management of whaling 鯨類の資源管理

Management of Whaling 鯨類の資源管理

Hiroyuki Matsuda（松田裕之）

Ocean Research Institute, U. of Tokyo （東大海洋研 )

IWC/SC Japan DelegateWWF Japan Adviser

（自然保護専門委員）　

Overview 　今日の話題• To avoid both over-exploitation and ban乱獲も禁漁も避ける

• Fallacy to Seek 0 Risk ゼロリスク探求症候群• Precautionary Approach vs. Maximum Sustainabl

e Yield 予防措置と MSY• Adaptive Management 順応的管理と不確実性• Revised Management Procedure is an AM改定管理方式は順応的管理

• PP & AM are needed, PA is not.順応的管理があれば予防措置は不要

• Whaling & Ecosystems 捕鯨管理と生態系監視




• AM is needed, PA is not.順応的管理があれば予防措置は不要


捕鯨史 = 乱獲と禁漁の歴史 History of whaling = overexploitation & ban

• 1946 Blue Whale Unit– ( シロナガスクジラ換算制 )

• 1975 New Management Procedure–不確実性への配慮がなく、非現実的

• 1992 Revised Management Procedure–改定管理方式（ RMP) agreed by IWC/SC

– Revised Management Scheme not yet.

7

Both overexploitation and non-use make no sustainable intake. 乱獲も禁漁もだめ

• fN: Catch• SustainableSustainable if

0 < f < r• Stock collapse if

f > r• Maximum SustaiMaximum Sustai

nable Yield (MSY) nable Yield (MSY) if if ff = = rr/2/2 Stock size

Pro

du

ctio

n/Y

ield

KK/2

Kr/4

NfK

Nr

dt

dN

1

r f

Do we know the exact MSY?

NoBe conscious uncertainty.

Requiem to MSY への鎮魂歌

• Ecosystem is uncertain, non-equilibrium and complex

• MSY ignores all the three.

Recovery probability of mackerel

90年代の未成魚乱獲を続けると

70-80年代の漁獲圧なら資源

回復

確率

非定常複雑性不確実Species replacement AM makes chaos.

被食者密度

捕食者密度

Constant Harvest Ratio is Dangerous.漁獲率 ( 努力 ) 一定方策は危ない

• dN / dt = r [1 – (N / K)q] N – fN,

• Maximize yield at fMSY = rq / (1 + q).

• If estimates of r, K, q and f includes uncertainty, MSY is not achieved, nor extinction risk is not eliminated.

• Any level of constant fishing effort does not eliminate the risk of stock collapse.

fMSY is neither sufficient nor necessary to stock conservation. FMSY は資源保全に不必要不十分

High uncertainty in rLow uncertainty in r

Ext

inct

ion

risk

&

expe

cted

yie

ld

8

Threat of biodiversity is serious if the population is below MVP

• Minimum viable population (MVP) is defined as threat of demographic stochasticity (e.g., all mothers make sons = 50) and genetic degradation (=500).

• The “50/500” law does not guarantee a zero-risk.

• If population size > 10,000, the mean time to extinction is usually far too long (I ignore > 1 million yrs).

2

Precautionary principlePrecautionary principle Rio Declaration 1992, Rio Declaration 1992, Principle 15Principle 15

• “In order to protect the environment, the precautionary approach shall be widely applied by States according to their

capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation.

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Should any few risk be avoided? (IWC/SC 2001 report, p.93)

• Constant rate of exploitation of whales with environmental variability was still “equivalent to an unsustainable ‘mining’” (still positive risk)

• Under the RMP, “the time scales were far too long (1045 years)” (>>the age of cosmos)

• “the long time-scale was necessary to examine the mechanisms of the interaction between environmental variability and exploitation.” ????

Can you imagine goods of larger number than I do? 私より大きい数が言えますか ?

• Human Population – 世界人口 – 1010

• Age of Cosmos – 宇宙年齢– 1010 yrs

• Astronomic scale – 星の数 – 1011-1020

• DNA combination – 生物進化 – 1030

• Anti-whalers risk threshold – 反捕鯨団体が拒否するリスク – 1045 yrs

• Macroscale Tunnel Effects 101050

?

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Fallacy of Seeking Zero-Risk

Ri sk factors Mortal i ty Ri sk factors Mortal i ty

Motorcycl i ng 2000 Rodeo 3

Al l factors 1000 Fi re 2.8

Smoki ng 300 Tri hal omethan etc 0.8Cancer from smoki ng 120 Peanut butter 3spoons/ day 0.8

Fi re fi ghti ng 80 Beef steak 85g/ day 0.5

Hung gl i der 80 Fl ood 0.06

Coal mi ni ng 63 Struck by l i ghteni ng 0.05

Farmwork 36 Fal l i ng stars <10-5

Automobi l e 24The number of died person per 100,000 per year生涯リスクは上記の数字が（松田注:年齢，年代により）大きく変わらないとすれば約70倍したものとなる．

Qi’s anxiety ( 杞憂 )

Kitoh’s anKitoh’s anxietyxiety

(( 鬼憂鬼憂 ))A small falled leaf fire 　　 ?

Rodricks

Recipe for environment-friendly life

Keep Accountability and AdaptabilityJustify by ourselves, not by USALive in a Rabbit Hatch, Do not Use more Energy than 20 Elephants!

