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Survival and Growth of Cultured Hard Clam Seed Planted in Spring, Summer and Fall in Long Island, New York Waters Gregg Rivara, CCE-Suffolk John Aldred, East Hampton Town Debra Barnes, NYS DEC Robert Cerrato, MSRC, SBU ---PAGE BREAK--- Some Background • 87% decline in ‘wild’ hard clam landings in New York since 1976 • Decline of bay scallop, lobster and inshore fisheries due to brown tide, disease and regulation has put additional pressure on hard clam fishery • Twelve of the thirteen L.I. towns have hard clam resource enhancement programs; there are three public hatcheries • Harvest returns of notata variety clams in local harvests have generally been erratic; in some cases, the recovery of overall hard clam populations has not seemed to meet with community expectations. ---PAGE BREAK--- Typical Practices • A town’s own or purchased seed is grown through one season at high density in protected grow out systems • At best, seed averages ~15mm shell length in a NY season • Seed is distributed into uncultivated public bottom in fall, often favoring traditionally productive sites • In some cases, seeding begins earlier to thin growing systems • Little overwintering is done, due to effort required ---PAGE BREAK--- Research Has Shown - But • Seed density and size influences predation – But, the public expects concentrated harvests and seed size immune to predation can’t be achieved in one season in NY • Large sediment grain sizes offer some protection from predators – But, many traditionally productive areas exhibit other characteristics • Overwinter survival of protected seed, planted in the fall, showed good survival over a range of sizes – But, the public expects the enhancement of ‘natural habitats’, precluding concentrated protected plantings – And… ---PAGE BREAK--- Overwinter Survival in Shellfish Growing Bags 1999-2000 F ig u re 2 P e rce n t S u rviva l o f C la m s in S h ellfish G ro w in g B a g s O ve rw in tere d in N o rth w e st C re ek , T h ree M ile H a rb o r, A cc a b o n ac H arb o r, F re s h P o n d , N a p e ag u e a n d L a k e M o n t au k. 1 99 9- 20 00 24. 1 92. 2 83. 6 18.9 19.2 5.9 51. 2 51. 2 72. 4 12.4 0.2 4 0 10 20 30 40 50 60 70 80 90 100 N W C TM H AC C F P NA P N AP m ud LM H arbo r Percent Survival E arly - 8 /9 9 -7 /0 0 @ 1 4 .2 m m L a te - 1 0 /9 9 -7 /0 0 @ 1 6 .4 m m Overwinter Survival of Smaller Seed Planted Earlier Seemed Greater Than That of Larger Seed Planted Later ---PAGE BREAK--- Objectives • Determine relative survival of hatchery produced clam seed field planted through the growing season using seed typically available at the time • Test the overall hypothesis that seed size and planting time will not significantly affect overall survival into the next growing season • If so, earlier distribution of smaller seed will be a viable management strategy, allowing for more seed production in finite culture space, resulting in an overall increase of recruitment into the fishery ---PAGE BREAK--- Hypotheses Tested • Small seed planted early will be larger and in better condition than larger seed planted late, exhibiting better overwinter survival • Small, early planted seed is expected to suffer higher predation losses than large, late planted seed, but predator related mortality will be large for all plantings, rendering size specific differences unimportant • Better condition of small seed will counterbalance increased predation; survival of different plantings into the next season will be similar ---PAGE BREAK--- ---PAGE BREAK--- Research Plan • Plant the same cohort three times: June, August, October at 25 clams/m2 • Six locations, different conditions, no site preparation • Triplicate, large scale plantings (900m2) plus netted control boxes • At each planting look for clams from previous plantings one square meter quadrats