At the Mandalay Bay Resort and Casino on the Las Vegas Strip, the Shark Reef Aquarium’s sharks aren’t just on display—staff members say they also follow a tightly scheduled feeding routine designed for health and observation. Aquarists at the aquarium feed 15 species of sharks three times each week in a tank described by staff as holding 1.3 million gallons of water, where they also tend to thousands of other animals.
During feedings, handlers dangle fish over the water, and at least one of the most recognizable species, the zebra shark, can move quickly to take prey. Becky O’Brien, the aquarium’s lead aquarist, said it can take only seconds for a zebra shark to snatch herring when she dangles it above the tank, where over a dozen sharks swim.
O’Brien said her work with marine life included surprises. She described herself as someone who always wanted to work with marine life, but said she ended up as a “shark dietitian” at the aquarium, where the team feeds not only sharks but also works around the feeding behaviors of multiple species housed together.
The aquarium’s feeding program also includes both volume and variety, according to O’Brien. She said the aquarium feeds a mix of fish—mackerel, herring, blue runner and sardines—with the goal of creating a varied diet like sharks might eat in the wild. O’Brien said in one week the aquarium goes through over 300 pounds (136 kilograms) of fish, and she said some of that fish is wild-caught while some comes from sustainable fisheries.
O’Brien said the feeding routine also involves preparation for nutrition and for how the sharks consume food. She said fish are “stuffed with vitamins,” and that staff hide those supplements inside the food so the animals do not spit them out, describing it as similar to giving a dog medicine mixed into a treat.
Staff also train sharks to participate in targeted feeding. O’Brien said animals learn to go to specific areas of the tank for their meals, including by touching a target to receive food, and she framed that training as part of how the aquarium manages feeding beyond simply tossing fish into the water.
Outside of the feeding action, O’Brien said lunchtime gives staff a chance to assess the sharks’ conditions. She said if sharks turn down food, it can be a sign of illness, or that they may be focused on mating behaviors. She added that sharks are described as eating ravenously before breeding season, which she said runs from March to June, and that many males eat less during the season.
Samantha Leigh, a professor at California State University, Dominguez Hills who studies marine nutritional physiology, said sharks’ diets consist of proteins and lipids. Leigh said those nutrients help sharks maintain their fatty livers, which allow them to move up and down in the water. She also said that in the wild sharks eat a range of prey across the food web, from microscopic zooplankton to seals and even other sharks, while in captivity many sharks are fed restaurant-quality seafood.
Aquarium staff said the Shark Reef Aquarium also treats feeding and animal care as an opportunity to support longer-term conservation. O’Brien described the zebra shark as an endangered species whose population has declined due to fishing and coral reef habitat loss, and she said the aquarium partners with other organizations to transport zebra shark eggs to Indonesia for rewilding to help restore wild populations. She said she hopes visitors watching the feedings will develop concern for the ocean and protect it.
Keeping sharks healthy over time can also involve differences in age and feeding performance. The aquarium’s general curator, Jack Jewell, said many of the sharks live well beyond their wild lifespan and pointed to an older sand tiger shark as an example, saying he estimated the animal is between 33 and 36 years old—about 10 years older than their typical maximum age in the wild. Jewell said older sharks can have a harder time catching prey and compared the aquarium’s work to food delivery drivers who bring meals to people’s doorsteps.
On a recent day inside the aquarium, visitors watched other species alongside the sharks as staff members fed fish by hand. The aquarium’s feeding scene included sea turtles and lookdown fish, and aquarist Lukas Seoane fed a bow mouth guitarfish using tongs, with the guitarfish plucking fish from the handler’s grasp. Seoane said, “Every time I’m done feeding these guys, I think I want to go out and get some sushi,” adding, “If it’s good enough for them, it’s good enough for me.”