For most of us in the shellfish farming business, this story started in the hatcheries. Shellfish hatcheries now supply a large fraction of the seed or young shellfish needed to support commercial production, stocks for shellfish restoration, and some recreational and tribal fisheries. Locations are shown on the map (use pointer).
The inconsistent supply of naturally set oysters and other shellfish means the growers are dependent on the hatcheries, particularly during the lean years. If they are unable to effectively replenish oysters on harvested grounds, production in subsequent years suffers. Also, the oysters enhance habitat on bare mudflats for young crabs, and as we shall see promote the settlement of juvenile oysters and clams.
There is a good connection between increasing CO2 in the air, vs CO2 in the water and pH – as CO2 increases pH decreases.
Estimated aragonite saturation states of the surface ocean for the years 1765, 1995, 2040, and 2100 (Feely et al., submitted), based on the modeling results of Orr et al. (2005) and a Business-As-Usual CO2 emissions scenario.
During the 2009 sampling season, pCO2 was high throughout pretty much the whole sampling period. Corresponding to this, pH and both aragonite and calcite saturation states were low, with aragonite actually undersaturated during 8 of 10 sampling events. The peak spatfall observed (after the expected peak of spatfall for the whole season, since we started sampling so late) started during the best water chemistry conditions we observed last summer and tapered off over the next few weeks as conditions deteriorated. Whether this is coincidental or not, I don’t think we can say based on this data set. Dashed black line in top panel is atmospheric CO2 concentration, dashed red line in 2nd panel is equilibrium or saturation of aragonite and calcite.
During 2010, pCO2 values were much lower than in 2009, and saturation states were higher, with only a few times when aragonite got as low as saturation, and calcite never did. pH was also higher. Peak spatfall again occurred during some of the “best” conditions, in terms of having low pCO2 and relatively high saturation states and pH. The only time with lower pCO2 and higher saturation/pH appears to have been during the very beginning of the sampling season, possibly during a spring bloom in early May (pCO2 actually dipped below atmospheric values, suggesting biological drawdown of CO2).
Puget Sound Restoration Fund
Thanks to Dan Cheney, Simone Alin, Brian
Allen, Bobbi Hudson & Calm Cove Oyster Co.
University of Washington (APL, Oceanography)
Pacific Shellfish Institute
Puget Sound Restoration Fund
Pacific Coast Shellfish Growers Association
Department of Ecology
Funded by the Puget Sound Partnership
Shellfish Hatcheries – Oregon,
Washington, and beyond
Effects on Willapa/Grays Harbor ecology and growers
25% of the CO2 we emit is absorbed by the world’s oceans
Ocean acidification is the gradual decrease in pH due to
Increased acidity leads to increased mortality in calcium
dependent creatures – shellfish, plankton, corals, algae
The Manoa Loa data and ocean acidity
The Acid Ocean
1950 1960 1970 1980 1990 2000 2010 2020
y = (1.738 ± 0.0293)x – 3105.9
R2 = 0.94
y = (1.855 ± 0.224)x – 3364
R2 = 0.310
y = (-0.0019 ± 0.00025)x + 11.82
R2 = 0.265
Mauna Loa atmospheric CO2 (ppmv)
Aloha seawater pCO2 (µatm)
Aloha seawater pH
•Water upwelled off coast is loaded with more CO2 than
anywhere else in the world (10% higher than Atlantic).
•The North Pacific is at the end of a deep circulation line.
•It’s full of old water (cold, salty, CO2-rich, low pH).
Increasing acidity from
CO2 lowers saturation level
Shelled organisms need
high aragonite to grow.
mortality when aragonite
values decrease and their
aragonite shell dissolves.
Puget Sound Partnership funded an oyster monitoring
project during 2009-2010 settlement seasons
Big Cove, Totten Inlet
Dabob Bay, Hood Canal
Weekly samples of seawater, spatfall
and planktonic larvae, May – Sept.
Data correlated with oceanographic
measurements (DIC, TA, pH,
carbonate ion conc. & aragonite sat.)
Fewer Local Food Sources
Increasingly Eutrophic Waters
Troubled Local Economies
No sign yet in Puget Sound that there is an effect
on natural shellfish populations
Monitoring should continue given risk factors
and potential impacts
Answering the question will be tricky given
natural variability in recruitment.
Ocean acidification drives home the reality of a
big, global phenomenon.
Knowing about potential local effects increases
the urgency to reduce global CO2 emissions.
There are outreach opportunities we can and
should seize since climate change and global
warming are THE topics of the day among our
Calm Cove Oyster Co.