average mutual information and fisheries impacts manuel zetina rejn
DESCRIPTION
Impact evaluation Time Relative Biomass 0 10% -10% Biomass MC TR Resilience= (R) Persistence (P) Recovery time (TR) Magnitude of change (MC) Disturbance Δ F’sTRANSCRIPT
Average Mutual Information and fisheries impacts
Manuel Zetina Rejón
Simulation scenarios
0
0.5
1
1.5
2
2.5
0 5 10 15 20 25 30 35 40 45 50Years of simulation
Rel
ativ
e fis
hing
effo
rt
• Campeche sound– Shrimp– Demersal– Pelagic– Beach seine– Octopus
• Terminos Lagoon– Finfish– Oyster– Blue crab
• All fisheries
Impact evaluation
Time
Rela
tive
Bio
mas
s
0
10%
-10%
Biomass
MC
TRResilience=
(R)
Persistence(P)
Recovery time(TR)
Magnitudeof change
(MC)
Disturbance
Δ F’s
Effects of fisheries
AllShrimp
Demersal
Pelagic
Beach seine
OctopusFinfish
-10-8-6-4-20246810
-10 -8 -6 -4 -2 0 2 4 6 8 10Axis 1 (49 %)
Axi
s 2
(20
%)
Persistence
AllShrimp
Demersal
PelagicBeach seine
Octopus
Finfish
-15
-10
-5
0
5
10
15
-15 -10 -5 0 5 10 15Axis 1 (72 %)
Axi
s 2
(9 %
)
Magnitude of Change
AllShrimp
Demersal
PelagicBeach seine
Octopus
Finfish
-15
-10
-5
0
5
10
15
-15 -10 -5 0 5 10 15Axis 1 (70 %)
Axi
s 2
(10
%)
Recovery time
AllShrimp
Demersal
PelagicBeach seine
Octopus
Finfish
-10-8-6-4-20246810
-10 -8 -6 -4 -2 0 2 4 6 8 10Axis 1 (57 %)
Axi
2 (1
6 %
)
Resilience
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Time
Rela
tive
Biom
ass
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Time
Rela
tive
Biom
ass
Resilience indicator:Area of change (AC)
),()( tit MaxBBMax
),()( tit MinBBMin
dtBMinBMaxACfin
ini
t
ttt )( )()(
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Time
Rela
tive
Biom
ass
Low Impacts = Low ACHigh Impacts = High AC
Area of Change
0.20.40.60.81.01.21.41.61.82.0
0.20.40.60.81.01.21.41.61.82.0
2 6 10 14 18 22 26 30 34 38 42 46 50 2 6 10 14 18 22 26 30 34 38 42 46 50 2 6 10 14 18 22 26 30 34 38 42 46 50
Years of Simulation
0.20.40.60.81.01.21.41.61.82.0
ShrimpSC
Rel
ativ
e B
iom
ass
DemersalSC
PelagicSC
Beach seineSC
FinfishLT
OctopusSC
OysterLT
Blue crabLT
All
AC=102.8 AC=43.3 AC=201.3
AC=22.8 AC=37.0 AC=77.9
AC=0 AC=0 AC=258.4
AllPelagic
Finfish
Shrimp
Demersal
Octopus
Beach seine
R 2 = 0.97
1
21
41
61
81
101
121
141
161
50 100 150 200 250 300AC
MA
GN
ITU
DE
OF
CH
AN
GE
AllPelagic
Finfish
Shrimp
Demersal
Octopus
Beach seine
R2 = 0.96
1
6
11
16
21
26
31
36
REC
OVE
RY
TIM
E
Information Theory (Ulanowicz, 1986)Average Mutual Information ( I ) measures the probability that a unit of energy flows to certain destination.
When uncertainty of the destination is high, I is bigger, quantifies degree of articulation in network/models.
Measure of organization, higher in mature and complex systems.
The I is higher while more complex trophic links.
I = Lower I = Higher
Hypothesis
When a fishery catch or remove biomass of group of species with simple trophic links, the impact of this fishery could be more severe, making ecosystem's stability and resilience vulnerable when high biomasses are extracted from the system
Average Mutual Information ( IF )
n
ii
t
iF I
CCI
1
AC vs. IF
Oyster Blue crab Beach seine
Octopus Demersal
Shrimp Finfish
Pelagic All
R 2 = 0.6
-
0.5
1.0
1.5
2.0
2.5
3.0
- 1.0 2.0 3.0 4.0 5.0 6.0 7.0
I F
log
AC
Realistic Model
Simulation scenarios
(changes in fishingintensity)
Evaluationof Impacts
ModelValidation
Research strategy
0.20.40.60.81.01.21.41.6
Time seriesObserved data
0.5
1.0
1.5
2.0
2.5
3.0
1984 1988 1992 1996