per plot) • Exhaustively sample all 54 plots during the following summer (120, one square meter quadrats per plot) ---PAGE BREAK--- Research Plan • Perform predator surveys using five methods (Green, Blue crab traps, shell bags, suction dredge, diver observation) • Sediment grain size analyses • Initial and final clam condition indices • Temperature recorders at each site • Monitor sites for presence of harmful algae (Suffolk County Dept. Health Services) • Mark corners of each plot with earth anchors, GPS points and buried rebar (216 total) ---PAGE BREAK--- Pre-test retrieval of clam seed and colored stone by suction dredge after ± 6 hours (30mx30m plot) #Seeded/m² #Retrieved/m² % return 2001 notata 33 20.7(sd=9.4) 62.2 2001 stone 33 24.9(sd=15.3) 72.3 2002 notata 25 15.9(sd=6.1) 63.6 2002 stone 25 19.1(sd=7.7) 76.4 ---PAGE BREAK--- j8 j9 2z a1 o1 o2 o1 a1 o2 1y 5x 1 2 3y 3 June Planting August Planting October Planting a1 o1 o2 o1 a1 o2 2y j7 Buffer 3z j10 1z Strip (3m) j6 o4 a6 o6 B B B o4 4x o6 a6 B B B Buffer Buffer N 4 Strip 5 Strip 6 B B B August Planting (3m) October Planting (3m) June Planting B B B o4 a6 o6 o4 o6 a6 B B B 2x Buffer 3x 4z Strip (3m) 4y a8 o8 o9 j1 o8 a8 o9 5y 1x j5 7 8 5z 9 October Planting June Planting j3 August Planting a8 o8 o9 o8 a8 o9 j4 j2 Key traps (green, blue, shell bag suction dredging B= boxes(June, August, October) x= June j= June ( 10 for predators) y= August a= August (12 for predators+seed) z= October o= October (12 for predators+seed) 30mx30m Plot Set-up Latin Square Configuration ---PAGE BREAK--- Laying out plots ---PAGE BREAK--- Earth Anchor & Ice ---PAGE BREAK--- 2002 Large Plot Interim Suction Samples – Survival Huntington 2002 Samples 0 10 20 30 40 50 60 70 80 90 100 June August October Sampling Date Percent Survival Southampton 2002 Samples 0 10 20 30 40 50 60 70 80 90 100 June August October Sampling Date Percent Survival East Hampton 2002 Samples 0 10 20 30 40 50 60 70 80 90 100 June August October Sampling Date Percent Survival Brookhaven 2002 Samples 0 10 20 30 40 50 60 70 80 90 100 June August October Sampling Date Percent Survival Southold 2002 Samples 0 10 20 30 40 50 60 70 80 90 100 June August October Sampling Date Percent Survival Great South Bay 2002 Samples 0 10 20 30 40 50 60 70 80 90 100 June August October Sampling Date Percent Survival ---PAGE BREAK--- 2002 Large Plot Interim Suction Samples – Shell Length Huntington 2002 Samples 0 5 10 15 20 June August October Sampling Date Shell Length (mm) Southampton 2002 Samples 0 5 10 15 20 June August October Sampling Date Shell Length (mm) Southold 2002 Samples 0 5 10 15 20 June August October Sampling Date Shell Length (mm) Brookhaven 2002 Samples 0 5 10 15 20 June August October Sampling Date Shell Length (mm) East Hampton 2002 Samples 0 5 10 15 20 June August October Sampling Date Shell Length (mm) Great South Bay not yet available ---PAGE BREAK--- Mid-winter Ice ---PAGE BREAK--- Suction Dredge Rig ---PAGE BREAK--- Suction sampling in shallow water ---PAGE BREAK--- Samplers working through quadrat markers ---PAGE BREAK--- Sample from shell hash bottom ---PAGE BREAK--- Retrieved seed ---PAGE BREAK--- Brookhaven 0 10 20 30 40 June August October Planting Date Percent Survival East Hampton 0 10 20 30 40 June August October Planting Date Percent Survival Great South Bay 0 10 20 30 40 June August October Planting Date Percent Survival Huntington 0 10 20 30 40 June August October Planting Date Percent Survival Southold 0 10 20 30 40 June August October Planting Date Percent Surviva 2003 Large Plot Suction Samples- Survival Southampton plot markers lost to ice ---PAGE BREAK--- Brookhaven 10 20 30 June August October Planting Date Shell Length (mm) East Hampton 10 20 30 June August October Planting Date Shell Length (mm) Great South Bay 10 20 30 June August October Planting Date Shell Length (mm) Huntington 10 20 