What are the top 5 primary consumers in the ocean?

The top five primary consumers in the ocean include zooplankton, which feed on phytoplankton; small fish such as anchovies and sardines that consume various plankton; sea urchins that graze on algae; herbivorous marine mammals like manatees; and some species of marine turtles that feed on seagrasses and algae. These organisms play a crucial role in the marine food web, converting primary production into energy for higher trophic levels.