Natural variation obscures effects
An overarching concern is that society will not
recognize the effects of climate change because the
natural variability of the marine environment and
fisheries production is so great. Only in the last
few years has it become clear that there are
climate patterns of a decadal scale that affect
production on a ocean basin scale, perhaps even
globally for some species. Will global climate
affect the frequency of these natural oscillations,
or change their magnitude? At present, there is no
answer. However, society has the opportunity to
monitor the environmental changes and learn about
their effects, so that better production forecasts
can be made for the use of fisheries managers.
Positive and negative effects
Whether or not the climate changes, there are
several actions that can be considered. Most
important among the strategies are those needed to
promote sustainability and are useful and
practical, even in the absence of climate change.
Further, when developing strategies, we need to
consider both the problems and the opportunities
that are being presented.
Changes in stocks
Foremost for capture fisheries is the
development of national and international scale
resource management regimes, and associated
monitoring systems, that are able to compensate for
shifting amounts and distribution of fisheries.
Great advances have been made in recent decades to
develop ocean-wide and regional fishery management
bodies. More work needs to be done in building
their effectiveness, including the ability to deal
with stocks that move between national borders and
between EEZs and the open ocean. These bodies need
to consider both the conservation of the species
and the welfare of the people who depend on them
for income and for food. It is much easier to reach
agreement on shifting stocks before the change
takes place.
Coastal zone management
In near-coastal areas, it is important to
consider the needs of fisheries, and marine species
in general, when designing coastal zone management
plans or specifications to cope with a changing
climate. For example, if coastal protection
measures against a rising sea include coastal dams,
there can be no inland movement of beaches and
marshes that are critical to many species'
reproduction. Careful planning is necessary to meet
the needs of marine life and of coastal
infrastructure and agriculture.
Human Health, Harmful Algal Blooms, &
Pollution Adaptations
To reduce the possibility of impacts on humans
and on marine life from a possible increased
prevalence of marine pathogens and toxins such as
cholera, ciguatera and red tides, health
authorities should consider increased monitoring
and prospective actions that might be taken. The
possible actions may include reducing the nutrients
entering the marine environment. Authorities also
to be alert to the release of pollutants due to a
rising sea level
Use of aquaculture
In some situations, aquaculture may be useful as
a vehicle to stabilize food supplies and
employment. With careful consideration of the
impacts, it could also be used in its ocean
ranching form, as when young fish are released into
the ocean for growth and later harvesting to
augment wild stocks.
Research
Foster interdisciplinary research, with
scientists meeting periodically to exchange
information on observations and research results,
and meeting with managers to ensure the proper
interpretation of results and the relevance of
research.
Infrastructure adaptations
In responding to shifting populations and
species, it is expected that the industry will
respond with faster, longer range fishing craft,
install on-board processing equipment, or use
floating processors when feasible, and find
alternative means of transport when coastal roads
are flooded, and relocation is not possible.
Governments should also consider constructing and
maintaining appropriate infrastructure for storm
forecasting, signalling systems and safe refuges
for dealing with possible rising sea level and
increased storminess. There may be opportunities to
take advantage of reduced need for ice
strengthening of vessels and infrastructures in a
warmer climate, except perhaps for areas with
increased icebergs.
Aquaculture
In adapting to climate change, aquaculturists
should consider the following (Everett et al.,
1995):
- Warming will mean generally longer growing
seasons and increased rates of biological
processes&emdash;and often of production.
- Warming will require greater attention to
possible oxygen depletion.
- In some areas, the species grown may have to
shift to those more tolerant of warmer and
perhaps less-oxygenated waters.
- Coastal culture facilities may need to
consider the impacts of sea-level rise on
facilities and the freeing of contaminants from
nearby waste sites.
- Competing wild fisheries production (and
indeed, agriculture) may not vary much at the
world level, but there could be significant
regional changes in quantity and species
mix.
- Precipitation, freshwater flows, and lake
levels will likely change. Strong regional
variations are likely.
- Warming waters could introduce disease
organisms or exotic or undesired species before
compensating mechanisms or intervention
strategies have become established.
- Less ice cover and thinner ice will
generally mean less ice damage to facilities and
a longer season for production and
maintenance.
- Covering culture tanks, or keeping them
indoors under controlled light, may be needed
more often to protect larvae from solar
UV-B.
- Several of the above and other factors, such
as competing demand for coastal areas, may argue
for technological intensification in ponds and
non-coastal facilities.
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reference source
Everett, J.T., E. Okemwa, H.A. Regier,
J.P. Troadec, A. Krovnin, and D.
Lluch-Belda (1995): Fisheries. In: The
IPCC Second Assessment Report, Volume 2:
Scientific-Technical Analyses of Impacts,
Adaptations, and Mitigation of Climate
Change (Watson, R.T., M.C. Zinyowera, and
R.H. Moss (eds.)]. Cambridge
University Press, Cambridge and New York,
31 pp.
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