Ecology

Ecosystem Roles

Whale Sharks generally are alone, unless there is a large school of fish then many will be in one another’s company.

Whale Sharks are filter fish, so their presence effects populations of zooplankton and smaller nekton. Plankton are microorganisms that float in the ocean. At this time, the plankton levels and waters are healthy. However, if the plankton levels rise, the water begins to look cloudy or murky. By eating plankton, Whale Sharks keep the the plankton populations under control. The Whale Sharks' presence is a sign of the overall health of our ocean.

There are two siphonostomatoid copepods (a form of parasite) that live on or in Whale Sharks. They are also the unfortunate hosts to smaller sharksuckers like the white suckerfish. These usually hang around Whale Sharks' mouths.

In 2017, researchers in Japan discovered a new species of amphipod (a crustacean without a hard carapace) behind the gills of a female Whale Shark. Scientists weren’t sure how they got to be inside her mouth, but they do know this is an ideal spot for these tiny crustaceans. They feed on small pieces of detritus such as phytoplankton and other decomposed, organic material, and they’re protected from larger predators.

What do Whale Sharks eat?

They feed on plankton, krill, jellyfish, crab larvae, anchovies, sardines, mackerels, small tuna, and small squid.

Predation

Due to their size, Whale Sharks have few predators. However, human activity has decreased their population size. When young, Whale Sharks are smaller, so they are more susceptible to predators like blue marlin, blue sharks, and orcas. Off the coast of Australia, one fully grown Whale Shark was recorded with large bite marks and missing a fin. Assumptions are that those injuries were from a great white shark.

Key words: zooplankton, parasite, crustacean, carapace, detritus, phytoplankton.

Citations:

• Whale Shark (rhincodon typus). Whale Shark (Rhincodon typus) - DAWE. (n.d.). Retrieved November 5, 2021, from https://www.awe.gov.au/environment/marine/marine-species/sharks/whale-shark.

• Vazquez, P. C. and J. (n.d.). Rhincodon typus (whale shark). Animal Diversity Web. Retrieved November 5, 2021, from https://animaldiversity.org/accounts/Rhincodon_typus/.

• Baker, H. (2020, November 4). New species of crustacean discovered in a whale shark's mouth. Marine Madness. Retrieved November 5, 2021, from https://marinemadness.blog/2019/11/02/new-species-of-crustacean-discovered-in-a-whale-sharks-mouth/.

• Threats to the Whale Shark. WhaleSharkie.com. (n.d.). Retrieved November 5, 2021, from https://whalesharkie.weebly.com/threats-to-the-whale-shark.html.

Photos: 1-sharkshowacu.jpg (892×593) (internapcdn.net); ruzx9ydtl6p51.jpg (700×467) (redd.it)