4 May 2004 1

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

world fisheries?

• 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.

Anonymous straw man says

4 May 2004 2

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

world fisheries?

• 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 adaptive management sometimes results in undesired outcomes;

• I say the MSY theory does not guarantee coexistence of species = food web constraint;

• 4WFC organizer gave us the title of “getting more fish and reconciling fisheries with conservation”;

4 May 2004 3

Today’s my talk

• We can get more fish sustainably;

• MSY theory does not guarantee biodiversity;

• Adaptive management is dangerous;

• Recommendations

4 May 2004 4

Can the world catch not really increase?

http://www.fao.org/fi/publ/circular/c920/intro.asp#A2

Species base statistics

4 May 2004 5

Landings of demersal marine fish has not grown since 1970s （ FAO1996)

http://www.fao.org/WAICENT/FAOINFO/FISHERY/publ/sofia/fig5e.asp

4 May 2004 6

Landings of small pelagic fish is still increasing with fluctuation

http://www.fao.org/WAICENT/FAOINFO/FISHERY/publ/sofia/fig4e.asp

anchoveta

sardine

chub mackerelAtlantic herring

4 May 2004 7

Fig. 1. Global trends of mean trophic level of fisheries landings, 1950 to 1994 Pauly et al. (Science1998:279:860;)

Fishing Down– Is this bad?

Marine areas

inland areas

Peruvian anchovy increased

mea

n tr

ophi

c le

vel Catch of lower trophic

levels is a smaller impact.Decrease of mean trophic level in environment is bad.

4 May 2004 821

I often eat lower trophic level fish, but should eat more.

650 yen (US$6) with coffee650 yen (US$6) with coffee

4 May 2004 9

Whales consume fish more than human(Tamura & Ohsumi 1997)

0

50

100

150

200

250

300

Fisherieslanding

Biomass ofWhales

Consumptionby whales

Mill

ion

tonn

es

Tooth whalesBaleen whales

4 May 2004 10

“Initial” and recent biomass of whales

0

10

20

30

40

50

Initial stock Current stock

Bio

mas

s (m

illio

n to

ns)

right whale

Bryde's whale

Minke whale

gray whale

sei whale

humpback whale

bowhead whale

fin whale

blue whale

Source: SeaWorld web site except minke whales (F. Kasamatsu, book in Japanese)

4 May 2004 11http://www.icrwhale.org/02-E.htm

Nothern Pacific minke whales eat anchovy.

4 May 2004 12

Two phenotypes of whales-fisheries competition idea

By Japan Gov.

Whales destroyWhales destroythe ocean.the ocean.

“...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

Fisheries destroyFisheries destroythe ocean.the ocean.

4 May 2004 13

Who is more familiar with environment?Rich or poor nations?

Analysis of Ecological footprint （ source WWF 2002)

http://www.wwf.or.jp/activity/lpr2002/

EFP

World 2.28

High Income 6.48

Intermediate 1.99

Low income 0.83

EFP

Afganistan 0.95

Iraq 1.38

Israel 4.44

Germany 4.71

Japan 4.77

Canada 8.84

USA 9.70

EFP: global ha/person

4 May 2004 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

4 May 2004 15

Pelagic fish stock is unstable-- species replacement --C

atch

in J

apan

(10

00 m

t) AnchovyHorse mackerelsPacific sauryChub mackerelSardine

Matsuda & Katsukawa 2002 Fish Oceangr

4 May 2004 16

Cyclic Advantage HypothesisMatsuda et al. (1992) Res. Pop. Ecol. 34:309-319

The next dominant to sardine is anchovy –-- Yes! As I predicted in 1992.

The second next is chub mackerel-- Many people agree now

Anchovy, Pacific saury, jack mackerel

mackrelsardine

4 May 2004 17

Why did sardine stock collapse in 1990s?

• Natural fluctuation (Watanabe et al. 1995 CJFA

S)– Failure of recruitments (getting older)– Fallacy of critical period theory– We can get more sardine in 1980s, more a

nchovy and Pacific saury now.

• At low stock level, fishing pressure may prevent from recovering...

4 May 2004 18

Q&A

Q: Will western Pacific chub mackerel really recover?

