The ecological niche of shallow water organisms: integration of mechanicistic model to hypothesize a coastal management

The main environmental drivers shaping the ecological niche of aquatic ectotherms are habitat temperature and food, which are highly variable shallow waters due to low depth and human activity. Such variability may have repercussions on organismal life history (e.g., body size, fecundity) and to provide mechanistic predictions of the ecological responses at varying environmental conditions and possible implications in terms of growth and reproduction of organisms is a current challenge. Here I present an integrated approach combining biophysical and bioenergetic as a tool for the better management of shallow water systems. Since, life history traits in ectotherms depend on energy from food and body temperature and they are expected to significantly affect the Darwinian fitness (number of eggs per individual per life span) of main structuring species. I choose two Sicilian lagoons (Stagnone di Marsala and Pantano di Ganzirri) to test the approach. I characterised the amount of food available to secondary consumers (e.g., chlorophyll-a, lipids, proteins and carbohydrates) by seasonal samplings and the hourly water temperature for one year in different sites at different depths (i.e. 25-50-100 cm) in every basin. Food and temperature are the main input drivers to run the Dynamic Energy Budget model (DEB) of all target species (fish and bivalves) using DEB parameters estimated through intensive lab procedures (e.g., assimilation and somatic maintenance). DEB model preliminarily run in the Stagnone di Marsala with the bivalve Cerastoderma glaucum is able to estimate main life history traits at varying depths with a large consistency with field validation as also supported by a sensitivity analysis.