ITHACA, New York – Invasive gobi roundfish have affected fisheries in the Great Lakes and Finger Lakes by competing with native species and eating the eggs of some species of game fish.
But camouflaged bottom dwellers can be difficult to find and collect – especially when they first enter a new surface of water and have low numbers and may be easier to remove.
In a proof-of-principle study, Cornell researchers described a new technique in which they analyzed environmental DNA – or eDNA – from water samples in Cayuga Lake to collect accurate information about the presence of these invasive fish.
The study, “Estimates of nuclear eDNA frequencies and abundances of allele populations in experimental mesoscale and field samples,” was published January 12 in the journal Molecular Ecology.
While eDNA technologies have been increasingly studied over the past decade, previous methods have usually focused on whether a species is present in an ecosystem.
“ With these new developments in eDNA methods, we can not only know which invasive species are present in the environment, but since we identify the genetic diversity in samples, we can also predict the number of individuals and possibly where they came from, Said Kara Andres, first author of the paper and graduate student in the laboratory Co-author David Lodge, Professor of Ecology and Evolutionary Biology at the College of Agriculture and Life Sciences (CALS), and Francis J. DeSalvo is director of Cornell University’s Atkinson Center for Sustainability.
“For the first time, we are demonstrating that there is sufficient genetic information in environmental samples to study the origins, contact and status of invasive, elusive, threatened or difficult to monitor species in any other way without the need for direct contact,” added José Andres, Senior Associate Researcher in the Department of Ecology and Biology. Evolutionist at CALS and lead author of the study.
Since the method provides a genetic signature of the individuals in the sample, scientists may be able to determine where they came from by matching their DNA with groups from other regions.
“We will be able to tell if the round gobies were introduced by ships from Europe, which is why they originally arrived in the Great Lakes, or by some other means of input.” Kara Andres said knowing this information might be useful if we hope In stopping new introductions in the early stages.
Additionally, knowledge of the genetic diversity of a species can be helpful in conservation efforts; Reduced genetic diversity can indicate a dwindling or weak population that requires managing their genes
The Cornell Effect on New York State
“In the near future, this type of technology is likely to revolutionize how we monitor environmental management and conserve agencies’ wild populations,” said Jose Andres.
The researchers conducted controlled experiments using small, artificial environments – boxes filled with water containing one, three, five, or 10 gobies in them. After gathering the genetic information from all the copepods, they took water samples from each container to see if they could match the DNA from the samples with the individuals in the boxes. Also try to estimate the number of fish in each box based on the water sample alone. Kara Andres said they succeeded either way.
Researchers validated their methods in Lake Cayuga, where they found large numbers of gobies, especially in shallow areas.
“This delicate approach could overcome many of the logistical and financial challenges faced by scientists and conservation managers who study these species, allowing for the allocation of the most valuable resources to improve conservation outcomes,” said Kara Andres.
Suresh Sethi, Assistant Professor in the Natural Resources Department at CALS, is a co-author of the study.
The study was funded by the National Science Foundation and the United States Department of Defense.