The Lay of the Land: Understanding Quahog Management in Rhode Island

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The Lay of the Land: Understanding Quahog Management in Rhode Island presented by Jeff Mercer of the RI DEM at May 19th, 2014 Rhode Island Shellfish Management Plan Stakeholder meeting

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The Lay of the Land: Understanding Quahog Management in Rhode Island

  1. 1. The Lay of the Land: Understanding Quahog Management in Rhode Island Jeff Mercer RI DEM, Principal Biologist May 19, 2014
  2. 2. 39.1 Million Clams 6.96 Million Pounds $5.15 million Dollars 534 Fishermen Quahogs by The Numbers 2012 Landings 1. Squid $19 Million 2. Lobster $12 Million 3. Sea Scallop $9 Million 4. Summer Flounder $7 Million 5. Quahog $5 Million CHERRY 3% CHOWDER 10% LITTLE NECK 64% TOP NECK 23%
  3. 3. • Management Goals – What do we hope to accomplish through management? • Management Tools – What are the specific ways which we manage the resource and fishery? • Assessment Methods – How do we go about assessing existing strategies and potential modifications to management? Outline
  4. 4. Management Philosophy The marine fishery resources belonging to, allocated to, and of interest to Rhode Island need to be preserved and protected, at healthy, sustainable levels- – Because of their ecological value, and – Because they are renewable natural resources that provide food, recreation, income, employment, and other economic, social, and cultural benefits.
  5. 5. • Maintain the health of the State’s marine ecosystem • In accordance with sustainable harvest levels, manage harvest in ways that – Make full and effective use of available harvest opportunities, while minimizing discards, ecological impacts, habitat degradation, and other wasteful practices – Balance the interests of different user groups and stakeholders Management Goals
  6. 6. • Recreational Harvesters – Provide fair, open, and equitable access and harvest opportunities with certain preferences to residents of the State • Commercial Industry – Maintain an economically strong viable and diverse industry – Support the business interest of fishermen and economic interest of the industry – Support safe fishing operations – Support enhanced marketing opportunities • Prospective Fishermen – Provide meaningful access opportunities without unduly impacting the interests of those currently engaged in the industry • General Public – Maintain the health of the State’s marine ecosystem – Provide a stable supply of safe, fresh, locally caught seafood Management Goals
  7. 7. – Minimum Size – Harvest Methods – Licensing – Daily Catch Limits – Area Based Management • Limited Access Time • Reduced Daily Limits • Rotational Harvest • Spawner Sanctuaries – Transplants – Harvesting and Handling Requirements (OWR &DOH) Management Tools
  8. 8. – Fishery Dependent • Landings Data - SAFIS • Catch Per Unit Effort (CPUE) – Fishery Independent • Dredge Survey • Other field surveys – Life History Studies • Age and Growth • Maturity schedule • Fecundity • Natural Mortality Models Bay-Wide Population Modeling Area-Specific Depletion Modeling Computer Simulations Assessment Methods
  9. 9. Harvesting and Handling – OWR & DOH Density 8-20 X Greater than Avg • Pollution closures act as de facto marine reserves • 50% of nitrogen in quahog has origin from waste water • More tolerant to hypoxia than predators = predation refuge
