Title: Can we say goodbye to the MSY theory and a pessimistic view of the state of the world fisheries?
1Can 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.
2Can 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
3Todays my talk
- We can get more fish sustainably
- MSY theory does not guarantee biodiversity
- Adaptive management is dangerous
- Recommendations
4Can the world catch not really increase?
Species base statistics
- http//www.fao.org/fi/publ/circular/c920/intro.asp
A2
5Landings of demersal marine fish has not grown
since 1970s (FAO1996)
http//www.fao.org/WAICENT/FAOINFO/FISHERY/publ/so
fia/fig5e.asp
6Landings of small pelagic fish is still
increasing with fluctuation
http//www.fao.org/WAICENT/FAOINFO/FISHERY/publ/so
fia/fig4e.asp
7Fishing 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)
8I often eat lower trophic level fish, but should
eat more.
650 yen (US6) with coffee
21
9Whales consume fish more than human(Tamura
Ohsumi 1997)
10Initial and recent biomass of whales
Source SeaWorld web site except minke whales (F.
Kasamatsu, book in Japanese)
11Nothern Pacific minke whales eat anchovy.
http//www.icrwhale.org/02-E.htm
12Two 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.
13Who 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/
14My 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
15Pelagic fish stock is unstable-- species
replacement --
Matsuda Katsukawa 2002 Fish Oceangr
16Cyclic Advantage HypothesisMatsuda 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
17Why 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...
18QA
- Q Will western Pacific chub mackerel really
recover?
A It depends on the fishing pressure
19Large fluctuation of recruitmentin Northeastern
Pacific chub mackerel
Strong year classes appeared twice
Kawai et al. 2002 Fish Sci
20Strong 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
21Fishers missed chance of recoveryKawai,,Matsuda,
Fish. Sci. 2002
actual
stock abundance (million tons)
22Probability of stock recoveryKawai,,Matsuda
2002 Fish Sci
Probability of stock recovery
- The decade of 1990s was Japans lost 10 years
23Future 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)
24Todays my talk
- We can get more fish sustainably
- MSY theory does not guarantee biodiversity
- Adaptive management is dangerous
- Recommendations
25Requiem 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
26Kyoto 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
27Examples 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)
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1
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28Examples 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
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6
4
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29Conclusion 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
30Todays my talk
- We can get more fish sustainably
- MSY theory does not guarantee biodiversity
- Adaptive management is dangerous
- Recommendations
31Feedback 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
32Feedback 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
33Feedback control may result in extinction of
other species (sp. 6).
ratio
de9/dt u(N9-N9)
34Conclusion 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.
35Todays my talk
- We can get more fish sustainably
- MSY theory does not guarantee biodiversity
- Adaptive management is dangerous
- Recommendations
36Recommendations 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)
37Recommendations 2
- Switch a target fish for sp. replacement
(Matsuda Katsukawa 2002 Fish. Oceanogr) - Monitor the ecosystems
- Conserve immatures
- Improve technology for selective fishing
- Conserve both fishes and fisheries
- Say goodbye to MSY reference points
38I 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