# Presentation: 555817

## Nate Mantua
JISAO Climate Impacts Group
University of Washington 
NOAA Climate and Living Marine Resources Workshop Pacific Marine Environmental Lab
May 14,  2008     Seattle, WA

- Nate Mantua
- JISAO Climate Impacts Group
- University of Washington
- NOAA Climate and Living Marine Resources Workshop Pacific Marine Environmental Lab
- May 14,  2008     Seattle, WA

**Climate considerations in the management of anadromous fishes in the Pacific Northwest**

## Outline

- A bit of background
- Short term harvest planning
- Long-term recovery planning
- Water resources and hatchery operations

**The Ocean Phase: most of a **
**salmon’s life, typically half the**
**mortality, and nearly all the growth**

## Salmon hatcheries - not to be confused with fish farms

## Abundance varies

- Salmon fisheries are managed at the level of stocks (or independent population groups)
- Stock-sizes vary, so the success of abundance-based management depends in part on accurate pre-season run-size forecasts
- and accurate stock distribution forecasts for mixed stock fisheries

- The abundance of Pacific salmon has likely been at historic highs since the 1980s
- Hatcheries have contributed ~60% of the increase
- The ocean’s carrying capacity for salmon appears to have doubled!
- From Nathan Taylor UBC Fisheries Centre

**Millions of adults**

## A North-South see-saw in salmon production

- Warm PDO

- Cool PDO

- Warm PDO

- ???

- Cool PDO

**spring chinook returns to the Columbia River mouth (1000s)**

**Alaska pink and sockeye catch (millions)**

**Notes:**
Alaska catch data from Alaska Dept of Fish and Game reports as compiled by Steven Hare (1910-2001)
Columbia River spring chinook returns estimated by ODFW and provided to me by John Harrison at the NW Power Council. 

Data shown have been smoothed with a 5 year running average,2  endopoints simply repeat data at end of the series so they are not true 5 year running averages.

## These are hard times for west coast salmon and salmon fisheries

- Wild salmon abundance now just a few percent of historic levels, and hatchery programs have only partially mitigated for the lost abundance
- 1990s ushered in the era of ESA listings
- 28 of 52 west coast ESUs currently listed as either threatened or endangered with extinction under the ESA
- 1990s also ushered in an era of sharply reduced harvest opportunities for west coast salmon fishers

## Klamath River fish kill 2002

- Disease, high fish densities, low flows and a very warm river resulted in massive kill of adult chinook salmon in the lower Klamath River

- Conservation concerns over the offspring from the 2002 returns led to a curtailed CA/OR chinook season in 2005, and sharp restrictions in 2006

- www.oregonwild.org

**Notes:**
“Our findings are very similar to those of two other reports prepared by the U. S. Fish and Wildlife Service and the Yurok Tribal Fisheries Program,” said Steve Turek, a DFG senior environmental scientist and one of the authors of the report. “We found that the primary cause of the fish-kill was a disease outbreak caused by two pathogens brought on by stressful environmental conditions and high densities of fish.”

The two pathogens responsible for the death of more than 33,000 adult salmon and steelhead in September 2002 were the myxozoan parasite Icthyopthirius multifilus commonly referred to as Ich, and the bacterial pathogen Flavobacterium columnare referred to as Columnaris.
These pathogens are common in aquatic systems and are present at all times in the Klamath River.
The report finds that unusually low flows, low river volumes and an above-average run of salmon resulted in abnormally high fish densities in the lower 36 miles of the Klamath River. Apparently, large numbers of fish congregated in the lower river one to two weeks before the onset of the fish-kill.

**Notes:**
1 The closures south of Cape Falcon, in northern Oregon, are due to a sudden, unprecedented decline in the number of Sacramento River fall Chinook returning to the river this year.  The stock is the driver of commercial and recreational salmon fisheries off California and most of Oregon. The minimum conservation goal for Sacramento fall Chinook is 122,000 - 180,000 spawning adult salmon (this is the number of salmon needed to return to the river to maintain the health of the run). As recently as 2002, 775,000 adults returned to spawn. This year, even with all ocean salmon fishing closures, the return of fall run Chinook to the Sacramento is projected to be only 54,000. 

