Erin Meyer-Gutbrod studies the movement of right whales, reef fish in response to climate change
Published on: September 28, 2021; Updated on: September 28, 2021
By Rose Cisneros and Bryan Gentry, [email protected], 803-576-7239
Warming oceans are pushing some marine populations out of their habitats and putting them at risk, according to a new study by Professor Erin Meyer-Gutbrod of the University of South Carolina.
The change in temperature is affecting creatures large and small, from the critically endangered North Atlantic right whale to more common fish whose habitats are losing oxygen. Meyer-Gutbrod published two research papers this month that examine ocean changes over the past 15 years and provide a cautionary tale for those who manage waterways and fisheries.
By understanding how the inhabitants of the ocean will move with warming waters, we can more effectively preserve species that are important to the ecosystem and the economy.
The preservation of our ecosystems and the maintenance of biodiversity impact everyone. Human well-being is intimately linked to the environment.
Right whales travel to find food
At 140,000 pounds and 52 feet long, the North Atlantic right whale is among the largest creatures in the world. It is twice the size of a humpback whale, but just under half the size of the blue whale.
But the species has long faced the dangers of human activity. In fact, it gets its name because it’s the “right” whale to hunt, according to the National Oceanic and Atmospheric Fisheries Administration.
Meyer-Gutbrod, an assistant professor in the School of Earth, Oceans, and Environment, began studying the effects of climate change on right whales in the North Atlantic as a doctoral student at Cornell University. It is an attractive species to study because long-term monitoring provides plenty of historical data to compare and its endangered status means people pay more attention to its findings.
“The United States and Canada maintain protective policies to reduce [human-caused] impacts on the species,” she says. “This means that my research can have a direct impact on conservation and management.”
And that advice couldn’t come at a better time. In the summer of 2017, the United States National Marine Fisheries Service discovered 17 dead right whales, most of which had died after being struck by ships or entangled in fishing gear. Twelve were found in the Gulf of St. Lawrence, hundreds of miles north of the whales’ normal summer feeding grounds in the Gulf of Maine.
Meyer-Gutbrod investigated why whales moved. His findings, published in the journal Oceanography, trace the transition to a “regime shift”, a prolonged change caused by high water temperatures.
What we see are right whales reacting to a climate change in their prey environment.
Meyer-Gutbrod’s findings paint a grim picture for the right whale. She says a northward shift of the Gulf Stream has warmed the Gulf of Maine from below, causing a decline in zooplankton that right whales eat.
As whales left their traditional feeding grounds in search of food, they left protected waters, causing more deadly ship strikes and entanglements in fishing gear.
“What we’re seeing are right whales responding to a changing climate in their prey environment,” Meyer-Gutbrod said. in fishing gear, largely because there were no protective policies in place in this unexpected habitat.
To compound the problem, less food availability and disruption of feeding environments lead to lower calving rates. Newborn calves are more likely to die earlier and more often from malnutrition.
Estimates indicate that there are less than 360 right whales left. The population decline is so severe that right whales have been elevated to the list of critically endangered species in 2020.
But there is good news. Meyer-Gutbrod’s research identifies ways the United States and Canada can help protect right whales, such as monitoring ocean conditions and whale sightings to potentially predict changes in new right whale habitats. As whales move, protective regulations should move with them, she says.
Meyer-Gutbrod calls for quick action to adapt regulations to the movement of whales.
“Canada and the United States will need to adopt more aggressive management plans,” says Meyer-Gutbrod. “Failure to adopt such measures and significantly reduce sources of anthropogenic mortality could result in the extinction of the right whale population before the end of the century.”
Fish move to find oxygen
Meyer-Gutbrod’s research also explores how ocean warming affects underwater oxygen and the fish that depend on it.
His recent research published in Biology of global change, co-authored with a team of researchers from the University of California, Santa Barbara, reveals that ocean oxygen concentrations are falling. Lower oxygen levels push some species of fish into shallower waters while pushing others deeper, which has ecological and economic ramifications.
When fish leave their normal feeding grounds, it disrupts all other populations that depend on those fish – and that includes us.
Their research is the first to track changes in the distribution of fish in the same location while tracking the decline in oxygen over a 15-year period.
Fish can drown if there is not enough oxygen in the water. So either they move to more oxygenated areas or they risk dying due to a lack of oxygen. For some species, this means finding shallower waters, where atmospheric oxygen mixes with surface water.
However, other research indicates that fish may need to move to deeper, cooler waters to avoid anthropogenic warming at the surface. When fish move up to avoid low oxygen and move down to avoid warm waters, this leads to a compression of usable habitat.
“The depth band they can occupy becomes narrower and narrower over time,” says Meyer-Gutbrod.
This habitat shrinkage leads to overpopulation and could affect fishing practices.
“If you cast your net in the water,” says Meyer-Gutbrod, “and you get a ton of fish — more than you’re used to — you may think, ‘Oh, that’s a good year for the fish. Maybe the population is recovering. But instead, it could be that all the fish are just being crushed into a narrower area. You could get fishing regulations changed to increase fishing allocations due to this increase in landings.
Scientists do not yet know the consequences of this narrowing of the band. What they do know is that the fish are being driven out of their optimal habitat. And they are not alone.
The local impacts of climate change
Meyer-Gutbrod’s research is more than an esoteric look at profound changes underwater and 1,500 miles away. It has impacts close to home.
For example, whale watchers often congregate on the South Carolina coast to spot right whales during breeding and calving season, meaning the species’ decline would be felt here in the US. ‘State of Palmetto.
As for fish, if the compressed habitat leads to overfishing, it could affect the human food supply and the economics of fishing. Despite different environments, humans, whales and fish live in an interconnected global ecosystem.
But there are ways to help.
“Find ways to reduce the carbon footprint in your life and in your community. Communicate with your politicians about protecting our vulnerable ecosystems and reducing human impacts.
“Preserving our ecosystems and maintaining biodiversity impacts everyone,” says Meyer-Gutbrod. “The Earth’s biosphere provides services that humans rely on, including the production of oxygen and food. Human well-being is intimately linked to the environment.
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Subjects: Faculty, Research, College of Arts and Sciences