New research shows that even fish that are used to living in hot and dry areas are having a hard time as the climate gets warmer. These fish are known for being tough, as they can survive streams that often dry up or stop flowing during droughts or extreme heat. However, they are now starting to struggle because of rising temperatures and less rainfall due to climate change.

Add Asianet Newsable as a Preferred Source

A recent study led by researchers from the University of Buffalo analyzed data over 40 years from nearly 1,500 streams in dry regions of the United States and Australia. The findings showed a decrease in the number of fish species in these areas. The study focused on xeric climates, which are very dry and receive little rain throughout the year.

Which Fish Are At Risk?

Many streams in these areas are intermittent, meaning they do not flow all year round. In fact, more than half of all streams and rivers in the US are intermittent, and in the southwestern US, this number is even higher, at 80%.

Some freshwater fish have adapted to survive in these dry conditions, living and breeding even when water is scarce. But the research shows that these fish are now facing challenges beyond what they can handle.

Experts looked at climate and fish population data from 1980 to 2022 and found a clear trend: temperatures were increasing, while rainfall and streamflow were decreasing.

In the US rainfall dropped by an average of 0.137 millimetres per year. In Australia, the decline was 0.083 millimetres per year. The number of days streams had no water flow increased by half a day per year, and the longest stretches without water grew by 0.62 days annually.

The study included 191 fish species from dry regions. In US streams, about two species per stream disappeared over the study period. While data from Australia was not detailed enough to draw strong conclusions, similar patterns may be occurring there.

Species most affected were small fish that rely on plant and algae-based food sources, which depend on steady water flow.

Is Climate Change the Only Cause?

While the study did not find a direct link between reduced streamflow and the loss of fish species, though the connection is strong enough to suggest a relationship. The researchers believe that climate change is a major factor.

However, it is not the only one. Other challenges include:

• Invasive species that compete with or prey on native fish

• Urban development altering natural water systems

• Water pollution from treated wastewater

• Physical changes to streams, such as straightening or rerouting them

Many of the streams studied have been heavily modified by humans, making it harder for fish to survive as climate conditions get worse.

Why Is It Important

As the planet continues to warm, more regions are expected to face hotter, drier conditions. This means what’s happening in parts of the US and Australia could soon happen elsewhere. The decline in fish species is not just a concern for conservationists. Their loss can affect everything from water quality to the survival of birds and mammals that depend on them for food and immediate action is required to address the situation.