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00/10/051 フィードバック管理 と資源評価 松石隆先生、菅野泰治 先生、西村欣也先生は じめ北大の皆様に感謝.

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Presentation on theme: "00/10/051 フィードバック管理 と資源評価 松石隆先生、菅野泰治 先生、西村欣也先生は じめ北大の皆様に感謝."— Presentation transcript:

1 00/10/051 フィードバック管理 と資源評価 松石隆先生、菅野泰治 先生、西村欣也先生は じめ北大の皆様に感謝

2 00/10/052 Feedback Management Uncertainty in stock assessment –Accountability Dynamic change in abundance –Adaptability (tuning catch effort) Successive Monitoring!!!

3 00/10/053 Revised Management Procedure (RMP) in IWC Moratorium of commercial whaling since 1982 (until RMP?) RMP was adopted in 1994, but has not yet enforced.

4 00/10/054 Feedback Management for Sika deer in Hokkaido, Japan http://www.marimo.or.jp/Kushiro_shichou/ezosika/ 試される大地

5 00/10/055 Density-dependent hunting pressure (adaptability) %P>50%: Emergent Decrease (<4 years) 25% < %P : Gradual Decrease 5% < %P : Gradual Increase %P <5% or after the severe winter: Ban-on-Hunting Hokkaido, tested land

6 00/10/056 Stage-Structured Model N c, N f, N m : No. of calves(0.5), females & males( ≧ 1.5) L fc (t)= L mc (t)= exp[-Q(t)H c (t)]exp[-M c (t)]exp[-R c (t+1)], L ff (t) = exp[-Q(t)H f (t)]exp[-M f (t)]exp[-R f (t+1)], L mm (t) = exp[-Q(t)H m (t)]exp[-M m (t)]exp[-R m (t+1)], sika deer has little density effect and I ignored Hokkaido, tested land

7 00/10/057 2 Risk Management We set the upper and lower limit (%P - & %P + ) of population size P such that, within the next 1 century, Prob{P<1000 individuals} < 1% Prob{%P %P + } < 5%. Therefore, %P -  5%, %P +  50% Hokkaido, tested land

8 00/10/058 3 Population Indices Catch & Watch per hunter day Spotlight census Helicopter census Train accidents Damage of agriculture & forestry –Uncertainty of absolute size Hokkaido, tested land

9 00/10/059 Population index by spotlight census for eastern Hokkaido Population estimation has large uncertainty Hokkaido, tested land

10 00/10/0510 Fallacy of 120 000 deer hypothesis >30000 deer were killed every year since 1995 Male deer is still abundant Natural growth rate is 15-20% Population began to decrease? 160-240 thousand deer in 1993 Hokkaido, tested land

11 00/10/0511 RMP for south Pacific minke whale P t+1 -P t = r[1-(P t /K) z ]P t -C t –think uncertainty in r, K, P t /K and P t (relative and absolute P) –no age structure –ignore uncertainty in z (density- effect)

12 00/10/0512 IWC/SC concensus 2000 minke whale is commercially exploitable. Catch Limit is determined by L t =2.12r (P t /K-0.54)P t Scientific whaling catches now 400!

13 00/10/0513 South Pacific minke whale may be decreasing! (Butterworth et al. 1999)

14 00/10/0514 Recent IWC (SOWER) census data suggests Minke whale population is 30%-70% as was in ca1990. Anti-whaling NGO may think “Whaling is over”. Japan Gov’t may think “this census is uncertain…”

15 00/10/0515 Why do minke whale decrease? Artifact in monitoring Ecosystem change –Short resource (krill) –Competition with other whales Super-Compensation

16 00/10/0516 “Artifact Hypothesis” RMP is realizable only under effective monitoring; Scientific whaling does not satisfy RMP. Precautionary approach. Commercial whaling is Critically Endangered

17 00/10/0517 Competition hypothesis Competition decreases –Recruitment or fecundity? –Adult mortality? Why did the minke whale increase in the 1980s?

18 00/10/0518 Super-Compensation Demographic Momentum due to drastic change in catch effort from the 1970 to 1990, Age structure changed greatly. Same phenomenon as southern bluefin tuna

19 00/10/0519 Age structure is changing

20 00/10/0520 Demographic Momentum by a Leslie type Model Age at maturity = 11years Moratorium in t=0 RMP begin in t=30 Tune recruitment, >Tune total stock. Monitor age structure!!! Scientific Whaling is useful

21 00/10/0521 Conclusion Feedback management should investigate stock size and age structure. Temporal decrease of minke whale may be explained by demographic momentum.


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