LANSING, Michigan – The big bass virus was discovered in two additional lakes in the northern Michigan peninsula after an initial discovery last month in Cedar Lake (Iosco County).
This time, LMBV was found in bass-bass at Beaver Lake (Alpen County) during a fish kill investigation in Avalon Lake (Montmorency County). Recent discoveries show that the virus spreads north to Michigan.
Prior to this autumn, the virus previously affected adult grandmothers in the early 2000s in the southern lakes of Michigan. In these lakes, the pathogen killed 1
"The big bass virus has probably compromised the small bass immune system in Beaver Lake, causing secondary bacterial infections to become more lethal and allowing the virus to be a direct factor in killing fish," says Gary Whale Divisional Division Manager. "Since these latest discoveries are at the northern end of the LMBV, we can see different answers than what is documented in southern Michigan."
LMBV is one of more than 100 naturally occurring viruses that affect fish and is closely related to viruses found in frogs and other amphibians. Its origin and distribution methods are unknown, but fishermen are considered to be a promising way. Anyone who moves live, infects fish from one water body to another, or uses polluted or uncleaned gear or boats in uninfected waters can easily spread the virus. LMBV is not known to infect humans, and infected fish – if carefully prepared – is safe to eat.
LMBV usually causes fish killings during periods when fish are most heavily loaded. Potential stress factors include very hot weather, increased recreational fishing, and possibly water weeds or other treatments made during hot weather. Anything that can be done to reduce stress on fish will reduce the effects of this virus and the subsequent fish deaths.
There are several external signs that the fish has LMBV. The virus is found in lakes where there are no reports of diseases or killings of fish. Affected fish usually appear normal, although they may be lethargic, swim slowly and less responsive to the activity around them. Dying fish are often seen near the surface and can hardly stand upright. In an internal study, infected fish usually have swollen and yellowish swimming bladders.
Large bass virus can not be eradicated from lakes and infected fish can not be treated. The best way to stop the virus is fishermen and boats that properly clean their equipment and do their part to prevent the spread. The simple steps include:
- Cleaning all fishing gear between trips.
- Do not move fish or parts of fish from one water body to another.
- Gently work on the bass if you intend to release them. for a long time, if you plan to release them.
- Minimize bass targeting during very hot weather.
- Report dead or dying adult bass, especially when they are in cash of 25 or older – reports can be made online at Michigan.gov/EyesInTheField.
tFor more information on fish diseases, visit DNR's website Michigan.gov/FishHealth.
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