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Fisheries and aquaculture
Key messages

The effects of climate change, in particular of ocean warming, on wild fish distributions and
aquaculture are difficult to distinguish from those of high exploitation rates or technological
developments.

Wild fish stocks seem to be responding to changing temperatures and food supply by
changing their geographical distribution.

Future climate change is likely to lead to an increased catch potential in the Arctic, and to a
decreased or constant catch potential in other European seas.

Climate change can influence where aquaculture is possible, which species are raised, and the
efficiency of the production.
Relevance
Industries related to the capture of wild fish as well as marine aquaculture are sensitive to climate
change. This section gives an overview of the observed and projected impacts of climate change on
fisheries and aquaculture. Due to the scarcity of quantitative information, this information is not
presented as an indicator.
The total fisheries catch of the EU, concentrated mainly in the north-east Atlantic, is the third largest
fishery in the world. Commercially relevant wild fish stocks are subject to high levels of exploitation,
in many cases at levels that exceed their reproductive capacity. In Europe’s seas, overfishing is a
problem, with 30 % of commercial stocks (those which are assessed) being fished outside safe
biological limits. Recently, scientists have also brought attention to the likely effects of climate
change on fish stocks. Stocks are thought to respond to warming conditions both physiologically and
ecologically. Warming waters are expected to affect fish distribution, migration patterns, phenology
(timing), food availability (see Section Error! Reference source not found.) and recruitment. In
response, the geographical distribution and productivity of fish stocks could be changing (Simpson et
al., 2011). It is furthermore speculated, that ocean acidification (see Section Error! Reference source
not found.) may eventually impact on the lowest levels of the food web which ensures availability of
food for fish, and hence impact fish productivity. The high levels of fish exploitation, however, mean
that it is very difficult to distinguish between changes due to fisheries and those due to ocean
warming.
Although marine aquaculture depends critically on coastal habitats that will be affected by climate
change, it is still very difficult to distinguish between possible climate change effects, natural
variability in the environment around cages, and technological improvements that generally support
the development of the industry. The industry’s concerns are related to changes in the frequency and
strength of storms which may pose a risk to infrastructure such as salmon cages and to sea-level riseinduced changes in shoreline morphology which may change the location of habitats suitable for the
industry. The emergence, spread and severity of diseases, parasites and pathogens, and the spread of
nuisance and non-native species could also potentially be damaging. In Ireland and the UK, rising
temperatures may create the opportunity to rear species adapted to warmer water. However, market
forces are seen as the more important factor to determine whether existing farmed species will be
displaced by new ones (Callaway et al., 2012).
Past trends
Climate change has had a number of effects in the north-eastern Atlantic, where 72 % of commonly
observed species have responded to warming waters by changing their abundance and/or distribution
[Climate change, impacts, and vulnerability in Europe]
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(see Figure Error! No text of specified style in document..1). Traditionally, exploited fish such
as cod have moved further northwards in the region, particularly in the North Sea most likely as a
result of a shift in the thermal regime of the North Sea.
Figure Error! No text of specified style in document..1
Observed
change
in
the
distribution of demersal fish in response to observed rise in sea surface
temperatures
Note:
Changes in abundance in response to observed temperature change are relative changes (unitless).
Source: (Simpson et al., 2011), reprinted with permission from Elsevier
Furthermore, warming seas have allowed potentially new exploitable stocks to move into some areas.
While warming can lead to an increase in fish biodiversity in a region, there is often a concurrent
decrease in the size structure of the fish population. For example, in the North Sea the relatively small
species sprat, anchovy and horse mackerel have increased in recent decades, whereas the larger
species cod and plaice have decreased at their southern distribution limit (Perry, 2005). This change
may have important socio-economic consequences as the stocks moving out of the North Sea tend to
have a higher value than the stocks moving into it.
As catch of wild fish species has been decreasing while the demand for fish and fish products has
increased, a large increase in the total European aquaculture production has been observed over the
past 15 years (EEA, 2010). Today EU and European Free Trade Association (EFTA) aquaculture
production is at a level of 1.8 million tonnes of fish, shellfish and crustaceans, generating a turnover
of EUR 3.2 billion and 65 000 jobs. Often aquaculture production is situated in coastal communities
that rely almost solely on income from that industry, and hence these communities are vulnerable to
changes that affect the industry.
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[Climate change, impacts, and vulnerability in Europe]
Projections
Projections of changes in total catch of marine fish and invertebrates as a consequence only of
temperature changes has shown the potential of a large-scale redistribution of global catch potential
with an increase in high latitude regions and a decline in the tropics. The exclusive economic zone
(EEZ) regions with the highest increase in catch potential by year 2055 include Alaska (US),
Greenland, Norway and Russia, whereas the biggest loss would occur in Chile, China, Indonesia and
the US (excluding Alaska and Hawaii) (Cheung et al., 2009, 2012). Hence, the biggest loss in catch
potential is likely to occur outside Europe, but it would affect parts of the world that are particularly
vulnerable to such changes because of the high importance of fisheries to national economies and
diets, and limited societal capacity to adapt to potential impacts and opportunities (Allison et al.,
2009). Large differences in changed catch potential are likely to occur within Europe, with the
greatest increase in the Arctic.
Climate change may create new opportunities for aquaculture, in particular by raising warm-water
species in previously unsuitable locations. Changes in aquaculture, however, also strongly depend on
market forces and consumers’ tastes, which may have a stronger influence on production than
temperature and technological advancements.
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