Towards a more complete understanding of the life cycle of brown shrimp (Crangon crangon): modelling passive larvae and juvenile transport in combination with physically forced vertical juvenile migration
Authored by Axel Temming, Ute Daewel, Corinna Schrum
Date Published: 2011
DOI: 10.1111/j.1365-2419.2011.00597.x
Sponsors:
European Union
Platforms:
No platforms listed
Model Documentation:
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Abstract
In this study we developed and utilized a complex model approach to
investigate the impact of stage-specific transport processes on the
development and spatial distribution of brown shrimp (Crangon crangon)
post-larvae and juveniles in the German Bight. First, we focused on
drift processes during the pelagic larval stage by coupling an
individual-based model for egg and larval development `off-line' to a 3D
hydrodynamic model utilizing the Lagrangian method. Secondly, we
investigated tidal-induced transport processes after juvenile
settlement. To determine the tidal cycle, the model coupling was
accomplished `on-line' by resolving the individual-based model and
hydrodynamic model with the same time step. The vertical migration of
juveniles, a prerequisite for the selective tidal stream transport
(STST), was modelled as a sub-grid scale physical process (balance of
forces: gravitation, buoyancy, Stoke's friction and dynamic uplift) and
considered complex particle dynamics. We applied the model to test
temperature and salinity cues as possible tidal indicators utilized by
juvenile brown shrimp. Our results indicated that transport processes
could significantly change the timing and spatial distribution of
post-larval abundance. We also showed that the small-scale hydrodynamic
forcing acting on the bodies of juvenile brown shrimps was sufficient to
account for the vertical migration required to use STST. For both
investigated tidal cues STST performing juvenile brown shrimp were
transported on-shore. A faster and more continuous STST was calculated
for the salinity cue, resulting in larger abundances of brown shrimp in
estuarine areas.
Tags
Simulation
Temperature
Crustacea
North-sea
Wadden sea
Baltic sea
Tidal-stream transport
Platichthys-flesus l.
Dollard ems estuary
Western sweden