Fish go deep to beat the heat

Fish go deep to beat the heat
Redthroated Emperor Credit: James Cook University

A James Cook University study shows fish retreating to deeper water to escape the heat, a finding that throws light on what to expect if predictions of ocean warming come to pass.

JCU scientists tagged 60 redthroat emperor at Heron Island in the southern Great Barrier Reef. The fish were equipped with transmitters that identified them individually and signaled their depth to an array of receivers around the island.

The experiment monitored fish for up to a year and found the fish were less likely to be found on the reef slope on warmer days. Scientists think the probably head for deeper in response to warmer temperatures.

The research team considered temperature, air pressure rainfall, wind and moon phases as reasons for the shift, but discovered the only significant correlation was with temperature - the redthroat emperor were consistently monitored when water was less than 24 degrees Celsius.

Lead researcher Dr Leanne Currey said most studies looked at the effect would have on fish biology, not on how they would distribute themselves to compensate for higher temperatures. "This is a commercially important fish and we are looking at a significant depth shift," she said.

Dr Currey said the species are caught by commercial and recreational anglers near coral reefs and was the second most favoured fish for the reef line fishery behind the coral trout.

"If it's not around in the shallows in the future then fishers will have to redirect their efforts and it may be significantly harder to catch them," she said. The fish has been known to tolerate depths of up to 160 metres.

Dr Currey said instead of diving deeper, the species may instead shift south in search of cooler water at the same depth. She said some redthroat emperor had recently been caught off Perth, far from their normal habitat further up the West Australian coast.

Dr Currey said the next logical phase of the research was to investigate whether the fish could adapt physiologically to warmer sea temperatures, as it appeared other species could.


Explore further

Why offspring cope better with climate change—it's all in the genes!

More information: Assessing environmental correlates of fish movement on a coralreef, DOI: 10.1007/s00338-015-1318-7
Citation: Fish go deep to beat the heat (2015, August 7) retrieved 17 September 2019 from https://phys.org/news/2015-08-fish-deep.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
999 shares

Feedback to editors

User comments

Aug 07, 2015
Animals are adapting to the earth's changes. Who knew!?!?!

Aug 07, 2015
It should also be added:

In the 11 full years April 2004 to March 2015, for which the ARGO system has been providing reasonably-calibrated though inevitably ill-resolved data (each buoy has to represent 200,000 km3 of ocean temperature with only three readings a month), there has been no warming at all in the upper 750 m, and only a little below that, so that the trend over the period of operation shows a warming equivalent to just 1 C° every 430 years.


Aug 07, 2015
I understand the importance of monitoring the habits of commercially harvested fish, but the abstract (its a pay-per view paper), does not suggest a very good study.

This article has a catchy title, and will inspire more fear in the plebs, but is built on a paper that seems to do a lot of speculating.

1/5

Aug 07, 2015
Look at the deniers trying to minimize this news. It is happening, whether they "believe" it or not.

Aug 07, 2015
Look at the deniers trying to minimize this news. It is happening, whether they "believe" it or not.

No data, no meat.

Aug 07, 2015
More fodder for the ignorant hungry Chicken Littles...gobble up.
Take a gander at the GBR's water temperature trend.
http://jenniferma...er-reef/

NWM
Aug 07, 2015
The fish I talked to said they don't have to swim to the top to get warm anymore.

Aug 07, 2015
Grouper is not a recognized language.

Aug 07, 2015
Grouper is not a recognized language.

But stupid is and you are fluent.

Aug 08, 2015
This comment has been removed by a moderator.

Aug 10, 2015
I understand the importance of monitoring the habits of commercially harvested fish, but the abstract (its a pay-per view paper), does not suggest a very good study
I do agree. Maybe these fish just react to https://en.wikipe...rfishing in this way. Would you return to places, where both your mum, both dad were caught?

Well, they are the second favourite of the anglers, who I expect would rather go fishing on warmer days. This is pure junk "science".

Aug 10, 2015
The Great Barrier Reef is a marine park where there is no commercial fishing and Australians don't commerically fish redthroat emperor.

Now I suggest actually reading the article. Not that I don't think the study isn't drawing a slightly-long bow with its conclusions, being such a small study. But what the feck does it have to do with commercial fishing?

Aug 10, 2015
Dr Currey said the species are caught by commercial and recreational anglers near coral reefs and was the second most favoured fish for the reef line fishery

leetennant, were you born that stupid or dropped as a baby.

http://www.heron-.../cruises

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more