## Forecasts for short-term (3-6 month) harvest and allocation planning

- pre-season run-size predictions for every river: *“how many fish will there be in the ocean this summer fishing season?  Whose fish are they? How much protection do depleted stocks need?”*
- run-size forecasts are based on assumptions about productivity trends (typically a persistence forecast) and information about the number of spawning adults, jack returns, and juveniles produced in hatcheries ... use fish to predict fish, yet forecast errors are frequently 50-100%!
- No climate information has been formally used, but many studies have looked to “climate indicators” for help in reducing forecast errors

## Oregon (OPI) coho marine survival 

**Persistence forecasts often fail because productivity varies by an order of magnitude...**

**Notes:**
To answer this question we’ve looked at environmental measures that track conditions or processes that may influence survival
Survival: smolt to adult survival of hatchery coho
Return Year:  year adults return to spawn, from 1999 back to 1970 when time series begins; note the declining trend and periods of high interannual variability
We (and others) have gathered empirical evidence showing that OPI coho survival is related to environmental changes that are likely influencing the entire marine food-web, with impacts on predator/prey distributions, abundance, and types. 

## Sept 1997 El Niño

***Sept 1998 La Niña***

- West-coast sub-arctic habitat is dynamic and sensitive to changing wind patterns (frequently influenced by El Niño and La Niña)

## upwelling food webs in our coastal ocean: the California Current

**upwelling food webs in our coastal ocean: the California Current**

**Cool water, weak stratification**
**high nutrients, a productive “subarctic” food-chain with abundant forage fish and few warm water predators**

**Warm stratified ocean, few**
**nutrients, low productivity “subtropical” zooplankton, a lack of forage fish and abundant predators**

**Typically high NW salmon survival**

**Typically low NW salmon survival**

**Notes:**
For the California Current, the broad upwelling ecosystem off the coast of southern British Columbia south to the US/Mexico border, climate variations appear to influence the entire food web. The left panel of this schematic depicts a cool, weakly stratified upper ocean. Nutrients are easily upwelling into the surface layer, and these conditions coincide with a highly productive subarctic food web. Predation pressure on juvenile salmon (smolts) is slight, in part because of an abundance of other smolt-sized forage fish (herring and anchovies) and a relative lack of migratory predators like hake and jack mackerel.  The net result is high smolt survival and excellent feeding conditions for maturing salmon.
In contrast, warm periods bring a sharply stratified coastal ocean which inhibits the upwelling of deep nutrient rich water, thereby limiting phytoplankton productivity. The warm water eras also see a dominance of “subtropical” zooplankton species, a relative lack of forage fish, and an influx of warmwater predators like hake and jack mackerel that are typically found to the south or in offshore waters. The net result is poor smolt survival due to intense predation pressure (by fish and diving birds), as well as poor growth for maturing salmon. 

## coastal ocean impacts on coho marine survival (Logerwell et al. 2003, Fish. Oceanogr.)

**1000 juvenile**
**Salmon (smolts)**

**10’s to 100’s post-smolts early summer**

**A few to ~100 adults in 2nd summer**

_**key factors**_**? **
**Stratification **
**spring transition date**
**spring winds, upwelling and transport**

**?**

- 1st spring at sea

- 1st winter at sea

_**key factors**_**? **
**Stratification **
**winter winds, downwelling and transport**

**?**

**coastal ocean impacts on coho marine survival ****(Logerwell et al. 2003, Fish. Oceanogr.)**

## 4 index Ocean Conditions Model  “hindcasts” for OPI coho marine survival, 1969-1998   

- Logerwell et al. 2003, Fish. Oc.

**R****2****= .75**

**Empirically based models often do a good job “explaining” the past with environmental factors, but errors are generally large in forecast mode**

**Notes:**
However, we have constructed a general additive model based on non-parametric partial regressions between each factor and the OPI survival time series. The resulting hindcasts from this model capture a significant amount of the interannual variability, the absolute values of OPI survival, the long-term decline, and the persistently low survival rates in the 1991-1998 period.

## Coho Forecasting Systems

**Coho Forecasting Systems**

- Coastal Ocean Conditions
- Sea surface temperatures
- Sea level
- Nearshore winds

**Oregon coho salmon survival**

- Plankton surveys

- http://www.cses.washington.edu/cig/fpt/orcohofc.shtml

**Notes:**
El Niño (La Niña) winters: intense (weak) Aleutian Low; low (high) streamflows; weak (intense) trade winds, coastally trapped warm (cold) water currents; warmed (cooled), strongly (weakly) stratified upper ocean

General additive model: non-parametric partial regressions between each factor and the OPI survival time series. The resulting hindcasts capture a significant amount of the interannual variability, the absolute values of OPI survival, the long-term decline, and the persistently low survival rates in the 1991-1998 period.

