Manuel Paper prop.ppt - INCOFISH

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					Average Mutual Information and fisheries
impacts


        Manuel Zetina Rejón
                            Simulation scenarios



                          2.5                                                           •   Campeche sound
                                                                                             –   Shrimp
                           2                                                                 –   Demersal
Relative fishing effort




                                                                                             –   Pelagic
                                                                                             –   Beach seine
                          1.5                                                                –   Octopus


                           1                                                            •   Terminos Lagoon
                                                                                             –   Finfish
                                                                                             –   Oyster
                          0.5                                                                –   Blue crab


                           0                                                            •   All fisheries
                                0   5   10   15    20     25     30     35   40   45   50
                                                  Years of simulation
Impact evaluation



       Persistence
           (P)                                         Magnitude
                      Recovery time                    of change
10%                                                       (MC)
                          (TR)

 0

-10%
                                                 MC
                                      Resilience=
        Disturbance                       (R)     TR

           Δ F’s
                            Time
                                                       Biomass
Effects of fisheries
                          10                                                                         15
                                  Persistence                                                             Magnitude of Change
                          8
                                                                                                     10
                          6
                                                                      Octopus
                          4
                                                                                                     5

          Axis 2 (20 %)
                                       Finfish




                                                                                 Axis 2 (9 %)
                                             Shrimp                                                            Octopus              Pelagic
                          2                                    Beach seine
                                                All                                                             Beach seine                   All
                          0                                                                          0
                                      Pelagic                                                                                        Shrimp
                          -2                                                                                                       Finfish
                                                                                                     -5            Demersal
                          -4
                          -6
                                                                                                 -10
                          -8                                  Demersal
                          -10                                                                    -15
                                -10 -8 -6 -4 -2 0 2 4             6     8   10                     -15       -10     -5     0     5       10         15
                                            Axis 1 (49 %)                                                             Axis 1 (72 %)
                          15                                                                         10
                                  Recovery time                                                           Resilience
                                                                                                      8
                          10
                                                                                                      6
                                                                                                                                          Shrimp
                                                                                                      4
          Axis 2 (10 %)




                           5                                                                                                                   All


                                                                                      Axi 2 (16 %)
                                        Octopus                                                       2       Beach seine
                                                          Shrimp
                                         Beach seine                All                                                         Pelagic
                           0                                                                          0
                                                       Finfish Pelagic                                    Octopus
                                                                                                     -2              Demersal
                          -5
                                                                                                     -4
                                            Demersal
                                                                                                     -6
                          -10                                                                                                                 Finfish
                                                                                                     -8
                          -15                                                                        -10
                                -15   -10    -5     0     5        10       15                         -10 -8 -6 -4 -2 0 2 4              6     8    10
                                              Axis 1 (70 %)                                                        Axis 1 (57 %)
                   Resilience indicator:
                   Area of change (AC)



                   1.4
                                                             BMax (t )  MaxB(i ,t )
                   1.2


                    1
                                                             BMin (t )  MinB (i ,t )
Relative Biomass




                   0.8


                   0.6
                                                             t fin

                                                    AC   ( BMax (t )  BMin (t ) ) dt
                   0.4


                   0.2
                                                             tini
                    0


                             Time



                                    Low Impacts = Low AC
                                    High Impacts = High AC
                   Area of Change
                    2.0
                    1.8                            Shrimp                                   Demersal                                   Pelagic
                    1.6
                                                       SC                                        SC                                        SC
                    1.4
                    1.2
                    1.0
                    0.8
                    0.6
                    0.4                        AC=102.8                                      AC=43.3                                AC=201.3
                    0.2


                    2.0
                                           Beach seine                                      Octopus                                     Finfish
Relative Biomass




                    1.8
                    1.6                            SC                                            SC                                          LT
                    1.4
                    1.2
                    1.0
                    0.8
                    0.6
                                                 AC=22.8                                     AC=37.0                                 AC=77.9
                    0.4
                    0.2



                    2.0
                    1.8                             Oyster                                 Blue crab                                     All
                    1.6                                LT                                         LT
                    1.4
                    1.2
                    1.0
                    0.8
                    0.6                             AC=0                                        AC=0                                AC=258.4
                    0.4
                    0.2

                          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
                      36
                                 R 2 = 0.96
                      31                                                          All
                                                                  Pelagic

                      26




RECOVERY TIME
                      21
                                                 Shrimp
                      16

                      11       Demersal
                                               Finfish
                               Octopus
                      6
                                  Beach seine
                      1
                      161
                                          R 2 = 0.97
                      141                                                         All
MAGNITUDE OF CHANGE




                                                                  Pelagic
                      121

                      101

                       81                     Finfish
                       61
                                                       Shrimp
                                Octopus
                       41

                       21              Demersal
                                   Beach seine
                           1
                                      50         100        150     200     250         300
                                                            AC
  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
                            Ci 
                I F     Ii 
                           C   
                      i 1  t  
AC vs. IF


            3.0
                                                                                            2
                                                                                       R = 0.6

            2.5
                                        All
                                          Pelagic
            2.0
                            Shrimp                               Finfish
   log AC




            1.5                       Demersal
                                                          Octopus
                                       Beach seine
                                                                             Oyster     Blue crab
            1.0


            0.5


            -
                  -   1.0       2.0         3.0            4.0             5.0        6.0        7.0
                                                     IF
Research strategy



                             Simulation
    Realistic                 scenarios        Evaluation
     Model               (changes in fishing   of Impacts
                              intensity)




                                        1.6
                                        1.4
                                        1.2
                                        1.0                   Time series
                                        0.8
                                        0.6                  Observed data
                                        0.4
                                        0.2



                                                3.0


                 Model                          2.5

                                                2.0
                Validation                      1.5

                                                1.0

                                                0.5


                                                      1984     1988   1992   1996

				
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