“In conclusion, the development of the Sacramento-San Joaquin watershed has greatly simplified and truncated the once-diverse habitats that historically.

“In conclusion, the development of the Sacramento-San Joaquin watershed has greatly simplified and truncated the once-diverse habitats that historically supported a highly diverse assemblage of populations. The life history diversity of this historical assemblage would have buffered the overall abundance of Chinook salmon in the Central Valley under varying climate conditions. We are now left with a fishery that is supported largely by four hatcheries that produce mostly fall Chinook salmon.” 1 The closures south of Cape Falcon in in northern Oregon, were due to a sudden, unprecedented decline in the number of Sacramento River fall Chinook returning to the river. 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 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. In 2008, even with all ocean salmon fishing closures, the return of fall run Chinook to the Sacramento was projected to be only 54,000. What caused the Sacramento River fall Chinook stock collapse? (NOAA tech memo 2009)

Climate and Pacific salmon
ENVIR/ATMS/ESS/SMA 585A February 3, 2011

Outline the NW salmon crisis
A bit about biodiversity of salmon and the role of climate in salmon habitat ENSO and PDO Global warming impacts

NRC (1996): Upstream: Salmon and Society in the Northwest
The Northwest Salmon Crisis: commercial landings in the Columbia River 1911 1920’s 30 Millions of pounds landed 1870’s 1988 20 1977 10 1950 1863 1993 NRC (1996): Upstream: Salmon and Society in the Northwest

Why the decline? The industrial economy+natural variability
fur trade, mining, timber harvests, grazing, irrigation, dams, overfishing, poor hatchery practices, poor management and poor ocean conditions (Lichatowich 1999: Salmon Without Rivers) We have reduced opportunities for wild salmon at every stage of their lifecycle (loss of habitat), and we have reduced their capacity for adaptation (loss of species diversity, abundance and distribution through harvests, hatcheries, and habitat loss and degradation)

The climate/habitat/biodiversity ratchet (Lawson 1993)
Habitat quality and quantity, species diversity + Climate variability Fish Population 1900 1950 2000

A highly simplified salmon lifecycle
Freshwater spawning (and then you die) Freshwater rearing (high mortality rates) Migrate to estuaries or quickly to sea (more intense predation) Rapid ocean growth period (or feed another predator) Harley Soltes/Seattle Times

Within the Pacific salmon (Oncohynchus) genus, there is a diverse set of life history types, some of which is organized by species -- but for every rule, there are exceptions. Steelhead and chinook salmon, for instance, have especially wide ranges of life history types within their respective species. Even sockeye, which typically have juveniles that rear in lakes for 1 or 2 years, can also have stream or river type rearing patterns.

Adaptive Traits (Temporal)
There is a diversity of peak smolt migration timing for wild coho for west coast populations Even within a life history pattern, there are many adaptive traits that vary across different stocks of the same species. This map shows the diversity of peak amolt migration timing from freshwater to marine environments) for west coast coho populations. Possible factors leading to variations in smolt migration timing are stream temperature and streamflow patterns in freshwater, the timing of the spring bloom in coastal marine and estuarine systems, or some combination of these habitat factors.

Adaptive Traits (Spatial)
Chinook salmon ocean migration patterns vary by population Adaptive traits can also include behaviors like ocean migration patterns. This set of maps highlights the diversity of ocean migration routes taken by different stocks of chinook salmon from Oregon rivers.

habitat is the template upon which life history diversity is forged
Different populations have evolved different ways of living in different environments Fraser sockeye spawning timing vs. incubation temperature There are clear life history traits shaped by habitat spawning timing, freshwater rearing periods, smolt migration timing, ocean migration patterns habitat is the template upon which life history diversity is forged Incubation temperature Salmon have successfully colonized and occupied each stream type (snow-melt, rain-dominant, and everything in-between) Different stocks employ distinct life history behaviors tuned to the predictable seasonal rhythms Spawning timing

