New York's lakes are home to a variety of fish species, some of which require cold water to survive.
However, a new study has found that climate change is shrinking the cold-water habitat for these fish, threatening their survival and the benefits they provide to humans and nature.
The study also suggests some ways to adapt to the changing conditions and protect the lake fish.
Warmer Waters Threaten Cold-Water Species
HOANG DINH NAM/AFP via Getty Images
A new study by researchers from Cornell University and the Rensselaer Polytechnic Institute, both in New York has found that climate change is reducing the availability of cold-water habitat for lake fish in New York.
The study, published in the journal Global Change Biology, analyzed data from 620 lakes across the state and found that the average duration of ice cover decreased by 24 days from 1975 to 2014.
This resulted in higher water temperatures and lower dissolved oxygen levels, which are unfavorable for cold-water fish such as lake trout, brook trout, and whitefish.
The researchers used a model to simulate the effects of different climate scenarios on the thermal and oxygen conditions of the lakes.
They found that under a high-emission scenario, the average annual maximum water temperature would increase by 3.8°C, and the average annual minimum dissolved oxygen concentration would decrease by 2.1 mg/L by 2090.
These changes would reduce the suitable habitat for cold-water fish by 52% compared to 1975.
The study also projected that by 2090, under a high-emission scenario, only 15% of the lakes would be suitable for cold-water fish, compared to 67% in 1975.
This would have significant implications for the biodiversity and ecosystem services of New York's lakes, as well as the recreational and commercial fisheries that depend on them.
The researchers estimated that the annual economic value of lake fishing in New York was $1.8 billion in 2017, and that cold-water fish accounted for 40% of that value.
In most lakes, the deoxygenation of bottom waters caused by browning outpaces the spread of cool-water habitat, forcing cold-loving species between unsuitable strata.
The oxythermal squeeze that results from warmer surface waters and decreasing bottom-water oxygen poses an existential threat to the survival of populations of cold-water creatures like salmonid fish.
The researchers suggested that adaptation strategies are needed to protect and restore the cold-water habitat for lake fish in New York.
Some of these strategies include reducing nutrient inputs from agriculture and urban runoff, which can cause algal blooms and oxygen depletion; restoring natural shorelines and riparian vegetation, which can provide shade and buffer temperature fluctuations; and enhancing fish stocking and habitat restoration programs, which can increase the resilience and diversity of fish populations.
The researchers also emphasized the importance of reducing greenhouse gas emissions, which are the main drivers of climate change and its impacts on lake ecosystems.
They urged policymakers and stakeholders to consider the findings of their study and take action to mitigate and adapt to the changing conditions of New York's lakes.
