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Pelagic Indicators. EU INCO-DEV Knowledge Base for fisheries management (KNOWFISH) Tracey Fairweather & Carl van der Lingen Marine and Coastal Management. Why do we want indicators?. UNCED (1992) & UN CSD (1994) - Indicators: decision-making in self-regulating system - PowerPoint PPT Presentation
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Pelagic IndicatorsPelagic Indicators
EU INCO-DEV EU INCO-DEV Knowledge Base for fisheries management (KNOWFISH)Knowledge Base for fisheries management (KNOWFISH)
Tracey Fairweather & Carl van der LingenTracey Fairweather & Carl van der LingenMarine and Coastal ManagementMarine and Coastal Management
Why do we want indicators?Why do we want indicators? UNCED (1992) & UN CSD (1994) - Indicators:UNCED (1992) & UN CSD (1994) - Indicators:
decision-making in self-regulating system decision-making in self-regulating system convey crucial technical information to non-technical usersconvey crucial technical information to non-technical users framework for evaluating managementframework for evaluating management
SA committed to WSSD goal of implementing EAF:SA committed to WSSD goal of implementing EAF: quantitative ecosystem indicators & define reference pointsquantitative ecosystem indicators & define reference points integrate ecological, environmental, social & economic integrate ecological, environmental, social & economic
perspectivesperspectives
Challenges: Challenges: Selection Selection Reference pointsReference points CommunicatingCommunicating Response timeResponse time
The SA Pelagic Case Study…The SA Pelagic Case Study…
Fishery overviewFishery overview Catches, products, Catches, products,
management…management…
Candidate indicatorsCandidate indicators Selected examplesSelected examples
ConclusionsConclusions Management implications…Management implications…
Fishery OverviewFishery Overview Fish caught using Fish caught using
a purse-seine net.a purse-seine net.
Multi-species Multi-species fisheryfishery
3 dominant species 3 dominant species >95% of landings>95% of landings
Other species:Other species: juvenile Cape juvenile Cape
horse mackerel horse mackerel (maasbanker)(maasbanker)
chub mackerelchub mackerel lantern fishlantern fish light fishlight fish
anchovy
sardine
redeye round herring
Catches & VariabilityCatches & Variability Large volume fishery Large volume fishery
avg. ~ 300 000t p.a.avg. ~ 300 000t p.a. 2004 = 42004 = 4thth consecutive consecutive
yr landings >500 000tyr landings >500 000t
Sardine catches have Sardine catches have steadily increased in the steadily increased in the last decade.last decade.
Fishing predominantly Fishing predominantly inshore off the west and inshore off the west and southwest coasts. southwest coasts.
Small pelagic species are Small pelagic species are subject to inherent, large-subject to inherent, large-scale fluctuations in scale fluctuations in population size.population size.
Anchovy
Sardine
Catch distribution 1987-19980
100
200
300
400
500
600
1949
1952
1955
1958
1961
1964
1967
1970
1973
1976
1979
1982
1985
1988
1991
1994
1997
2000
2003
year
tho
usa
nd
s o
f t
on
s
ANCHOVY
SARDINE
REDEYE
Products & Socio-EconomicsProducts & Socio-Economics Anchovy are reduced to fish oil Anchovy are reduced to fish oil
and meal (70% caught are and meal (70% caught are recruits ~ 6 months). recruits ~ 6 months).
sardine are canned - pet & sardine are canned - pet & human consumption, frozen or human consumption, frozen or used for bait (adult fish).used for bait (adult fish).
Redeye are reduced to fish oil Redeye are reduced to fish oil and meal, some are canned.and meal, some are canned.
Value of the fishery ~ R1 billion Value of the fishery ~ R1 billion in 2003.in 2003.
Fishery employs ~ 8 000 workers Fishery employs ~ 8 000 workers 5 300 full-time 5 300 full-time 2 500 part-time2 500 part-time 700 sea-going700 sea-going 7100 factory workers7100 factory workers
SA’s most transformed fishery.SA’s most transformed fishery.
