Final answer:
The correct way to display live shellfish in a tank in a foodservice establishment is to maintain proper water quality, which involves monitoring water conditions to ensure the health and survival of aquatic life.
Step-by-step explanation:
To display live shellfish in a tank, a foodservice establishment must maintain proper water quality. This is critical because the aquatic life relies on specific conditions to thrive. For example, during the winter, aquatic life exists in liquid water by consuming more resources to survive. Moreover, organisms like jellyfish exchange gases and nutrients with their surrounding environment. Phytoplankton population changes also indicate the importance of water quality and its interplay with sunlight exposure. The osmolarity of the water is significant as well, dictating water diffusion into or out of a fish's body, depending on whether the water has low or high osmolarity, respectively.
In controlled environments such as tanks, the maintenance of water quality means that conditions need to be carefully regulated. This includes managing light availability, which is absorbed to varying degrees at different depths, and simulating the food web, as Dr. Harmon did in his experiments involving artificial pond microcosms with stickleback fish and sources of zooplankton. In these specialized environments, maintaining proper water quality requires attention to various factors, as even oil spills can reduce light penetration, affecting marine organisms.