Opening up about using Closed Areas to
Manage Scallop Fisheries
Bryce Stewart, Leigh Howarth, Marija Sciberras, Katherine Yates & Miles Hoskin
Howard Wood
Sustainability of Global Scallop Fisheries
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Lan
din
gs
(to
nn
es
)
UN FAO Fisheries & Aquaculture Department (2013)
The Effect of Fishing on Scallops
Catch per unit effort for scallops
Bradda Inshore
0
30
60
90
120
150
180
1950 1960 1970 1980 1990 2000
CP
UE
(n
o. /
m /
hou
r)
Age composition of scallops Bradda Inshore
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10
20
30
40
50
60
3 4 5 6 7 8 9 10 11 12+
Age (years)
Co
mp
osi
tio
n (
%)
1937
2004
The Effect of Fishing on Scallops
Ecosystem Effects of Scallop Fisheries
Biodiversity Settlement Habitat
Public Pressure
http://www.youtube.com/watch?v=nkfz5fOPSck
Principles for Improving the Management of
Scallop Inshore Fisheries 1. Encourage industry stewardship of the resource (spatial or catch
based ownership) – reduce the “race for fish”
2. Allow stocks to recover towards more natural size / age structures – improve yield per recruit & reproductive output
3. Provide spawning refuges – high densities of large individuals
4. Minimise the effects of the fishery on juveniles – improve future yields
5. Reduce by-catch & conflicts with other fisheries
6. Reduce the effect of fisheries on benthic habitats – maintain / recover biodiversity & improve recruitment
Beukers-Stewart & Beukers-Stewart (2009)
Are Closed Areas
The Solution? Georges Bank
/ NE USA
Case Study: UK Scallop Fisheries
Great or King
scallops
Pecten maximus
Queen scallops
Aequipecten
opercularis
UN FAO Fisheries & Aquaculture Department (2013)
Arran
(NTZ)
Port Erin (CA)
Cardigan Bay
(SAC)
Skomer
Island (MNR)
Lundy Island
(NTZ) Devon (IPA)
Llyn Peninsula
(SAC)
IRELAND UNITED
KINGDOM
Scotland
Northern
Ireland
England Wales
Isle of Man Scallop Fishery
• Scallops dominate fisheries
landings into the Isle of Man
• Fishery appears sustainable
but is much less productive
than in the past
• Dredging for scallops has
reduced biodiversity & habitat
complexity on the main fishing
grounds
• IoM have set up a network of
marine protected areas to
improve fisheries sustainability
Closed Area
Scallop Recovery in Port Erin Closed Area
Density (1989-2006)
0
5
10
15
20
25
1989 1991 1993 1995 1997 1999 2001 2003 2005
Den
sit
y (
no
./100m
2)
Closed Area
Fished Area
10 TIMES HIGHER!!
Beukers-Stewart et al. (2005) MEPS
Scallop Recovery in Port Erin Closed Area
Density (2008)
Murray, Hinz & Kaiser (2009)
Scallop Recovery in Port Erin Closed Area
9 TIMES HIGHER!
Biomass (2006)
0
0.5
1
1.5
2
2.5
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3.5
4<
50
51
-60
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-70
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-80
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-90
91
-10
0
10
1-1
10
11
1-1
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12
1-1
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50
15
1-1
60
> 1
60
Shell length (mm)
Den
sit
y (
no
./100m
2) Fished area
Closed area
20 TIMES HIGHER!!
Scallop Biomass & Reproduction
• Large scallops
Egg production
(33 x fished area)
• High densities
Fertilisation
• Combination
Larval production
(100 x fished area?)
Closed area Fished area
(2006)
Fisheries Benefits?
Larval Export?
Spill-over?
Neill & Kaiser 2008
Pascal Dubois
Fisheries Benefits?
