Whale Shark season has officially opened to tourists in the Sea of Cortez according to the Ministry of Environment and Natural Resources, or Semarnat. Semarnat is the Mexican federal government agency responsible for environmental protection, restoration, and conservation of ecosystems and natural resources of the country. The 2017 whale shark season has seen Semarnat very stringent about regulations that were previously unenforced, including radio contact and GPS reporting requirements when boats enter the feeding areas of the fish.

Three individual feeding zones for the whale sharks exist in the area located in the Magote, near the middle of the spit of land that extends out in front of La Paz, the capital city of Baja California Sur. From October through April, vessels granted the proper licenses may transport guests to the feeding grounds of the largest fish in the ocean, with an experienced snorkel leader and up to six additional people allowed in the water at a time.

Whale sharks are fish, not air-breathing mammals as the use of the name “whale” suggests. They are a slow-moving filter-feeding carpet shark, and the only member of the genus Rhincodon, as well as the only extant member of the family Rhincodontidae. The species originated about 60 million years ago, and is famously the largest living non-mammalian vertebrate. Whale sharks are found in tropical oceans, preferring warm waters that rarely fall below 72 degrees fahrenheit. Their lifespan is suggested at 70 years, but research is still being conducted to determine accuracy of the number.

Whale sharks have a mouth up to 5 feet wide, that contains 300 to 350 rows of tiny vestigial teeth that play no role in feeding. Instead, similar to a whale, the giant fish filter-feed through ten filter pads that rest at the back of their throat, eating amongst the smallest creatures in the ocean: plankton. This mode of feeding occurs in only two other types of sharks, the megamouth shark and the basking shark.

The Magote in the Sea of Cortez is rich with the plankton the fish needs for its survival. Topography maps show a drop off in the underwater landscape, changing the depth from 6-10 feet in the shallows to a quick drop of 22-33 feet. The currents caused by this shelf in the ocean floor results in the common ocean phenomenon called plankton blooms, which are large concentrations of phytoplankton, microscopic plants that float in the upper, sunlit layers of the water.

Whale sharks are considered an endangered species and receive staunch protection under international and Mexican law. While it is legal to swim with them as they feed, strict rules are enforced. A limited number of boats can be in each whale shark feeding zone at one time, and no SCUBA diving gear is permitted while in the water with the fish. Swimmers must stay a minimum of six feet from the shark, and absolutely no touching is permitted, as the oils on our skin can cause life-threatening infection to them.