Research & ManagementResearch & Management Fishery independent surveys Fishery independent surveys
conducted twice a yearconducted twice a year recruitment strength (May)recruitment strength (May) spawner biomass (Nov)spawner biomass (Nov)
Hydro-acoustics used to Hydro-acoustics used to estimate fish biomass. estimate fish biomass.
Multi-species fishery = Multi-species fishery = significant by-catch problems.significant by-catch problems.
By-catch problem 1: juvenile By-catch problem 1: juvenile anchovy & sardine school anchovy & sardine school togethertogether..
By-catch problem 2: adult By-catch problem 2: adult sardine & redeye school sardine & redeye school together.together.
Commercial catches sampled by Commercial catches sampled by inspectors, field station inspectors, field station personnel and observers.personnel and observers.
Candidate IndicatorsCandidate Indicators
Mean length of catch Mean length of catch Total mortality Total mortality Exploitation rateExploitation rate Ratio of by-catchRatio of by-catch Length at 50% maturity Length at 50% maturity Centre of gravity of catchesCentre of gravity of catches
Methods from literature Methods from literature Addressed stakeholder concernsAddressed stakeholder concerns
Length at 50% maturityLength at 50% maturity L50 documented as declining L50 documented as declining
following heavy exploitation and following heavy exploitation and collapse of the collapse of the sardine sardine resource resource and increasing during stock and increasing during stock recovery. recovery.
Such plasticity could be caused by Such plasticity could be caused by a number of factors in a number of factors in combination.combination.
Maturity ogives calculated for 5 Maturity ogives calculated for 5 periods within the time series.periods within the time series.
annual sardine Lannual sardine L5050 & sardine & sardine spawner biomass = highly spawner biomass = highly significant positive correlation significant positive correlation (R(R22=0. 452, p<0.01, n=49).=0. 452, p<0.01, n=49).
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
caudal length (cm)
% m
atu
re f
emal
es
1953-64
1965-75
1976-87
1988-95
1996-04
50%
15
16
17
18
19
20
21
22
1953 1958 1962 1966 1970 1974 1978 1982 1987 1991 1996 2000 2004
year
cau
dal
len
gth
(cm
)
0
1
2
3
4
5
mill
ion
s o
f to
ns
sardine L50
sardine spawner biomass
L50L50 Each moving average data series for Each moving average data series for
sardine sardine provided increasingly better fits:provided increasingly better fits:
3yr R3yr R22=0.575 (0.715 polynomial)=0.575 (0.715 polynomial) 5yr R5yr R22=0.729 (0.818 polynomial)=0.729 (0.818 polynomial) 7yr R7yr R22=0.821 (0.870 polynomial)=0.821 (0.870 polynomial)
Anchovy Anchovy data collected during annual data collected during annual fisheries independent surveys since 1984.fisheries independent surveys since 1984.
Annual anchovy L50 has no correlation Annual anchovy L50 has no correlation (R(R22=0.008) to spawner biomass est. =0.008) to spawner biomass est.
Shorter-lived species = less Shorter-lived species = less maneuverability in age at maturity. maneuverability in age at maturity.
This indicator will be of limited use for This indicator will be of limited use for monitoring anchovy. But suggested monitoring anchovy. But suggested descriptive indicator descriptive indicator for sardine.for sardine.