  10. 10. Harvesting and Handling – OWR & DOH • Pollution closures act as de facto marine reserves • 50% of nitrogen in quahog has origin from waste water • More tolerant to hypoxia than predators = predation refuge 0 500 1000 1500 2000 2500 3000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Landings(MT)&Licenses(#) # of Licenses Meat Weight (MT)
  11. 11. Minimum Size 0 10 20 30 40 50 60 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 ShellWidth(mm) Age (yrs) Legal Size Growth Curve Sexual Maturity *1987 moved from 1.5” length to 1” width
  12. 12. 0 500 1000 1500 2000 2500 3000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Landings(MT)&Licenses(#) Year # of Licenses Meat Weight (MT) * NMFS Landings Data Harvest Methods 31,000,000 lbs
  13. 13. 0 500 1000 1500 2000 2500 3000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Landings(MT)&Licenses(#) Year # of Licenses Meat Weight (MT) * NMFS Landings Data Harvest Methods 31,000,000 lbs = 3,500 Elephants
  14. 14. 0 500 1000 1500 2000 2500 3000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Landings(MT)&Licenses(#) Year # of Licenses Meat Weight (MT) * NMFS Landings Data Harvest Methods
  15. 15. 0 500 1000 1500 2000 2500 3000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Landings(MT)&Licenses(#) Year # of Licenses Meat Weight (MT) * NMFS Landings Data Harvest Methods
  16. 16. TITLE 20 § 20-6-7 Use of dredges …no person shall take any oysters, bay quahaugs, or soft-shell clams from the waters of this state by dredges, rakes, or other apparatus operated by mechanical power or hauled by power boats. Harvest Methods
  17. 17. 0 500 1000 1500 2000 2500 3000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Landings(MT)&Licenses(#) Year # of Licenses Meat Weight (MT) * NMFS Landings Data Harvest Methods
  18. 18. Licensing 0 500 1000 1500 2000 2500 3000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Landings(MT)&Licenses(#) Year # of Licenses Meat Weight (MT) * NMFS Landings Data
  19. 19. • Open Access (through mid 1990s) • 1st Moratorium (1995 – 1998) • Open Access (1999) • 2nd Moratorium (2000-2002) • New Licensing Program (2003) Licensing
  20. 20. • Use of License Endorsements to limit access to certain species • Use of Exit/Entry Ratios to control effort levels – Currently 2:1 for Quahog Endorsement • Annual process of regulatory review and modification, based on input from industry and advice from RI Marine Fisheries Council Licensing
  21. 21. Licensing 0 500 1000 1500 2000 2500 3000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Landings(MT)&Licenses(#) Year # of Licenses Meat Weight (MT) * NMFS Landings Data
  22. 22. 1984 1985 1986 1987 19881989 1990 1991 1992 1993 1994 1995 1996 1997 19981999 2000 20012002 20032004 20052006 2007 2008 2009 2010 2011 2012 0 100 200 300 400 500 600 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 AbundanceinMillions(t) F Rate (t-1) Licensing – Stock Assessment model
  23. 23. License Type 2003 Total 2013 Total Net Change MPL 1191 829 -362 PEL w/QH 924 376 -548 CFL w/QH 271 420 +149 Student SF 107 48 -59 65 & ↑ SF 50 268 +218 TOTALS 2,543 1,941 -602 Licensing
  24. 24. 0 200 400 600 800 1000 1200 1400 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 #ofLicenses Year MPURP PEL CFL SFO65 STUD MPURP Active PEL Active CFL Active SFO65 Active STUD Active Licensing - # of Active Licenses
  25. 25. 0 20 40 60 80 100 120 140 1-5 6-10 11-25 26-50 51-100 101-150 151-200 201-250 251-306 #ofFishermen Days Fished PEL MPURP CFL SF065 Stud Licensing - 834 Total Active ~ 150 Fishermen
  26. 26. 0 20 40 60 80 100 120 #ofActiveFishermen Age PEL MPURP CFL SFO65 STUD 93 fishermen under 40 years old Licensing – Age of Fishermen
