WP2 (End-to-end model) is a model development package. It will build up from a 3-D full life cycle population model that has already been developed for European anchovy by Politikos et al. (2015). This model will be further elaborated, based on the knowledge that will be accumulating from WP1 and expanded to a multispecies (anchovy and sardine) 3D fish model. The latter will be two-way linked to a comprehensive lower trophic level model (POM-ERSEM) (Petihakis et al. 2009) that is currently implemented within the HCMR operational POSEIDON system (www.poseidon.hcmr.gr) (Korres et al. 2010). The already developed anchovy model will be revisited, corrected (regarding concepts and parameters) and calibrated based on the knowledge accumulating from WP1. The dynamic energy allocation module for growth and reproduction will be tuned using field estimates of seasonal changes in growth, condition and egg production from WP1. An additional new bioenergetics model will be developed for sardine; the structure of the sardine model will be similar to anchovy. Model skill assessment will be based on data collected during the project as well as those archived in the HCMR databases.
The objective is to develop a multispecies (anchovy & sardine) full life cycle (from egg to adult) individual based model that will be two-way linked to the lower trophic level model (POM-ERSEM) that has been implemented in the Aegean Sea.
Description of work
The end-to-end model will be synthesized by two main sub-models: (a) a lower trophic level ecosystem model composed by a hydrodynamic and a biogeochemical model and (b) a higher trophic level model which, in this first (pelagic) version, will include the main forage pelagic fishes in the Aegean Sea, namely, the anchovy and sardine. The abiotic environment will be represented with outputs from a hydrodynamic model (POM) that is currently operational in the Aegean Sea (Korres et al. 2010). It will provide the three dimensional fields of physical variables (currents, temperature) as inputs to the fish modules. Regarding the association of fish growth and reproduction with their environment, a biogeochemical model (ERSEM) (Petihakis et al. 2009) will provide the plankton densities which will serve as available energy via consumption for the fish modules.
Task 2.1 Model development (Month 1-16)
This task involves the development and implementation of a multispecies (anchovy & sardine) full life cycle (from egg to adult) individual based model and its extension to population model using the super-individual approach (Let et al. 2009). A 3-D full life cycle population model for the North Aegean Sea anchovy has already been developed in Politikos et. al. (2015). Here, it will be revisited, corrected (regarding concepts and parameters) and calibrated based on the knowledge accumulating from WP1. The dynamic energy allocation module for growth and reproduction will be tuned using field estimates of seasonal changes in growth, condition and egg production from WP1. An additional new bioenergetics model will be developed for sardine; the structure of the sardine model will be similar to anchovy. Finally, in order to explore fisheries scenarios a fishing mortality module will be implemented, using existing information from each species fishery and analytical stock assessments (age-dependent fishing mortality, realized fishing grounds) as well as current regulation measures (spatial and temporal closures, minimum landing sizes) that will be parameterized in the fish modules. The model will ultimately have the ability to simulate the spatiotemporal catch fields.
Task 2.2 Model skill assessment (Month 13-18)
Model predictions will be compared against data on the distribution and abundance of small pelagic fish from past surveys. Growth & reproduction data from WP1 will also be used. Quantitative methods for model skill assessment, outlined in Stow et al. (2009), will be used when applicable.
D2.1 Report on coupled models construction (Month 12)
D2.2 Manuscript on full life cycle models of anchovy and sardine (Month 16)
D2.3 Manuscript on model validation and initial model runs (Month 18)