This mass-balance model for Pacific oyster nurseries is designed to be used by farmers to estimate the food requirements of a given stock or the maximum stock sustained within a given food range. Please check here the type of nursery systems that the model simulates, the assumptions and limitations. Detailed model explanation is provided in this paper published at Journal of Shellfish Research.

      You can use the model by typing your values in the red frame cells and customize the parameters in the cells with yellow background (using the drop-down list). Results will be updated but not saved:

    Some comments on model application

    1. Nursery systems:

    1.1 This model simulates Pacific oyster nurseries that operate in systems such as a FLUPSY or land-based with tanks, silos, or trays.

    1.2 The system might be sitting in a natural ecosystem (estuary, bay or other coastal area), might be interconnected with bloom tanks, or fed with algae cultures.

    1.3 The model simulates the entire production system as a one compartment:

    1.3.1 For instance, if your nursery has bloom tanks you can simulate the entire system: a) insert the sum of the volume of the oyster holding unit and of the bloom tanks, b) insert the water exchange (flow rate or turnover) with the surrounding waterbody, and c) and insert a low and a high phytoplankton growth rate to test a range of community net primary production scenarios inside the system. Or you can simulate only the oyster holding unit: a) insert the volume of that unit, and b) insert the water exchange (flow rate or turnover) with the bloom tanks.

    1.3.2 If you want to simulate for instance a FLUPSY in an estuary: a) insert the volume of the FLUPSY, and b) the flow rate from the surrounding water of the entire FLUPSY not of the individual silos. Or you can simulate the individual silo inserting in the model its water volume and individual flow rate.

    2. Assumptions and limitations:

    2.1 This is a one compartment budget model that aims to capture average boundary ranges to operate the system, whereby:

    - the sources include the water inflow into the oyster nursery system and phytoplankton growth rate (in the option with the bloom tanks);

    - the sinks include the Pacific oyster filtration and the system outflow (assumed equal to the inflow).

    2.2 The mass balance is solved at steady state to ensure a given food concentration in the holding tanks. The optimum concentration to maintain in the production unit should correspond to the minimum food concentration that maximizes ingestion or to the optimum concentration for growth. The default parameterization for the Pacific oyster is set to 44 cells/microliter, in the advanced settings, based on Tamayo et al. (2014) and Walne (1972).

    2.3 Important effects that occur at a smaller scale like changes in the water flow rate due to oyster size/densities or tank shape are not simulated in the model.

    2.4 The option with bloom tanks assumes these are interconnected with the oyster holding tank, which together are the simulated unit. In this case the water inflow is the water that enters from the outside (an adjacent ecosystem for instance) into the bloom tanks forced by tidal height or pumped.

    2.5 The model includes an allometric filtration rate function (Gerdes 1983) and the temperature dependence effect that assumes optimum filtration rate for the Pacific oyster at 19ºC (Bougrier et al. 1995).

    2.6 The salinity effects on filtration rate are not simulated thus it is assumed that water salinity is higher than 20 psu.

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