LESSONS IN CLIMATE CHANGE
PROJECTIONS AND ADAPTATION:
From One Living Resource To Another
Dr. John T. Everett and Dr. H. Suzanne Bolton
National Marine Fisheries Service
16: FISHERIES
IPCC, 1995: Scientific-Technical Analyses of Impacts, Adaptations,
and Mitigation of Climate Change
Dr. John T. Everett, Convening Lead Author
National Oceanic and Atmospheric Administration
United States Department of Commerce
Lead Authors
Dr. Jean-Paul Troadec
Dr. Ezekiel Okemwa
Brest, France
Mombasa, Kenya
Dr. Henry A. Regier
Dr. Daniel Lluch Belda
Toronto, Canada
La Paz, BCS, Mexico
Andre Krovnin
Moscow, Russia
Examples of
Sensitivities
Species
• Scallop and fish eggs that rely on a gyre to return them to
their habitat on a certain day or week
• Fish eggs in streams or on the sea floor that require a
minimum current speed for oxygenation
• Species that require an influx of freshwater to induce
spawning or to kill predators
• Temperatures above or below the stock’s lethal limit
Societal
• Immobility of communities dependent on one type of
species
• Societies without money needed to buy replacement foods
• Fishers unable to deal with new vessel and gear demands
Species Sensitivities
• Changes: temperature, sea level, river flows, salinity,
currents, winds, storms, and variability
• Species are dependent on one or more of above
• Species can move rapidly if habitat and paths exist
• Fish are cold-blooded. Life processes, like growth,
are faster when warmer (within limits)
• Many species have narrow ecological niches, but
there are many species to fill niches
• Small changes cause large disruptions to a species
• Mixes will change until stability is reestablished.
1992....
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Million Tons
120
Fisheries Production
100
80
M arine
60
40
Aquaculture and USA
figures are non-additive
Fres hwater
Aq.
USA
Societal Sensitivities
• Species in more stable environments are
usually more valuable
• Fishers can follow fish, communities won’t
• Political borders or economics stop pursuit
• Developing nations dependent on fish as food
or export earnings are most sensitive
Important Findings
• Freshwater fisheries and aquaculture at mid
to higher latitudes should benefit from
climate change
• Saltwater fisheries production should be
about the same
• Locally, fishery areas and species mix are
expected to shift
Important Findings #2
• Climate impacts add to those of overfishing,
lost wetlands and nurseries, pollution, UV-B,
and natural variation
• Inherent instability in world fisheries will be
exacerbated by a changing climate
• Overfishing is more important than climate
change today; as progress accelerates, the
relationship should reverse in 50-100 years.
CC Impact Ranking for
Fisheries
1. Small rivers and lakes, in areas of higher
temperatures and less rain
2.
Within EEZs, particularly where fishers
cannot follow migrating fish
3.
In large rivers and lakes
4.
In estuaries
.
5
High seas
Adaptation Options
1. Establish better fishery management institutions
to reduce societal impact
2. Adapt processing plants and infrastructure to
increase flexibility
3. Expand aquaculture to increase seafood and
employment stability
4. Monitor several health problems (red tides,
ciguatera, cholera)
5. Intervene to redistribute species
6. Manage coastal development to maintain habitat
Oceanography
Hydrodynamic predictions are limited with little
guidance on:
•
•
•
Upwelling
Storms and ENSO
Strength and direction of currents
Sea Level will rise globally, but vary regionally in:
•
•
•
Uniformity
Pollution effects
Habitat loss
Oceanography
• Global climate is warming; in question is:
• rate of change
• manner of change (smooth or fits and starts)
• extreme events (frequency and strength)
• Polar ice masses will shrink; in question is:
• extent of melting and calving
• timing
Global Climate Model
Limitations
•
Areal specificity of results
•
Robustness of ocean/atmosphere linkage
•
Infancy of ecological models
•
Neglect of indirect effects of changing
temperature
•
Difficulty in factoring variabilities of living
organisms
•
Limitation of data predicting species
interactions
BIOLOGY
Climate Change and Species Reproduction
• Time factor favors existing plasticity, not
evolution
• Broad ranging distributions favored over narrow
