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Michael Melnychuk, Tim Essington, Olaf Jensen, Trevor Branch, Ana Parma, John Pope, Tony Smith, Jason Link, Selina Heppell, Steve Martell Can fisheries.

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Presentation on theme: "Michael Melnychuk, Tim Essington, Olaf Jensen, Trevor Branch, Ana Parma, John Pope, Tony Smith, Jason Link, Selina Heppell, Steve Martell Can fisheries."— Presentation transcript:

1 Michael Melnychuk, Tim Essington, Olaf Jensen, Trevor Branch, Ana Parma, John Pope, Tony Smith, Jason Link, Selina Heppell, Steve Martell Can fisheries under catch shares better track management targets ? Pew Charitable Trusts Webinar November 3, 2011

2 Catch shares → Allocation of quota to individuals such that competition among individuals is reduced

3 2000 – 2004

4 Do catch share fisheries better track management targets than fisheries not under catch shares ? targets:annual quota (C/Q) exploitation rate target (F/F target ) biomass target (B/B target ) Hypotheses: Adherence to targets: catch shares > quota only > effort controls Strength of response: C/Q > F/F target > B/B target

5 Target F F F F : F target 4 metrics: Mean SD(target) Minor exceedance Major exceedance

6 Summary of response variables C/Q n = 259 stocks F/F target n = 172 B/B target n = 205 Frequency Mean C/QMean F/F target Mean B/B target

7 Variables of interest Catch control type Other covariates accounted for: Region Taxonomic/habitat-association Year of fishery development Average catch L max Propensity for being under catch shares ResponsesPredictors 3 ratios with management targets: Catch/quota F/F target B/B target 4 metrics: Mean SD(target) Minor exceedance Major exceedance X

8 Mean C/Q SD(target C/Q) Minor (10%) overages Major (25%) overages C/Q analysis Catch shares Partial catch shares Quota only * * Coefficient estimate

9 Catch shares Partial catch shares Quota only Effort regulations Mean F/F target SD(target F/F target ) Minor (10%) over-exploitation Major (50%) over-exploitation * F/F target analysis Coefficient estimate

10 Catch shares Partial catch shares Quota only Effort regulations Mean B/B target SD(target B/B target ) Minor (10%) depletion Major (50%) depletion Coefficient estimate B/B target analysis

11 Summary Compared to non-catch shares, catch share fisheries had: less variability in C/Q less frequent (major) overfishing Effects of both quota management and catch shares Catch shares are one of many possible tools that can be used to help meet management objectives Next step: what particular aspects of catch share systems tend to lead to the outcomes we’ve observed ?

12 Thank you: Data collection: Kate Stanton, Rachel Finley, Jordan Watson Funding: Lenfest Ocean Program RAM Legacy database: Dan Ricard and all contributors Interviews : U.S. – Alaska: J. DiCosimo, J. Heltzel, M. Fina, S. Hare, S. Kelley, J. Regnart; U.S. – W Coast: J. DeVore, M. Burner, C. Niles, I. Stewart; U.S. – NE/Mid-Atl. Coast: C. Legault, T. Chute, D. Hart, J. Idoine, G. Shepherd, B. Beal, N. Meserve, K. Taylor, B. Spear, D. Boelke, T. Hoff, K. West, J. McNamee; U.S. – SE Coast/G. Mexico: J. McGovern, P. Hood, A. Strelcheck, S. Gerhart, J. Kimmel, J. Smith; Canada – W Coast: A. Keizer, B. Ackerman, W. Li Ou, P. Ridings, J. Rogers, J. Schweigert, E. Wylie, M. James; Canada – E Coast: P. Cahill, V. Docherty, J. Hansen, D. Coffin, M. Baker, D. Ball, H. Bishop, J. Buie, S. Campana, G. Chouinard, J. Conlin, P. Couillard, A. Frechet, J. Gaudette, C. Hendry, P. Koeller, M. LeCouffre, L. Legere, D. Lemelin, B. Lester, C. MacDonald, B. Morin, M. Moriyasu, D. Pezzack, D. Roddick, A. Rumbolt, T. Siferd, J. Simon, S. Smith, G. Stevens, H. Stone, C. Waters, R. Federizon; Europe: J. Sigurjónsson, J. Horwood, B. Deas, A. LeGarrec, C. Olesen, M. Anderson, M. Welvaert, G. van Balsfoort, P. Breckling, N. Holdsworth; Australia: C. Dichmont, N. Klaer, G. Tuck, S. Wayte, S. Auld, S. Gaddes, S. Koh, S. Weekes, B. Taylor, K. Crosthwaite, T. Ward, C. Gardner; New Zealand: D. Foster, D. Sykes, G. Clement; Argentina: J. Hansen, A. Giussi, M. Renzi; South Africa: A. Brandao, D. Butterworth, S. Halloway, S. Johnston, C. de Moor, R. Rademeyer, G. Maharaj, R. Bross, A. Badenhorst.