Freshwater habitat has seasonal rhythms that vary with physiographic setting
Puget Sound Precip Skagit Oct Feb Jun Oct Feb Jun Puyallup Because of the PNW region’s complex topography, the seasonal variations in precipitation yield a wide range of hydrologic regimes. Even within Puget Sound there are vastly different seasonal hydrographs in spite of essentially homogenous seasonal precipitation: the relatively high elevation Skagit basin yields peak runoff in June, when its heavy snowpack melts; the Skagit Basin contains enough low elevation terrain that a second, smaller seasonal peak occurs in late fall/early winter. The Puyallup Basin has more area at lower elevations, but still carries an appreciable snowpack. The balance of terrain yields a pair of seasonal runoff peaks, one in mid-winter, the other in June. The Skokomish River has most of its basin at relatively low elevations, low enough that the basin rarely builds an appreciable snow pack. Seasonal runoff closely matches the seasonal precipitation. Because of consistent sub-freezing winter temperatures in the Columbia Basin, inland PNW streams tend to have an even larger spring/summer runoff peak and an extended low flow period from late summer through early spring. One common factor to all streams in the Northwest is a late summer low flow period. This period is relatively brief in the Skagit, but extended in the Skokomish. Oct Feb Jun Skokomish Oct Feb Jun

Ocean Type Stream Type Chinook Life History (Estuary) (Fall) (Ocean)
Salmon have successfully colonized and occupied each stream type (snow-melt, rain-dominant, and everything in-between) Different stocks employ distinct life history behaviors tuned to the predictable seasonal rhythms; for instance, stream-type (spring run) chinook populations are strongly associated with snowmelt dominated watersheds (or sub-basins). One race, described as a "stream-type" Chinook, is found most commonly in headwater streams of large river systems. Stream-type Chinook salmon have a longer freshwater residency, and perform extensive offshore migrations in the central North Pacific before returning to their birth, or natal, streams in the spring or summer months. Stream-type juveniles are much more dependent on freshwater stream ecosystems because of their extended residence in these areas. A stream-type life history may be adapted to areas that are more consistently productive and less susceptible to dramatic changes in water flow. At the time of saltwater entry, stream-type (yearling) smolts are much larger, averaging 3 to 5.25 inches ( mm) depending on the river system, than their ocean-type (subyearling) counterparts, and are therefore able to move offshore relatively quickly.The second race, called the "ocean-type" Chinook, is commonly found in coastal streams in North America. Ocean-type Chinook typically migrate to sea within the first three months of life, but they may spend up to a year in freshwater prior to emigration to the sea. They also spend their ocean life in coastal waters. Ocean-type Chinook salmon return to their natal streams or rivers as spring, winter, fall, summer, and late-fall runs, but summer and fall runs predominate. Ocean-type Chinook salmon tend to use estuaries and coastal areas more extensively than other pacific salmonids for juvenile rearing. The evolution of the ocean-type life history strategy may have been a response to the limited carrying capacity of smaller stream systems and unproductive watersheds, or a means of avoiding the impact of seasonal floods. Ocean-type Chinook salmon tend to migrate along the coast. Populations of Chinook salmon south of the Columbia River drainage appear to consist predominantly of ocean-type fish. (Ocean) (Spring) Stream Type

Habitat = seasonal rhythms + variability

Climate and freshwater habitat issues
Winter floods: scouring incubation period flows, heavy siltation of redds, flushing alevins, fry and parr out of favored habitat Spring snowmelt freshet: some populations have smolt migrations timed to “ride” the high flows to the ocean Low summer/fall streamflow + high stream temperature: Increased physiological stress, susceptibility to diseases and parasites, reduced rearing and spawning habitat, thermal blocks to adult migration At extreme high temperatures (T > 21°C for prolonged period) salmon die

Coastal upwelling Spring and summer winds from the north cause upwelling of cold, nutrient rich waters into the coastal waters of the western US

The average year in winds
Winter winds and pressure over the North Pacific Summer winds and pressure over the North Pacific L L From these two charts, you can see several important details of the strong seasonal changes in our prevailing winds. In the cold half of the year (okay, we’ll call it winter, but it’s really Oct-April), the dominant feature of the North Pacific surface pressure field is low pressure over the Aleutians. From day to day, you might not see such a large area of low pressure over the Aleutians, but over the course of many days you see the frequent development and eastward tracking of low-pressure cells (storms). The seasonally dominant Aleutian Low brings strong onshore flow into the NW from the west-southwest. Also note that there is a smaller center of high pressure located off the coast of Southern California and Baja. In the warm half of our year, the Aleutian Low and storminess over the north Pacific are much diminished and migrate to higher latitudes. The subtropical High pressure cell off California intensifies and expands northward. High pressure typically brings fair weather. Because winds blow clockwise around High pressure cells in the N. Hemisphere, the surface winds blow from north to south along the coasts of WA-OR-CA, but especially northern CA. Iin summer, the strong onshore flow typical of winter is much less frequent and intense, and in fact quite intermittent. We do see a few days of wet onshore weather in summer, but not many. H H “Subtropical High” “Aleutian Low”

