Spatially explicit seston depletion index to optimize shellfish culture

Abstract

Cultivated bivalves rely on natural seston for growth and metabolic processes. Because seston is a limited resource, there is a need to better understand its distribution and fluxes within culture embayments, so farms can be positioned optimally within these dynamic systems. In this study, a simple numerical tool was developed and implemented to address actual management issues related to the positioning of oyster Crassostrea virginica farms in the Richibucto Estuary (eastern Canada). The versatile procedure relied on hydrodynamic modelling and tracer advection−dispersion to reproduce the spatial and temporal dynamics of seston availability. The model identified 3 areas of interest within the estuary, each with unique water renewal rates and seston concentrations. The method also revealed major interactions between the different areas, and proved efficient in quantifying the effects of topographical alterations on seston availability. Our results suggest that such basic modelling tools produce relevant information in a timely manner, and thereby facilitate the necessary dialogue between science advisors, industry stakeholders and resource managers.

Measuring the effects of bivalve mariculture on water quality in northern New Zealand using 15 years of MODIS-Aqua satellite observations

“…Gernez et al 2014Gernez et al , 2017, direct monitoring of harvest species (e.g. Filgueira et al 2014) and bio-physical modelling (Broekhuizen et al 2005, Guyondet et al 2013, Rowe et al 2017).…”

Picophytoplankton contribution to Mytilus edulis growth in an intensive culture environment

“…In such cases, phytoplankton depletion has a direct negative effect on shellfish performance (Smaal et al 2013). Dense populations of bivalves have the filtration capacity to effectively reduce suspended seston concentrations (Dame 1996;Strohmeier et al 2005;Guyondet et al 2013) and impose a strong control on phytoplankton populations (Dame 1996;Prins et al 1998;Newell 2004;Maar et al 2007;Cranford et al 2009;Strohmeier et al 2012;Filgueira et al 2014b). Food availability, however, is not only a function of particle concentration, but also particle size characteristics and the suspension feeder's capacity to retain these particles (Strohmeier et al 2012).…”

Comparing physical and biological impacts on seston renewal in a tidal bay with extensive shellfish culture

“…Whereas these basin-wide carrying capacity assessments have been successfully applied, the strong filtration induced by shellfish also modulates the spatial distribution of phytoplankton and other particulate organic matter (POM) and affects their replenishment (Grangeré et al, 2010;Guyondet et al, 2013). Generally, seston distribution and renewal are thought to be predominately driven by hydrodynamic conditions in estuaries worldwide ranging from Chesapeake Bay (North et al, 2004) to smaller ones (Carter, 1976;Chaparro et al, 2008;Moser et al, 2005).…”