Bull sharks, one of the largest and most violent ocean predators, appear to be benefiting from the rising water temperature, unlike other marine species.
Researchers at Mississippi State University (MSU) discovered that the number of individual sharks, all juveniles, recorded each hour in Mobile Bay was five times higher in 2020 than at the start of the study in 2003.
Rising Water Temperature
According to a study published Thursday in Scientific Reports, rising sea surface temperatures over the last two decades have resulted in a five-fold rise in the population of juvenile bull sharks in Mobile Bay.
From 2001 to 2020, the average sea temperature increased from 72.1F (22.3C) to 73.4F, indicating that bull sharks benefit from the climate emergency.
This finding comes as researchers warn of a "cataclysmic" global extinction spurred by record ocean temperatures.
The MSU researchers evaluated data from 440 bull sharks caught, tagged, and released by Alabama's Department of Conservation and Natural Resources over a 17-year period, and compared it to meteorological data acquired by remote sensors in Mobile Bay.
Bull shark abundance has increased fivefold, demonstrating the influence of altering environmental circumstances, according to the researchers.
The researchers discovered that sea surface temperatures above 22.5 degrees Celsius were connected with an increased risk of bull shark presence, according to computer modeling data.
"As climate change persists, coastal communities will continue to change, altering the structure of ecological communities and the success of nearshore fisheries," the report says.
Read Also: Bull Sharks Seen To Be Active During Midday, In Higher Temperature, Study Says
Resilience Of Bull Shark
Lindsay Mullins, the study's lead author from the university's coastal research center, said the species is normally located in warm, shallow coastal waters in both fresh and saltwater habitats, therefore they are thriving in the warmer waters while other animal species are beginning to suffer.
The findings emphasize the species' resilience in response to climate change and coastal urbanization, a "surprising" conclusion.
"It is, sort of, contrary to that narrative that we normally think, which is that for many species, warming water is a detriment," she said.
While sharks near U.S. waters have benefited from aggressive coastal conservation efforts, the worldwide picture for sharks remains bleak due to overfishing or bycatch.
However, it is unknown how the bull shark population will adapt to further rises in sea surface temperature. It is also uncertain how continuous population growth would affect the local ecosystem.
While bull sharks are known for their ability to help balance and maintain the health of coastal ecosystems by regulating prey populations, the scientists believe that increased numbers will affect fishing opportunities in the region and may lead to increased interactions with humans, the study suggested.
According to Mullins, despite the increasing prevalence of bull sharks reported by the MSU study, the threat to people has not grown in proportion.
"It's important to remember that these changes in abundance are relatively gradual, and have been already increasing over the last several decades," she said.
According to the University of Florida's international shark attack file (ISAF), coastal-dwelling bull sharks are often regarded as the most dangerous in the world, having been responsible for several dozen verified human fatalities and suspected of numerous further attacks.
In 2023, the number of shark bite deaths from all species doubled to ten from the previous year.
A 16-year-old girl was killed by a bull shark in a river in Perth, Australia, last month, and a lady was severely hurt while swimming in Sydney Harbour in January after being attacked by the shark.
Related Article: Bull Shark Abundance Shows Population Resilience to Increasing Temperatures, Climate Change in Mobile Bay