13 ▬ Alaska, U.S. ▬ West coast, U.S. ▬ West coast, Canada ▬ East coast, Canada ▬ Europe ▬ Australia ▬ New Zealand ▬ Other Probability density Mean C/QSD(target C/Q) Catch/quota ratios n = 130 n = 41 n = 88 ▬ Frequency

14 ▬ Alaska, U.S. ▬ West coast, U.S. ▬ NE & mid-Atl., U.S ▬ Europe ▬ New Zealand ▬ Other Probability density Mean F/F target SD(target F/F target ) F/F target ratios n = 54 n = 24 n = 67 n = 27 ▬ Frequency

15 ▬ Alaska, U.S. ▬ West coast, U.S. ▬ West coast, Canada ▬ NE & mid-Atl., U.S. ▬ Europe ▬ Australia ▬ New Zealand ▬ Other ▬ Frequency Probability density Mean B/B target SD(target B/B target ) B/B target ratios n = 67 n = 28 n = 82 n = 28

16 Catch share propensity scores Controls for non-random application of catch share “treatments” Logistic regression: CS ~ Region + Habitat + avCatch + devYear + L max Use estimated coefficients to predict probability of each fishery being under full catch shares during 2000–2004 Use propensity scores as covariates in subsequent analyses

17 Catch share propensity scores Average propensity score Region Habitat Catch control

18 Propensity score matching ● Actual full CS X Actual non-CS

19 Propensity score matching Mean C/Q SD(target C/Q) Minor (10%) overages Major (25%) overages Mean F/F target SD(target F/F target ) Minor (10%) overfishing Major (50%) overfishing Mean B/B target SD(target B/B target ) Minor (10%) depletion Major (50%) depletion 2.5 th %ile97.5 th %ile Grand mean of: Response CS – Response Non-CS Mean difference of response variable

20 Proportion of stocks in some undesirable state Probability of exceedance C/Q F/F target B/B target (OK)(Bad)

21 Mean C/Q SD(target C/Q) Minor (10%) overages Major (25%) overages Fixed effect coefficients (full model) C/Q Catch shares Partial catch shares Quota only Average catch Development year L max Propensity score Random effect conditional modes * *

22 F/F target Catch shares Partial catch shares Quota only Effort regulations Average catch Development year L max Propensity score Mean F/F target SD(target F/F target ) Minor (10%) over-exploitation Major (50%) over-exploitation Fixed effect coefficients (full model) Random effect conditional modes

23 B/B target Catch shares Partial catch shares Quota only Effort regulations Average catch Development year L max Propensity score Mean B/B target SD(target B/B target ) Minor (10%) depletion Major (50%) depletion Fixed effect coefficients (full model) Random effect conditional modes

24 Filters applied Excluded oceanic sharks/tunas Excluded rarely targeted stocks Excluded stocks with catch shares or TACs established during Excluded stocks with missing time series data or reference points Excluded stocks whose assessments were not trustworthy (F, B only) Excluded stocks with >50% landings in recreational sector Excluded fisheries under moratorium (C/Q, F only)

25 Sensitivity tests Removed propensity score covariate Excluded stocks whose F target or B target reference points were estimated with Schaefer model Excluded ICES/NAFO-managed stocks Excluded stocks with C/Q < 0.5 Excluded stocks under moratorium (biomass analyses) Considered only full catch share and quota-only categories big reduction in sample size

26 C/QF/F target B/B target Catch shares Partial catch shares Quota only Effort regulations ─ 2728 Total Number of stocks included in analyses after filtering

27 Mixed-effects model analysis Y ~ (CControl + PS) + avCatch + devYear + L max + Region + Habitat Y ~ (CControl + PS) + devYear + L max + Region + Habitat Y ~ (CControl + PS) + avCatch + devYear + Region + Habitat Y ~ (CControl + PS) + avCatch + L max + Region + Habitat Y ~ (CControl + PS) + Region + Habitat Y ~ Intercept + avCatch + devYear + L max + Region + Habitat Y ~ Intercept + devYear + L max + Region + Habitat Y ~ Intercept + avCatch + devYear + Region + Habitat Y ~ Intercept + avCatch + L max + Region + Habitat Y ~ Intercept + Region + Habitat Catch control included Catch control not included

28 Type of response variable : Metric for each response variable : Current catch to current quota (C/Q) Current exploitation rate to target exploitation rate (F/F target ) Current biomass to target biomass (B/B target ) 5-year mean e.g. mean C/Q Standard deviation around target e.g. SD(target C/Q) Exceedance of minor undesirable threshold e.g. P(C/Q > 1.1) Exceedance of major undesirable threshold e.g. P(C/Q > 1.25)


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