16.2.8.2.5. Fisheries
High-latitude marine fisheries are very productive. For example, those in the
northern Pacific Ocean and the Bering Sea contribute more than 28% to total
world landings of fish, mollusks, and crustaceans. In some northern countries,
fisheries and fish products account for a large proportion of gross domestic
product. In Greenland, the shrimp industry contributed more than 30% to GDP
in 1986. Landings of fish in the Northwest Territories and in Nunavut, in the
commercial and the subsistence sectors of the economy, are valued at CDN$12
million.
Shifts in oceanic circulation associated with global warming are likely to
affect the distribution of commercially important fish and their migration routes
(Buch et al., 1994; Vilhjalmsson, 1997). For example, the first catches of two
species of Pacific salmon (Oncorhnchus nerka, O. gorbuscha) recently have been
made in estuaries on Banks Island, Canada. These locations are well outside
the known range for these Pacific species (Babaluk et al., 2000). Changes in
ocean currents, nutrient availability, salinity, and the temperature of ocean
waters can be expected to influence the disposition of larval and juvenile organisms,
the growth rates of individuals, and the population structure of different fish
species (Otterson and Loeng, 2000). For example, recruitment appears to be significantly
better in warm years (Loeng, 1989), an example of which is increased landings
of cod (Gadus morhua) associated with warmer air and surface water temperatures
(Brander, 1996). During a warm phase between the 1920s and the 1960s, Norwegian
herring fed in Icelandic waters but disappeared when the water temperature cooled
by 1°C (Vilhjalmsson, 1997). Quinn and Marshall (1989) report positive correlations
between salmon returns and reduced sea ice. However, species that are adapted
to cold water, such as the Greenland turbot and the Alaskan King crab, declined
in numbers during these warm phases, although other factors also contributed
to the decline of crab stocks (Weller and Lange, 1999). However, the underlying
mechanisms that account for changes in population sizes are poorly understood.
This topic is a high research priority, particularly because plankton production
and trophic interactions may be significantly altered by changes in climate.
Research and management advice for fish stocks is provided by the International
Council for the Exploration of the Seas (ICES). This authority and others face
formidable challenges if the distributions of fish populations change in response
to global warming (Hønneland et al., 1999; Freese, 2000).
16.2.8.2.6. Reindeer husbandry
Husbandry of different subspecies of Rangifer tarandus is widely practiced
in different regions of the Arctic, particularly in Eurasia. Between 1991 and
1997, Russia's domestic reindeer stock declined from 2.3 million to 1.6
million animals. Whether climate change contributed to this decline is uncertain
(Weller and Lange, 1999), but climate warming is likely to alter husdandry practices.
Concerns include the presence of deep snow with an ice surface that stops animals
from obtaining forage, lichens and graminoids that are ice-covered, destruction
of vegetation as a result of "overgrazing," exposure of soil that
encourages establishment of southerly weedy species under a warmer climate (Vilchek,
1997), and an increased likelihood of damage from more frequent tundra fires.
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