Plankton are microscopic organisms that drift through the water and include things like algae, diatoms, and zooplankton. They are a food source for many small fish and other organisms, but they are not typically a major food source for sharks.
There are a few reasons why sharks do not typically eat plankton. First, plankton are too small for most sharks to eat. Sharks typically hunt for larger prey that is more energy dense. Second, plankton are not very nutritious. They are low in calories and protein, and they do not provide the sharks with the energy that they need to survive.
Some smaller shark species, such as the basking shark and the whale shark, do feed on plankton. These sharks have specialized filter-feeding adaptations that allow them to filter large amounts of water and capture the small plankton. These sharks are able to survive on plankton because they are able to filter huge volumes of water and extract the nutrients that they need.
Overall, most sharks do not eat plankton because they are too small and not very nutritious. However, a few smaller shark species have specialized adaptations that allow them to feed on plankton.