  27. 27. 0 20 40 60 80 100 120 #ofActiveFishermen Age PEL MPURP CFL SFO65 STUD Only 19 full-time fishermen under 40 years old (100+ days) Licensing – Age of Fishermen
  28. 28. 0 2 4 6 8 10 12 0 500 1000 1500 2000 2500 3000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 UnemploymentRate(%) Landings(MT)&Licenses(#) Year # of Licenses Meat Weight (MT) Unemployment Rate * NMFS Landings Data Licensing – & unemployment
  29. 29. Daily Catch Limits License Type Endorsements Limits Cost Full Harvest Principal Effort (PEL) Quahog Soft Shell Whelk Other 12 bu/day (3 in MAs) $150 License No Fee for 1st Endorsement $75 each add’l Multipurpose (MPL) N/A 12 bu/day (3 in MAs) $300 Limited Harvest Commercial Fishing (CFL) Quahog Soft Shell Whelk Other 3 bu/day $50 License $25 for each Endorsement Student *Quahog only 3 bu/day $50 Over 65 *Quahog only 3 bu/day No Fee Recreational (Resident) N/A ½ bu/day (1 peck in MA) No license Recreational (Non-res) N/A 1 peck/day (1/2 peck in MA) $200 / $25/ $11
  30. 30. 𝑁𝑖𝑗 = 𝑁𝑖𝑗−1 ∗ 1 − 𝑝 ∗ 𝑒− 𝐹 𝑖𝑗−1+𝑀 + 𝑁𝑖−1𝑗−1 ∗ 𝑝 ∗ 𝑒− 𝐹 𝑖−1𝑗−1+𝑀 N = population size F = fishing mortality rate P = promotion probability governed by von Bertalanffy growth equation derived from Henry & Nixon (2008) M = natural mortality rate i = size class j = year Inputs to Model 1. Landings 2. Fisheries Independent Abundance Index 3. Fishing Effort Index Daily Catch Limits – Size-structured Stock Assessment Model
  31. 31. 0 20 40 60 80 100 120 140 160 #ofQuahogs(millions) Year Landings Size Structured Stock Assessment Model Gibson, 2010
  32. 32. 0 100 200 300 400 500 600 #ofQuahogs(millions) Year Abundance Landings Gibson, 2010 Daily Catch Limits – Size-structured Stock Assessment Model
  33. 33. Polynomial Logarithmic Stock-Recruitment Models Great South Bay, NY How Many Quahogs do We Need? Kraeuter et al, 2005 Density Dependence 0.75 Adults/m2 = Recruitment Failure Daily Catch Limits
  34. 34. 0 100 200 300 400 500 600 #ofQuahogs(millions) Year Abundance Landings Recruitment Failure 0.75 Adults/m2 X 125km2 Fishable Area Daily Catch Limits – Size-structured Stock Assessment Model
  35. 35. Kraeuter et al, 2005 Daily Catch Limits – Spawning Stock & Recruitment
  36. 36. 0 100 200 300 400 500 600 #ofQuahogs(millions) Year Abundance Landings Reduced Recruitment 1.5 Adults/m2 X 125km2 Fishable Area Daily Catch Limits – Size-structured Stock Assessment Model
  37. 37. West Passage Conditional B Conditional A Greenwich East Passage ma ma ma ma West Passage 25.9% Conditional A 23.6% Conditional B 20.9% Greenwich Bay 14.4% East Passage 11.9% Management Areas 0.9% Coastal Ponds 0.8% Not Identified 0.7% Sakonnet 0.6% Mt Hope Bay 0.3% Block Island 0.0% • No info on Closed Waters • Tagging Areas are Large Area Based Management
  38. 38. • 1993-2013 • Use hydraulic dredge to sample adult populations • Stratified Random Sampling Design • 2368 tows of 30 m • 26,000+ clams Area Based Management – Dredge Survey
  39. 39. • Not corrected for dredge efficiency • High densities correspond to productive fishing grounds • Shallow areas poorly assessed • Closed Areas highest densities Area Based Management – Dredge Survey
  40. 40. Adapted from Gaylord, et al., 2005 Habitat Area Habitat Area Protected Fished P F Protected P Area Based Management
  41. 41. Habitat Area Habitat Area Protected Fished P F 49% of Studies Fisheries Yield Higher with Traditional Management 51% of Studies Fisheries Yield Higher with MPAs Gaines, et al., 2010 Area Based Management
  42. 42. Habitat Area Habitat Area Protected Fished P F Protected P Area Based Management
  43. 43. Habitat Area Habitat Area Protected F P F P PPP P P PP P P F FF Area Based Management Rhode Island Management
