Relationship of ocean environmental factors to salmon growth, - - PowerPoint PPT Presentation

Relationship of ocean environmental factors to salmon growth, survival and maturation

Brian Wells Fisheries Ecology Division NOAA Fisheries 110 Shaffer Road Santa Cruz, CA 95060 brian.wells@noaa.gov http://brianwells.googlepages.com/ (831) 420-3969

General questions

• 1. At what scale are we dealing?
• 2. What variables sufficiently describe the environment of interest?
• 3. What defines a ‘good’ environment?
• 4. Can we develop a simple scalar that can act to inform us on the ‘quality’
• f the ocean condition?
• 5. In what ways does the environment relate to salmon dynamics?

General questions

• 1. At what scale are we dealing?
• 2. What variables sufficiently describe the environment of interest?
• 3. What defines a ‘good’ environment?
• 4. Can we develop a simple scalar that can act to inform us on the ‘quality’
• f the ocean condition?
• 5. In what ways does the environment relate to salmon dynamics?

• 1. At what scale are we dealing?

There is large-scale variability but this can only be affectively examined using gross indicators that yield little mechanistic information and they have failed to be fine enough to improve forecasting models

• 1. At what scale are we dealing?

Based on coastal geography we can divide the California Current into somewhat distinct environments.

General questions

• 1. At what scale are we dealing?
• 2. What variables sufficiently describe the environment of interest?
• 3. What defines a ‘good’ environment?
• 4. Can we develop a simple scalar that can act to inform us on the ‘quality’
• f the ocean condition?
• 5. In what ways does the environment relate to salmon dynamics?

• 2. What variables sufficiently describe the environment of interest?

Let’s start by examining central California

Transition Date

Easterly Wind

u b l n e T r u e c

Transition Date

Easterly Wind

u b l n e T r u e c

Transition Date

Easterly Wind

u b l n e T r u e c

Transition Date

Easterly Wind

u b l n e T r u e c

With these conditions SST and SLH are reduced.

General questions

• 1. At what scale are we dealing?
• 2. What variables sufficiently describe the environment of interest?
• 3. What defines a ‘good’ environment?
• 4. Can we develop a simple scalar that can act to inform us on the ‘quality’
• f the ocean condition?
• 5. In what ways does the environment relate to salmon dynamics?

• 3. What defines a ‘good’ environment?

San Francisco Monterey Bay

One that promotes production of the natural community structure?

San Francisco Monterey Bay

Biological data Krill abundance Rockfish numbers Seabird nesting success Environmental data Spring transition date Wind direction Wind speeds Upwelling Retention Sea Surface Temp Sea Level Height

• 3. What defines a ‘good’ environment?

Shortbelly Recruitment Deviations [log(SBProduction) ]

Transi sitio tion

East st st stre ress ss

Wind s nd speed eed Upwellin lling SST SST SL SLH

Shor

• rtbe

belly Produ duction

• n

1975 975-20 2005 ( 05 (less s 76,77 77,78) 78) North s h stress ess East st stress ss Wind s nd speed eed Upwellin lling SST SST SL SLH

Spring Summe mmer

Ret eten ention

• n

Krill ill

Nor

• rth

h stress ess Retent ntion

• n

General questions

• 1. At what scale are we dealing?
• 2. What variables sufficiently describe the environment of interest?
• 3. What defines a ‘good’ environment?
• 4. Can we develop a simple scalar that can act to inform us on the ‘quality’
• f the ocean condition?
• 5. In what ways does the environment relate to salmon dynamics?

=

• 4. Can we develop a simple scalar that can act to inform us on the ‘quality’
• f the ocean condition?

=

Krill Shortbelly Murre SLH SST Retention Upwelling Trubulence

• N. Winds
• E. WInds

Trans Environmental Condition

Community Production

• 3
• 2
• 1

1 2 3

• 6
• 4
• 2

2 4

• 4. Can we develop a simple scalar that can act to inform us on the ‘quality’
• f the ocean condition?

