10 hours ago
https://www.eurekalert.org/news-releases/1123512
EXCERPTS: A new study reveals that some of the ocean’s most powerful predators are running hotter, and that they are likely paying an increasingly steep price for it. The significance of this headline finding is the “double jeopardy” in which it places these iconic animals, which have high fuel demands due to their lifestyle and physiology, as they now face a future of warming oceans and declining food resources.
The research, led by scientists at Trinity College Dublin in collaboration with the University of Pretoria’s (UP) Faculty of Veterinary Science, shows that warm-bodied fish such as tunas and some sharks, including the legendary Great White and Ireland’s iconic basking shark, burn nearly four times more energy than their cold-blooded counterparts. This means they are likely to face an increasing risk of overheating as oceans warm, which may result in a reduction of suitable habitat and an enforced relocation towards the poles.
The study, published today in leading international journal Science, focuses on “mesothermic” fishes, a rare group comprising fewer than 0.1% of all fish species, which can retain metabolic heat and keep parts of their bodies warmer than the surrounding seawater. This ability has evolved independently several times in some sharks and tunas, enabling higher swimming speeds, long-distance migrations, and enhanced predatory performance.
[...] These findings seemingly help to explain long-observed patterns in the ocean, where large fishes tend to occur in cooler waters, at higher latitudes, or at greater depths. They also migrate seasonally, tracking favourable temperatures.
Unsurprisingly, the scientists predict that under future warming scenarios suitable habitat for large mesotherms will shrink, and particularly so during summer months. And while some species, such as Atlantic bluefin tuna, can temporarily increase heat loss or dive to cooler waters, even they may be pushed to their limits if surface waters continue to warm.
Dr Snelling, UP, says: “This research shows that being a high-performance predator in the ocean comes at a greater cost than we previously appreciated. As the oceans warm, these species are being pushed closer to their physiological limits, which could have consequences for where they can live and how they survive.” (MORE - missing detail, no ads)
EXCERPTS: A new study reveals that some of the ocean’s most powerful predators are running hotter, and that they are likely paying an increasingly steep price for it. The significance of this headline finding is the “double jeopardy” in which it places these iconic animals, which have high fuel demands due to their lifestyle and physiology, as they now face a future of warming oceans and declining food resources.
The research, led by scientists at Trinity College Dublin in collaboration with the University of Pretoria’s (UP) Faculty of Veterinary Science, shows that warm-bodied fish such as tunas and some sharks, including the legendary Great White and Ireland’s iconic basking shark, burn nearly four times more energy than their cold-blooded counterparts. This means they are likely to face an increasing risk of overheating as oceans warm, which may result in a reduction of suitable habitat and an enforced relocation towards the poles.
The study, published today in leading international journal Science, focuses on “mesothermic” fishes, a rare group comprising fewer than 0.1% of all fish species, which can retain metabolic heat and keep parts of their bodies warmer than the surrounding seawater. This ability has evolved independently several times in some sharks and tunas, enabling higher swimming speeds, long-distance migrations, and enhanced predatory performance.
[...] These findings seemingly help to explain long-observed patterns in the ocean, where large fishes tend to occur in cooler waters, at higher latitudes, or at greater depths. They also migrate seasonally, tracking favourable temperatures.
Unsurprisingly, the scientists predict that under future warming scenarios suitable habitat for large mesotherms will shrink, and particularly so during summer months. And while some species, such as Atlantic bluefin tuna, can temporarily increase heat loss or dive to cooler waters, even they may be pushed to their limits if surface waters continue to warm.
Dr Snelling, UP, says: “This research shows that being a high-performance predator in the ocean comes at a greater cost than we previously appreciated. As the oceans warm, these species are being pushed closer to their physiological limits, which could have consequences for where they can live and how they survive.” (MORE - missing detail, no ads)