15
16
17
18
19
20
21
1953 - 59 1961 - 67 1969 - 75 1977 - 83 1985 - 91 1993 - 99
year
cau
da
l len
gth
(cm
)
0.0
0.5
1.0
1.5
2.0
bio
mas
s (x
106
ton
s)
L50 FS 7 biomass 7
15
16
17
18
19
20
21
1953 - 57 1961 - 65 1969 - 73 1977 - 81 1985 - 89 1993 - 97
year
cau
da
l len
gth
(cm
)
0.0
0.5
1.0
1.5
2.0
bio
mas
s (x
106 t
on
s)
L50 FS 5 biomass 5
15
16
17
18
19
20
21
1953 - 55 1962 - 64 1971 - 73 1980 - 82 1989 - 91 1998 - 2000
year
cau
dal
len
gth
(c
m)
0.0
0.5
1.0
1.5
2.0
2.5
bio
mas
s (x
106 t
on
s)
L50 FS 3 biomass 3
3 year
5 year
7 year
15
16
17
18
19
20
21
1953 - 59 1961 - 67 1969 - 75 1977 - 83 1985 - 91 1993 - 99
year
cau
da
l len
gth
(cm
)
0.0
0.5
1.0
1.5
2.0
bio
mas
s (x
106
ton
s)
L50 FS 7 biomass 7
15
16
17
18
19
20
21
1953 - 57 1961 - 65 1969 - 73 1977 - 81 1985 - 89 1993 - 97
year
cau
da
l len
gth
(cm
)
0.0
0.5
1.0
1.5
2.0
bio
mas
s (x
106 t
on
s)
L50 FS 5 biomass 5
15
16
17
18
19
20
21
1953 - 55 1962 - 64 1971 - 73 1980 - 82 1989 - 91 1998 - 2000
year
cau
dal
len
gth
(c
m)
0.0
0.5
1.0
1.5
2.0
2.5
bio
mas
s (x
106 t
on
s)
L50 FS 3 biomass 3
3 year
5 year
7 year
RxBi Proportion of By-catchRxBi Proportion of By-catch estimated separately for each of 3 target fisheries: anchovy, estimated separately for each of 3 target fisheries: anchovy,
sardine & redeye. Rsardine & redeye. RssBBAA & R & RRRBBAA will be discussed. will be discussed.
RRssBBAA = mainly juvenile sardine. = mainly juvenile sardine. NB management issue.NB management issue. RRssBBAA & ratio of sardine SB to & ratio of sardine SB to
anchovy SB = strong correlationanchovy SB = strong correlation RR22=0.791 & p<0.01=0.791 & p<0.01
RRRRBBAA = mainly juvenile redeye. = mainly juvenile redeye. Similar pattern to RSimilar pattern to RSSBBAA
RRRRBBAA & ratio redeye SB to & ratio redeye SB to anchovy SB = strong correlationanchovy SB = strong correlation
RR22=0.682 & p<0.01=0.682 & p<0.01
RRssBBAA & R & RRRBBA A can be used as can be used as descriptive indicatorsdescriptive indicators. .
0%
10%
20%
30%
40%
1987 1989 1991 1993 1995 1997 1999 2001 2003
year
pro
p o
f d
irec
ted
cat
ch
0
1
2
3
4
5
sard
ine
bio
mas
san
cho
vy b
iom
ass
PSBa
Bs/BaSardine by-catch
0%
2%
4%
6%
8%
10%
12%
1987 1989 1991 1993 1995 1997 1999 2001 2003
year
pro
p o
f d
irec
ted
cat
ch
0
2
4
6
8
red
eye
bio
mas
san
cho
vy b
iom
assPRBa
Br/Ba
Redeye by-catch
RxBi – Management ImplicationsRxBi – Management Implications Flowcharts intro in 1998 for catch Flowcharts intro in 1998 for catch
categorization (adult TL>16.5cm). categorization (adult TL>16.5cm). Revised in 2003 (adult TL>14cm).Revised in 2003 (adult TL>14cm).
Given the annual L50 – only Given the annual L50 – only 16% 16% of of sardine directed catchsardine directed catch (R (RSSBBSS) ) should be considered should be considered adultadult..
Given TL cut off – Given TL cut off – 71%71% of of sardine sardine by-catch by-catch (R(RSSBBAA) should be ) should be considered considered adult adult sardine, NOT sardine, NOT juvenile.juvenile.
Given the annual L50 – only Given the annual L50 – only 12%12% of of RRSSBBRR should be considered should be considered adultadult..
These results contradict what is These results contradict what is known about the fishery. known about the fishery.
% of sardine-directed sardine catch which is adult
0%
20%
40%
60%
80%
100%
1999 2000 2001 2002 2003
year & category
%
L50 flowchart
% anchovy-directed sardine by-catch which is adult
0%
20%
40%
60%
80%
100%
1999 2000 2001 2002 2003
area & category
%
L50 flowchart
% redeye-directed sardine by-catch which is adult
0%
20%
40%
60%
80%
100%
1999 2000 2001 2002 2003
area & category
%
L50 flowchart
Exploitation rate = F/ZExploitation rate = F/Z
Sardine Sardine Z calculated using Z calculated using von Bertalanffy parameters.von Bertalanffy parameters.