=

Krill Shortbelly Murre SLH SST Retention Upwelling Trubulence

• N. Winds
• E. WInds

Trans

This environmental index can act as a indicator of ecosystem productivity and the bars directions allow you to interpret the influence of each variable on system health.

• 4. Can we develop a simple scalar that can act to inform us on the ‘quality’
• f the ocean condition?

Environmental Condition

Community Production

• 3
• 2
• 1

1 2 3

• 6
• 4
• 2

2 4

Higher value is good

General questions

• 1. At what scale are we dealing?
• 2. What variables sufficiently describe the environment of interest?
• 3. What defines a ‘good’ environment?
• 4. Can we develop a simple scalar that can act to inform us on the ‘quality’
• f the ocean condition?
• 5. In what ways does the environment relate to salmon dynamics?

• 3
• 2
• 1

1 2 3 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Central Valley Return Year

Wells Index Std Value 200 400 600 800 1000 1200 1400 1600 Central Valley Index Abundance Cross Correlation = 71%

The index leads the Central Valley return numbers in the last 15 years. So, the first relationship to note is that the environment clearly relates to salmon numbers.

• 5. In what ways does the environment relate to salmon dynamics?

The environmental condition index

Juvenile Salmon Condition

Collections of Juvenile salmon 1998-2005 In 2005, salmon entered ocean at an average condition to previous years but when collected during summer at Farallons they were in much worse condition than average.

Farallons in Summer

Length Weight Condition

Golden Gate

Adult Salmon Abundance

Collections of Juvenile salmon 1998-2005 Abundance of krill around Farallons ultimately relates to adult abundance (SI Index) two years later. Return yr/1st yr at sea

2005 2006 2007 2008

So, the environment affects survival and abundance. How about other factors? Let’s look at the variables as they relate directly to salmon and post first year variability (that following the high mortality at emigration).

• 5. In what ways does the environment relate to salmon dynamics?

Current forecast approach

• 5. Central Valley: In what ways does the environment relate to salmon

dynamics?

We use the residuals from this forecasting model to determine the effect

• f environment on population variability.

We examine relationships for a suite of variables across seasons against the residuals.

• 5. Central Valley: In what ways does the environment relate to salmon

dynamics?

Residuals from forecasting model vs. Environmental variable Residuals

(higher number indicates that the CV was underestimated by the sibling model and vice versa)

Spring Summer Transition SLH Flow SST Upwelling Retention Scalar Year of Emigration Second year at sea Third year at sea Year of Emigration Second year at sea Third year at sea Autumn Second year at sea Third year at sea

Spring Summer Transition SLH Flow SST Upwelling Retention Scalar Year of Emigration Second year at sea Third year at sea Year of Emigration Second year at sea Third year at sea Autumn Second year at sea Third year at sea

Take home points: 1. The effect of environment is apparent during the summer and Autumn of age 2 return. 2. Most of the age 2 relationships are linear. 3. In the second year, conditions conducive to increased production (e.g., lower SST and SLH) cause us to underestimate remaining cohort strength. There will be more Age 3 fish returning than expected!

Residuals from forecasting model vs. Environmental variable Residuals

(higher number indicates that the CV was underestimated by the sibling model and vice versa)

2nd yr 2nd yr Summer Autumn SLH SST Retention SLH Upwelling

Using Age 2 returns and environmental variables from the year of emigration and second year consolidated using a statistical model we can build forecasting models that include environmental condition. Ln(CVI) = 0.28 (Ln(Jack#)) + 0.25(Latent Env Var.) + 6.63; R2 = 0.92

400 800 1200 1600 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

CVI

• 0.6
• 0.3

0.3 0.6

SLH SST Curl Upwelling

Summer Fall Retention

Actual Env Biology Ln(CVI) = 0.83502(Ln(Jack Number)) + - 2.179; R2 = 0.66

• 5. Central Valley: In what ways does the environment relate to salmon

dynamics?

