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Can we say goodbye to the MSY theory and a pessimistic view of the state of the world fisheries?

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The Maximum Sustainable Yield theory always guarantees the stock persistence; ... Landings of demersal marine fish has not grown since 1970s (FAO1996) ... – PowerPoint PPT presentation

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Title: Can we say goodbye to the MSY theory and a pessimistic view of the state of the world fisheries?


1
Can we say goodbye to the MSY theory and a
pessimistic view of the state of the world
fisheries?
Anonymous straw man says
  • FAO suggested that the total world landings do
    not increase any more.
  • The Maximum Sustainable Yield theory always
    guarantees the stock persistence
  • The adaptive management is one of the best ways
    against uncertain ecosystems.

2
Can we say goodbye to the MSY theory and a
pessimistic view of the state of the world
fisheries?
  • 4WFC organizer gave us the title of getting more
    fish and reconciling fisheries with conservation
  • FAO suggested that the total world landings do
    not increase any more.
  • The Maximum Sustainable Yield theory always
    guarantees the stock persistence
  • The adaptive management is one of the best ways
    against uncertain ecosystems.
  • I say the MSY theory does not guarantee
    coexistence of species food web constraint
  • I say the adaptive management sometimes results
    in undesired outcomes

3
Todays my talk
  • We can get more fish sustainably
  • MSY theory does not guarantee biodiversity
  • Adaptive management is dangerous
  • Recommendations

4
Can the world catch not really increase?
Species base statistics
  • http//www.fao.org/fi/publ/circular/c920/intro.asp
    A2

5
Landings of demersal marine fish has not grown
since 1970s (FAO1996)
http//www.fao.org/WAICENT/FAOINFO/FISHERY/publ/so
fia/fig5e.asp
6
Landings of small pelagic fish is still
increasing with fluctuation
http//www.fao.org/WAICENT/FAOINFO/FISHERY/publ/so
fia/fig4e.asp
7
Fishing Down Is this bad?
Marine areas
Catch of lower trophic levels is a smaller impact.
mean trophic level
Decrease of mean trophic level in environment is
bad.
inland areas
Fig. 1. Global trends of mean trophic level of
fisheries landings, 1950 to 1994 Pauly et al.
(Science1998279860)
8
I often eat lower trophic level fish, but should
eat more.
650 yen (US6) with coffee
21
9
Whales consume fish more than human (Tamura
Ohsumi 1997)
10
Initial and recent biomass of whales
Source SeaWorld web site except minke whales (F.
Kasamatsu, book in Japanese)
11
Nothern Pacific minke whales eat anchovy.
http//www.icrwhale.org/02-E.htm
12
Two phenotypes of whales-fisheries competition
idea
...in a complicated food web structure, indirect
effects of culling top predator (whales) on
abundance of target fish is either positive or
negative,... By Yodzis 2001 Trend Ecol Evol
Whales destroy the ocean.
Fisheries destroy the ocean.
By Japan Gov.
13
Who is more familiar with environment? Rich or
poor nations? Analysis of Ecological footprint
(source WWF 2002)
EFP
Afganistan 0.95
Iraq 1.38
Israel 4.44
Germany 4.71
Japan 4.77
Canada 8.84
USA 9.70
EFP
World 2.28
High Income 6.48
Intermediate 1.99
Low income 0.83
EFP global ha/person
http//www.wwf.or.jp/activity/lpr2002/
14
My comments on whale-fisheries competition
  • Top predators eat fish more than human
  • We can get more fish if top predators decrease
  • Top predators have decreased.
  • Whales eat anchovy, do not directly compete with
    human or fisheries.
  • We must consider reconciling with conservation

15
Pelagic fish stock is unstable -- species
replacement --
Matsuda Katsukawa 2002 Fish Oceangr
16
Cyclic Advantage Hypothesis Matsuda et al. (1992)
Res. Pop. Ecol. 34309-319
  • The next dominant to sardine is anchovy
  • -- Yes! As I predicted in 1992.
  • The second next is chub mackerel
  • -- Many people agree now

17
Why did sardine stock collapse in 1990s?
  • Natural fluctuation (Watanabe et al. 1995 CJFAS)
  • Failure of recruitments (getting older)
  • Fallacy of critical period theory
  • We can get more sardine in 1980s, more anchovy
    and Pacific saury now.
  • At low stock level, fishing pressure may prevent
    from recovering...