  44. 44. Habitat Area Habitat Area Protected P F P P f • Management = 67.8km2 • Est. Fishable Area ~ 125km2 F P F F P F Pp f p p f P P Area Based Management Rhode Island Management Management Areas = 67.8km2 Estimated Fishable Area ~ 125km2
  45. 45. Area Based Management – Greenwich Bay
  46. 46. Area Based Management – Greenwich Bay DEC JAN FEB MARCH APRIL GB Sub Area 1 & 2 CLOSED OWR 8-12 Jan 2 and starting Jan 6 8-12 MWF 8-12 MWF 8-12 MWF 8-12 MWF High Banks & Pot C Open Open Open Open Open Bristol CLOSED 8-12 MWF beginning Jan 3 Open Open Open Bissel/Fox Opens 2nd Wed* Open* Open* Open* Open* Mill Gut Opens 2nd Wed Open Open Open Open
  47. 47. • LESLIE'S METHOD • Assume • Nt= No - Ct • Kt = Ct = cumulative catch • Nt = No-Kt • but, “N" is not an observable variable in most studies,so after multiplying through by q (the catchability coefficient) • qNt = qNo - q(Ct) • CPUE= a + b (Kt) • Fit a regression then – a) the slope of the line is an estimate of q – b) the intercept is qNo = CPUEo – c) the initial population can be estimated by Intercept a/ slope b Area Based Management – Leslie Depletion Model
  48. 48. Area Based Management – Leslie Depletion Model 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 MeanCPUE(marshmallows/handful) Cumulative Catch (Total # of Marshmallows)
  49. 49. Area Based Management – Leslie Depletion Model 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 MeanCPUE(marshmallows/handful) Cumulative Catch (Total # of Marshmallows)
  50. 50. Area Based Management – Leslie Depletion Model 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 MeanCPUE(marshmallows/handful) Cumulative Catch (Total # of Marshmallows)
  51. 51. Area Based Management – Leslie Depletion Model 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 MeanCPUE(marshmallows/handful) Cumulative Catch (Total # of Marshmallows)
  52. 52. Area Based Management – Leslie Depletion Model 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 MeanCPUE(marshmallows/handful) Cumulative Catch (Total # of Marshmallows) 240 Total Marshmallows
  53. 53. Area Based Management – Leslie Depletion Model y = -0.1519x + 38.173 R² = 0.9817 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 MeanCPUE(marshmallows/handful) Cumulative Catch (Total # of Marshmallows) Starting N Catch exp rate Volume Start Dens. End Dens. F Rate End N 251 240 0.955 12 20.9 0.94 3.1 11
  54. 54. Area Based Management – Leslie Depletion Model y = -0.1162x + 34.888 R² = 0.9657 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 MeanCPUE(marshmallows/handful) Cumulative Catch (Total # of Marshmallows) Estimated 262 Total Marshmallows Starting N Catch exp rate Volume Start Dens. End Dens. F Rate End N 262 207 0.791 12 21.8 4.56 1.56 55
  55. 55. Area Based Management – Leslie Depletion Model y = -0.1162x + 34.888 R² = 0.9657 0 5 10 15 20 25 30 35 40 0 50 100 150 200 250 MeanCPUE(quahogs/fisher/day) Cumulative Catch (Total # of Quahogs) Starting N Catch exp rate Area Start Dens. End Dens. F Rate End N 262 207 0.791 12 21.8 4.56 1.56 55
  56. 56. Area Based Management – Leslie Depletion Model December 2009 – March 2010 y = -0.0002x + 1362.9 R² = 0.2653 0 200 400 600 800 1000 1200 1400 1600 0 500,000 1,000,000 1,500,000 MeanCPUE(quahogs/fishermen/day) Cumulative Catch (# of quahogs) Starting # Start #/m2 Catch End # End #/m2 5,963,116 2.82 1,458,649 4,504,467 2.13 2002-May 2010 Area = 2,109,619 m2 F Rate = 0.281
  57. 57. Area Based Management – Leslie Depletion Model • May 2010 pollution line changes