Commercial Catch Rates
Beukers-Stewart et al. (2003) ICES J Mar Sci; Beukers-Stewart et al. (2006) J Shellfish Res
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2001/0
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2005/0
6
CP
UE
SW Coast
East Coast
Conservation Benefits Closed Area
- Increased biodiversity
- More long-lived and
fragile animals
- Increased habitat
complexity (upright
hydroids, bryozoans
etc)
- Feedback to
commercial species
Bradshaw et al. (2001; 2003)
NTZ
Arran No-Take Zone (NTZ)
• Scotland’s first No-take Zone (October 2008)
• Passed by Scottish parliament after years of campaigning by
COAST
• Designed to benefit both fisheries and conservation
University of York Research (2010-13)
Leigh Howarth Howard Wood
Angus Robson
Habitat - Photoquadrats
Tim Cross
Last three years - macroalgae within the NTZ was
found to contain hundreds of juvenile scallops
Leigh Howarth
Juvenile Scallop Density
• Abundance of scallop settlement was significantly greater
inside the reserve
Howarth et al., (2011)
Adult Scallops
*Error bars represent ±1 SE.
Kings Queens
Over 3 years
• Scallop density higher in
reserve for 3 years year
running
• Kings 1.5 times greater
inside reserve
• Queens over 3 times
greater inside reserve
Den
sit
y (
No
/100m
)
Reserve
Fishing
grounds
Scallops older and larger within reserve
0
10
20
30
40
50
<1
0
11-2
0
21-3
0
31-4
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41-5
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51-6
0
>6
1Siz
e c
om
po
sit
ion
(%
) Queen scallops NTZO…
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5
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15
20
25
30
35
<5
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51-6
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61-7
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0
81-9
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91-1
00
101
-110
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-120
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-130
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-140
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-150
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-160
>1
61
Siz
e c
om
po
sit
ion
(%
)
Size range (mm)
King scallops NTZ
OUT
Reserve
Fishing
grounds
Reserve
Fishing
grounds
Scallops & Closed Areas in the UK
Area Species Response Factors
Arran NTZ P. maximus Moderately higher
densities, size and age
inside
Variable settlement,
moderate fishing pressure
outside, some illegal
fishing, short duration of
protection.
Arran NTZ A. opercularis Moderately higher
densities, size & age
inside
As above
Port Erin CA P. maximus Much higher densities,
size and age inside
Regular settlement, high
natural densities, high
fishing pressure outside,
well enforced, long history
of protection
Port Erin CA A. opercularis Higher densities outside Variable settlement, low
natural densities, low
fishing pressure.
Llyn Peninsula SAC P. maximus Higher densities inside Moderate fishing pressure
outside, some illegal
fishing, long duration of
protection
Llyn Peninsula SAC A. opercularis Higher densities outside As above
Continued…
Area Species Response Factors
Cardigan Bay SAC P. maximus Similar densities inside &
outside
High natural disturbance,
short duration of
protection.
Cardigan Bay SAC A. opercularis Similar densities inside &
outside, highly variable
As above
Skomer MNR P. maximus Higher densities inside Negligible fishing for
scallops outside, long
duration of protection
Skomer MNR A. opercularis Similar densities inside &
outside
As above
Lundy NTZ P. maximus Similar densities and
population structure inside
& outside
Very low natural densities,
low settlement, low fishing
pressure outside, some
illegal fishing.
Devon IPA P. maximus Much higher densities,
size and age inside
High natural densities,
well enforced, long
duration of protection.
Key Messages… So Far
• Species biology is important
- permanent closures for long lived species
- flexible closures for short lived species
• Location is important – you need to understand
- distribution of suitable habitat
- larval dispersal and settlement patterns
- patterns of fishing pressure
• Recovery may be a lengthy process
• Levels of natural disturbance are important
• Enforcement is important
- industry and stakeholder buy-in is key
Implementation & Management The Real Challenge
The English Experience Marine Conservation Zones (MCZs)
127 MCZs recommended – but now only 31 being consulted on
The Northern Ireland Experience
Access priorities of the
Northern Ireland Scallop Fleet
Yates (2012)
The Northern Ireland Experience
Areas
suggested for
protection from
dredging
Closed areas
suggested for
scallop fishery
management
Are Closed Areas the Solution?
• Scallop fisheries appear ideally suited to management with networks of closed areas
• BUT… effective management outside MPAs is also essential
• A suite of tools are often needed (e.g. minimum sizes, gear modifications, effort restriction, stock enhancement)
• Mapping of benthic habitats, larval dispersal, fishing activity and resources is key to developing effective networks of closed areas
• Closed areas should be set up to benefit both fisheries & conservation wherever possible
• Industry and stakeholder involvement will improve effectiveness and reduce management costs
We All Want Sustainable Seafood
Obrigado!
Science without Borders
http://sciencewithoutborders.international.ac.uk
