Benthic-pelagic uncoupling between the Northern Patagonian Frontal System and Patagonian scallop beds

Abstract

Availability of planktonic food in the bottom is the most important factor to explain the persistence and recurrent localization of Patagonian scallop (Zygochlamys patagonica) populations. The establishment of the scallop Sea Bay bed (SBB) has been related with food supply from the Northern Patagonian Frontal System (NPFS). In this article outputs from high resolution numerical models combined with particle tracking methods were used to identify for the first time potential physical mechanisms of food transfer. The model results showed no evidence of benthic-pelagic coupling between the NPFS and the SBB. They also revealed that the dominant instantaneous semidiurnal tidal currents and the mean N-NE flow on the inner-middle Patagonian shelf are the main dynamical mechanisms preventing particles released at the surface of the NPFS to reach the SBB area. Sensitivity studies changing the stochastic numerical method for solving the particle trajectories, the release month and location of the particles, the magnitude of the horizontal turbulent diffusion and the frequency of the wind forcing did not alter this conclusion significantly.