Quahog Grow-out (Plus a few other clams) Dale Leavitt Growing Quahogs • Obligate infaunal clam • What does that mean? • Needs to be in sediment at some point in their life. • Usually planted sometime after they get to 8 mm (1/3 inch) • Normally can rear up to 15 mm (>1/2 inch) over the first summer (in nursery) • Have been planted under growout nets as small as 3 mm (1/8 inch) • If held out of sediment much beyond 20 mm (3/4 inch) then get • Deformed shells • Increased mortality • Need to be protected through much of their life • Size refuge at 35-40 mm (1.5 inch) What technology should I use? • Dependent on location and species • Categorize according to location in environment • In Bottom Quahog & other infaunal clams • On Bottom • Suspended • Floating • Only real decisions • Intertidal • Subtidal 1 In Bottom Process • Define planting bed • Prepare bed • Plant seed • Cover • Maintain • Harvest Cover Netting 2 Netting INTERNET Define planting bed • Bed size dependent on multiple factors • Covering material • Mostly 14’ wide with farmer defined lengths • Number of seed that you are planting • Target: 50-100 clams/ft2 • Start at low density and build up • Can plant smaller seed at higher density (500 clams/ft2) if plan to thin out after first year. • Example • Wish to plant 100,000 seed at 75/ft2 • 100,000/75/ft2 = 1,333 ft2 required • 1,333/12 = 111 ft of mesh or ~ 100 foot net Mark out plot 3 Bed Preparation Another option? Hydraulic Option 4 Plant the seed Seed Prices Seed Prices 5 75 clams/ft2 Covering the crop Anchoring the net 6 Anchoring materials Sand tubes Rebar Lead line Anchoring the Net The completed plot 7 Net Maintenance Damaged nets Mending 8 Improper site maintenance!!! Winter management Results of ice damage 9 One solution http://www.deq.state.va.us/Portals/0/DEQ/CoastalZoneManagement/task11-07-04a.pdf Other culture techniques Bottom bag culture 10 Other culture techniques SC bottom cages for clams Other culture techniques Florida Soft Bags Rolls of soft bag arrays with wire 11 Cedar Key hard clam farm Florida clam boat 12 Harvest 13 Hydraulic Dredge The Dredge and Pump Setup Pump Outtake Hose Intake Hose Working The Dredge 14 Grading clams Quahog grading 15 Speed Rack aka Culling Box Tumbling grader Clam Roller 16 Hydroponic pumice Alternative Shellfish Species for Farming in the Northeast U.S. Dale Leavitt Professor Marine Biology & Aquaculture Extension Specialist It is risky to put all of your eggs in one basket! • Need to diversify crop • Economic • Disease • There is a continual effort to identify alternate species for culture and to develop technologies to culture them commercially 17 Selecting alternative species • The criteria for the selection of aquatic animals suitable for large-scale production may fall into three major categories: • Marketing • Biology • Adaptability of the organism Selection Factors • Marketing • Taste and Flavor • Appearance • Texture • Market behavior • Processing considerations • Biology • Growth rate • Packing tolerance & Feed availability • Seed production • Hardiness • Adaptability • Available sites • Culture technologies • Management systems • Financial requirements Potential alternative species • Soft shell clam (Mya arenaria) • Surf clam (Spisula soldissima) • Razor clam (Ensis directus) • Blood ark (Anadara ovalis) • Bay scallop (Argopecten irradians) • Sea scallop (Placopecten magellanicus) • Mussel (Mytilus edulis) • Green sea urchin (Strongylocentrotus droebachiensis) • Sugar kelp (Saccharina latissima) 18 Soft shell clam (Mya arenaria) • Infaunal bivalve • Prefers sand to sandy mud • “Cold water” species • Digs deep – predator avoidance • Relatively static once established • The traditional steamer clam in the northeast • Market well established and strong Strong history of culture • Started in beginning of the 20th century • Manipulated sediment surface to attract natural set • Directed attempts to farm in 1940’s Modern era - soft shell clam culture • Mid-1980’s – Beals Island Regional Shellfish Hatchery (BIRSH)(ME) • Focus on public enhancement • Also supplied seed for private aquaculture attempts • Now called the Downeast Institute • Late 1990’s – Salem State University (MA) established a soft shell clam culture program • Provides seed to municipalities and also to private growers 19 Public Aquaculture • Large effort in enhancement of soft shell clam stocks • Throughout northeast region • Subsidizes the hatchery production of seed for development of private farms Current status of soft shell clam culture • In the past 10 years, soft shell clams have made the transition from experimental to commercial • Supported primarily by catching wild seed - using some variation of the clam tent • Hatchery seed now being used in areas where wild seed harvest