30 June August October Planting Date Shell Length (mm) Southold 10 20 30 June August October Planting Date Shell Length (mm) 2003 Large Plot Suction Samples- Shell Length Southampton plot markers lost to ice ---PAGE BREAK--- Brookhaven 0 2 4 6 8 10 12 14 16 June August October Planting Date Condition Index East Hampton 0 2 4 6 8 10 12 14 16 June August October Planting Date Condition Index Great South Bay 0 2 4 6 8 10 12 14 16 June August October Planting Date Condition Index Huntington 0 2 4 6 8 10 12 14 16 June August October Planting Date Condition Index Southold Suction Samples 0 2 4 6 8 10 12 14 16 June August October Planting Date Condition Index 2003 Large Plot Suction Samples – Condition Index Southampton samples lost to ice ---PAGE BREAK--- ‘Control box’ ---PAGE BREAK--- Brookhaven 0 20 40 60 80 100 June August October Planting Date Percent Survival East Hampton 0 20 40 60 80 100 June August October Planting Date Percent Survival Great South Bay 0 20 40 60 80 100 June August October Planting Date Percent Survival Huntington 0 20 40 60 80 100 June August October Planting Date Percent Survival Southampton 0 20 40 60 80 100 June August October Planting Date Percent Survival 2003 Control Box Samples- Survival Southold samples not found ---PAGE BREAK--- Brookhaven 0 10 20 30 40 June August October Planting Date Shell Length (mm) East Hampton 0 10 20 30 40 June August October Planting Date Shell Length (mm) Great South Bay 0 10 20 30 40 June August October Planting Date Shell Length (mm) Huntington 0 10 20 30 40 June August October Planting Date Shell Length (mm) Southampton 0 10 20 30 40 June August October Planting Date Shell Length (mm) 2003 Control Box Samples- Shell Length Southold samples not found ---PAGE BREAK--- Preliminary Results • Clams planted earlier grew larger than those planted later in both unprotected and protected plantings • Best survival in unprotected plots was from October plantings • June and August mortality in unprotected plots occurred soon after planting • Best survival in boxes was from June plantings • Predation major factor influencing survival • In general, boxed clams were larger than plot clams • No convincing evidence for differences in condition index after the winter ---PAGE BREAK--- More to do • All 2002 and 2003 ‘control box’ clam condition indices and comparisons • Additional 2002 growth data • Temperature data • Predator analysis • Sediment analysis • More results-driven analysis within and among sites ---PAGE BREAK--- Discussion • Intensive vs. extensive plantings. • Assess successful seedings, look for similarities. • Increase overwintering efforts to yield larger seed? • More consideration of field preparation and predator protection/reduction? Is this too much like aquaculture? ---PAGE BREAK--- Acknowledgements • New York Sea Grant Project # RATD-10 • Cornell Cooperative Extension of Suffolk County • NYS Department of Environmental Conservation • Town of Babylon • Town of Brookhaven • Town of East Hampton • East Hampton Town Trustees • Town of Huntington • Southold Town Trustees • Southampton Town Trustees • Town of Smithtown • Town of Southold ---PAGE BREAK--- Acknowledgements Associate Investigators: • Thomas Carrano, Brookhaven • Craig Hassler, East Hampton • Glen Hulse, Huntington • Shawn Kiernan, Southampton • Mike Litwa, Babylon • Kathleen McShane, Smithtown • William Nazzaro, Southampton Field Assistants: • Mike Patricio • Kim Tetrault • Jonathan Polistena • Robert Sater • Dave Bender • Lorne Brousseau • Frank Quevedo • Jennifer Gaites • Josh Thiel • Beth Ann Balazsi • Ellen Spencer • Lily Leon • Jackie Stent • Soren Dahl • Joe Ferdinandsen • Frank Thorpe • Kendall Klett • Sean Ackley • Dan Lewis • Nathan Phillips • Anthony Pasquale • Melanie Douglass • Sarah Raynor • Christopher Rice • Tara Clark • Mike Granieri • Cindy Browning • Bailey Larkin ---PAGE BREAK---