Wellfleet Shellfish – Part I SERI Meeting 11-22-13

Cape Cod Cooperative Extension & Woods Hole Sea Grant Marine Program: • Diane Murphy • Joshua Reitsma • Abigail Franklin

Shellfish and Climate Change

• Species’ range expansion – Includes shellfish pests/predators/diseases(e.g. Dermo) – Some formerly Gulf or mid-Atlantic now as far north as Maine & Canada

• Temperatures: warmer seasons/waters may create more favorable conditions for human pathogens (e.g. Vibrio spp.)

• Projections of sea level rise raise concerns over low-lying communities & infrastructure (septics & sewage treatment)

• Projections of increases in rainfall and frequency & intensity of storm events – Create crop losses and additional harvest restrictions and closures (e.g.

hurricanes Katrina & Sandy)

Ocean Acidification

• CO2 readily dissolves in seawater – leading to lower pH levels • Calcium carbonate can dissolve in sufficiently acidic water

– Difficult for shell-forming organisms to grow in these conditions – Particularly difficult for larval stage during shell formation/metamorphosis

• WA State hatcheries experiencing sig. mortalities due to upwelling of corrosive, acidic, deep-ocean waters

• East & Gulf coasts not subject to this same upwelling but can

have acidification of estuarine sediments – challenging nearshore shellfish populations

Economic Impact of OA

Wellfleet – Observations & Research

Newer Arrivals

• Introduced/ invasives

– Releases

– Ballast

– Shipping/boating

• Favorable conditions can enable range extensions

Some of Many!

Cochlodinium polykrikoides

• Warm waters

– favor growth of algal cells

– abundant nutrients fertilize their growth

• Wind & tidal currents confine cells to dense aggregations

‘Rust Tide’ Effects

• Slow or arrested growth

• Oyster shell overgrowth

• Seed mortalities

• Deposits on gear and animals

Wellfleet Long-Term Data

• Disease Testing – ongoing – Quahogs and oysters

• Shellfish Habitat Assessment – 2003 – present – Yearly July 1 – September 1 period – Oysters – Quahogs (mesh + unmeshed treatments)

• YSI Water Monitoring – L-Pier 2004 – present – Egg Island channel

Shellfish Disease Response

• QPX and hemocytic leukemia (neoplastic disease)

• Dermo, MSX, JOD

• Vp (time:temperature relationship)

– Analysis using MPN and PCR

Bamboo Worm (Clymenella torquata)

• Native Range: Bay of Fundy to North Carolina (Gosner 1978)

• Segmented polychaete worm

• Size: To 6 inches (150mm)

• Tube-building lives upside down in sediment

• Detritus feeders

– Ingest sand & mud as they burrow

– Excess sand & mud deposited outside tube

• Non-native on west coast – problems for oyster growers

Bamboo Worms – Core Samples

B = bamboo worms and their casings ONLY

O = all other worms and leathery casings combined

Four-Eyed Amphipod (Ampelisca)

• Native amphipod

• Size: up to 20 mm (3/4”)

• Abundant offshore, lower intertidal, muddy/sandy sediment

• Several species in this genus

• Build parchment-like tubes

• Can foul mesh – suffocate clams – within only a few weeks (Kraeuter & Castagna, 2001)

• May enhance abundance of quahogs in offshore wild populations – found predators were >7 x more abundant in sand vs. mud habitat (MacKenzie et al., 2006)

Shellfish Habitat Assessment

• Why assess shellfish habitat?

– Habitat value affects dredging projects

– Habitat value affects dock permitting

– Optimize shellfish restoration efforts, including fisheries management

– Help shellfish farmers maximize yields of cultured shellfish

Shellfish Habitat Assessment Tool

• Shellfish farmers & resource managers noticed differences in shellfish growth & survival – Causes

• different seed, culture methods, or skill levels?

• due purely to differences among sites?sponsedeveloped low-cost tool to quantitativly assess habitat

– Ten years with over twenty sites tested • incl. East Harbor, Hatches Harbor, Herring

River, Pamet River • four standard sites adjacent to aquaculture

zones – Barnstable Harbor – Brewster – Cape Cod Bay – Orleans – Pleasant Bay – Wellfleet Harbor

SHA Gear

12” 4” T-connectors

6”

1” PVC cut to the following lengths:

(12) – 12” lengths

(6) – 6” lengths

(12) – 4” lengths

(20) – T-connectors

Shellfish Habitat Assessment

• Concluded 11th year of research

– 4 long-term sites

• Site-specific variations in shellfish growth & survival

Shell Length (mm) – Oysters 2003-2012 Oyster Shell Length

Year

2002 2004 2006 2008 2010 2012

She

ll Le

ngth

(m

m)

0

10

20

30

40

50

60

70

Barnstable Harbor

Cape Cod Bay-Brewster

Pleasant Bay

Wellfleet Harbor

DGR (mm/day) – Oysters

2003-2012 Oyster Daily Growth Rates

Year

2002 2004 2006 2008 2010 2012

Daily

Gro

wth

Rate

(m

m/d

ay)

0.0

0.2

0.4

0.6

0.8

Barnstable harbor

Cape Cod Bay-Brewster

Pleasant Bay

Wellfleet Harbor

Wellfleet Cumulative Survival Wellfleet Harbor SHA Cumulative Oyster Survival and Mortality

Year

2002 2004 2006 2008 2010 2012

Pe

rce

nt

(%)

