Where did the Black Bass go?

Matthew Lewis brings the power of a very specific genetic identifier to light

On Oct. 17, 2019, Matthew Lewis came to Embry-Riddle Aeronautical University to talk about the serious topic of Black Bass losing their diversity. As an avid fisherman, Lewis always knew his calling was with the fish. In the last decade, he received his Masters degree in fisheries but had the underlying passion for the medical field. Those two passions were the stepping stones that got him to where he is today. 

As Lewis was looking for his niche, he had a job as a lab manager and helped publish a paper about how Parkinson’s disease can be linked to gut microbiomes that came with the undisclosed price of a high stress environment. To get away, he would fly-fish for Redeye Bass. Eventually he had an epiphany that he should be studying fish and doing so would be the perfect remedy to his stressful life. Lewis began seeking out a field that would make him feel like he never worked a day in his life.

Lewis started his new path with writing a book called “Fly Fishing for Redeye Bass: An Adventure Across Southern Waters” covering the actual process and raising awareness about conservation efforts. Not much was known about Redeye Bass let alone the numerous subspecies of bass which was a leading factor for him to write this book and an even more pertinent factor to get involved with this pressing issue.

Once at Auburn University, Lewis was pursuing a PhD research program in conservation genetics with a focus on his beloved Redeye Bass. There are three common types of bass: Largemouth, Smallmouth and Spotted bass. Those are what inexperienced or non-fisherman dignify as the types of bass when in all actuality there are about 19 subspecies of Black Bass. Having the knowledge of the different subspecies is vital because of the implications if native diversity is not maintained.

Some implications are difference in sizes which directly relates to restrictions on what is caught also known as bag limit and the possibility that a subspecies may qualify for endangerment protection. Redeye Bass have a slower growth rate compared to other bass species affecting bag limits of anglers that intend to catch bass specifically. However if the bag limit would get more restrictive, that still would not stop hybridization breeding out pure subspecies. 

In the early stages of bass classification, any identification done was purely off of phenotypes, physical markings. When hybridization started to notably increase, identification became a test of genotype that went as specific as molecular markers in DNA. Researchers collected hundreds of samples of subspecies to catalog the specific molecular DNA of a purebred bass species. Then technology started enhancing to reduce errors resulting in an identifier called single nucleotide polymorphisms (SNPs).

SNPs made sampling for hybridization and purity easier which allowed for better ideas on what actions to take to make sure the diversity stays at a max and no subspecies go extinct. Lewis admits that another issue that is found with the results of genotypes in a sample is that not only are non-native bass and native bass hybridizing but also two different subspecies who are both native to the same region have been documented hybrizing.

Most hybridization has been assumed to be because of human interaction of introducing a non-indigigous species of bass to produce more optimal bass. In this new case of two coevolving species of bass, it is to the contrary, researchers can not understand this phenomena. Even more perplexing to Lewis is that a species of bass that is only native to a region in Alabama was documented near the Embry-Riddle campus in Arizona. He indicated that there will be more research on both situations.

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