Researchers Predict That Larger Fish Species Suffers From Oxygen Deficiency Due to Global Warming and Human Activities

Compared to lesser species, larger fish are more likely to encounter an oxygen shortage in warmer water.

Researchers remarked that the same holds true for fish with big cells. Additionally, compared to freshwater fish, saltwater fish are less tolerant to low oxygen levels in the ocean.

The researchers' ultimate goal is to anticipate which aquatic species are in danger as a result of habitat changes brought on by global warming and human activity based on these findings.

Large and small cells in fishes

(Photo : Milos Prelevic/Unsplash)

Fishes and other aquatic species are facing a serious dilemma due to declining dissolved oxygen levels.

Because of increased pollution and water heating brought on by climate change, oxygen levels are declining.

When environmental conditions change, general biological principles can help us determine which fish characteristics are advantageous or disadvantageous.

 According to scientist Wilco Verberk, "after we have found these guidelines for fish, we can eventually anticipate which fish species are most at risk from environmental change," as per ScienceDaily.

The significance of oxygen in fish susceptibility to warmer water is a hot topic of discussion among scientists.

For instance, some studies examined how fish react to the oxygen concentration in the water but do not account for the water temperature or the size of the fish.

As a result, the reported patterns are variable.

"Many oxygen hypotheses are being fiercely debated. The problem is that the various effects are lumped together," said Verberk.

To settle this debate, Verberk and colleagues carefully isolated the various impacts and accumulated information on oxygen shortage tolerance from 195 fish species.

They discovered after analyzing the data that only in warm water do bigger fishes exhibit greater sensitivity to oxygen stress.

The researchers also discovered distinctions between freshwater and saltwater fish. Scientific investigations much too frequently exclusively contrast marine and terrestrial life.

It's true that, occasionally, species found in freshwater and on land are combined. It is a squandered chance since taking these variations into account can significantly improve our comprehension of how climate change affects the ecosystem.

Freshwater fishes appear to be more tolerant to oxygen-depleted water than marine fishes, according to research by Verberk and colleagues.

Different selection pressures on freshwater fish throughout their evolutionary history are likely to blame for the explanation.

The temperature in the ocean is generally consistent, while in freshwater, fish are more frequently exposed to hotter temperatures.

Also Read: Eutrophication Could Lead to More Silent Seas, Study Finds

Eutrophication

Due to the increased availability of one or more limiting growth elements like sunshine, carbon dioxide, and fertilizers that are necessary for photosynthesis, eutrophication is characterized by excessive plant and algae development.

As lakes deteriorate and accumulate silt over generations, eutrophication naturally takes place, as per Nature.

However, limiting nutrients, such as nitrogen and phosphorus, have been introduced into aquatic ecosystems through both point-source discharges and non-point loadings, which have exacerbated the rate and extent of eutrophication.

This has severe effects on fisheries, drinking water supplies, and recreational water bodies

For instance, aquaculture researchers and pond managers frequently purposefully eutrophicate bodies of water by adding fertilizers to improve primary production and boost the density and biomass of fish that are vital for enjoyment and commerce.

Scientists did, however, connect algal blooms to nutrient enrichment brought on by anthropogenic activities like agriculture, industry, and sewage disposal throughout the 1960s and 1970s.

Blue-green algal blooms, contaminated water sources, diminished recreational options, and hypoxia are some of the known effects of cultural eutrophication.

The projected yearly cost of damage caused by eutrophication in the United States alone is $2.2 billion.

Related article: Typhoons and Marine Eutrophication Are Probably the Missing Source of Organic Nitrogen in Ecosystems