abundance and productivity trends of alaskan chinook ...gaining perspective on the magnitude of the...

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Quantitative Fisheries Center at Michigan State University Abundance and productivity trends of Alaskan Chinook salmon stocks: gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University Joe Spaeder AYK-SSI Research Coordinator

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Page 1: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Abundance and productivity trends of Alaskan Chinook salmon stocks:

gaining perspective on the magnitude of the problem

Matt Catalano Fisheries and Allied Aquacultures, Auburn University Joe Spaeder AYK-SSI Research Coordinator

Page 2: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Analysis Background • Arctic-Yukon-Kuskokwim Sustainable Salmon

Initiative – Seven hypotheses about possible causes of declines of AYK

region Chinook populations

– Thirteen member AYK SSI sponsored Expert Panel

– Development of a “Chinook Research Action Plan” for the AYK region

Page 3: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Outline

• Chinook stock status, trends, evidence of declines

• Comparative analysis of productivity trends among stocks

• Evidence for density-dependent effects on productivity

Page 4: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Outline

• Chinook stock status, trends, evidence of declines

• Comparative analysis of productivity trends among stocks

• Evidence for density-dependent effects on productivity

Page 5: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

What is the pattern we seek to explain?

• Episodes of low abundance and productivity

• Failure to meet escapement goals

• Restrictions on subsistence harvest

• Infrequent directed commercial fisheries

• Changes in age/length/sex composition

Page 6: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

What data do we have? • 12 Chinook salmon stocks • Escapement

– Weirs, air surveys, counting towers, telemetry, mark-recapture

• Harvest – Commercial trip tickets – Subsistence post-season surveys

• Age/sex/length composition • Often cannot enumerate the entire escapement

Page 7: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Alaska Chinook Data Sets Stock Region Years Kuskokwim AYK 1976-2011 Yukon AYK 1982-2010 Anchor Cook Inlet 1977-2011 Deshka Cook Inlet 1979-2010 Ayakulik Kodiak Island 1976-2010 Karluk Kodiak Island 1976-2010 Nelson Alaska Peninsula 1976-2011 Alsek Southeast Alaska 1976-2007 Blossom Southeast Alaska 1975-2007 Situk Southeast Alaska 1982-2010 Stikine Southeast Alaska 1981-2009 Taku Southeast Alaska 1973-2010

Page 8: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

The State-Space Model • Estimation of observation and process errors

• Age-structured: incorporates maturity variation

• Uncertainty due to missing data

• Recruitment is treated as unobserved

• Estimation of time-varying parameters

• Method of choice for ADFG

Page 9: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Abundance

Page 10: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Yukon River Harvest

1961 1965 1969 1973 1977 1981 1985 1989 1993 1997 2001 2005 2009

Year

Thou

sand

s of

Sal

mon

050

100

150

200

250

CommercialSubsistence

Page 11: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Kuskokwim River Harvest

1976 1979 1982 1985 1988 1991 1994 1997 2000 2003 2006 2009

Year

Thou

sand

s of

sal

mon

050

100

150

200

commercialsubsistence

Page 12: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Maturity

Page 13: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Source: Ken Harper USFWS

Page 14: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Source: Ken Harper USFWS

Page 15: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Yukon Length-At-Age (Hamazaki 2009)

Page 16: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Growth: Scale Pattern Analysis Kuskokwim (Ruggerone 2007) Yukon (Ruggeronne et al. 2009)

Page 17: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Summary: Stock Status and Trends • Nearly all stocks currently experiencing low returns

• The returns are the lowest on record for half of stocks

• Decrease in mean length-at-age (Kusko and Yukon)

• Decrease in eggs per female (Kusko and Yukon)

• Differential growth patterns (Kusko and Yukon)

Page 18: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Outline

• Chinook stock status, trends, evidence of declines

• Comparative analysis of productivity trends among stocks

• Evidence for density-dependent effects on productivity

Page 19: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Measures of “Productivity” 1. Recruits per spawner

– Does not account for density dependence effects

2. Recruits per spawner residuals – Removes density dependence effects on

productivity

3. Time varying alpha parameter from SR model – “filters” out white noise to “uncover” underlying

productivity trends

Page 20: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

1. Productivity: Recruits Per Spawner

Page 21: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

2. Productivity: Recruits Per Spawner Residuals

• How do we obtain the residuals? – Fit Ricker stock-recruitment models

• lnRy = ln(α)+ln(Sy)-β*Sy+ϕ*vy-1+εy

– Differences between observed and model-predicted recruitment

Page 22: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Stock Recruit Models

Page 23: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Recruits Per Spawner Residuals

Page 24: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Correlations: ln(R/S) Residuals AYK Cook Inlet Kodiak Island Southeast

Kusko Yukon Anchor Deshka Ayakulik Karluk Nelson Alsek Blossom Situk Stikine Taku

Kusko

Yukon

Anchor

Deshka Pos Neg

Ayakulik 0.67 – 1.00 Karluk 0.33 – 0.67 Nelson 0.00 – 0.33 Alsek

Blossom

Situk

Stikine

Taku

Page 25: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

3. Productivity: Time-Varying Alpha

• Fit Bayesian state-space Ricker models • The productivity parameter, α, allowed to vary

over time via random walk process: lnRy = ln(αy) + ln(Sy) - β*Sy + εy

ln(αy) = ln(αy-1) + wy

• Similar results to Kalman Filter estimates

Page 26: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Time-Varying Alpha

Page 27: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Correlations: Time-Varying Alpha AYK Cook Inlet Kodiak Island Southeast

Kusko Yukon Anchor Deshka Ayakulik Karluk Nelson Alsek Blossom Situk Stikine Taku

Kusko

Yukon

Anchor

Deshka Pos Neg Ayakulik 0.67 – 1.00 Karluk 0.33 - 0.67 Nelson 0.00 – 0.33 Alsek

Blossom

Situk

Stikine

Taku

Page 28: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Summary: Comparative Productivity Analysis

• Moderate positive residual correlation between Yukon and Kuskokwim

• Positive correlations among Yukon CA, Anchor and Kodiak stocks

• No obvious correlation patterns with/among southeast AK stocks

Page 29: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Outline

• Chinook stock status, trends, evidence of declines

• Comparative analysis of productivity trends among stocks

• Evidence for density-dependent effects on productivity

Page 30: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Questions

• How much of the temporal pattern in productivity is attributable to density dependence?

• How much evidence is there for over-compensatory density dependence?

Page 31: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Density-Dependence: Methods

• Magnitude of alpha estimates

• Model comparison: Ricker vs. Beverton-Holt

Page 32: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Probability(alpha>7.4)

Page 33: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Probability(Ricker Model)

Page 34: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Conclusions

• Alpha was large enough to induce stable population oscillations for Kusko and Yukon

• Weak evidence for over-compensatory recruitment dynamics, except for the Kusko

Page 35: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Next Steps • Additional stocks

– Bayesian analysis of Chena/Salcha, Goodnews, Unalakleet R. stocks and possibly others

• Dec. 10-11 AYK SSI Chinook Salmon Outreach Workshop – New analyses – Management strategy evaluation workshop

Page 36: Abundance and productivity trends of Alaskan Chinook ...gaining perspective on the magnitude of the problem Matt Catalano Fisheries and Allied Aquacultures, Auburn University . Joe

Quantitative Fisheries Center at Michigan State University

Acknowledgments

Brian Bue - Bue Consulting Bob Clark - ADFG Steve Fleischman - ADFG Hamachan Hamazaki - ADFG Mike Jones - MSU ADFG staff HPCC at MSU