Researchers find weaker premature baby sharks hatching in different oceans due to increased temperatures because of the climate crisis. Authors of the study stress that weaker sharks are less effective hunters.
40% of all shark species lay eggs. Researchers have found a unique species in the Great Barrier Reef that spends up to 25 days in its egg cases.
Unfortunately, the extra heat brought by the warming of oceans causes embryonic epaulette sharks to devour through their eggs faster, which results in premature shark births.
How the Climate Crisis Threatens Sharks
A study published today in the Scientific Reports shows how future thermal regimes will cause sharks' metabolic and growth performances to drastically decline and upset the ecosystem.
Dr. Jodie Rummer, associate professor at the ARC Centre of Excellence for Coral Rees Studies and co-author of the study, says, "This is a huge red flag for us."
According to the study, temperatures affect body condition, performance, and development rates of marine life. Organisms that rely on the environment to regulate most biological processes are in a dire situation due to global thermal regimes' increase because of climate change.
The study notes that embryonic stages might be the most vulnerable to these drastic changes, especially for oviparous species currently living at the warm edge of distribution.
Rummer explains, "Sharks are important as predators because they take out the weak and injured and keep the integrity of the population strong."
"Healthy coral reefs need health predators," he adds.
Check Out : Coral Reef Restoration Needs Researchers Help
Researching Climatic Changes Effects on Epaulette Sharks
Hemiscyllium ocellatum, commonly known as Epaulette sharks, are long slender creamy, or brown sharks that can survive up to an hour without oxygen. But its most remarkable trait is its ability to "walk" on its fins.
The harmless sharks can grow up to a meter and thrive in the Great Barrier Reef's shallow waters.
Females lay "mermaid's purse"--leathery egg sacks.
To find out how temperature changes will affect epaulette eggs, scientists at the New England Aquarium in Boston monitored 27 epaulette shark eggs.
Divided into two, some sharks were reared in 27 degrees celsius water temperatures--the average summer temperature. Others were reared at either 29 or 31 degrees celsius--predicted temperatures for the middle and end of the 21st century.
Because of the translucence of the "mermaid's purse," researchers were able to closely monitor development, metabolic costs, and growth of both in ovo and upon hatch.
The 27-degree celsius-reared sharks emerge from their egg cases after 125 days. In comparison, the latter group emerged only after 100 days.
The baby sharks peaked in fitness at 29 degrees celsius in terms of fitness but fell drastically at 31 degrees celsius.
Carolyn Wheeler, the lead author of the study, says, "The hotter the conditions, the faster everything happened, which could be a problem for the sharks.
Simply put, weaker premature baby sharks will keep emerging from their egg cases with the warming of the oceans due to climate change.
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