not successful Seed Sources • Hatchery • Downeast Institute for Applied Marine Research & Education • Beals Island, ME • Kyle Pepperman– contact person kyle.pepperman@downeastin stitute.org. • Salem State University – Cat Cove Lab • Salem, MA • Scott Weston – contact person [email protected] 20 Soft Shell Clam seed Another source of seed: Collecting Natural Set 21 Clam Tents Some things you need to know: • Grown in the intertidal • No good technology for subtidal • We currently have a grower in RI trying it subtidally • Obligate infaunal clam • Once it achieves a size of ~3/4” (20 mm) it must be in sediment • Uses similar nursery/growout technology as quahog culture • Upweller nursery • Growout under netted raceways Clam Caps • Semi-rigid cap for placing over small raceways of clams • Constructed from Vexar (Tenax) • Configured as 3’ x 6’ caps • Can be handled by one individual • Plant seed then place cap over the top • Hold to substrate with wire staples 22 Field plant under nets 20-50 individuals per ft2 Maintenance Harvest • Relatively deep burrower • Intertidal • Hand digging • Hydraulic harvester • Subtidal • Hand harvest (fanning) • Power assisted (air or hydraulic) 23 Bottlenecks – Soft shell clam • This one seems to have made it over the commercial scale production hump • Hatcheries can supply seed • Technology to growout is available • Market is relatively strong – particularly in summer • Currently have both public and private culture activities ongoing Biggest problem (in Mass) is political friction between wild harvesters and farmers Surf Clam (Spisula solidissima) • Infaunal bivalve • Largest bivalve along the east coast (6 - 8”) • “Cold water” species • Lives in high energy sand to deepwater habitats • Shallow burrower • Dynamic and mobile • Traditional harvest for the chopped clam market • New product - 2” “steamer” History • Interest developed for farming surf clams in the 1980’s • at the NMFS Milford Lab • Commercial scale production attempted in early 1990’s on Cape Cod • Suggested product was a 2” size for the steamer market • Marketed as “butter clams” • Advantages • Cold hardy • Fast growth in warm water culture conditions, i.e. near-shore • Highly attractive product 24 Surf Clam Technology • Have experimented with a number of growout technologies • Two seemed to work • Florida soft bags • Square mesh “suitcases” • Clam “required” to be in sediment by ~¾” (20mm) Surf Clam Technology • Most productive is growout under netted raceways • Less effort per surface area • Market size (2”) in 18 months • Harvest • Traditional hand rake • Need to purge sand Bottlenecks – Surf Clam • “Cold water” species • High summer mortality if placed in the intertidal or in warm water location • Subtidal technology needed to minimize risk of summer overheating • Availability of seed • No hatcheries routinely producing seed • One in MA is currently has surf clam seed for sale • Must purge sand prior to market • Market for “Butter Clam” needs to be further developed 25 Stimpson’s Surf Clam (Mactromeris polynyma) Stimpson’s Surf Clam (Mactromeris polynyma) However…. 26 Razor Clam (Ensis directus) • Infaunal bivalve • Lives in low intertidal to subtidal • Another “cold water” species • Burrows deep • Dynamic and highly mobile • Will leave if conditions not to its liking • Conventional harvest • Historically for shucked product • More recently sold live History • Interest perked up in early 2000’s when wild harvest value jumped to $2.00/lb • NRAC supported a preliminary study to investigate growout technology • Finished in Dec 2003 • Distributed razor clam seed to established clam growers to try their best technology • SEMAC contracted for another round of razor seed for grower evaluation • NRAC has funded a new study to look at improving seed production in the hatchery • Started Summer 2012 Razor Clam Technology • Hatchery • successful with typical protocols • Setting • Set okay in downwellers • Set on sediment? • Nursery • All traditional technologies worked • Had problem with protozoan contamination during early post-set 27 Razor Clam Technology - Growout • Different growers tested technology • The results ranged from • complete emigration within a week • >90% retention/survival with strong growth • Best technology • In situ wooden box with mesh cover • Harvest • Hand dig • Salt Bottlenecks – Razor Clam • Seed • Hatchery seed - a potential problem! • Currently – early post-set survival unpredictable • No economic incentive to produce seed • Need to refine best method to growout • Optimal habitat or best containment technology? • Also have summer overheating problem • Market development may be required • Market product is 4” razor clam Blood Ark (Anadara ovalis) • Infaunal bivalve • Primarily subtidal • Prefers