Researchers at U.S. university Texas A&M recently released a study concerning whole genome sequencing used in fish stock research, claiming that the scientific technique could be the key to stronger stock management plans and preventing overfishing.
The study, titled “How Fish Population Genomics Can Promote Sustainable Fisheries: A Road Map” and published in the Annual Review of Animal Biosciences, detailed how fish genomics – a laboratory procedure that determines the DNA sequence of a fish’s genome – reveals critical data, such as spawning conditions and migratory behaviors, to researchers. The additional data allows researchers to better distinguish separate populations within a stock and more precisely define management areas for them.
According to the study, fish stock assessments have historically operated under two key assumptions: Each fish stock is a closed unit, and data extrapolated from one part of a stock represents the entire stock.
However, some researchers are now advocating for the use of more flexible boundaries, such as via whole genome sequencing, that adapt to changes in fish populations and their habitats. With advanced tools, real-time management is now achievable, allowing for accurate identification of fish populations and assignment to proper management areas.
“Our experience is that with whole genome sequencing, you get the best resolution to distinguish different populations of marine fishes. Based on this, we can identify the most informative genetic markers which can then be used for large-scale testing,” Leif Andersson, the study’s lead author, said.
Useful information, according to Andersson, may include the types of waters fish are spawning in, helping to determine whether one fish population is genetically different from another and, therefore, requires a separate management plan.
The Texas A&M researchers found just that while formulating the study, conducting several case evaluations using whole genome sequencing.
For Atlantic herring, they identified seven major groups based on spawning locations, with some populations spawning in high-salinity waters and others in brackish waters. In the case of Atlantic horse mackerel, they found a few highly adaptive variations, revealing that Atlantic populations were genetically distinct from Mediterranean populations.
With this information, fisheries managers can develop more targeted plans to help specific populations recover, preventing overfishing and potential collapse, according to the study.
Better yet for researchers, the cost of conducting the scientific procedure has gone down significantly from the prohibitive costs it once carried.
“The cost for genome sequencing is going down and is now quite cheap. I definitively think it is a well-justified investment for [studying] marine fish that are the target for marine fisheries,” Andersson said.
Besides its use for researchers and fishery oversight bodies, whole genome testing also, according to the study, provides valuable insights for fishers on how the populations they’re targeting are being managed.
“The wild-catch fishing industry can better monitor the demography of specific subpopulations and adjust fishing quotas to avoid overfishing,” Andersson said.
Even with improved scientific understanding, though, there are significant challenges to implementing or revising management areas, as changing management practices requires balancing scientific data with socioeconomic and political considerations, according to the study.
In regions like the Northeast Atlantic, management boundaries are inflexible and difficult to alter, even when backed by solid science, due to the political complexities around securing a sweeping agreement that effectively manages these stocks.
"These governments have not only failed in their obligations under the United Nations Fish Stocks Agreement to sustainably manage these fish; they are also jeopardizing predators such as seabirds, whales, and porpoises that may no longer have enough food in the water to keep their populations healthy," a recent Pew Charitable Trusts study said. "As a result, regional governments are nowhere near meeting biodiversity targets.”
Additionally, stock assessments depend on long-term, independent data, meaning the benefits of improved assessments may not come to fruition until after years of data collection.
While advances in genomics and fisheries science offer promising solutions for more effective management, overcoming logistical, political, and data-related hurdles will require time, collaboration, and incremental change, according to the study.
“Although sustainable management should be based on robust science, socioeconomic and political considerations often make applying the best science difficult,” the report said. “These major hurdles must be overcome before the full potential for how population genomics can contribute to sustainable marine fisheries is realized.”