Stonewall Banks Buoy SST
Fickle winds can cause large changes in upwelling habitat on short time-space scales Stonewall Banks Buoy SST June 18 - August 17.5C on July 14 ~11C on July 20 2x2 degree boxes are not adequate to resolve key features of salmon habitat in some locations, while in other locations this resolution is likely adequate at seasonal timescales. Likewise, trends analysis needs to be complemented with a look at long time series for shore station data. Higher frequency variability (at sub-yearly time scales) can be examined with hourly and/or daily buoy winds, and finer spatial patterns can be examined with satellite data. June July August Buoy SST plot courtesy of Pete Lawson 20 July 2005 SST NOAA CoastWatch image

Year-to-Year changes associated with ENSO variations can also be large -- note the 3 to 4 C decline in coastal SSTs between Septembers of and 1999 Sept 1997 El Niño Sept 1998 La Niña 17 13 18 14 15 12 3 to 4 degree C temperature drop along CA-OR-WA coasts between September 1997 and 1998

Warm extremes El Niño cold extremes La Niña

Typical winter winds and jet stream during El Nino winters
An intense Aleutian Low warms and stratifies the coastal ocean

Upwelling food webs in our coastal ocean
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” food web, a lack of forage fish and abundant predators 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. Recently, warm ocean years have generally been poor for NW chinook, coho and sockeye, but good for Puget Sound pink and chum salmon.

West Coast Nekton in Major changes in the distribution of pelagic fishes and squid lead to important “top-down” impacts on coastal food-webs too

A recent visitor that seems to like it here - prior to 1997 they’d never been observed in PNW waters, but were reported to be abundant in California waters in the 1930s. Humboldt Squid, Jumbo flying squid, Diablos rojos (Dosidicus Gigas): a voracious predator that can reach up to 2m in length and weigh up to 45 kg Jumbo squid are members of the flying squid family, Ommastrephidae, and are known to eject themselves out of the water to avoid predators. Jumbo squid are enormous impressive squids that can reach up to 2 m in length and weigh up to 45 kg. They have a large, tough, thick-walled mantle and long arms with hooked powerful suckers each and lightning-fast tentacles. These elusive and mysterious creatures are aggressive predators, which has earned them the nickname "red devils" or "diablos rojos" (from Mexican shrimpers who fish for jumbo squid during the shrimping off season). This name also comes from their red hue when hooked, which is likely used naturally as a camouflage mechanism to keep them from view of predators and/or prey in deep waters and simply the result of them being angry/scared when fished out of the water. Like other cephalopods, they are equipped with chromatophores and are able to change color and flash light to communicate. They also have the ability to squirt ink as a defense mechanism. Image from

New predator-prey interactions
From November 4, 2009 A black bear with a salmon near Tofino, Vancouver Island A black bear with a humboldt squid, also near Tofino, Vancouver Island

ENSO and salmon habitat
El Niño winters: intense Aleutian Low low snowpack and streamflow Weak tropical trade winds, coastally trapped warm water currents warmed, strongly stratified upper ocean for PNW coast La Niña winters: weak Aleutian Low, abundant snowpack and streamflow intense tropical trade winds, coastally trapped cold water currents cooled, weakly stratified upper ocean for PNW coast

Decadal variations in spring upwelling
In the 20th C. springtime upwelling winds varied strongly at interdecadal timescales (partly in step with the PDO) Schwing et al. 2006: GRL strong weak

