The State of the Science: What Oyster Related Tools Do We/Could We Have?

Suzanne Bricker and Chris Moore

Virginia Oyster Restoration Workshop Brock Environmental Center

Virginia Beach, VAMay 2, 2017

Chesapeake Bay Program Partnership Water Quality Assurance Process

Best Management PracticesCBP-approved practices or technologies are approved for credit toward achieving

WIP commitments

Watershed Implementation Plan

States and local partners develop plans to achieve

pollutant reductions

ChesBay TMDL / ModelA plan was developed to

reduce nitrogen, phosphorus, and sediment loads.

End Goal: Meet Water

Quality Standards

Water Quality Assessment2010 Chesapeake Bay did not meet

nitrogen, phosphorus, and sediment water quality standards

Nutrients cause water quality degradation:Too much of a good thing

Potomac River, MD

Florida Bay, FLCaloosahatchee Bay, FL

Corsica River, MD

Excessive algal blooms

Low dissolved oxygen fish kills

Harmful Algal Blooms

Loss of seagrasses due to loss of light penetration

Qiangdao, China

What is a Best Management Practice?

BMPs are practices / technologies used by the Chesapeake Bay Partnership to reduce nutrient pollution to help meet water quality goals.

• Structural BMP: runoff diversions, silt fence, stream buffers, groundcover vegetation, and oysters!

• Non-structural / programmatic BMP: preharvest planning/nutrient application management, manure transport, stormwater management.

Approved BMPS are given ‘credits’ for the amount of nutrients they remove.

BMPS are tools for nutrient reductions

Why the interest in nutrient BMPs?65% of US estuaries have moderate to high level degradation

from nutrients

From: Bricker et al. 2007. Effects of Nutrient Enrichment in the Nation’s Estuaries: A Decade of Change, National Estuarine Eutrophication Assessment Update

• Biological removal of nutrients directly from the water through filtration by shellfish, removes algae and particulates – improves water quality

Oysters as BMPs?

Eastern Oyster,Crassostrea virginica Source: Screenshots from Chesapeake Bay

Foundation time-lapsed video of a reef

Filter Feeders Influence Water Quality

The Stars of our Show: The Mighty Bivalve

Eastern Oyster, Crassostrea virginica Northern Quahog

Mercenaria mercenaria

Ribbed MusselGeukensia demissa

Blue MusselMytilus edulis

Geoduck clamPanopea generosa

Sampling on Chesapeake MD oyster farms providing water quality data and oysters

Map of oyster aquaculture study sites in Maryland

Ongoing study (Parker and Bricker) to estimate the ecosystem service of

(potential) nutrient removal capability of oysters, and the value represented by

the service being provided by oysters

Site 6

Single oyster bottom cage

Single oyster floating cage

Spat on shell bottom

Previous studies

Study sites

Research to help determine oyster related nutrient removal at local scale

Current Current

Width

DepthChl a

POM

Chl a

POM

Sections

1 2 3 n-1 n

Finfish, shellfish, algae

POM

(Ferreira et al., 2007)

algaealgae

particulates particulates

particulates

Models for a single oyster farm estimate production and nutrient removal

Parker and Bricker data used to calibrate to Chesapeake Bay

Simulations to determine potential impact of oyster reef and

aquaculture removal of nutrients in the entire waterbody

Shows feasibility and potential for using oysters as BMP

Research to determine impact of oyster nutrient removal at waterbody scale

System Wide Eutrophication Model2300 boxes

EcoWin2000 grid42 boxes

ApprovedConditionalRestrictedProhibited

Chesapeake Bay13,000 boxes

Long Island Sound

Oyster Calculator: A tool developed from research and modeling

http://oceanwealth.org/tools/oyster-calculator/

Determines water filtration based on area of reef, size and density of oysters. Determines associated fish production.Current conditions and desired conditions – set goals

Oyster reef restoration(want to add aquaculture

of oysters and kelp)

James River, VAJames River, VA

Using bivalve shellfish to improve water quality

Chesapeake Bay Partnership Program convened Oyster BMP Expert Panel in 2015

Best Management PracticesCBP-approved practices or technologies are approved for credit toward achieving

WIP commitments

Watershed Implementation Plan

States and local partners develop plans to achieve

pollutant reductions

ChesBay TMDL / ModelA plan was developed to

reduce nitrogen, phosphorus, and sediment loads.

End Goal: Meet Water

Quality Standards

Water Quality Assessment2010 Chesapeake Bay did not meet

nitrogen, phosphorus, and sediment water quality standards

Oyster BMP Expert PanelEvaluates reduction

effectiveness of proposed BMPs following the CBP

BMP Review Protocol

Oyster nutrient and sediment removal processes under evaluation

1.Tissue and shell nutrient content 2.Denitrification rates associated with oyster reefs 3.Burial in sediment

•First focus was nutrients removed via tissue of oysters harvested from private oyster aquaculture practices.

•Panel reviewed existing studies and data to determine tissue nitrogen and phosphorus content.

•Panel review continues.

Oyster BMP Expert Panel First Recommendations released December 19,

2016 • Decision framework illustrating the process by which nutrient removal recommendations will be generated.

• Recommended amounts of nutrient removal to be credited by the Chesapeake Bay Program for oyster tissue:

• Off-bottom private oyster aquaculture using hatchery-produced oysters

• On-bottom private oyster aquaculture using hatchery-produced oysters

• On-bottom private oyster aquaculture using substrate addition

(Under discussion whether reefs will be allowed credits)

• Derived from oyster growth data from Chesapeake Bay locations.• Determined five size class ranges based on shell height.

The Panel also recommended a methodology to determine site-specific estimates.

BMP NameLbs N Reduced/ millionmillion Oysters

Harvested

Lbs P Reduced/ millionmillion Oysters

Harvested

Diploid Oyster Aquaculture 2.25 Inch 110 22

Diploid Oyster Aquaculture 3.0 Inch 198 22Diploid Oyster Aquaculture 4.0 Inch 331 44

Diploid Oyster Aquaculture 5.0 Inch 485 44Diploid Oyster Aquaculture ≥ 5.5 Inch 683 66

Triploid Oyster Aquaculture 2.25 Inch 132 22Triploid Oyster Aquaculture 3.0 Inch 287 22Triploid Oyster Aquaculture 4.0 Inch 573 66

Triploid Oyster Aquaculture 5.0 Inch 970 110Triploid Oyster Aquaculture ≥ 5.5 Inch 1,477 154

Recommended Default Estimates for Nutrient Credits

Triploid oysters have greater nutrient tissue content than diploid oysters of same shell height because they have greater tissue biomass.

What does this mean for water quality management programs ?

• Research and sampling support development and improvement of tools for successful water quality management

• States can now use harvested oyster tissue from aquaculture as a nutrient BMP in Watershed Implementation Plans, can pursue inclusion in nutrient trading programs

• Models (FARM, Chesapeake Bay Model, Oyster Calculator) for predicting ecosystem services currently and with increased aquaculture production or area of restored reefs – assists setting restoration goals and forecasting results

• Oyster Calculator to be expanded for use in oyster related nutrient restoration – reefs and farms

Acknowledgements – Thank You!!

• Don Webster and organizers of

Watermen’s Trade Show seminar

• Chesapeake Bay Partnership

• Oyster Recovery Partnership – Julie

Reichert and Ward Slacum

• Jeffrey Cornwell and other Oyster BMP

Panel Members

• Julie Rose, NOAA NMFS Milford Lab

• Oyster growers who contribute to research