Almost 20 years have passed since then, finding nemo ‘ hit theaters and the lost ‘little clownfish on the reef’ swam into our minds. But reef fish have much more to offer than their beautiful scales and fictional stories.
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a The study was published May 11 in an open access journal PLOS biology We find that sea anemones and some reef-dwelling fish undergo dramatic physiological changes as they transition from rapid open-ocean swimming as larvae to reef-dwelling settlements.
Young sea turtle friends named Nemo and Squirt may have had something in common beyond their ages. Like sea turtles, many reef fish spawn away from where the animals eventually settle and live.Adult coral reef fish spawn larvae in the open ocean and larvae swim against a strong current to return to the reef where they live as adults. Other benthic marine organisms such as starfish, corals and sea urchins also follow this pattern.
“For reef fish, the first few weeks of life can be the most vulnerable time. ,” said co-author Jody L. Lamar, a marine biologist at James Cook University. pop science.
All this swimming takes a lot of energy from the little fish, but once they reach the bottom of the reef they have to switch gears sharply and survive in a hypoxic or hypoxic environment at night.
To learn more about how this adjustment works, the team collected daily measurements of cinnamon anemonefish (amphiprion melanopath) Larval swimming speed, oxygen renewal and hypoxia tolerance. They were observed in a laboratory environment from the time they were hatched until they settled, usually around day 9 of life.
“Reef fish, including clownfish, swim the fastest in their larval state relative to their body size,” said study co-author Adam Downey. pop science. Downey, now an animal physiologist at the University of Queensland, Australia, conducted this research as part of his doctoral program at James Cook University. “In our study, the top speed was over 12 centimeters.” [4.7 inches] However, for a fish the size of a pinky fingernail, 10 to 12 bodies per second lengthen. Relative to their size, reef fish larvae, including clownfish, outperform most other marine organisms and all humans in swim tests. ”
Furthermore, it was observed that hypoxic tolerance of fish increased from around day 5, while oxygen uptake decreased. To investigate how their bodies cope with these oxygen deprivations, they sequenced mRNA from larvae of different ages and examined changes in gene activity that occur during development. These physiological changes correlated with regions of genes in which hemoglobin is produced, and the activity of 2,470 genes changed during development.
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“These baby fish are able to alter the expression patterns of specific genes encoding oxygen transport and storage proteins to cope with such hypoxia in coral reefs,” Lamar said. . “These proteins, such as hemoglobin and myoglobin, are also present in our bodies and are important for taking oxygen from the environment and delivering it to our muscles, heart and other organs. Timing is everything!”
The study found that larvae of the cinnamon anemonefish (also known as cinnamon clownfish) have the highest rate of oxygen uptake among bony fish currently measured relative to their body size. The genetic changes that reef fish can make to take in more oxygen underpin the way they swim at speeds that even the most decorated Olympians would envy. Downey says some studies have measured clownfish lengths at up to 50 lengths per second, while Michael Phelps is just under 2 lengths per second.
Because the impacts of climate change threaten all marine life, the researchers believe that warmer waters could prevent clownfish from swimming because their energy needs are so high. In addition to coral bleaching, rising ocean temperatures are further jeopardizing coral reef ecosystems. ocean acidificationillness, etc.
“The next step is to investigate how different climate change stressors, such as temperature and pollutants, affect the ability of clownfish larvae to swim and successfully migrate from the open ocean to reefs.” Mr Downey said.