0

20

40

60

80

100

120

Live

Dead - unknown cause

Dead - drilled

Dead - cracked

Dead - moon snail

Survival & Mortality by Year

Barnstable Harbor SHA Oyster Survival and Mortality by Year

Year

2002 2004 2006 2008 2010 2012

Perc

en

t (%

)

0

20

40

60

80

100

120

Live

Dead - unkown cause

Dead - drilled

Dead - cracked

Dead - moon snail

Cape Cod Bay SHA Oyster Survival and Mortality by Year

Year

2002 2004 2006 2008 2010 2012

Perc

en

t (%

)

0

20

40

60

80

100

120

Live

Dead - unkown cause

Dead - drilled

Dead - cracked

Dead - moon snail

Pleasant Bay SHA Oyster Survival and Mortality by Year

Year

2002 2004 2006 2008 2010 2012

Perc

en

t (%

)

0

20

40

60

80

100

120

Live

Dead - unknown cause

Dead - drilled

Dead - cracked

Dead - beached

Shell Length (mm) – Quahogs 2003-2012 Average Quahog Shell Length

Year

2002 2004 2006 2008 2010 2012

She

ll Le

ngth

(m

m)

0

5

10

15

20

25

30

Barnstable Harbor

Cape Cod Bay-Brewster

Pleasant Bay

Wellfleet Harbor

DGR (mm/day) – Quahogs 2003-2012 Average Quahog Daily Growth Rate

Year

2002 2004 2006 2008 2010 2012

Da

ily G

row

th R

ate

(m

m/d

ay)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

Barnstable Harbor

Cape Cod Bay-Brewster

Pleasant Bay

Wellfleet Harbor

2003-2009 Wellfleet SHA Quahog Surival by Protection

Year

2002 2004 2006 2008 2010 2012

Perc

en

t S

urv

ival (%

)

0

20

40

60

80

100

120

Mesh

No Mesh

Wellfleet Survival by Protection

2003-2009 Barnstable Harbor SHA Quahog Survival

Year

2002 2004 2006 2008 2010 2012

Perc

en

t S

urv

ival (%

)

0

20

40

60

80

100

120

140

Mesh

No Mesh

%Survival by Protection

2003-2009 Cape Cod Bay SHA Quahog Survival

Year

2002 2004 2006 2008 2010 2012

Perc

en

t S

urv

ival (%

)

0

20

40

60

80

100

120

140

Mesh

No Mesh

2003-2009 Pleasant Bay Quahog Survival

Year

2002 2004 2006 2008 2010 2012

Perc

en

t S

urv

ival (%

)

0

20

40

60

80

100

120

Mesh

No Mesh

Water Quality Monitoring

• Continues at 4 stations: Wellfleet Harbor, Pleasant Bay, Barnstable Harbor, Cotuit Bay

• Up to 8 years of data being put up on website as weekly averages for now

http://www.ysieconet.com/public/WebUI/Default.aspx?hidCustomerID=88

YSI Weekly Means

Real Time Data: http://wqdatalive.com/public/103 Archived Data: http://www.capecodextension.org/marine-programs/water-quality-monitoring-2/archived-data/

Monitoring Water Conditions In-Situ

Vp Factoids

• Ubiquitous – found everywhere

– not water-body specific

• NOT associated with pollution or sewage

• Growth regulated by temperature

• More common in higher salinity and when water temperatures exceed 80oF

• Not all strains cause illness

• Infectious dose = several thousand cells

Refrigeration

• Refrigeration of 45o or below*

– Levels of Vp cells slowly decrease

– Cells can start to die under these conditions

*FDA Interpretive Summary: Quantitative Risk Assessment on the Public Health Impact of Pathogenic Vp in Raw Oysters (July 2005)

FDA Risk Assessment

• Probability of Illness

– Risk <0.001% for consumption of 10,000 Vp cells/serving

• equivalent to 70 Vp cells/gram of oysters

– Probability increases to 25% with consumption of 40 million Vp cells/serving

• Equivalent to 277,000 Vp cells/gram of oysters

– Probability increases to 50% with consumption of 100 million Vp cells/serving

• Equivalent to 694,000 Vp cells/gram of oysters

Current Local Vp Research

Vibrio Seasonality Study (CCCE/WHSG)

Vibrio Time Interval Study (CCCE/WHSG)

Develop more efficient methods of Vp detection (NRAC Grant)

Vibrio Seasonality Study

• Vibrio Seasonality Study (CCCE/WHSG)

– Study to examine effects of ‘season’ on Vp levels in oysters from 2 SE MA locations

– RWU (Dr. Smolowitz) lab analyses

– Initiated June 2013

• Work to continue in 2014

Vibrio Time Interval Study

• Vibrio Time Interval Study (CCCE/WHSG)

– Analysis of Vp levels in oysters at varying time intervals

• 5 hours out of water

• 1 hour back in water

• 5 hours back in water

• 19 hours in water

More Efficient Methods of Detection

• Develop more efficient methods of Vp detection (NRAC Grant)

– Develop 3 multiplex quantitative real-time PCR methods for detection of Vv & Vp and pathogenic genes in oysters

– Compare new PCR methods to MPN at 2 sites

• (MA & RI) over 1 year

• include water & sediment

– Testing post-harvest through retail

Thank-you!

Diane Murphy Fisheries & Aquaculture Specialist Woods Hole Sea Grant & Cape Cod Cooperative Extension Box 367 Barnstable, MA 02630 508-375-6953 dmurphy@whoi.edu