In short, Gadget indicates that Blackspot Seabream population of the Strait of
Gibraltar shows a concerning biomass level and that the total biomass gets the lowest
value in the last year analyzed (2016) (Fig. 19.15).
19.6.7 Simulation of Fish Populations (SimFish Model)
The simulation of fish population dynamics (SimFish model) is based on the model
proposed by Gutiérrez-Estrada et al. (2017) which was compiled in its first version in
the SimFish 1.0 program. An improved version has been implemented in SFish
Subclass 1.1. SFish works under three basic assumptions: (1) over a sufficiently long
period of time, the biomass of a fish population tends to reach a dynamic equilibrium
that oscillates around an average value (persistence principle); (2) the environmental
conditions under which the parameters of the general growth model calculated
remain constant throughout the simulation and; and (3) under the premise of
environmental invariability, the variation in the abundance of a population is linearly
dependent on the abundance of the resource in the past and the number of catches, so
Fig. 19.7 Length distribution from Moroccan fleet from 2014 to 2016. Dotted lines denote the
observed values while solid lines correspond to the model predictions
644
J. Gil-Herrera et al.
Gibraltar shows a concerning biomass level and that the total biomass gets the lowest
value in the last year analyzed (2016) (Fig. 19.15).
19.6.7 Simulation of Fish Populations (SimFish Model)
The simulation of fish population dynamics (SimFish model) is based on the model
proposed by Gutiérrez-Estrada et al. (2017) which was compiled in its first version in
the SimFish 1.0 program. An improved version has been implemented in SFish
Subclass 1.1. SFish works under three basic assumptions: (1) over a sufficiently long
period of time, the biomass of a fish population tends to reach a dynamic equilibrium
that oscillates around an average value (persistence principle); (2) the environmental
conditions under which the parameters of the general growth model calculated
remain constant throughout the simulation and; and (3) under the premise of
environmental invariability, the variation in the abundance of a population is linearly
dependent on the abundance of the resource in the past and the number of catches, so
Fig. 19.7 Length distribution from Moroccan fleet from 2014 to 2016. Dotted lines denote the
observed values while solid lines correspond to the model predictions
644
J. Gil-Herrera et al.