Use Any Parts of Bioresource.Do not Cull, but Eat Bioresource.Human First, Nature Second.

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Fallacy of applying PA to MSY予防措置自身が MSY 不達成のリスク要

因• If we adopt biased (precautionary)

estimates, expected yield is again negatively biased.

• MSY should be based on unbiased, most likely estimates (Error in quota is reversible if adaptive management is adopted)

• MVP should be based on biased estimates, or PP. (Lost of biodiversity is irreversible)

• MSY is usually >>MVP, but is <MVP in some local population.

Is sustainable use compatible with uncertain world?

持続的利用と不確実性は両立できるか ?

YesIf we adopt Adaptive Management.

順応的管理とはWhat is Adaptive Management?

• Adaptability （順応性）– 状況を見て政策を変える– その変え方を決めておく

• Accountability （説明責任）– 未実証の前提でリスク評価– 新たな知見を取り込み、過ちを改める

• Falsifiability （反証可能性）– どんな事態を招いたら失敗か事前に明記

順応学習とフィードバック制御Adaptive Learning & Feedback Control

勝川俊雄 T.Katsukawa ：博士論文 (2002) より

Data

Dynamics Model

State Variable

Decision Making of Fisheries Management

Fish Stock Dynamics with

Fishery

A Risk Management for sika deerA Risk Management for sika deer

H Matsuda, K Kaji, H Uno, H HirakawH Matsuda, K Kaji, H Uno, H Hirakawa & T Saito (Official English web site a & T Saito (Official English web site by Hokkaido Government:by Hokkaido Government:

http://www.hokkaido-ies.go.jp/HIESintro/ Natural/ ShizenHP2/SIKA/deerEng/http://www.hokkaido-ies.go.jp/HIESintro/ Natural/ ShizenHP2/SIKA/deerEng/

History of deer in Hokkaido Island= Overexploitation, hunting bans and

overabundance

10

100

1,000

10,000

100,000

1,000,000

1875 1895 1915 1935 1955 1975 1994

Catch

Damage on forests by deer http://www.marimo.or.jp/Kushiro_shicho

u/ezosika/cover.html

Density-dependent hunting pressure

%P>50% Emergency culling

25% < %PGradual population

reductions (catch females)

5% < %PGradual population increases (catch males)

%P <5% or after the severe winter

Hunting bans

http://www.hokkaido-ies.go.jp/HIESintro/Natural/ShizenHP2/SIKA/DTdeerHP.htm

Population began to decrease.Population began to decrease.

1993

95% CIManagement Program started in 1998

Female hunting

改定管理方式は順応的管理の先取りだった。 RMP is an AM

0

1

2

0 0.2 0.4 0.6 0.8 1

Relative Stock Size P t/P 0

Unusedresourcemanaged

resource

Protectedresource

Production

Catch quota

Fishing rate

MSY

limit stock level

MSY at 60%,0 catch at 54%

Underestimation of Uncertainty資源量推定誤差の過少推定

• Drastical decrease in Minke whale estimates with small errors

• Estimation is based on unverified assumptions

• Survey plan frequently changed over decades

• RMP underestimates uncertainty.

• Why is 54%K limit?• Adaptive Learning!Adaptive Learning!

Line Transect Estimation

0 50

100 150 200 250 300 350 400

1978/79 1983/84 1989/90 1994/95

Num

ber

of w

hale

s (t

hous

ands

)

0100200300400500600700800

Num

ber

of w

hale

s ob

serv

ed

1st Circum-polar Survey 2nd C.S.

3rd CircumpolarSurvey

Fisheries Management Rule; US and Japan 　　　　　

0

1

2

3

0 1 2

B t / BMSY

Fish

ing

coef

ficie

nt, F

1-a

Flimit(Fmsy)

Ftarget

Overfished

MNo lower stock limitUSA

Fishing is possible until stock collapseJapan

Uncertainty exists not only in whaling, but all fisheries.

= much looser than RMP

Conclusion: PP & AM are needed, PA is not.

• Precautionary Principle for irreversible damage is indispensable. ⇔ USA do neither join Kyoto Protocol nor Convention of Biological Diversity

• Precautionary Approach for sustainable use is unnecessary.

• Adaptive Management is useful.

Conscious of Uncertainty無知の知。不確実の知

• If BMSY >> MVP, we do not need precautionary approach for MSY.

• Instead, we need to monitor Bt, catch quota is banned when Bt is below a critical level.

• Even though BMSY is unknown, AM works well for sustainable use.

• This is RMP. This is AM.

Marine Ecosystems Concerns海洋生態系への懸念

R. A. Myers & B. Worm (2002) Nature in press. “Rapid worldwide deple-tion of large predatory fish communities” …We conclude that declines of large predators that initially occurred in coastal regions, have extended throughout the global ocean, with potentially large consequences on ecosystems.Top predators are good indicator of ecosystems.

Conclusion: Why is Management of Whaling Important?

1. Make a new method of stock estimation. 資源量推定法の見直し

2. RMP is a good example of AM that is recommended by USA and Japan. RMP は日米推奨の順応的管理の好例

3. Ecosystem-based Monitoring 生態系に与える影響を評価 Big project to Antarctic Area Monitoring.

management of whaling 鯨類の資源管理

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