To explore the role that fish play in aquatic ecosystems, a hydrodynamic ecological model (DYRESM-CAEDYM) was coupled to a novel fish population model. The coupled model (DYCD-FISH) combined two modelling approaches: a complex dynamic model and an individual-based model. The coupled model simulates fish growth population dynamics and predicts fish impacts on various ecosystem components, including nutrients and lower trophic levels. The model was employed to explore the role of the dominant fish in Lake Kinneret (Israel), Acanthobrama terraesanctae (Kinneret bleak, or in Hebrew, lavnun ha'kinneret; hereafter lavnun). Model results suggested that the lavnun has a significant impact (p <0.05) on the magnitude of output variables including its prey food (the predatory and microzooplankton), major nutrients such as ammonium (NH4) and phosphate (PO4), and on several phytoplankton species, but not on the seasonality of any of the output variables. Since the model incorporates trophic levels from nutrients to fish, it revealed the nonlinear dynamic impacts of fish on different ecosystem components and in particular has led to quantitative insights into the relative influence of top-down control on water quality attributes. Besides being an ecosystem research tool, DYCD-FISH can also be employed as a fishery management tool, and in particular facilitate ecosystem-based fishery management.
|Journal||Canadian Journal of Fisheries and Aquatic Sciences|
|Publication status||Published - 2011|