Week 5 - Humans and the Salmon Resources of the PS

Ray Hilborn

Bill Hershberger

Bill Pinnix

February 3, 1999

Harvest - Hilborn

Hatcheries and Aquaculture - Hershberger

Putting the physics and biology together - Pinnix

Hatcheries

I. Hatcheries have been a part of the salmon production system in Puget Sound for a long time.

A. Late 1800's when the first salmon hatcheries became operational.

(First sockeye salmon culture conducted at Baker Lake Station on the Skagit River in 1896. This station was closed in 1933, but was the source of sockeye for Lake Washington.)

(Nooksack and Samish River hatcheries "on-line" in 1899; Green River hatchery in 1905)

• Started as a response to diminishing salmon resources.
• Expansion generally followed that on the Columbia River.

B. Developed into a rather large system for salmon production.

(e.g., about 1.9 billion chinook salmon released in the Puget Sound region from 1950-1993)

1. Major differences among salmon species.

• Rearing differences on Table - major point is that cost and effort with each species is different and it is difficult to generalize about culture without taking this into consideration!

2. Estimated production of each species:

• Coho - from 1987-91 produced about 43 million annually [some larger stations (e.g., Minter Creek, Puyallup, Issaquah release 2-4 million annually]
• Pinks - One station on Hood Canal producing from 15,000 to 4 million per year.
• Chinooks - 1953-93 produced about 1.8 million annually.

II. Characteristics of the Puget Sound hatcheries.

A. Produce large numbers of fish to support the fishery at a high rate of harvest.

• [e.g., estimated that the recent (1982-89) total harvest rate on chinook and coho salmon returning to Puget Sound is 0.6-0.8]

B. Presence of Puget Sound as an estuary enhances survival of some species.

• [Data from Connie's paper showing high survival of coho salmon from Puget Sound - does not appear to be a situation that can be generalized across species (may be a result of a lack of data!)]

C. Has been rather large amount of exchange of stocks within the region and relatively few introductions from outside the region.

• Shortly after damming of the Columbia River there was an influx of, particularly chinook salmon from Eastern WA. However, has pretty much stopped.
• Overall, <1% of chinook introductions from out of the region (varies somewhat with hatchery and species)
• Notable donor stocks - Green River coho and chinook Skykomish and Skagit coho salmon
• Mention problems presented with developing ESU status.

D. Variation among species sub-groups not as diverse as in other locations.

• Summer/Spring run chinook found in White, Skagit, Skykomish, Skokomish, Nooksack and Dungeness Rivers. Also, not large populations! May be a reflection of a less varied environment than in the Columbia (also, smaller rivers!)

Aquaculture

I. Attributes of Puget Sound that facilitate aquaculture.

A. High quality marine environment.

• Somewhat of estuarine conditions!

B. Somewhat sheltered, esp. in small coves.

• Seas not as high and severe

C. Productive environment

• Especially in South Puget Sound where flushing rate is lower

D. Ready access to markets for products.

II. Major aquaculture production within Puget Sound

A. Salmon net-pen culture

1. Initiated with Pacific salmon, but now mostly Atlantic salmon.

• Production in 1995 - almost 10 million pounds (92% Atlantic salmon)

B. Shellfish culture

1. Oldest form of aquaculture in the Pacific Northwest.

• [Began about 150 years ago on Native Olympia oyster (Ostrea lurida)]
• Combination of overharvest and pollution necessitated a change to the Japanese oyster (Crassostrea gigas) in 1920's.

2. Primarily oysters, but reasonable amount of clams and mussels

88% oysters and 12% "other" shellfish

3. Major factors explaining success:

• Ownership of land (tideland)
• Uses inherent "energy" in the marine system (i.e., phytoplankton)

III. Future outlook for aquaculture in Puget Sound

A. Difficult - mainly due to urbanization and development.

Introduction Climate Background

Pacific Basin Climate

PDO ­ Decadal Scale

ENSO ­ Interannual Scale

References:

1.Mantua, N. J., S. R. Hare, Y. Zhang, J. M. Wallace, and R. C. Francis. 1997. A Pacific interdecadal climate oscillation with impacts on salmon production. Bulletin of the American Meteorological Society, 78(6): 1-11.
2. Trenberth, K. E. and J. W. Hurrell. 1994. Decadal atmosphere-ocean variations in the Pacific. Climate Dynamics 9, 303.

Large Scale Surface Currents Driven by Climate Patterns

Bifurcation of Subarctic Current

Alternates at Decadal scale

References:

1.Wooster, W. S. and A. B. Hollowed. 1995. Decadal-scale variations in the eastern subarctic Pacific. I. Winter ocean conditions, p. 81-85 In R. J. Beamish [ed.] Climate change and northern fish populations. Canadian Special Publication of Fisheries and Aquatic Sciences, 121
2.Chelton, D. B. and R. E. Davis. 1982. Monthly mean sea level variability along the west coast of North America. Journal of Physical Oceanography. 12(8), 757-784.

Salmon and Climate

Basin wide salmon production related to climate-ocean patterns

Alaska and PNW salmon production are out of phase

References:

1. Beamish, R. J., and D. R. Bouillon 1993. Pacific salmon production trends in relation to climate. Canadian Journal of Fisheries and Aquatic Sciences, 50, 1002-1016.
2. Hare, S. R., N. J. Mantua, and R. C. Francis. Inverse production regimes: Alaska and West Coast Pacific Salmon. Fisheries. 24(1), 6-14.

Climate and Puget Sound

Physical Oceanography of Puget Sound

Sills partition Puget Sound into subbasins

Whidbey Basin highly stratified, most estuarine

Hood Canal very productive, slow circulation

South Sound

Main Basin biological engine of Puget Sound

Main Basin

Estuarine Circulation
Net surface flow seaward
Net bottom flow landward
Upwelling
Admiralty Inlet
Brings Nutrients into Puget Sound
Tacoma Narrows
Brings phytoplankton to surface
Decadal scale changes in Puget Sound circulation

Exchange of water between Puget Sound and the Strait of Juan de Fuca is driven by surface density differences. The larger the difference, the greater the exchange.

Density controlled by
Temperature and salinity
Positive PDO
Decreased freshwater input
Decreased estuarine flow
Increase in stability
COUNTERINTUITIVE!!
Negative PDO
Large Freshwater Input
Enhanced estuarine flow
Enhanced mixing
Decrease in stability

References:

1.Ebbesmeyer, C. C., C. A. Coomes, G. A. Cannon, and D. E. Bretschneider. 1989. Linkage of ocean and fjord dynamics at decadal period. Geophysical Monograph 55: 399-417.

Biological Oceanography of Puget Sound

Food Web

Two main pathways

Fish producing pathway
Non-Fish producing pathway

Optimal conditions for plankton bloom

Intermediate stability
Moderate runoff
Neap tides
Light northerly winds
Sunlight
Optimal Stability VS Optimal Mixing
Not mutually exclusive

References:

1. Strickland, R. M. 1983. The Fertile Fjord. Seattle, Washington, University of Washington Press.
2. Gargett, A. E. 1997. The optimal stability 'window': a mechanism underlying decadal fluctuations in North Pacific salmon stocks? Fisheries Oceanography 6: 9.