Pacific Decadal Oscillation (PDO)
17/04/2017 Climate variability has a powerful influence on salmon production -- just a 1 to 2˚C swing in ocean temperatures is associated with a doubling of salmon biomass between “warm” and “cool” eras of the Pacific Decadal Oscillation Pacific Decadal Oscillation (PDO) Total Pacific salmon biomass Hatchery contributions For the North Pacific as a whole, salmon catches (and estimates of total abundance) peaked in the early and late 20th century, with a period of relatively low catches and abundance from the mid-1940s to the mid-1970s. There is compelling evidence that climate, specifically shifts between warm and cool phases of the Pacific Decadal Oscillation, was a primary factor behind these large changes in salmon production. Note that the changes in North Pacific ocean temperatures were approximately +/-1 degree C from the century long average, while associated changes in winter and springtime surface temperatures over Alaska and western Canada were a bit larger. From a 20th century climatological perspective, warm periods in Alaska favored increased salmon production for most regions, while warm periods in the PNW favored decreased salmon production in the PNW. It is important to recognize the fact that there are many factors influencing Pacific climate (like short-term El Nino events for instance), including century long warming trends. Data from Eggers; Figure from Schindler et al (2008): Fisheries 28

Global Warming Impacts on freshwater habitat

Changing Watershed Classifications: Transformation From Snow to Rain
Warming winter temperatures will cause snowlines to rise, a shift to more rainfall (and direct runoff) and less snowpack and snowmelt runoff in spring This set of maps was produced as part of the Columbia Basin Climate Change Scenarios project * Based on Composite Delta Method scenarios (multimodel average change in T & P) Source: Alan Hamlet, Columbia Basin Climate Change Scenarios Project Map: Rob Norheim

Dramatic changes in snowmelt systems
Snowmelt rivers become transient basins Transient basins become rainfall dominant Projected changes in the B1 scenario for the 2080s are similar to those for A1B 2040s Also note that these maps are showing ratios of snowpack to total oct-mar precipitation, so they aren’t accurately depicting streamflow Patterns for basins that cross into neighboring states or Canada Mantua et al 2010: Climatic Change

Mantua et al 2010: Climatic Change
Summer base flows are projected to drop substantially (5 to 50%) for most streams in western WA and the Cascades The duration of the summer low flow season is also projected to increase in snowmelt and transient runoff rivers, and this reduces rearing habitat Mantua et al 2010: Climatic Change

Models project more winter flooding in sensitive “transient runoff” river basins that are common in the Cascades Likely reducing survival rates for incubating eggs and rearing parr A warmer climate is likely to have impacts on flooding, stormwater, and wastewater management. Rising snowlines with warmer temperatures will increase runoff during storm events as more precipitation falls as rain and less as snow. The reduction in spring snowpack due to warmer temperatures, by itself, will likely reduce the risk of springtime flooding, but that factor will be opposed by the likely increases in spring soil moisture that come with early snowmelt. Theory and climate modeling studies also suggest that a warmer climate will bring an increased intensity of precipitation with individual storms, and if this general impact takes place in Washington it will increase the risk of urban flooding and combined sewer overflows. Mantua et al 2010: Climatic Change

Western Washington’s “maritime” summer climate becomes as warm as today’s interior Columbia Basin, temperatures in the interior Columbia Basin become as warm as today’s Central Valley in California 1980s These statements refer to summertime air temperature projections for the 2040s under composite A1B emissions scenarios; a similar amount degree of warming is projected for the 2080s under the composite B1 emissions scenario Mantua et al 2010: Climatic Change

Number of weeks T > 21C Thermal stress season Extended periods with weekly average water temperatures > 21C the season of thermal migration barriers for migrating salmon predicted to last up to 12 weeks in the mainstem Columbia River Weeks with T > 21C In recent years, periods with T>21 were confined to July and August; with projected warming, this periods broadens to span mid-June through mid-September Mantua et al 2010: Climatic Change

will global warming degrade marine habitat for salmon?
Back to the Pacific will global warming degrade marine habitat for salmon?

IPCC multi-model ensemble SST projections
1 degree of warming projected throughout the global tropics, 1.5 in the eastern eq. pacific and more Under a conservative (A1B) greenhouse gas emissions scenario, climate models typically project 2 to 3 ºC warming by 2090s for the north Pacific

Species distributions change with temperature
134 lb marlin caught 40 mi. west of Westport, WA, Sept 2, 2005 Photo obtained from the Seattle Times web-archives David Horsey’s recent cartoon depicts a pair of conflicted anglers in the 2040s lamenting the loss of salmon to global warming but appreciating the appearance of more tropical gamefish. It’s a funny take on what appears to have at least a germ of truth behind it… On September 2nd of this year, a lucky group of anglers targeting albacore 40 miles west of Westport caught a 134lb striped marlin. Marlin have been rare off the coast of Washington, but another striped marlin was brought to Westport in the exceptionally warm September of 1997. From the Seattle Post-Intelligencer, October 20, 2005

