Model and calibration

Short description of the model

Model Calibration

• 13 species
• 4 fleets
• 2006-2010 effort & catch data

The ecosystem-based model

Among the thirty exploited species in the coastal fishery of French Guiana, thirteen were selected for the model as shown in Table 1. They  represent 88% of the total landing from 2006 to 2009. A virtual fourteenth species which stands for marine producers was added. A potential trophic web displayed was built with these selected species, according to their diet  and their trophic level (Table 1).

The bio-economic dynamic model relies on a Lotka–Volterra prey–predator dynamics with  14 species  and  4 fleets exploiting them as displayed in Fig. 1.

${x}_{i}\left(t+1\right)={x}_{i}\left(t\right)\left(1+{r}_{i}+\sum _{\mathrm{species j}}{s}_{ij}{x}_{j}\left(t\right)-\sum _{\mathrm{fleet f}}{q}_{if}{e}_{j}\left(t\right)+{\mathrm{ϵ}}_{i}\left(t\right)\right)$

Data and calibration

Values used to define the model parameters came from different sources. In particular, daily observations of catches Hi,j(t) and fishing efforts ef(t) from the landing points all along the coast are available from January 2006 to December 2009.The literature and Fishbase  provided qualitative trophic interactions and intrinsic growth rates to start the calibration. Initial stocks, catchabilities, trophic intensities were estimated through a least square method fitting the historical and estimated catches.

 catches: ${h}_{if}\left(t\right)={q}_{fi}{e}_{f}\left(t\right){x}_{i}\left(t\right)\text{.}$ efforts: ${e}_{f}\left(t\right)\text{.}$

Updated on 02/02/2016