Largemouth Bass DNA Analysis

There are three subspecies of Largemouth Bass that we are concerned with in fisheries management. They are the Florida, Northern, and F1 (cross between the Northern and Florida) largemouth bass. Knowing the genetics of your largemouth bass is extremely valuable information. This information provides insight into the current condition of your fishery, as well as help determine which management actions are best to improve the fishery.

Along with the Northern , Florida, and F1 bass you can also have Fx bass. Fx bass do not have pure genetics and are a result of mix of genetics. In the past, DNA testing determined if a largemouth bass was Northern, Florida, F1, or Fx. The issue in the past has been with the Fx bass. If a bass was a Fx bass, we could not determine if it had more Northern or Florida characteristics. With continued improvement in DNA testing, we can now determine if an Fx bass is more Northern or Florida dominant. This is a result of the development of more DNA markers for the largemouth bass.

In the past, fish had to be sacrificed for DNA testing. This is no longer the case and now AES uses a simple fin clip for DNA analysis. For adequate DNA analysis, AES recommends testing a minimum of 10 fish. However, depending on your goals, lake size, and lake history more samples may be needed in order to attain a proper analysis.

Diagnostics (Disease Testing / Fish Kill)

Fish kills are a common occurrence, especially during the summer months. Fish kills often are caused by several factors such as poor water quality, toxins, viruses, bacteria, fungi, and parasites. With regards to water quality, the most common cause of a fish kill is due to inadequate oxygen levels.  In addition, other fish kill causes are ammonia poisoning, nitrite poisoning, or toxins such as pesticides. If your fish are not feeding, lying lazily in shallow water or at the surface, not swimming off rapidly when disturbed, gasping for air at the surface, swimming erratically, or floating alive on the surface and water quality issues have been eliminated; then an infectious disease is most likely the cause.

Early detection is critical for proper diagnosis and treatment. For proper diagnosis use alive fish in the process of dying that are showing signs of disease (i.e. eroded gills or fins, open sores, heavy mucus on skin or gills, pale or swollen gills, etc.) are best to use for diagnosis. Fish that are freshly dead that still have normal color, mucus, clear eyes, and red/pink gills can also be used though not preferred.

Contact an AES biologists if you are experiencing a fish kill or suspect that your fish are displaying signs of disease. An AES biologist can make a site visit and test the water quality and we will collect fish for further disease testing. If time is of the essence, our biologist can provide you with the proper protocol for submitting a sample of the fish directly to the lab.  A complete necropsy will be performed on each sample. This includes general examination of the fish, identification of bacteria and/or viruses, and histopathology. After all testing is complete; AES will submit a report including the results and recommendations.