Warmer ocean temperatures are forcing fish to change their hunting and feeding strategies, an adaptation that could lead to extinctions, SciTechDaily reported.
What happened?
A team of researchers in Germany has found that fish in the Baltic Sea respond to warmer water temperatures by snapping up the first prey they come across. This change in feeding behaviors leads fish to eat prey that tends to be smaller and more abundant.
As SciTechDaily explains, fish need more food energy when ocean temperatures rise because their metabolism increases. Consuming readily available, abundant prey can help satisfy a fish's short-term energy needs, but then it may miss out on larger prey, which provide more calories and longer-term sustenance.
What's more, the scientists posit that these changes in feeding habits could lead to a growing number of extinctions, as fish may inadvertently starve themselves due to a mismatch between their energy needs and caloric consumption.
The scientists arrived at these conclusions after analyzing 10 years of data documenting the stomach contents of six fish species and then applying model food web calculations.
"Adaptation of foraging behavior to local environmental conditions is usually a key to maintaining high levels of biodiversity in ecosystems," first author Benoit Gauzens told SciTechDaily. "It is therefore puzzling to see that this might not be entirely true in the context of temperature increase."
Why is this research concerning?
People living in coastal communities depend on fishing for their livelihoods. According to The Pew Environment Group, marine fisheries worldwide generate at least $80 to $85 billion in revenue annually. And that's only counting the market value of fish as they leave the boat — the entire impact of the industry could be closer to $240 billion each year, the organization says.
That's because fish is an important source of protein for many people — according to The Nature Conservancy, this food, along with other seafood, provides sustenance for more than 3 billion people around the globe.
Plus, fish play an important role in their ecosystems. They sustain the food web, acting as both prey and predator. They also provide certain ecosystem services like transporting nutrients across spatial boundaries.
Rising water temperatures can cause other problems for fish, too. In 2023, thousands of dead fish washed ashore on one Texas beach after low oxygen levels, caused by water temperatures exceeding 70 degrees Fahrenheit, suffocated them.
Warming waters aren't the only challenge fish face, however. For instance, up to one-fifth of fish species in the Mekong River face extinction as a result of unsustainable developments, including hydropower. Microplastics are a grave concern for all marine animals, who often confuse these small particles for food — one study even found that fish may be purposely seeking out these microplastics, as they smell similar to their prey.
What's being done about warming oceans?
According to the International Union for the Conservation of Nature, limiting planet-warming pollution is essential in curbing rising ocean temperatures and their negative impacts on marine ecosystems.
Globally, local and national governments are making changes to help put us on a path to a healthier planet for all. For instance, Tokyo requires most new buildings to have solar panels, and Los Angeles outlawed gas power in all newly constructed buildings.
You can help by voting for pro-climate candidates. You can also make small but impactful changes to the way you live — sign up for community solar, invest in an induction stove, weatherize your home, or ride your bike more.
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