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

1. The Lay of the Land:
Understanding Quahog
Management in Rhode Island
Jeff Mercer
RI DEM, Principal Biologist
May 19, 2014

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. • 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. 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. • 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. • 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. – 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. – 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. • Open Access (through mid 1990s)
• 1st Moratorium (1995 – 1998)
• Open Access (1999)
• 2nd Moratorium (2000-2002)
• New Licensing Program (2003)
Licensing

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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 0
20
40
60
80
100
120
140
160
#ofQuahogs(millions)
Year
Landings
Size Structured Stock Assessment Model
Gibson, 2010

32. 0
100
200
300
400
500
600
#ofQuahogs(millions)
Year
Abundance Landings
Gibson, 2010
Daily Catch Limits – Size-structured Stock Assessment Model

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. 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. Kraeuter et al, 2005
Daily Catch Limits – Spawning Stock & Recruitment

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. 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. • 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. • 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. Adapted from Gaylord, et al., 2005
Habitat Area
Habitat Area
Protected
Fished
P
F
Protected
P
Area Based Management

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. Habitat Area
Habitat Area
Protected
Fished
P
F
Protected
P
Area Based Management

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. 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. Area Based Management – Greenwich Bay

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. • 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. Area Based Management – Leslie Depletion Model
• May 2010 pollution line
changes

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. 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. 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. 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. 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. 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. 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. 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. 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. • 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. Greenwich Cove
Prohibited
Area Based Management

69. • ~100 million eggs/m2
• Larval Duration 8-12
days
• Large potential
reproductive output
Area Based Management

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. Area Based Management - Transplants
Since 1977 ~ 9 million lbs of quahogs transplanted

72. High
Banks
Potowomut
Sanctuary
Greenwich
Cove
Area Based Management – Transplants

73. Potowomut Spawner Sanctuary
Approved-Closed
High Banks Management Area
Approved
Area Based Management - Transplants

74. Area Based Management - Spawner Sanctuaries
Data from TNC

75. Questions?