Number of 3 year old fish

Ln(Age3) = 0.51 (Ln(Age2)) + 0.40(Latent Env Var.) + 5.41; R2 = 0.78 Ln(Age3) = 0.69(Ln(Age2)) + - 3.92; R2 = 0.44

Age 3 Abundance Estimates

200 400 600 800 1000

1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Year at sea

Age 3 Abundance

• 0.5
• 0.25

0.25 0.5

SLH SST Upwelling Curl Winter Spring Summer Retention

• 5. Klamath River: In what ways does the environment relate to salmon

dynamics?

Number of 3 year old fish

• 5. In what ways does the environment relate to salmon dynamics?

Let’s now focus on growth and delayed maturation. We will use Northern California Smith River Chinook salmon in this exploration.

El Niño We can use similar tactics to examine the effects of environment

• n growth
• 5. In what ways does the environment relate to salmon dynamics?

=

Basically, an environment not conducive to increased productivity leads to slow growth. We also demonstrate that slow growth leads to delayed maturation. And, therefore, increased mortality before fish have opportunity to spawn.

• 5. In what ways does the environment relate to salmon dynamics?

0.25 0.5 0.75 1 1975 1980 1985 1990 1995 2000

Brood year

Proportion maturing after Age 4

Observed Fitted by environmental data

delayed earlier

Delayed maturation of females.

0.25 0.5 0.75 1 1975 1980 1985 1990 1995 2000

Brood year

Observed Fitted by environmental data

delayed earlier

• 0.6
• 0.4
• 0.2

0.2 0.4

SLH SST Retention Upwelling Turbulence North Wind East Wind Environmental influences

Proportion maturing after Age 4 Delayed maturation of females.

0.25 0.5 0.75 1 1975 1980 1985 1990 1995 2000

Brood year

Observed Fitted by environmental data

delayed earlier

• 0.6
• 0.4
• 0.2

0.2 0.4

SLH SST Retention Upwelling Turbulence North Wind East Wind Environmental influences

A

Proportion maturing after Age 4

So, a good environment the year before fish typically come home promotes maturing at the appropriate age. And a poor environment delays maturation.

Delayed maturation of females.

Review the effects of environment on salmon

• 3
• 2
• 1

1 2 3 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Central Valley Return Year

Wells Index Std Value 200 400 600 800 1000 1200 1400 1600 Central Valley Index Abundance

0.25 0.5 0.75 1 1975 1980 1985 1990 1995 2000

Proportion maturing after Age 4

The environment affects abundance and recent declines may relate to retention locally. A poor environment can lead to delayed maturation of females A poor environment can lead to slow growth

Conclusions

We can develop a descriptive scalar that may provide a measure of ocean quality based on the interactions between ocean conditions and production of the community. We can use these techniques and we learn from them to detect variability in vital rates of Chinook salmon along the California coast. The mechanisms between environment and Chinook salmon dynamics may be large and regional scale. The environment not only affects mortality and stock abundance but dramatically affects the maturation dynamics as well of both males and females.

Conclusions

We can develop a descriptive scalar that may provide a measure of ocean quality based on the interactions between ocean conditions and production of the community. We can use these techniques and we learn from them to detect variability in vital rates of Chinook salmon along the California coast. The mechanisms between environment and Chinook salmon dynamics may be large and regional scale. The environment not only affects mortality and stock abundance but dramatically affects the maturation dynamics as well of both males and females.

Conclusions

We can develop a descriptive scalar that may provide a measure of ocean quality based on the interactions between ocean conditions and production of the community. We can use these techniques and we learn from them to detect variability in vital rates of Chinook salmon along the California coast. The mechanisms between environment and Chinook salmon dynamics may be large and regional scale. The environment not only affects mortality and stock abundance but dramatically affects the maturation dynamics as well of both males and females.

Conclusions

We can develop a descriptive scalar that may provide a measure of ocean quality based on the interactions between ocean conditions and production of the community. We can use these techniques and we learn from them to detect variability in vital rates of Chinook salmon along the California coast. The mechanisms between environment and Chinook salmon dynamics may be large and regional scale. The environment not only affects mortality and stock abundance but dramatically affects the maturation dynamics as well of both males and females.

Funding was provided by NOAA through the Fisheries and the Environment (FATE) program

Acknowledgements