  58. 58. Area Based Management – Leslie Depletion Model • May 2010 pollution line changes • Summer 2010 DEM conducts dredge survey • Densities as high as 26 quahogs/ m2 when adjusted for efficiency • SAP & RIMFC decide to open only Area A (north side)
  59. 59. Area Based Management – Leslie Depletion Model Dec. 2010- March 2011 y = -5E-05x + 1901.2 R² = 0.6006 0 500 1000 1500 2000 2500 0 1,000,000 2,000,000 3,000,000 4,000,000 5,000,000 6,000,000 MeanCPUE(quahogs/fishermen/day) Cumulative Catch (# of quahogs) Starting # Start #/m2 Catch End # End #/m2 40,983,314 27.09 5,866,505 35,116,809 23.21 Area = 1,512,589 m2 F Rate = 0.154
  60. 60. Area Based Management – Leslie Depletion Model Dec. 2011- March 2012 y = -8E-05x + 1728.2 R² = 0.5128 0 500 1000 1500 2000 2500 0 2,000,000 4,000,000 6,000,000 MeanCPUE(quahogs/fishermen/day) Cumulative Catch (# of quahogs) Starting # Start #/m2 Catch End # End #/m2 20,765,498 6.51 6,588,476 6,588,478 4.45 Area = 3,189,110 m2 F Rate = 0.382
  61. 61. Area Based Management – Leslie Depletion Model • May 2012 pollution lines extended • Dredge Survey results from Summer 2012 • Densities reduced from ~ 9/m2 to < 1/m2
  62. 62. Area Based Management – Leslie Depletion Model Jan 2013- March 2013 y = -0.0003x + 1471.7 R² = 0.4798 0 200 400 600 800 1000 1200 1400 1600 1800 2000 0 500,000 1,000,000 1,500,000 2,000,000 2,500,000 MeanCPUE(quahogs/fishermen/day) Cumulative Catch (# of quahogs) Starting # Start #/m2 Catch End # End #/m2 4,872,719 1.79 2,012,279 2,860,440 1.05 Area = 2,727,668m2 F Rate = 0.533
  63. 63. Area Based Management – Leslie Depletion Model Jan 2014 - March 2014 y = -0.0004x + 1522.1 R² = 0.4154 0 200 400 600 800 1000 1200 1400 1600 1800 2000 0 500,000 1,000,000 1,500,000 MeanCPUE(quahogs/fishermen/day) Cumulative Catch (# of quahogs) Starting # Start #/m2 Catch End # End #/m2 3,544,222 1.30 1,482,124 2,062,099 0.76 Area = 2,727,668m2 F Rate = 0.542
  64. 64. Habitat Area Habitat Area Protected P F P P f • Management = 67.8km2 • Est. Fishable Area ~ 125km2 F P F F P F Pp f p p f P P Area Based Management Rhode Island Management
  65. 65. Habitat Area Habitat Area Protected P F P P f • Management = 67.8km2 • Est. Fishable Area ~ 125km2 F P F F P F Pp f p p f P P Area Based Management Rhode Island Management
  66. 66. Habitat Area Habitat Area Protected Fished P F Protected P SOURCE SINK For reserves to be effective they must also increase populations beyond reserve borders through: 1. Larval Export 2. Adult Spillover (Transplants?) Area Based Management - Spawner Sanctuaries
  67. 67. • Larvae released randomly over 30 day period • Released in top 2 meters • Passive for 11 days • Swim towards bottom for 24 hours – randomness added • Site Specific Settlement – OFF LTRANS Area Based Management
  68. 68. Greenwich Cove Prohibited Area Based Management
  69. 69. • ~100 million eggs/m2 • Larval Duration 8-12 days • Large potential reproductive output Area Based Management
  70. 70. Marroquin-Mora & Rice (2008) • Too Dense? • Crowding may lead to poor condition and low reproductive output • CI = dry soft tissue wt X 1000/ (total wt - shell wt) Area Based Management Matt Griffin RWU/URI
  71. 71. Area Based Management - Transplants Since 1977 ~ 9 million lbs of quahogs transplanted
  72. 72. High Banks Potowomut Sanctuary Greenwich Cove Area Based Management – Transplants
  73. 73. Potowomut Spawner Sanctuary Approved-Closed High Banks Management Area Approved Area Based Management - Transplants
  74. 74. Area Based Management - Spawner Sanctuaries Data from TNC
  75. 75. Questions?

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