{"id":395694,"date":"2026-04-16T18:59:20","date_gmt":"2026-04-16T18:59:20","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/395694\/"},"modified":"2026-04-16T18:59:20","modified_gmt":"2026-04-16T18:59:20","slug":"warm-bodied-sharks-and-tunas-face-double-jeopardy-in-warming-seas-new-research","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/395694\/","title":{"rendered":"Warm-bodied sharks and tunas face \u201cdouble jeopardy\u201d in warming seas \u2013 new research"},"content":{"rendered":"

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image:\u00a0<\/p>\n

The large and warm-bodied great white shark (Carcharodon carcharias) has high fuel demands and risks overheating in warm oceans\u201d.<\/p>\n

view more\u00a0<\/a><\/p>\n

Credit: Andrew Fox<\/p>\n

A new study reveals that some of the ocean\u2019s 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 \u201cdouble jeopardy\u201d in which it places\u00a0these 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.<\/p>\n

The research, led by scientists at\u00a0Trinity College Dublin\u00a0in collaboration with\u00a0the University of Pretoria\u2019s (UP) Faculty of Veterinary Science,\u00a0shows that warm-bodied fish such as tunas and some sharks, including the legendary Great White and Ireland\u2019s 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.<\/p>\n

The study, published today in leading international journal\u00a0Science, focuses on \u201cmesothermic\u201d 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.<\/p>\n

To understand the cost of this high-performance lifestyle, the Trinity and UP scientists developed a novel way to estimate metabolic rate in free-swimming fish. By analysing biologging data\u2014from tiny sensors that record body and water temperatures\u2014the team calculated how much heat fish produce and lose in real time. They combined these new measurements, including data from huge basking sharks weighing up to 3.5 tonnes, with hundreds of lab measurements from smaller species.<\/p>\n

Dr Nicholas Payne, from Trinity\u2019s School of Natural Sciences,\u00a0is first author of the research paper. He said: \u201cThe results were really quite striking \u2013 after accounting for body size and temperature, we found that mesothermic fishes use about 3.8 times more energy than similarly sized \u2018ectothermic\u2019, or \u2018cold-blooded\u2019 fishes. In addition, a 10\u00b0C increase in body temperature more than doubles a fish\u2019s routine metabolic rate which, in practical terms, means warm-bodied predators must consume far more food to fuel their lifestyle.\u201d<\/p>\n

\u201cBut that heighted energy demand is only part of the story because as fish grow larger their bodies generate heat faster than they can lose it,\u201d adds\u00a0Dr Payne.\u00a0\u201cThis creates a mismatch driven by basic geometry and physics because bigger bodies retain heat more effectively, and in mesotherms, high metabolic rates amplify this effect.\u201d\u00a0<\/p>\n

The team found that larger fish become increasingly \u201cwarm-bodied\u201d simply because of this imbalance, and it is this scaling mismatch that creates an overheating dilemma with significant implications for these species.\u00a0<\/p>\n

Professor Andrew Jackson from Trinity\u2019s School of Natural Sciences\u00a0is senior author of the research paper. He said: \u201cBased on the data we were able to create theoretical \u2018heat-balance thresholds\u2019, which are the water temperatures above which large fish cannot shed heat quickly enough to maintain stable body temperatures without changing their behaviour or physiology. For example, a 1-tonne warm-bodied shark may struggle to remain in heat balance in waters above about 17\u00b0C.\u201d\u00a0<\/p>\n

\u201cAbove such thresholds, fish must slow down, alter blood flow, or dive into cooler depths to avoid dangerous warming but that comes at a cost too; it might be harder to find food, or catch it, for example \u2013 especially if your main weapon is speed and power.\u201d\u00a0<\/p>\n

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.\u00a0<\/p>\n

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.<\/p>\n

Dr Snelling, UP,\u00a0says: \u201cThis 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.\u201d\u00a0\u00a0<\/p>\n

\u201cWhat\u2019s particularly concerning is that these animals are already operating on a tight energy budget, and climate change is narrowing their options even further. Understanding these constraints is essential if we want to predict how marine ecosystems will shift in the coming decades.\u201d<\/p>\n

\u201cThe implications are really sobering as this new finding essentially places these animals in \u2018double jeopardy,\u201d adds\u00a0Dr Payne. \u201cMany mesothermic fishes are already heavily impacted by overfishing of themselves and also their\u00a0\u00a0prey species, so their elevated energy needs make them especially vulnerable when their food becomes scarce.\u201d\u00a0<\/p>\n

\u201cFossil evidence suggests that warm-bodied marine giants, like the infamous extinct Megalodon shark, suffered disproportionately during past climate shifts when seas changed and today\u2019s oceans are changing at unprecedented speeds, so the alarm bells are ringing loudly at this point.\u201d<\/p>\n

What are the potential implications of this research?<\/p>\n

Ultimately this crucial research provides a new framework for predicting which species are most at risk in a warming world and shows that many of the ocean\u2019s fastest and most formidable predators may also be among its most physiologically constrained. As climate change accelerates, understanding the hidden heat budgets of marine giants could prove critical to conserving them.<\/p>\n

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.<\/p>\n","protected":false},"excerpt":{"rendered":"image:\u00a0 The large and warm-bodied great white shark (Carcharodon carcharias) has high fuel demands and risks overheating in…\n","protected":false},"author":2,"featured_media":395695,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[85,46,141],"class_list":{"0":"post-395694","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-il","9":"tag-israel","10":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/395694","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/comments?post=395694"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/posts\/395694\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media\/395695"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/media?parent=395694"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/categories?post=395694"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/il\/wp-json\/wp\/v2\/tags?post=395694"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}