Sardine E < 0.4Sardine E < 0.4 Sardine E not correlated to Sardine E not correlated to
biomass.biomass. But sardine biomass has But sardine biomass has
increased steadily since 1984.increased steadily since 1984. Conclude: sardine Conclude: sardine
management successful.management successful.
Target reference point E*=0.4Target reference point E*=0.4 F=C/N & is assumed to include discards.F=C/N & is assumed to include discards.
Anchovy Anchovy Z derived from Z derived from ecosystem model.ecosystem model.
Anchovy E <0.4 Anchovy E <0.4 Anchovy E weakly correlated Anchovy E weakly correlated
to biomass to biomass Anchovy biomass has also Anchovy biomass has also
increased since 1984.increased since 1984. E = effective performance E = effective performance
indicator for both species.indicator for both species.
0.0
0.1
0.2
0.3
0.4
0.5
1984 1986 1988 1990 1992 1994 1996 1998 2000 2002
year
ex
plo
ita
tio
n r
ate
Fa/Ze
E*
0.0
0.4
0.8
1.2
1984 1988 1992 1996 2000 2004
year
exp
loit
atio
n r
ate Es Kerstan E*
Centre of gravityCentre of gravity To determine changes in the geographical location of catches To determine changes in the geographical location of catches
between years.between years.
Centre of gravity = centroid + axes showing extent of CV.Centre of gravity = centroid + axes showing extent of CV.
A centroid is the weighted mean location (longitude ; latitude) of A centroid is the weighted mean location (longitude ; latitude) of catches for a year.catches for a year.
Centroids of commercial catches of anchovy, sardine by-catch and Centroids of commercial catches of anchovy, sardine by-catch and directed sardine were calculated. directed sardine were calculated.
The majority of catches are taken close inshore between Saldanha The majority of catches are taken close inshore between Saldanha Bay and Gans Bay.Bay and Gans Bay.
The coastline and commercial catch position information was The coastline and commercial catch position information was linearised to aid interpretation of this indicator.linearised to aid interpretation of this indicator.
ECO-UP
1 – 100 100 – 200 200 – 300 300 – 400 400 – 600
Anchovy Catch (tons x 103)
Hout Bay
Cape Point Gans BayCape Agulhas
1993
1995 & 98
1990
1987
20022003
20001992
1999
19881991
1996
19972004
1989
1994
1 – 10 10 – 20 20 – 30 30 – 40 40 – 60
Sardine By-Catch (tons x 103)1995
19872003
2001
19981990
2004
1989
1994
1996
1991 1992 1993
1988
2000
19971999
1 – 100 100 – 200 200 – 300 300 – 400 400 – 600
Sardine Catch (tons x 103)
St Helena Bay
Cape Columbine
Saldanha Bay
19901987
1988
1989
1997 2003 20042002
1992
2001
1991
1999 20001998
1995 1996 1993 1994
1 – 100 100 – 200 200 – 300 300 – 400 400 – 600
Anchovy Catch (tons x 103)
Hout Bay
Cape Point Gans BayCape Agulhas
1993
1995 & 98
1990
1987
20022003
20001992
1999
19881991
1996
19972004
1989
1994
1 – 100 100 – 200 200 – 300 300 – 400 400 – 600
Anchovy Catch (tons x 103)
Hout Bay
Cape Point Gans BayCape Agulhas
1993
1995 & 98
1990
1987
20022003
20001992
1999
19881991
1996
19972004
1989
1994
1 – 10 10 – 20 20 – 30 30 – 40 40 – 60
Sardine By-Catch (tons x 103)
1 – 10 10 – 20 20 – 30 30 – 40 40 – 60
Sardine By-Catch (tons x 103)1995
19872003
2001
19981990
2004
1989
1994
1996
1991 1992 1993
1988
2000
19971999
1 – 100 100 – 200 200 – 300 300 – 400 400 – 600
Sardine Catch (tons x 103)
St Helena Bay
Cape Columbine
Saldanha Bay
19901987
1988
1989
1997 2003 20042002
1992
2001
1991
1999 20001998
1995 1996 1993 1994
1 – 100 100 – 200 200 – 300 300 – 400 400 – 600
Sardine Catch (tons x 103)
1 – 100 100 – 200 200 – 300 300 – 400 400 – 600
Sardine Catch (tons x 103)
St Helena Bay
Cape Columbine
Saldanha Bay
19901987
1988
1989
1997 2003 20042002
1992
2001
1991
1999 20001998
1995 1996 1993 1994Ann
ual C
atch
Ann
ual C
atch
ECO-UP
