Announcments
• Field Trip to Kitchell’s Cabin Next Week!
• Meet here at 1 if possible
• Purposes
• Learn new sampling techniques
• See new/different species of fish
• Listen to the Good Doctor’s stories
• DUE NEXT WEEK: DRAFT OF PAPER FOR
GRADE!!!
Outline for the Day
• Lingering Questions?
• Reading Quiz 2 and Announcement of Other
Quiz
• Discussion of Worm et al. 2006
• Fisheries Crisis Lecture
• Break
• Foraging Behavior and Diets Lecture
• Diet Analysis Lab
Reading Quiz 2
1.The authors argue that the loss of what
has had a great impact on marine
fisheries?
2. How do the authors define “collapsed
fishery”?
3. What is meant by the abbreviation
“LME”
4.What management practice do the
authors suggest for marine fisheries?
Discussion Topics
Was this a good or a poor paper?
Discuss the strengths and weaknesses
of the authors’ arguments
Evaluate this statement: “This trend is of serious
concern because it projects the global collapse of all
taxa currently fished by the mid-21st century”
Scientists as Advocates
• Is it possible to be both a good scientist and a good advocate?
• How has advocacy hindered scientific advancement?
• How has advocacy helped science?
2006 : Worm et al.
= 0 trained fisheries stock assessors (I think)
response
2006 : Worm et al.
Catch ≠ Abundance
NMFS reported in 2004 26% of stocks were overfished, in 2005 24% of stocks
....shall we extrapolate to show that US fisheries will be fine by 2018, no !
if you do the same thing with German unemployment it says no one in Germany
will be working by 2056 (100% unemployment)
Fisheries Crisis
Goals
• Context of paper, Background to widespread issue in
fisheries
• Global Trends in Fisheries
• Maximum Sustainable Yield
• Examples of Collapsed Fisheries
• Management Goals for Fisheries
http://www.fao.org
http://www.fao.org
Maximum Sustainable Yield
Agriculture Term
Population Growth
Population Size
K
K/2
Time
dN = rN K-N
K
dt
K/2
Population Size
Logistic
Growth
Equation
K
Population Size
Recruitment Rate
Populations influenced by other forces
Catch exceeds
recruitment
K/2
Year
MSY is "perfect condition"
Population Size
California Sardine Fishery
California Sardine Fishery
California Sardine Fishery
• Sardine demand increased when use shifted from human
consumption to fishmeal and oil circa 1920
• No catch limits: State scientists issue warning that draining
supplies should be avoided until research can detect overfishing
• 1930s: catch no longer increases in proportion to increases in
effort. California state scientists recommend a limit
• US Bureau of Fisheries, hesitant to limit a successful economic
enterprise during the Depression, deemed limits unnecessary b/c
evidence of sardine depletion, while strong, was not “clear-cut”.
• 1939: CA state experts replaced with “emergency appointees”
and state opinion mysteriously changes from “fishery is depleted”
to “all is well”.
• 1942: Sardine fishery collapses. Only began to recover in 1980s.
Species
Peak
Date
Peak
Landing
First
First
Warning Limits
Crash
Crash
Landing
Current
Landing
CA
Sardine
1938
800,000
tonnes
Mid
1920s
1942
140,000
(hit 0 by
1952)
0
tonnes
1942
North Atlantic Cod
North Atlantic Cod
North Atlantic Cod
• Optimism in 1970s that past mistakes (sardine) could be avoided
• Fishing intensity grew in 1960s with peak catch in 1968
• Canada extends jurisdiction from 12 to 200 nautical miles
offshore in the late 1970s
• Allowed the setting of conservative restrictions on catches to
20% of the total stock to promote rebuilding
• 1988 the Dept. of Fisheries and Oceans claimed a 5x increase in
Northern Cod since 1976; tooted horn as a shining example of
what cautious, science driven management could do for fisheries
• 1992: No cod left to catch; loss of fishery cost several billion $
• Science drastically underestimated stock size, resulting in much
more than 20% being harvested – for any year, data from 5
subsequent years was needed to estimate stock. Shorter time
periods simply returned the assumed mortality rate
Species
Peak
Date
Peak
Landing
(Tonnes)
First
First
Warning Limits
Crash
Crash
Landing
Current
Landing
2003-05
CA
Sardine
1938
800,000
Mid
1920s
1942
1942
140,000
(hit 0 by
1952)
0
North
Atlantic
Cod
1968
800,000
1989
1976
1992
0
6,000
Bluefin Tuna
Bluefin Tuna
• Bluefin and other tuna species were relatively unregulated until
the 1980s, in part due to it being an international fishery
• 1981 recommendation from international commission
recommended reducing tuna fishing to as near to 0 as possible
• Lobbyists convince commission to reduce fishing by 55%
instead of a ban
• Continuing trend of reducing fishing by less then recommended
• Total collapse still feared, total ban still considered, Japan
working on artificially raising young tuna
Species
Peak
Date
Peak
Landing
(Tonnes)
First
First
Warning Limits
Crash
Crash
Landing
Current
Landing
2003-05
CA
Sardine
1938
800,000
Mid
1920s
1942
1942
140,000
(hit 0 by
1952)
0
North
Atlantic
Cod
1968
800,000
1989
1976
1992
0
6,000
Bluefin
Tuna
1960
115,000
1981
1982
1992/yet
to be
seen
45,000
58,000
Management Goals
• Biological: MSY
• Economic
• Social
Management Goals
Management Strategies for Sustainable Fisheries
Protected Areas
Dedicated Access
Rest of CFL
Kitchell
Kornis
Weidel
Economic Incentives
Precautionary Regulation
Characteristics of Sustainable Fisheries
Good Governance
Appropriate Incentive
Dedicated
Access
Open Access
Kitchell
• Lowered demand for fish
• Wealth
• Knowledge of complex ecosystems
• Cooperation between fisheries and other governmental agencies