# Presentation: 271251

## 	Recent High Frequency Variability in the PDO: Impacts on the California Current Ecosystem and Salmon

- NOAA Fisheries
- Northwest Fisheries Science Center
- Seattle, WA & Newport, OR, USA
- Ed Casillas

## Atmopheric and Ocean Phase shifts are tracked by the Pacific Decadal Oscillation (PDO): negative values = cool phase; positive values = warm phase. 

- Atmopheric and Ocean Phase shifts are tracked by the Pacific Decadal Oscillation (PDO): negative values = cool phase; positive values = warm phase.

- Anomolie

- 20-30 yr period

- 20-30 yr period

## NE Pacific Ecosystem Response To PDO

- SST Cooler
- Secondary Productivity – Alaska , PNW
- Salmon Abundance -  Alaska ,  PNW

- SST Warmer
- Secondary Productivity – Alaska , PNW
- Salmon Abundance -  Alaska ,  PNW

_**Negative PDO**_

_**Positive PDO**_

## Issue Being Addressed

- Physical and biological elements of the ecosystems appear stable during each long term phase (cool or warm regime) of the PDO
- Question - If large scale regime shifts occur at a greater frequency (shorter duration), is the ecosystem able to respond accordingly?
- Because Global Warming could affect duration and variability in large scale forcing; do managers of fishery resources need faster responding forecasting tools?
- ANSWER – Yes and Yes

## PDO: May-Sep Average, 1925-2007

- At no time since 1900, nor during the Warm-Cool-Warm regimes was there a sign change longer in duration than 16 months (1957-58 El Niño), and there was never a period of PDO with an opposite change in sign for more than 8 months within a given year.
- However, we have had two shifts of four years duration recently: 1999-2002 and 2003-2006, thus we have a natural experiment to test the question

## Plankton, Salmon and Pelagic Fish Sampling

- Sample in May, June and September (50 stations) since 1998
- Sample Columbia River and Willapa Bay** **every 10 days from April through July  (AT NIGHT) at ~ 10 stations; since 1998
- Sample off Newport every two weeks, since 1996
- Have historical data on hydrography and zooplankton from 1970s and 1983; salmon abundance data from 1981-1985 but only some of these data are part of this talk

## PDO, SST and Copepods: time series since 1996

- PDO and SST highly correlated, as they should be.
- However there are time lags between PDO sign change and SST response of 3-5 months.
- Zooplankton richness anomolies reflect combination of assemblages from different water masses

## Different Water Masses in the Ca Current Ecosystem

- 2007 a “cool” year, similar to 1999-2002
- 1997-1998 + early 2005 were warm and fresh
- 2003-2006 intermediate T and S

## Variation in Other Biological Factors of the California Current Ecosystem During the 1998-2007 Period

**Coho Salmon Growth Condition**

**Notes:**
Large fluctuations
Warm years – more hake 
Cold years less hake, more jack mackerel and dogfish

## Are Growing Conditions Important To Salmon?

**Adult**
**return**

**Growth Factor**

**Growth Factor**

**Salmon food**

**Survival relates to**
**growth**

**Growth relates to**
**food**

**Food relates to**
**ocean conditions in the Ca Current Ecosystem**

## Size Matters

- Results from time of release study

- But its not the only factor!

## Predatory/Forage Fish Interaction Affects Salmon Survival

**Predatory/Forage Fish Interaction Affects Salmon Survival**

## Salmon Abundance in the Ca Current Reacts Quickly to change in PDO sign

- _Fall Chinook_

- _Spring Chinook_

## Findings

- Physical and biological features of the California Current ecosystem appear to change rapidly to phase shifts in the large scale forces reflected in the PDO
- Marine survival of salmon similarly appears to reflect rapid changes in ocean conditions of the northern California Current ecosystem
- Evaluating benefits of freshwater recovery actions will need to consider ocean conditions at seasonal and yearly periods and not just decadal time scales
- Because Global Warming could affect duration and variability in large scale forcing, managers of fishery resources will need faster responding forecasting tools?
- An example of one such forecasting tool documents current ocean conditions and potential impact of salmon survival 1 to 2 years ahead of their actual return (See webpage www.nwfsc.noaa.gov)

## Review of Last Years (2007) Ocean Conditions: off to a great start but fizzled in June 

- Winter not very stormy
- Upwelling began very early (March) but then weakened throughout the summer months
- Biological transition began in March (to cold water copepod species)
*Neocalanus* everywhere!!!
- Bottom water on shelf very cold and the saltiest in at least 12 years.
- But....SST very high during July-August
- Juv. coho salmon catches in trawl surveys high in June but by September the lowest in 10 years.

## Length of upwelling season and day of biological transition affect salmon survival

## Review of Last Years (2007) Ocean Conditions: off to a great start but fizzled in June 

- Winter not very stormy
- Upwelling began very early (March) but then weakened throughout the summer months
- Biological transition began in March (to cold water copepod species)
*Neocalanus* everywhere!!!
- Bottom water on shelf very cold and the saltiest in at least 12 years.
- But....SST very high during July-August
- Juv. coho salmon catches in trawl surveys high in June but by September the lowest in 10 years.

## Ocean Index – Forecasting Future Salmon Returns

- _[www.nwfsc.noaa.gov](http://www.nwfsc.noaa.gov/)__ (look for ocean indicator link)_

## Ocean Condition Index