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Cold-blooded animals

Facts for Prelims:

Source: TH

Context: Scientists have disputed the idea that as the planet warms, the bodies of cold-blooded marine species, including fish, will contract.


Conventional understanding: Warming temperatures lead to smaller body sizes in cold-blooded marine animals, suggesting that they may actually grow larger in response to warmer waters.


The recent study challenges the expectation due to several reasons:

  • Warm water pollution: The study suggests that warm water pollution, caused by the discharge of warm pollutants, can actually contribute to the growth of aquatic animals.
  • Accelerated growth at younger age: Contrary to previous assumptions, the study found that cold-blooded animals, or ectotherms, experience faster growth at a younger age in warm waters.
  • Sustained growth throughout life: The study discovered the positive effect of warmer waters on growth and they continue to experience growth throughout their lives, leading to a larger maximum body size.
  • Survival trade-off: While the warmer waters provide favourable conditions for growth, they also come with higher death rates.
  • Influence of warm water on young populations: The research revealed that even if the water becomes inhospitable to the fish due to excessive warmth, the growth boost is significant enough to create a larger population of young-and-large fish.


Highlights of the study: Aquatic animals/ectotherms/cold-blooded animals such as fish would actually grow larger due to warm water pollution, i.e. water heated by warm pollutants.