indicators for ecosystem based management: methods and applications verena trenkel, anik brindamour,...
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Indicators for ecosystem based management:
Methods and applications
Verena Trenkel, Anik Brind’Amour, Pascal Lorance, Stéphanie Mahevas, Marie-Joëlle Rochet
Ecology and Models for Fisheries Science
Ifremer, Nantes, France
Definition
An indicator is a variable which quantifies how well a human activity is managed, in relation to specified objectives. A structured suite of indicators will reveal important system changes.
Reduce quota
Fishingmortality
Demand for food &
wealth
Less fish
Fish biomass
Ecosystem based fisheries management
DPSIR framework
Objectives
Response
PressuresDrivers
Impacts
States
Reference points, directions & enveloppes
Indicator development
Objectives
Response
PressuresDrivers
Impacts
States
Reference points, directions & enveloppes
Indicators
Indicators
Indicators
Indicator development, selection, calculation, testing…
Methods development
Objectives
Response
PressuresDrivers
Impacts
States
Reference points, directions & enveloppes
MethodsMethods
MethodsMethods
MethodsMethods
MethodsMethods
MethodsMethods
Modelling pressure-state links, combining indicators, detecting trends, evaluating impacts…
Recent examples
Example: Developing food web indicatorsExample: Developing food web indicators
Has the food web structure changed in the Mediterranean?
Albouy et al. (2011)Albouy et al. (2011)
Morphometrics= diet & habitat
Food web
Po
siti
on
in
wat
er c
olu
mn
1
Species type
PA
GE
BO
GP
AG
EE
RY
SP
ON
DC
AN
PA
GE
AC
A
DIP
LA
NN
DIP
LV
UL
MA
CO
SC
OC
AP
OA
PE
ZE
US
FA
B
AR
GE
SP
YP
HY
IBL
ES
CO
MS
CO
SP
ICS
MA
SA
RD
PIL
SP
RA
SP
RG
AD
IAR
GM
ICM
PO
UT
RIS
CA
P
AP
HIM
INM
ER
LM
ER
SP
ICF
LE
TR
AC
ME
DT
RA
CT
RA
BO
OP
BO
OE
NG
RE
NC
PE
RIC
AT
CH
EL
LU
CE
UT
RG
UR
AS
PIC
UC
LE
PT
CA
VL
EP
TD
IEC
HE
LL
AS
TR
IGL
YR
TR
IPL
AS
GO
BIN
IGH
EL
IDA
CS
CO
RS
CR
SC
OR
EL
O
SC
OR
PO
RC
AL
MM
AC
DE
LT
QU
AL
OP
HP
ISB
LE
NO
CE
SC
OR
NO
TS
OL
EV
UL
AR
NO
RU
EA
RN
OT
HO
LE
PM
BO
S
AR
NO
LA
TC
ITH
MA
CA
RN
OIM
PM
ICU
VA
RB
OT
HP
OD
RA
JA
AS
TT
OR
PM
AR
EC
HE
MY
RC
EP
OM
AC
CO
NG
CO
NL
EP
ICA
US
YN
GA
CU
TR
AH
DR
AT
RA
HR
AD
GA
IDS
PP
ME
RN
ME
RM
UL
LB
AR
MU
LL
SU
RS
ER
AC
AB
SE
RA
HE
PG
AL
UM
EL
SC
YO
CA
NS
YM
PN
IGU
RA
NS
CA
01
23
Cluster analysis on mean individual species : All traits
hclust (*, "ward")speD
He
igh
t
FG1FG5 FG3 FG4 FG2 FG6 FG7
7 Functional groups
Temporal changes in food webs
10% 50% 100% 200%Increase Decrease
Golf of LionsIonian Sea
Aegean Sea
Example: Developing food web indicatorsExample: Developing food web indicators
1010
Ecological objective: Maintain pelagic food supply for higher trophic levelsKnowledgeFew top predators & piscivores have strong pelagic prey
dependance Operational objectives
Maintain herring and sprat in the Baltic Sea as prey for cod Maintain total forage fish biomass in North Sea
State & impact indicators Prey biomass in critical area Proxy: predator condition/growth/productivity
Reference level >x tons of prey species
Pressure management TAC, effort control, escapement rules
Example: Selecting indicators for pelagic ecosystemsExample: Selecting indicators for pelagic ecosystems
Is occupancy a sensitive indicator for population abundance?
In certain cases only:• occupancy can change much less than abundance• uncertainty in catches or effort can mask changes
Example: Simulation testing population indicatorsExample: Simulation testing population indicators
Demographic rates
DepthDepth
r, K
Demographic rates1
Spatial population dynamics
2
Spatiotemporal catch & effort distribution
Spatiotemporal abundance distribution
Observations4
Time
Occ
upan
cy
5 Indicator calculation
Fishery dynamics
Eff
ort
3
Density
Trenkel et al In Press, Testing CPUE-derived spatial occupancy as an indicator for stock abundance: application to deep-sea stocks. Aquatic Living Resources DOI: 10.1051/alr/2013060 Trenkel et al In Press, Testing CPUE-derived spatial occupancy as an indicator for stock abundance: application to deep-sea stocks. Aquatic Living Resources DOI: 10.1051/alr/2013060 Trenkel et al In Press, Testing CPUE-derived spatial occupancy as an indicator for stock abundance: application to deep-sea stocks. Aquatic Living Resources DOI: 10.1051/alr/2013060
Which management indicators are sensitive and robust to uncertainty?
Example: Simulation testing management indicatorsExample: Simulation testing management indicators
ModelManagement scenarios
+
Uncertainties
Indicators
SENSITIVE to management?ROBUST to uncertainty?
Which management indicators are sensitive and robust to uncertainty?
Example: Simulation testing management indicatorsExample: Simulation testing management indicators
-5 -4 -3 -2 -1
43
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45
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47
Huret et al. 2010.
Spatialized recruitment and natural mortality
ECOMARSIBM Larvaire
Mahévas et al. 2011
Vermard et al 2008
Spatial and seasonal distribution of populations
Pelletier et al 2009
Assessing indicator performance for management
Spatial and seasonal distribution of fleets and economic behavior
Spatial modelling of fisheries dynamics Lehuta et al 2010. IJMS & 2012. FR
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45
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CB
D
A
E
Lehuta et al 2013.
Do fishing pressure differences affect differentially fish community states?
Example: Developing fishing pressure indicatorsExample: Developing fishing pressure indicators
Input Fishing intensity Fishing selectivity
Fishing mortality
Average F across species
SD(F) across species or size-classes
Catch Total catch per unit area CV(catch) across species; No species => 85%;% piscivores
Do fishing pressure differences affect differentially fish community states?
Example: Developing fishing pressure indicatorsExample: Developing fishing pressure indicators
Fishing pressure varies in space & time, but differential impacts are difficult to detect
High &selectiveremovals
Diverse catch
Piscivores preferred
For more information on our work on indicators
Come and see me
Read our publicationshttp://wwz.ifremer.fr/emh/Publications-EMH