Farmed seafood supply at risk if we don't act on climate change
Study shows marine fish farms are not climate change safety nets

Date:
December 13, 2021
Source:
University of British Columbia
Summary:
The supply of farmed seafood such as salmon and mussels are
projected to drop 16 per cent globally by 2090 if no action is taken
to mitigate climate change, according to a new study. Ocean-farmed
seafood or mariculture is often seen as a panacea to the problems
of depleted stocks of wild fish and growing human demand, and is
expected to grow substantially in the coming years. But the new
modelling study highlights the industry is as vulnerable to the
effects of climate change as any other. If we continue to burn
fossil fuels at our current rate, the amount of seafood such as
fish or mussels able to be farmed sustainably will increase by
only eight per cent by 2050, and decline by 16 per cent by 2090.



FULL STORY ==========================================================================
The supply of farmed seafood such as salmon and mussels are projected
to drop 16 per cent globally by 2090 if no action is taken to mitigate
climate change, according to a new UBC study.


========================================================================== Ocean-farmed seafood or mariculture is often seen as a panacea to the
problems of depleted stocks of wild fish and growing human demand,
and is expected to grow substantially in the coming years, says lead
author Dr. Muhammed Oyinlola (he/him), a postdoctoral research fellow at
the Institute for the Oceans and Fisheries (IOF). But the new modelling
study highlights the industry is as vulnerable to the effects of climate
change as any other. "If we continue to burn fossil fuels at our current
rate, the amount of seafood such as fish or mussels able to be farmed sustainably will increase by only eight per cent by 2050, and decline
by 16 per cent by 2090." By comparison, in a low emissions scenario
where the action is taken to mitigate climate change, mariculture is
projected to grow by about 17 per cent by the mid-21st century and by
about 33 per cent by the end of the century, relative to the 2000s.

The model takes into account many factors, including changing ocean temperatures, suitable mariculture areas in the future, and the supply
of fishmeal and fish oil. It examined approximately 70 per cent of the
world's mariculture production as of 2015, focusing on Exclusive Economic Zones, where most of the world's seafood farming occurs.

Climate change will affect mariculture production differently
depending on where farms are in the world, and what they produce, says
Dr. Oyinlola. The hardest-hit regions in the high-emissions scenario --
Norway, Myanmar, Bangladesh, the Netherlands, and China -- could see
their mariculture production decline by as much as 40 to 90 per cent.

Climate effects on mariculture include changes in the area of viable
ocean in which to farm fish as well as the stock of food used to feed
them. Fish farms tend to use fishmeal and fish oil, which are largely
composed of smaller fish such as herring and anchovy -- stocks which
are also threatened by climate change.



========================================================================== "Some regions produce more bivalves, such as mussels, oysters and clams,
and in these regions, the impact is smaller," Dr. Oyinlola said. "In
regions that produce more finfish, such as salmon, the impact will
be high due to reduction in the supply of fishmeal and fish oil."
Under current carbon emission rates, finfish farming, such as salmon,
is projected to decrease globally by three per cent by 2050, and 14
per cent by 2090. Bivalve farming is projected to increase by 2050 and
decrease by 2090 under both climate scenarios.

Countries where mariculture is prominent especially for finfish
production, such as Norway, Iceland, Finland, Chile, and Bangladesh,
will be hit hardest, according to Dr. Oyinlola, whereas regions that
produce more bivalves will be more stable or in Canada's case, will grow.

Vegetarian fish: feeding fish soybeans The study also found that
substituting fishmeal and fish oil for plant-based foods such as soybeans
could help alleviate the effects of climate change for fish farms.

When a quarter of the fish food was substituted with alternatives,
under a low emissions scenario, mariculture production was projected to increase by 25 per cent by 2050 and 31 per cent by 2090.

With no change to current emissions, when a quarter of the fish food
was substituted with alternatives, mariculture production was projected
to increase by 15 per cent by 2050 and four per cent by 2090. When half
the food was substituted in both climate scenarios, these percentages increased.

"This study highlights the need to diversify mariculture development
from the current focus on fish," said senior author Dr. William Cheung (he/him), IOF professor and director. Climate-adapted mariculture
would include species that are not dependent on fishmeal and fish oil,
such as shellfish or algae, or those that can utilize non-fish-based
feed. "Farming these species generally helps to reduce exposure of
seafood farming to climate hazards." While there is enthusiasm about
ocean mariculture helping to increase the production of seafood, the
study shows if humans don't relieve climate change, such enthusiasm
will be tempered, says Dr. Cheung. "Climate change affects everything, including aspects of seafood farming we've not previously considered. We
need to act, and quickly, to mitigate climate change rather than
rely on one solution to solve all our seafood production problems." ========================================================================== Story Source: Materials provided by University_of_British_Columbia. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Muhammed A. Oyinlola, Gabriel Reygondeau, Colette C. C. Wabnitz,
Thomas
L. Fro"licher, Vicky W. Y. Lam, William W. L. Cheung. Projecting
global mariculture production and adaptation pathways under
climate change.

Global Change Biology, 2021; DOI: 10.1111/gcb.15991 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211213111643.htm

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