Conclusions…Conclusions…Indicator & what Indicator & what it measuresit measures
Ecosystem -Ecosystem -Biological InfoBiological Info
Stakeholder Stakeholder ConcernConcern
Potential Potential UsefulnessUsefulness
L50L50 – how big – how big sardine are when sardine are when they maturethey mature
Large biomass = Large biomass = large L50large L50
Indicates stock Indicates stock collapsecollapse
Descriptive Descriptive IndicatorIndicator
PSBPSBAA – –
proportion juv. proportion juv. sardine in sardine in anchovy catchanchovy catch
Relative recruitment Relative recruitment of the two speciesof the two species
Catch juv = negative Catch juv = negative impact on adultsimpact on adults
Flexibility to deal Flexibility to deal with fluctuationswith fluctuations
Max 20% trade-off Max 20% trade-off (sliding sigmoid (sliding sigmoid curve) included in curve) included in OMP-04OMP-04
Z Z && E E – prop of – prop of fish dying & how fish dying & how heavily fishedheavily fished
Fishing at a low Fishing at a low exploitation rate. exploitation rate. Mgmt has been Mgmt has been conservative to conservative to rebuild stocks. rebuild stocks. Impact of F ltd.Impact of F ltd.
Impact of F is critical Impact of F is critical @ low biomass@ low biomass
Conclusions…Conclusions…Indicator & what Indicator & what it measuresit measures
Ecosystem -Ecosystem -Biological InfoBiological Info
Stakeholder Stakeholder ConcernConcern
Potential Potential UsefulnessUsefulness
LbarLbar – mean – mean length of catchlength of catch
Monitor fisheryMonitor fishery Change is size = Change is size = problem problem
Market implicationsMarket implications
NB Lbar + L50NB Lbar + L50
Need to manage Need to manage by-catchby-catch
Centroids – mean Centroids – mean location of location of catchescatches
Extended range = Extended range = high biomass high biomass Expansion or Expansion or contraction of fish contraction of fish distribution = fisherydistribution = fishery
What does change What does change in distribution mean?in distribution mean?
Has implications…Has implications…
Population Population structure = key structure = key issue – need to issue – need to monitor TAB monitor TAB
Few indicators were applicable to anchovy for two main reasons: the logistics of data collection and the implications of being a short-lived particularly small pelagic fish.
Can we incorporate KNOWFISH Can we incorporate KNOWFISH indicators into management ?indicators into management ?
Determine appropriate suite of indicators for management using refined Determine appropriate suite of indicators for management using refined selection criteria from a rigorous scoring procedure, e.g.:selection criteria from a rigorous scoring procedure, e.g.:
Rochet and Rice 2005: Rochet and Rice 2005: concreteness, theoretical basis, public concreteness, theoretical basis, public awareness, cost, measurement, availability of historic data, awareness, cost, measurement, availability of historic data, sensitivity, responsiveness, specificity.sensitivity, responsiveness, specificity.
Degnbol & Jarre 2004:Degnbol & Jarre 2004: acceptability among stakeholders, acceptability among stakeholders, observability, relation to fisheries management (traffic light approach).observability, relation to fisheries management (traffic light approach).
Assess if indicators are redundant, consider cost and ease of translation Assess if indicators are redundant, consider cost and ease of translation into practical management measures.into practical management measures.
Where possible, these indicators will be incorporated into Pelagic Where possible, these indicators will be incorporated into Pelagic fisheries management in the coming year.fisheries management in the coming year.
Thank youThank you
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