Transcript How will Fisheries and Managers Adapt to Climate Change

The Future of Fisheries:
science, policy and
societal challenges
Andrew A. Rosenberg,
University of New Hampshire
Predicting natural mortality rates and reproduction-mortality tradeoffs from fish life history data.
Myers, RA | Doyle, RW
Canadian Journal of Fisheries and Aquatic Sciences. Vol. 40, no. 5,
pp. 612-620. 1983.
A method for estimating natural mortality and evolutionary constraint on fish
life histories is presented based on the assumption that observed life
histories are evolutionarily stable. I
Rapid worldwide depletion of predatory fish
communities
8
Atlantic
Catch per 100 hooks
4
0
1960 1980 2000
8
Indian
4
10
8
4
0
Atlantic
1960 1980 2000
8
Indian
4
Atlantic
4
2
0
8
1970
2000
Indian
4
0 1960 1980 2000 0 1960 1980 2000 0 1970
2000
8
8
Pacific
Pacific
Pacific
8
Myers and
4
4
4
Worm (2003)
0
1955 1965 1975
0
1955 1965 1975
0
1960 1970 1980
(t/km2)
Biomass of table fish in 1900
( Christensen et al. 2003)
and in 2000….
The History of Fishing
Expansion to new areas,
fishing methods
and products
resulting in massive
overexploitation of marine
ecosystems
1,264,000 metric tons based on 19-century fishing logs
carrying capacity, Myers et al 2001
Average size cod
in the catch
1850s, 20 lbs.
Biomass
of cod on
the
Scotian
Shelf in
1852
Average size
cod in the
1990s, 6.5
lbs.
Relative cod size
Localized Fishery Expansion
Change in Relative Concentration of Fishing Effort
1935
1907
Analysis by S. Claesson, UNH
Minimum Catch for
Downeast Maine –
1861
223 vessels averaging
45 tons caught:
12,456 mt of cod
Est. total Gulf of Maine Catch
1861
78,600 mt
Total Gulf of Maine
Cod Catch
1998 - 4156 mt
1999 - 1646 mt
2000 - 3730 mt
2007 - 3440 mt
Cod Landings in the Gulf of Maine
90,000
80,000
Weight (mt)
70,000
60,000
50,000
40,000
30,000
20,000
10,000
0
1850
1870
1890
1910
1930
Year
1950
1970
1990
2010
Mean Trophic Levels from Statistical Bulletin Landing Data (1901-1935)
and
LME Northeast US Continental Shelf Landings (1950-2003)
Mean Trophic Level (3.25MTI) 1901-2003
4.10
4.00
3.90
3.70
3.60
3.50
3.40
2001
1996
1991
1986
1981
1976
1971
1966
1961
1956
1951
1946
1941
1936
1931
1926
1921
1916
1911
1906
3.30
1901
MTL
3.80
Year
Halibut = 4.59
Pollock = 3.75
Cusk = 4.22
Haddock = 3.58
Cod = 4.01
Herring = 3.46
TL: www.seaaroundus.org
Evidence for ecosystem effects
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Large declines in overall abundance of many stocks are
have been documented
Fisheries can effect the structure and functioning of
ecosystems at all levels
Regime shifts can be caused by physical forcing, fishing,
or a combination of both.
Shifting baselines alter perceptions of marine ecosystems,
masking the extent of ecosystem change.
Realizing that there is a theoretical limit to the
productivity that can be taken from the oceans and that
we may currently be at or approaching that limit,
National Academy of Sciences 2006. Dynamic Changes in
Marine Ecosystems: Fishing, Food Webs, and Future Options
What do we have to adapt to?
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Loss of abundance
Loss of biodiversity
Changes in distribution of species
Changes in productivity of ecosystems
Changes in species composition
Changes in variability from year to year
and place to place
Changes in resilience (the ability of
ecosystems to recover
Lessons Learned (from Ram and
others) for the Future of Fisheries

Beware the false dichotomy between
environmental changes or fishing effects. Both
are inevitably affecting resources
 As species composition, ranges and productivity
shift, fisheries will adapt to those changes, very
rapidly
 If management continues on a course of reducing
flexibility, both management and fisheries will fail
 If fisheries are to be flexible, overcapacity is
intolerable
More Lessons…

It is ecosystems that will undergo changes, not
just individual stocks, so an ecosystem-based
approach is essential

Ecosystem plans must be adaptable to changing
conditions. It will be impossible to adapt one
species at a time

