Climate change `double whammy' could kill off fish species
Warming waters rob fish of ability to both move and adapt to cope

Date:
August 9, 2021
Source:
University of Reading
Summary:
New study of 150 million years of fish evolution provides
first evidence to support scientific theory that commonly-eaten
fish species will become smaller as waters warm under climate
change. However, it reveals unexpected finding that they will
also produce fewer new species, meaning they will be less able to
move to more suitable environments and to adapt through evolution,
as the planet warms faster than ever.



FULL STORY ==========================================================================
Many commonly-eaten fish could face extinction as warming oceans due to
climate change increases pressure on their survival while also hampering
their ability to adapt.


==========================================================================
New research suggests that fish like sardines, pilchards and herring
will struggle to keep pace with accelerating climate change as warmer
waters reduce their size, and therefore their ability to relocate to
more suitable environments.

The study, published in Nature Climate Change, also provides the first
evidence to counter the scientific theory that decreased movement
will result in more species, by suggesting the opposite is true. This
means many species will also be less able to evolve to cope with warmer temperatures, increasing their risk of dying out.

Professor Chris Venditti, an evolutionary biologist at the University of Reading, and co-author of the study, said: "Warming waters are a double
whammy for fish, as they not only cause them to evolve to a smaller size,
but also reduce their ability to move to more suitable environments.

"Our research supports the theory that fish will get smaller as oceans
warm under climate change, but reveals the worrying news that they will
also not be able to evolve to cope as efficiently as first thought. With
sea temperatures rising faster than ever, fish will very quickly get
left behind in evolutionary terms and struggle to survive.

"This has serious implications for all fish and our food security, as
many of the species we eat could become increasingly scarce or even non-existent in decades to come." The study, led by the Center for
Advanced Studies in Arid Zones (CEAZA) in Chile and the University of
Reading in the UK, used statistical analyses of a large dataset of
globally distributed fish species to study their evolution over the
past 150 million years. The study provides first solid evidence of how historical global temperature fluctuations have affected the evolution
of these species.



==========================================================================
It focused on Clupeiforms -- a highly diverse group of fish found all
over the world, which includes important species for fisheries, such as anchovies, Atlantic herring, Japanese pilchard, Pacific herring, and South American pilchard. However, the findings have implications for all fish.

Fish have thus far only had to deal with a maximum average ocean
temperature rise of around 0.8DEGC per millennium. This is far lower than current warming rates reported by the National Oceanic and Atmospheric Administration of 0.18DEGC per decade since 1981.

The findings support the long-held expectation among scientists that
fish will generally get smaller and move less as world warms, due to
having to increase their metabolism and therefore needing more oxygen
to sustain their body functions. This will impact fish species because
larger fish are able to travel longer distances owing to their greater
energy reserves, whereas smaller fish are less able to seek out new environments with favourable conditions as the climate changes.

However, the research contradicts the assumption that an increase in
smaller fish will mean more new species emerging because of concentrating genetic variations within local areas.

Instead, the scientists found warmer waters would lead to fewer new
species developing, robbing fish of another of their key weapons to cope
with climate change.

Overfishing has also been found to make fish smaller in size, so the
new study adds to the list of pressures they face as a consequence of
human actions.

========================================================================== Story Source: Materials provided by University_of_Reading. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Jorge Avaria-Llautureo, Chris Venditti, Marcelo M. Rivadeneira,
Oscar
Inostroza-Michael, Reinaldo J. Rivera, Cristia'n E. Herna'ndez,
Cristian B. Canales-Aguirre. Historical warming consistently
decreased size, dispersal and speciation rate of fish. Nature
Climate Change, 2021; DOI: 10.1038/s41558-021-01123-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210809144038.htm

--- up 13 weeks, 3 days, 22 hours, 45 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)