INSUBCONTINENT EXCLUSIVE:
This happened to coincide with the world's fourth global bleaching event
They measured the body size of the fish once a month and measured the temperature around the individual anemones every four to six days
Then the team analyzed the collected data.
"Individual fish can shrink in response to heat stress."
Credit:
Morgan Bennett-Smith
The results: Over the course of those months, 101 of the 134 clownfish
shrank at least once in response to heat stress, and doing so boosted their likelihood of survival up to 78 percent compared to the 33 fish
And between breeding pairs, there were distinctive growth ratios between the dominant and subordinate fish; those pairs that shrank together
individual repeatedly over a period of five months," said Versteeg
"In the end, we discovered it was very common in this population
It was a surprise to see how rapidly clownfish can adapt to a changing environment, and we witnessed how flexibly they regulated their size,
have not yet identified a possible mechanism for the shrinkage, but suggest the triggering of neuroendocrine pathways via thyroid hormones
might play a role, since those hormones regulate growth
The adaptive strategy could also be a means of adjusting to changing metabolic needs
But there are trade-offs: While shrinking in response to heat waves ensures greater survivability, there can also be a corresponding
decrease in birth rates."Our findings show that individual fish can shrink in response to heat stress, which is further impacted by social
conflict, and that shrinking can lead to improving their chances of survival," said senior author Theresa Rueger, also of Newcastle
"If individual shrinking were widespread and happening among different species of fish, it could provide a plausible alternative hypothesis
