Final answer:
The quantity for mussels (app) depends on the maximum number that can be farmed sustainably. The limiting factor for mussels is the amount of phytoplankton they feed on. Data on the growth rates of mussels under different phytoplankton concentrations can be used to justify or refute this suggestion.
Step-by-step explanation:
The quantity for mussels (app) would depend on the maximum number of mussels that can be farmed each month while maintaining a sustainable system. According to the scenario, the limiting factor for mussels is the amount of phytoplankton they feed on. To justify or refute this suggestion, data on the rates of growth of newly established mussel cultures in a lab under different phytoplankton concentrations could be used. By comparing the rate of growth of mussel cultures under different phytoplankton concentrations, it would be possible to determine the impact of phytoplankton on mussel farming.