Pushing to the limits of exploitation for each
species or in each circumstance is incredibly
risky. Be careful
If management continues on a course of reducing flexibility,
both management and fisheries will fail
Georges Bank Cod
Fishing
Mortality
Spawning Stock
Biomass (mt)
1.6
1.4
250,000
SSBMSY
200,000
1.2
1
150,000
0.8
50% SSBMSY
100,000
0.6
0.4
50,000
FMSY
0.2
0
0
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
Year
Fishing Mortality
Fmsy
SSB
SSBmsy
MSST (50% SSBmsy)
2004
George’s Bank Cod
Gulf of St. Lawrence Cod
700 000
Biomasse (t) - Biomass (t)
600 000
500 000
Status quo 3+ (2007 = 67,277 t)
400 000
Status quo SSB (2007 = 44,333 t)
300 000
200 000
100 000
0
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
2006
Année - Year
250 000
150 000
100 000
50 000
Année - Year
2006
2004
2002
2000
1998
1996
1994
1992
1990
1988
1986
1984
1982
1980
1978
1976
0
1974
Landings and TAC’s for Northern
Gulf of St. Lawrence cod.
Canada Dept. Fisheries and
Oceans 2007
Recrutement à 3 ans ('000)
Recruitment at age 3 ('000)
200 000
Is fishing affecting the rebuilding ??
Gulf of St. Lawrence Cod
70%
Changement de la biomasse mature (%)
Change in spawning stock biomass (%)
60%
2003
Observations
50%
Regression
40%
30%
1996
1995
1998
20%
1994
10%
2004
2006
0%
0
1 000
2 000
3 000
4 000
1997
5 000
2002
6 000
7 000
8 000
-10%
-20%
2001
2005
Débarquements (t) - Landings (t)
Courtesy A. Frechet, DFO Canada
2000
1999
If fisheries are to be flexible, overcapacity is intolerable
North Sea Cod
300,000
1.4
1.2
250,000
1
FLimit
0.8
BPrecautionary* (Trigger for recovery) plan)
150,000
F
SSB (t)
200,000
0.6
100,000
0.4
BLimit
50,000
0.2
0
0
1963
1966
1969
1972
1975
1978
1981
1984
1987
1990
1993
1996
Year
#REF!
BLim
Bprecautionary
F (ages 2-4)
FLim
1999
2002
2005
P. Dengbol
As species composition, ranges and productivity shift
fisheries will adapt to those changes, very rapidly
Political Pressure to Keep Fishing
P. Degnbol
P. Degnbol
When fishing
pressure remains
high, stocks show
little recovery
Rosenberg et al. 2006. Frontiers in Ecol. Env.
When fishing
pressure is
reduced, stocks
can recover
Rosenberg et al. 2006. Frontiers in Ecol. Env.
Incentives
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Current incentives are to resist restrictions
not make them work.
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The privilege to fish must be linked to
conservation performance.
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Incentives must be changed to support
conservation through linking compliance
to access.
The fishing does not exist in isolation.
Changing policies to consider all impacts
changes the dynamics of policy-making
Can Catch Shares Prevent Fisheries Collapse?
C. Costello, S. D. Gaines, J. Lynham
Science 2008
Shifts Due to Climate,
in Productivity and Susceptibility
Expected for Species within regions
Productivity and
Susceptibility Analysis
Adapted from Hobday
Precautionary Measures to Prevent Overfishing
Science 2006
Fishing grounds identified from logbooks
Almost all are near shore, many are well within bays.
Centroids of New Fishing Grounds
identified from fishing logs
Number of Cod landed on small grounds near Mt Desert in 1861.
Near shore areas were essential cod habitat in the mid-1800s.
518
Bald Rock Ground
Eastern Bay
6356
Egg Rock Broken Ground
Average distance from shore for previously
unrecorded, mid-19th century fishing
grounds = 9.27 km
4595
Inner
Blue Hill Bay
4053
14345
Bass Harbor
Average distance from shore for grounds
mentioned in Rich (1929) = 22.59 km
1269
Turtle Island
Shoals
99
Martin’s Ridges
250
Cranberry Isles
Harbor
Changing Productivity
Left: Maine’s River Fisheries in 1882, USFC
Report, 1883. 4,549,500 pounds. Photo:
Waldoboro alewife fishery, 1874, from
Bunting, “A Day’s Work, Part I.”
From W. Leavenworth, UNH
Ocean ecosystems provide many services,
most of which are undervalued
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•
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Food
Medicines
Recreation & tourism
Trade
Education & research
Water purification
Shoreline protection
Nutrient cycling
Moderation of climate
Cultural, spiritual, and religious values
Five Features of EBM
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Common goal – conserve ability of the
ecosystem to provide a full suite of services
Manage based on natural, not jurisdictional,
boundaries
The sectors of human activity interact so
management should be integrated
Impacts of human activities on an ecosystem are
often cumulative across both time and space
Tradeoffs in services among sectors must be
made and should be explicit
It is ecosystems that will undergo changes, not just individual stocks,
so an ecosystem-based approach is essential
Rosenberg &
MacLeod 2005
Changing Uses
Scientific Consensus Statement on
Marine Ecosystem-Based Management
WHAT IS ECOSYSTEM-BASED MANAGEMENT FOR THE
OCEANS?
Ecosystem-based management is an integrated approach
to management that considers the entire ecosystem,
including humans. The goal of ecosystem-based
management is to maintain an ecosystem in a healthy,
productive and resilient condition so that it can provide
the services humans want and need. Ecosystem-based
management differs from current approaches that usually
focus on a single species, sector, activity or concern; it
considers the cumulative impacts of different sectors.
Is the whole greater than
The sum of the parts?
Lessons Learned (from Ram and
others) for the Future of Fisheries

Beware the false dichotomy between
environmental changes or fishing effects. Both
are inevitably affecting resources
 As species composition, ranges and productivity
shift, fisheries will adapt to those changes, very
rapidly
 If management continues on a course of reducing
flexibility, both management and fisheries will fail
 If fisheries are to be flexible, overcapacity is
intolerable
More Lessons…

It is ecosystems that will undergo changes, not
just individual stocks, so an ecosystem-based
approach is essential

Ecosystem plans must be adaptable to changing
conditions. It will be impossible to adapt one
species at a time

Pushing to the limits of exploitation for each
species or in each circumstance is incredibly
risky. Be careful
From Robert Wilson: The Hidden Assassins (2006)
“You’re smiling, Javier…. I’m impressed
‘I’m solitary but not depressed’, said Falcon.
‘That’s not bad going for a middle-aged homicide detective’, said
Pablo.
‘Being a homicide detective isn’t such a problem for me. There
aren’t that many murders in Seville and I crack most of them, so
my work with the homicide squad actually gives me the illusion that
problems are being resolved. And, as you know, an illusory state ca
contribute to sensations of well-being,’ said Falcon.
‘If I were trying to resolve something like global warming, or the
oceans’ dwindling fish stocks, then I’d probably
be in much worse mental shape.’