How biophysical interactions associated with sub-and mesoscale structures and migration behavior affect planktonic larvae of the spiny lobster in the Juan Fernandez Ridge: A modeling approach
Authored by Carolina Parada, Billy Ernst, Carolina Medel, Carmen E Morales, Oscar Pizarro, Carlos Conejero
Date Published: 2018
DOI: 10.1016/j.pocean.2018.02.017
Sponsors:
No sponsors listed
Platforms:
Java
Ichthyop
Model Documentation:
Other Narrative
Model Code URLs:
Model code not found
Abstract
The Juan Fernandez Ridge (JFR) is a chain of topographical elevations in
the eastern South Pacific (similar to 33-35 degrees S, 76-81.5 degrees
W). Rich in endemic marine species, this ridge is frequently affected by
the arrival of mesoscale eddies originating in the coastal upwelling
zone off central-southern Chile. The impacts of these interactions on
the structure and dynamics of the JFR pelagic system have, however, not
been addressed yet. The present model based study is focused on the
coupled influence of mesoscale-submesoscale processes and biological
behavior (i.e., diel vertical migration) on the horizontal distribution
of planktonic larvae of the spiny lobster (Jasus frontalis) around the
JFR waters. Two case studies were selected from a hydrodynamic Regional
Ocean Modeling System to characterize mesoscale and submesoscale
structures and an Individual-based model (IBM) to simulate diel vertical
migration (DVM) and its impact on the horizontal distribution and the
patchiness level. DVM behavior of these larvae has not been clearly
characterized, therefore, three types of vertical mechanisms were
assessed on the IBM: (1) no migration (LG), (2) a short migration (0-50
m depth, DVM1), and (3) a long migration (10-200 m depth, DVM2). The
influence of physical properties (eddy kinetic energy, stretching
deformation and divergence) on larval aggregation within meso and
submesoscale features was quantified. The patchiness index assessed for
mesoscale and submesoscale structures showed higher values in the
mesoscale than in the submesoscale. However, submesoscale structures
revealed a higher accumulation of particles by unit of area. Both
vertical migration mechanisms produced larger patchiness indices
compared to the no migration experiment. DVM2 was the one that showed by
far the largest aggregation of almost all the aggregation zones. Larval
concentrations were highest in the submesoscale structures; these zones
were characterized by low eddy kinetic energy, negative stretching
deformation, and slight convergence. Stretching deformation flow
appeared to be triggered by the eddy-eddy interactions and the Robinson
Island barrier effect, and it likely promotes the aggregation of the
spiny lobster larvae in the Juan Fernandez system. These results
highlighted the importance of the coupled effect of physical (mesoscale
and submesoscale oceanographic features) and biological processes (DVM)
in the generation of larval patchiness and concentration of spiny
lobster larvae around the JFR, which could be key for their survival and
retention in those waters.
Tags
individual-based models
Population connectivity
California current system
Diel vertical migration
Humboldt current system
Marine populations
Central-southern chile
Patchiness
Mesoscale and submesoscale features
Juan fernandez ridge
Spiny lobster larval dispersion
Regional ocean modeling system and
Southeastern pacific-ocean
Boundary upwelling
systems
Satellite chlorophyll-a
Coastal
transition zone
Peru-chile undercurrent