18
QA
  • Q Will western Pacific chub mackerel really
    recover?

A It depends on the fishing pressure
19
Large fluctuation of recruitment in Northeastern
Pacific chub mackerel
Strong year classes appeared twice
Kawai et al. 2002 Fish Sci
20
Strong year classes were caught before the age at
maturity
1970s 1980s 1990s 1993-
immatures 65.0 60.0 87.0 90.6
Kawai et al. 2002 Fish Sci
21
Fishers missed chance of recovery Kawai,,Matsuda,
Fish. Sci. 2002
actual
stock abundance (million tons)
22
Probability of stock recovery Kawai,,Matsuda
2002 Fish Sci
Probability of stock recovery
  • The decade of 1990s was Japans lost 10 years

23
Future of Pelagic Fish Populations in the
north-western Pacific
  • If overfishing of immatures continues,
  • Chub mackerel will not recover forever
  • If cyclic replacement hypothesis is true,
  • Sardine will not recover forever
  • Do not catch immatures too much
  • The overfishing is an experiment for my
    hypothesis. (Adaptive mismanagement)

24
Todays my talk
  • We can get more fish sustainably
  • MSY theory does not guarantee biodiversity
  • Adaptive management is dangerous
  • Recommendations

25
Requiem to Maximum Sustainable Yield Theory
  • Ecosystems are uncertain, non-equilibrium and
    complex.
  • MSY theory ignores all the three.
  • Does MSY theory guarantee species persistence?
  • - No!!

surplus production
Stock abundance
26
Kyoto Declaration and Plan of Action on the
Sustainable Contribution of Fisheries to Food
Security in 1992 (FAO)
  • Article 14 When and where appropriate, consider
    harvesting multiple trophic levels in a manner
    consistent with sustainable development of these
    resources.

http//www.fao.org/fi/agreem/kyoto/kyoe.asp
27
Examples of biological community at MSY (Matsuda
Abrams in review)
  • Solution maximizing total yield from community

MSY solution often reduces species and links
(c)
(d)
(e)
(b)
(a)
5
4
6
6
6
6
5
5
5
4
4
3
3
3
2
1
1
2
1
2
1
2
1
2
28
Examples of biological community at MSY (Matsuda
Abrams in review)
Constrained MSY that guarantee coexistence
exploit more species, more trophic levels.
(c)
(d)
(e)
(b)
(a)
6
6
6
6
6
4
5
5
5
4
4
4
3
3
3
3
1
1
2
1
2
1
2
1
2
29
Conclusion of story 2
  • MSY theory does not guarantee species coexistence
  • Fisheries must take care of biodiversity
    conservation explicitly
  • Foodweb constraint to reconciling fisheries
    with conservation

30
Todays my talk
  • We can get more fish sustainably
  • MSY theory does not guarantee biodiversity
  • Adaptive management is dangerous
  • Recommendations

31
Feedback control in fishing effort is powerful...
  • A straw man says
  • Even though the MSY level is unknown, the
    feedback control stabilizes a broad range of
    target stock level.

f(N)
Stock size N
32
Feedback control with community interactions also
result in undesired outcomes. (M A in
preparation)
r (0.454,1.059,1.186,0.247,-0.006,-0.028,-0.059,
-0.704,-0.308,-0.238)
A (aji)
e9 0.1, ei 0
33
Feedback control may result in extinction of
other species (sp. 6).
ratio
de9/dt u(N9-N9)
34
Conclusion of story 3
  • Single stock monitoring is dangerous
  • Target stock level is much more sensitive than we
    have considered in single stock models.
  • We must monitor not only stock level of target
    species, but also the entire ecosystem.

35
Todays my talk
  • We can get more fish sustainably
  • MSY theory does not guarantee biodiversity
  • Adaptive management is dangerous
  • Recommendations

36
Recommendations 1
  • Do fishing down in food items!!
  • Eat small pelagic fishes
  • We can eat more fish, not use as fish meal!!
  • Reduce discards before and after landings (our
    dishes)
  • Establish food market of temporally fluctuating
    fishes at lower trophic levels
  • Improve technology for effective use of lower
    trophic levels (Japan Soc. of Fisheries)

Seafoods)
37
Recommendations 2
  1. Switch a target fish for sp. replacement
    (Matsuda Katsukawa 2002 Fish. Oceanogr)
  2. Monitor the ecosystems
  3. Conserve immatures
  4. Improve technology for selective fishing
  5. Conserve both fishes and fisheries
  6. Say goodbye to MSY reference points

38
I express sincere thanks to
  • The organizers for comfortable hospitality,
  • especially Yvonne Sadovy
  • The audience who chose this session
  • I apologize that
  • I must confess that I said as the straw man said
  • my English is very awk
  • I looked for positive answer for the session title
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