwestern Wisconsin, with prevalence ranging from 1–2% to as high as 20–30% in some lakes.
Black Crappie Sarcoma has been observed in several Minnesota lakes, including Prior Lake (Scott Co.), Independence Lake (Hennepin Co.), Blue Lake (Isanti Co.), Koronis Lake (Stearns Co.).
- Are fish with the disease safe to eat?
Do not eat infected fish. Due to a lack of concrete scientific knowledge about the disease, the MN DNR does not recommend consumption of affected fish.
Additionally, the lesions caused by this disease can reduce filet quality and palatability.
- How can I prevent the spread?
- Release any black crappie showing suspicious lesions immediately back to the water.
- Clean, and dry all gear before moving to another waterbody (Clean In Clean Out policy can be followed to eliminate most invasive species including pathogens.)
- Wash your hands with soap and water, hand sanitizer or disinfecting wipes before handling other fish.
- Never transport live fish between waterbodies. Dispose of unwanted baitfish and fish parts in the trash.
- If you catch a suspected diseased fish:
- Anglers with valid fishing licenses, who wish to help MN DNR, may bring affected fish to their local area fisheries office on ice within 12 hours of catching them.
- Alternatively, anglers may contact the Fish Health Lab for guidance and sample submission.
- Note: Any retained fish count toward your daily bag limit.