Return year	Prediction	Observed	Explanation
2000	~5%	~2-3%	 lagged response between environmental and ecosystem changes
2001	3-5%	 ballpark of estimates based on last summer’s jack returns
2002	4-8%
	v. close to obs	underest returns by factor of 2
	** direct plankton sampling (communities & biomass) also gave good forecast	

Key variables: spring transition date, spring/summer upwelling winds, 1st winter ocean feeding, water column stratification & coastal ocean transport (winter & spring temps) 

One possible explanation (Pete Lawson) for the overprediction in 2000 relates to a lagged response between environmental and ecosystem changes observed in 1999, the year RY 2000 adults entered the ocean. Early in 1999 upper ocean temperatures off Oregon were cool, the surface was weakly stratified, the spring transition came a little earlier than average, and spring upwelling was well above averge, each factor favorable for high OPI coho SAR rate. In contrast, direct plankton sampling in 1999 found that highly productive subarctic zooplankton communities did not flourish until late-summer 1999 (according to Bill Peterson, NMFS Newport). This delayed biological response may have contributed to our model’s overestimate of the actual SAR rates.  In the spring of 2000, the subarctic zooplankton communities were already flourishing off Newport, so 2001 predictions may not overpredict. 

Increased returns of Col. Basin spring chinook in 2000 and 2001--and our results--provide compelling evidence that the “persistence forecast” used in the “Doomsday 2001” study was overly pessimistic, at least in part because of climate-induced changes in marine habitat. Abundant streamflow from 1995 through 2000 also likely contributed to improved production for many of the Northwest’s wild salmon populations in streams and estuaries.

An important finding is that variability in winter time SST is uncorrelated with springtime winds and the spring transition date. Springtime upwelling winds and the spring transition date are significantly negatively correlated (-.43), which makes sense because a late spring transition essentially shrinks the number of upwelling days in the April-May-June period under consideration --likewise, an early spring transition extends the number of upwelling days. The spring transition and springtime upwelling winds are weakly correlated with SSTs in the following winter (JFM) season. 
The weak or non-existent correlations between seasons highlights the strong presence of random intraseasonal variations in coastal ocean conditions in the NE Pacific. 

## Lessons learned

- Time and space scale of climate information provided must match the scale of management decisions in order to be useful
- Our basin-scale research results were inappropriate for local scale management decisions
- Collaborating with a fishery scientist charged with supplying pre-season salmon predictions solved our scale mis-match problem
- A better understanding for the complexity of the climate impacts on salmon pathway allowed for a sobering assessment of predictability limits
- Key aspects of ocean conditions for coho salmon _are not likely predictable_, and this result highlights the importance of monitoring

## Monitoring Systems

- http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/a-ecinhome.cfm

## Multi-year to decadal forecasts

- Skillful forecasts for the PDO or other modes of Pacific Decadal Variability are of great interest to salmon fisheries
- It is now widely known that climate matters for Pacific salmon, but the lack of skillful forecasts limits the utility of this information

## The longer view: salmon recovery and restoration planning

**Will climate change derail well-intended plans?**
- NOAA Fisheries is crafting *recovery plans* and criteria for getting ESA-listed stocks *delisted*
*Biological Opinions* are crafted to guide water management operations so they comply with ESA mandates in major salmon producing watersheds like the Columbia, Klamath, and Sacramento River basins
- Large-scale conservation planning in the NGO world seeks advice on where to invest effort and $
- Federal, state, and local agencies are looking for guidance on how and where to invest efforts to protect and restore salmon
- Watershed-scale salmon restoration efforts are widespread across the west

##  Snohomish R. Chinook Recovery Planning Case Study

- Evaluate the benefits of alternative habitat restoration plans under different future climate scenarios using linked hydrologic and salmon-lifecycle models
- Battin et al. 2007: PNAS

- Snohomish R.

**Notes:**
- Ultimately, we will build similar models for juvenile chinook as well (more complicated)

## Impacts of Climate Change on Salmon Recovery in the Snohomish River (Battin et al. 2007: PNAS)

- Impacts of Climate Change on Salmon Recovery in the Snohomish River (Battin et al. 2007: PNAS)

- Climate Change will make
- salmon restoration more difficult:
- Decreasing Summer Low Flows
- Increasing Winter Peak Flows
- Increasing water temperatures in critical periods

- Decreasing Spawning Flows

- Increasing Winter Flows

## Additional climate considerations for NW salmon management

_**Water management**_
- In all anadromous river basins, operations seek to balance multiple demands on water supplies; “normative” in-stream flows are the primary goal to optimize salmon production, but this usually conflicts with hydropower, irrigation, flood control, and transportation goals
_**Hatchery operations**_: the NW has enormous investments in this infrastructure, and hatcheries are now the backbone of west coast salmon fisheries.
- Hatchery operations make no allowance for climate considerations
- Climate information has the potential to inform decisions on smolt release number and timing, facilities siting, mothballing failing programs, or building new ones...