Hydrodynamic Model used for Larval Dispersal Modelling
We used hydrodynamic models to estimate expected larval connectivity inS. umbilicalis . Simulated three-dimensional ocean currents from
these models were used to advect passive particles in the Lagrangian
larval dispersal model described below. The hydrodynamic model outputs
were from the NEMO Atlantic Margin Model (AMM15; Graham et al. 2018),
which has a model horizontal resolution of 1.5 km and 51
terrain-following vertical layers. Simulated flow fields are available
at hourly intervals (see Graham et al. 2018 for details of evaluation)
and the flow fields from June-Sept 2014 were used to encompass the
spawning season of S. umbilicalis . Coscia et al. (2020)
demonstrated little interannual variability in the patterns of
connectivity matrices of larvae advected using AMM15 output (2008-2014),
hence, the background connectivity for 2014 was taken as the annual
connectivity. This annual background connectivity between the spawning
sites (described below) was used for calculating multi-year spread.