As rising sea surface temperatures and anthropogenic activities drive declines in marine biodiversity worldwide and facilitate expansions of southern species’ ranges into the Arctic Ocean, marine biodiversity surveys become increasingly valuable to inform large-scale conservation and management decisions. Although decisions, such as Canada’s commitment to protect 30% of its oceans by 2030, require reliable surveys of marine species distributions, traditional methods for surveying marine species across Canada are spatially and taxonomically biased. Traditional approaches often restrict researchers from sampling in remote, ice-covered areas and are time-consuming and expensive, causing past surveys to generally be focused on charismatic animals or those with economic importance.
Researchers seized an unprecedented opportunity to map marine species distributions across Canada during the C3 expedition, which took place over five months in 2017 and included a diverse group of Canadians who participated in knowledge sharing as they sailed from the Atlantic coast, across the Arctic to the Pacific coast. In a recent study, researchers documented how collecting environmental DNA during the voyage allowed them to overcome typical biases associated with sampling biodiversity at an interoceanic scale.
eDNA sample collection sites across DFO Marine Ecoregions. Map credit: Jacquemot et al. (2024).
eDNA as a tool for mapping species distributions
Collecting eDNA sample. Photo credit: Loic Jacquemot
By collecting environmental DNA (eDNA), researchers were able to detect which marine animals were present in an environment based on the genetic material found in samples of sea surface water that they collected across the coasts. “Taxonomically, one sample can be used to assess biodiversity ranging from microorganisms to marine mammals,” said Loic Jacquemot, a postdoctoral researcher at the University of British Columbia’s Institute for the Oceans and Fisheries. In addition to providing researchers with a comprehensive survey of marine animals in an ecosystem, “water samples are quick and easy to collect… which makes eDNA particularly suitable for use across large spatial scales, and in remote regions like the Canadian Arctic,” explains Jacquemot.
The role of eDNA in tracking rapid environmental change
Collecting eDNA sample. Photo credit: Loic Jacquemot
eDNA is increasingly being used to map regional species distributions. This study, which included researchers from Laval University, The University of British Columbia, and Fisheries and Oceans Canada, was the first to demonstrate that eDNA is a reliable tool to explore marine biodiversity at continental scales. Despite researchers sampling across three oceans, eDNA detected fine regional-scale differences in the types of species that made up communities across the coasts. The detection of several species of salmon outside of their Pacific native habitat in Arctic waters illustrated the rapid and ongoing changes in ecosystems. These large-scale shifts into the coastal Arctic “pose potential concerns for local Arctic populations whose diet and culture rely on native Arctic species, such as the Arctic char, which could face competition from Pacific salmon,” said Jacquemot. Using eDNA to monitor shifts in biodiversity at the continental scale “would allow us to keep our finger on the pulse and inform conservation and management decisions,” explained Brian Hunt, Associate Professor with UBC’s Institute for the Oceans and Fisheries.
The ability to detect the distribution of not only widespread, but also rare and endangered, species using eDNA allows researchers to identify critical habitats and biodiverse areas requiring protection. As ecosystems change rapidly, this study demonstrates the potential for “involving communities across the country in routine collections of eDNA alongside visual observations of species to inform conservation decisions at the scale of Canada,” said Hunt.
Collecting eDNA sample. Photo credit: Loic Jacquemot
Future marine conservation amid shifting distributions
“I think this study further emphasizes the richness and diversity of ecosystems and species we are fortunate to witness around Canada, as well as our responsibility to protect them…We have the necessary tools to monitor these changes and implement better protection strategies,” said Jacquemot. This unprecedented, comprehensive survey of marine biodiversity detailed current species distributions across Canada, providing a foundation for predictions about how these distributions may shift with future climate change. “As species shift their distributions in response to warming temperatures, marine conservation areas are now designing mobile boundaries to account for these movements. I hope this kind of work can provide guidance to adapt these boundaries more effectively,” said Jacquemot.
Mapping Biodiversity Coast-to-Coast-to-Coast Across Canada’s Three Oceans Using eDNA Metabarcoding was published in Environmental DNA.
Tags: Arctic, Atlantic, biodiversity conservation, Brian Hunt, Canada, Climate change, Conservation, eDNA, fisheries management, IOF postdoctoral fellows, Loïc Jacquemot, Pacific, Pelagic Ecosystems Lab