A: It depends on the fishing pressure

4 May 2004 19

Large fluctuation of recruitmentin Northeastern Pacific chub mackerel

Strong year classes appeared twice

Kawai et al. 2002 Fish Sci

4 May 2004 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

4 May 2004 21

Fishers missed chance of recoveryKawai,…,Matsuda, Fish. Sci. 2002

F during 1970-80s

actual

stoc

k ab

unda

nce

(mil

lion

tons

)

4 May 2004 22

Probability of stock recoveryKawai,…,Matsuda 2002 Fish Sci

The decade of 1990s was “Japan’s lost 10 years”

百万トン資源回復確率

百万トン資源回復確率

Pro

babi

lity

of

stoc

k re

cove

ry

4 May 2004 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 hy

pothesis. (Adaptive mismanagement)

4 May 2004 24

Today’s my talk

• We can get more fish sustainably;

• MSY theory does not guarantee biodiversity;

• Adaptive management is dangerous;

• Recommendations

4 May 2004 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!!

Stock abundance

surp

lus p

rodu

ctio

n

4 May 2004 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

4 May 2004 27

2

54

3

5

3

6

4

4

Examples of biological community at MSY (Matsuda & Abrams in review)

1 2

3

5

6

(b)

1 2

3

5

6

4

(a)

1 2

5

(c)

3

6

4

Solution maximizing total yield from community

MSY solution often reduces species and links;

1 2

6

4

(d)

1

3

6

(e)

2

54

3

54

4 May 2004 28

2

4 5

3

5

Examples of biological community at MSY (Matsuda & Abrams in review)

1 2

3

5

6

(b)

1 2

3

5

6

4

(a)

1 2

5

(c)

100% 92% 61% 12% 6%

4

3

6

4

exploit more species, more trophic levels.

1 2

6

4

(d)

1

3

6

(e)

Constrained MSY that guarantee coexistence

2

4 5

4

3

6

4

3

5

4 May 2004 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

4 May 2004 30

Today’s my talk

• We can get more fish sustainably;

• MSY theory does not guarantee biodiversity;

• Adaptive management is dangerous;

• Recommendations

4 May 2004 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.

( )dN f N qENdt

*dE U N Ndt

Stock size N

f(N)

N*N* N*

4 May 2004 32

Feedback control with community interactions also result in undesired outcomes.

(M & A in preparation)

1. 0.74 0.19 0.31 0. 0. 0. 0. 0.7 0.460.74 1. 0.87 0.08 0.46 0.66 0.48 0.73 0.84 0.0.19 0.87 1. 0.96 0.08 0.14 0.83 0. 0. 0.680.31 0.08 0.96 1. 0. 0. 0. 0.28 0. 0.880. 0.46 0.08 0. 0.1 0. 0. 0.92 0.15 0.840. 0.66 0.14 0. 0. 0.1 0.01 0. 0.5 0.690. 0.48 0.83 0. 0. 0.01 0.1 0.56 0. 0.0. 0.73 0. 0.28 0.92 0. 0.56 0.1 0.28 0.0.7 0.84 0. 0. 0.15 0.5 0. 0.28 0.1 0.0.46 0. 0.68 0.88 0.84 0.69 0. 0. 0. 0.1

r = (0.454,1.059,1.186,0.247,-0.006,-0.028,-0.059,-0.704,-0.308,-0.238)

ii ji j i i

j

dNr a N qe N

dt

A = (aji) =

e9 = 0.1, ei = 0

13

42

5 6

7

8

9 10

4 May 2004 33

Feedback control may result in extinction of other species (sp.

6).

de9/dt = u(N9-N9*)ratio

4 May 2004 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.

4 May 2004 35

Today’s my talk

• We can get more fish sustainably;

• MSY theory does not guarantee biodiversity;

• Adaptive management is dangerous;

• Recommendations

4 May 2004 36

Recommendations #11. Do fishing down in food items!!

• Eat small pelagic fishes

2. We can eat more fish, not use as fish meal!!3. Reduce discards before and after landings

(our dishes);

4. Establish food market of temporally fluctuating fishes at lower trophic levels

5. Improve technology for effective use of lower trophic levels (Japan Soc. of Fisheries)

Seafoods)

4 May 2004 37

Recommendations #2

1. Switch a target fish for sp. replacement (Matsuda & Katsukawa 2002 Fish. Oceanogr)

2. Monitor the ecosystems3. Conserve immatures; 4. Improve technology for selective fishing5. Conserve both fishes and fisheries;6. Say goodbye to MSY reference points;

4 May 2004 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