The animation from researchers at Bangor University, the Norwegian Institute for Nature Research (NINA), the Norwegian Veterinary Institute, and UiT The Arctic University of Norway explains how genetic diversity evolves.
Their ongoing research investigates the consequences of a management response to an invasive fish parasite. In several Norwegian lakes, authorities used the biocide rotenone to remove all fish, and thus the parasite. Afterwards, these lakes were restocked with captive-bred fish. Researchers are now examining what that reset has meant for the broader genetic diversity of the fish populations. Their concern is that these sudden population collapses may have caused significant genetic losses. With reduced genetic diversity, recovering populations may be less resilient to disease, less able to cope with environmental change, and more vulnerable to future challenges.
Charlie Gregory, PhD student at Bangor University who won funding for the research to be animated said: “The fish may be back in the lakes, but their genetics may not be the same. We're aiming to see how genetic diversity can be lost and why genetic monitoring needs to be part of any major conservation project, especially for freshwater ecosystems.”
Using fish samples collected before and after the biocide treatment, the researchers are tracking how much genetic variation disappeared during the removal and restocking process. Dr Amy Ellison, Lecturer in parasitology and chronobiology at Bangor University, told us that the team expects to find signs of reduced diversity and shifts in disease resistance in the new populations.
The project also offers a broader view of how ecosystems respond to such interventions. In addition to studying the fish themselves, the research team is also examining how parasite communities react when their hosts suddenly vanish.
Dr Rachel Paterson, researcher at the Norwegian Institute for Nature Research, said: “This work highlights a problem in conservation management where solving one problem may inadvertently create another. The rotenone treatment successfully eliminated the invasive parasite but we need to ask if it came at a significant genetic cost to other species. These lakes provide a rare opportunity to quantify exactly what's lost when we're forced to reset entire populations, and this knowledge will be invaluable for making more informed decisions in similar situations worldwide.”
Freshwater systems worldwide face pressures from habitat loss, invasive species, pollution and climate change, and understanding how populations recover after major declines is vital for guiding future management actions.
Dr Alex Papadopulos, Reader in Molecular Ecology and Genomics at Bangor University, added: “Genetic diversity is the raw material populations need to adapt and survive. This work is exploring how and why we need to factor genetic consequences into our decision-making framework when responding to invasive species and considering conservation projects in freshwater systems.”