• Environmental change miscues window of
reproductive opportunity
• Progeny number/size varies with adult/young heat
sensitivities
• Sex ratio, mode, or opportunity (asexuality,
hermaphrodism) can change
• Reproductive sensitivities increase with an
increase in UV-B
BIOLOGY
Changes in Habitat
• Affect availability of environmental cues and food
during migrations
• Foodweb members respond independently to
changing habitat
• Shifting populations may favor “exotic”
competitors or opportunists
• Altered habitat and populations may complicate
conservation efforts
• Shrinking polar habitats threaten established
foodwebs and available platforms
• Alteration in upwellings disrupt communities
BIOLOGY
Behavioral Strategies versus
Climate Change
• Relocating dependent upon availability of
favorable temperature range
• Sessile forms release motile larvae at
whims of currents
• Migratory routes shift with changing
circulation patterns, temperature, and
food availability
• Inter-specific behavior disruptions as
species vary independently
BIOLOGY
Impact on Biochemical Processes
• Temperature affects protein, lipid, nucleic, and
hormonal activities
• Environmental factors trigger alternate pathways
• Metabolic regulation exacts costs on organisms
• Eurythermal organisms more adaptive than
stenotherms
• Endothermal organisms more adaptive than
ectotherms
• Sensitivity of processes may vary with age
BIOLOGY
Changing Ecosystem Interactions
• Ecosystems tend to respond as individuals not as
community
• Difficulty in studying complex and diverse ocean
ecosystems
• Subtle climate change may alter niche and
cascade events
• Shifting environmental cues may decouple timed
events
• Understanding of complex interrelationships
hampers predictions
BIOLOGY
Indirect Effects
• Erosion, runoff, melting, and inundation
increase contaminant input
• Introduced toxins and pathogens thrive in
warmer medium
• Loss of pathogens/parasites with narrow
life requirements
• Conservation efforts complicated by
changing habitat
IMPLICATIONS FOR CETACEANS
Ocean Chapter Predictions
Predicted Impacts on Marine Mammals and seabirds
• Loss of habitat (ice edge, haul-outs)
• Shift in trophic structure and
productivity centers
• Increase in disease and biotoxins
Cannot predict the MAGNITUDE and SIGNIFICANCE
of these changes
IMPLICATIONS FOR CETACEANS
Reproduction
•
•
•
Large mammals not well adapted to
withstand extreme events
slow growth
slow maturation
low fecundity
Genetic diversity and numbers are key to
survival
IMPLICATIONS FOR CETACEANS
Habitat and Migratory Routes
•
•
•
•
•
•
Changing polar and migratory foodweb and
environmental cues
Loss in Arctic ice edge, polynyas, and timing of
phytoplankton bloom
Continued Antarctic recession and calving alter krill-based
feeding
Altered trophic structure:
- Emigration of non-endemic species
- Migration and reduction of ice-dependent prey
poleward
Change in circulation patterns jeopardizing nutrient flow
Increased UV-B effects on plankton and land-based
mammals
IMPLICATIONS FOR CETACEANS
Behavioral and Metabolic
• Increasing metabolic expense of
accommodating climate change
• Changes in lipid composition with change in
foodweb
• Shifting of ranges to accommodate climate
and trophic changes
• Loss of some habitat ( e.g., polynyas)
requires behavioral change
IMPLICATIONS FOR CETACEANS
Ecosystem
Changes in habitat trophic structure
Arctic
- to open water zooplankton-base
Antarctic
- to higher trophic prey if herbivores decrease
Migratory
- to higher trophic prey if upwellings and
circulation alter
IMPLICATIONS FOR CETACEANS
Ecosystem (con’t.)
• Increase in metabolic stress:
• Pathogens and parasite interactions increase risk of disease
• Anthropogenic contaminants compromise immune systems
• Increase competition with man
• Directly by fishing competition
• Indirectly
» by conflict with needs of mariculture
» by pressures to conserve habitat
Management Suggestions
• Elevate importance of maintaining sustainable fish
populations
• Advocate interdisciplinary ecosystem research
• Expand definition of sustainable level to
accommodate climate change pressures
• Emphasize flexibility in the design of open ocean
sanctuaries
• Increase role in planning, regulating, and managing
land and marine resources