Global warming and Coastal Cooling?
Because the land warms faster than the ocean, this may intensify the sea level pressure gradient between the oceanic High and Thermal Low over land, which would intensify upwelling winds… which would cool the ocean even more, and further increase the temperature contrast West coast H L “Oceanic High” Over Cooler water “Thermal Low” Over Warm land See Bakun, Patterns in the Ocean, pages See Bakun, Patterns in the Ocean, p

IPCC multi-model ensemble summer and winter SLP projections
2090s A1B IPCC models Taken as a group, IPCC climate models project trends to a stronger North Pacific High in summer, and a deeper Aleutian Low in winter JJA H DJF 1 degree of warming projected throughout the global tropics, 1.5 in the eastern eq. pacific and more L H

What are the biological implications of ocean acidification?
Barrie Kovish Pink Salmon Reduced calcification rates for calcifying (hard-shelled) organisms and physiological stress Shifts in phytoplankton diversity and changes in food webs Reduced tolerance to other environmental fluctuations Potential for changes to fitness and survival, but this is poorly understood Vicki Fabry Pteropods The subarctic waters in the North Pacific (where Pacific salmon are found) are among the most vulnerable in the world to ocean acidification. This is due to deep ocean currents that transport “old” carbon rich waters to the N. Pacific, cold temperatures that increase the solubility of CaCO3, and intense upwelling that brings these carbon rich waters to the surface where most of the biological activity is concentrated. Because of this situation, the saturation states for the carbonate species aragonite and calcite are low or even marginal for calcifying organisms in the upper ocean --- a low saturation state for carbonates means calcifying organisms have difficulty forming their shells, and undersaturated water can actually be corrosive and dissolve their shells; at greater depths the carbon-rich low pH waters are corrosive to calcifying organisms. An increased uptake of atmospheric CO2 by the oceans will continue to decrease the saturation state for carbonates, bringing corrosive waters closer and closer to the surface. Experiments have shown that pteropods, a small free-swimming snail that is an important prey item for salmon, have shells that dissolve when exposed to low pH waters like those projected for later this century. Pteropods are a dominant This could compromise food webs in ways that are detrimental to salmon growth, fitness, and survival. Coccolithophores Copepods (Slide provided by Dick Feely, NOAA) 41

Lots of uncertainty in future ocean habitat for salmon
Upwelling winds, El Niño and the Pacific Decadal Oscillation - will these behave as they have in the past century? How will ocean acidification impact salmon food-webs? How might salmon behavior change if the seasonal cycle became highly variable? Or if there was a distinct lack of seasonality in the climate and habitats they occupy? Would there be a “general” life history behavior?

Cumulative impacts across the full life-cycle of salmon
Floods, warmer temps Thermal barriers to migration for salmon: 70-72F (21-22C) The key for understanding climate change impacts on salmon comes with understanding the cumulative impacts of all the factors that influence salmon during their life cycle. Climate change (global warming) can be considered as being a part of habitat change and habitat degradation, but the ultimate impacts of climate change on NW salmon cannot be assessed in isolation from the impacts of other factors influencing habitat, or harvest and hatchery practices. This framework also suggests that at least some of the negative impacts of climate change on salmon can be mitigated by alleviating existing negative impacts on salmon that come with other aspects of habitat, hatchery and harvest practices. Early snowmelt; lower+warmer summer/fall flows Warmer, lower streamflow Warmer, more stratified, but upwelling? Acidification?

Impacts will vary depending on life history and watershed types
Low flows+warmer water = increased pre-spawn mortality for summer run and stream-type salmon and steelhead Clear indications for increased stress on Columbia Basin sockeye, summer steelhead, summer Chinook, and Lake Washington sockeye and Chinook, and coho and steelhead more generally Increased winter flooding in transient rain+snow watersheds a limiting factor for egg-fry survival for fall spawners + coho and steelhead parr overwinter survival in high-gradient reaches Harley Soltes/Seattle Times

“In conclusion, the development of the Sacramento-San Joaquin watershed has greatly simplified and truncated the once-diverse habitats that historically.

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“In conclusion, the development of the Sacramento-San Joaquin watershed has greatly simplified and truncated the once-diverse habitats that historically.

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