The Aquarium is closed Thursday, October 16 and Friday, October 17, due to a facilities-related issue. Unfortunately, we are unable to welcome guests while we resolve this situation. Please check back here for any impact to opening hours for Saturday, October 18.
A lot of heavy lifting goes on behind the scenes to care for the animals at the National Aquarium.
No two Aquarium animals are exactly the same, and no two exhibits are either. Sometimes, those differences are hard to see ... especially without a scale! Most people don't think about the weight of the water in the Aquarium, or the thousands of pounds of salt mixed into it. Weight also affects animal care, from determining the amount of food an animal needs to managing their sheer size. Caring for the Aquarium's exhibits and large animals takes some muscle!
Thousands of animals at the Aquarium live in saltwater habitats, making salt one of the most important (and heaviest!) parts of caring for marine life. Salt is invisible once dissolved in water, but it's not so invisible when it arrives in huge bags. That's right! The Aquarium's Life Support team mixes all our salt water behind the scenes. Staff start by creating a super salty mixture of 30,000 gallons of fresh water and 8,000 pounds of salt. Then, they add 30,000 more gallons of fresh water to dilute the mixture and make it safe for the animals. The salt water is stored in reserves until an exhibit needs a refresh.
In one year, the Aquarium uses over 517,000 pounds of salt, which is about the weight of 207 sports cars. But where do those half a million pounds of salt go? Atlantic Coral Reef, Blacktip Reef and Shark Alley contain similar amounts of salt water (between 225,000 and 335,000 gallons) and each uses about 14,000 pounds of salt, totaling over 42,000 pounds per year for all three exhibits. Dolphin Discovery's much larger habitat holds over one million gallons of water and requires 173,000 pounds of salt annually. Jellies Invasion and over 70 other smaller exhibits and holding spaces use the remaining 301,779 pounds.
The salt water provides a healthy home for marine life at the Aquarium, including large animals like sharks, dolphins, eels and more.
As mammals, humans often think the larger the creature, the bigger the appetite. But that's not always the case, especially for fish. Each animal requires a specific diet based on size, metabolism and species.
The largest sand tiger shark at the Aquarium weighs 220 pounds and is over 6 feet long, making it slightly larger than the average American man. Sharks have a slow metabolism and digest food slowly, so they only eat three times a week. Animal Care staff pole-feed each sand tiger shark 2.5 pounds of restaurant-quality fresh and frozen fish each week, including bronzini, herring, squid, mackerel and blue runner.
Atlantic bottlenose dolphins, on the other hand, are warm-blooded mammals that need to eat more food, more frequently. The largest dolphin at the Aquarium is about 9 feet long and weighs over 485 pounds. Dolphins have a high metabolism and use a lot of energy to maintain a constant body temperature, so each dolphin eats 112 to 140 pounds of fish every week! Staff give the colony restaurant-quality seafood, such as capelin, herring, sardines, smelt, mullet and squid.
For two species that seem similar in size, sharks' and dolphins' eating behaviors are strikingly different!
Some of the ocean's most graceful swimmers can weigh a surprising amount. Even though green moray eels, like those in Atlantic Coral Reef, and reticulated whiptail rays, like those in Blacktip Reef, look weightless in the water, their size affects their care. Despite their graceful appearance and nearly identical length of about 6 feet, green moray eels weigh up to 65 pounds, while Lady Ray, the largest ray at the Aquarium, weighs 230 pounds!
Green moray eels' tendency to hide, their sliminess and their weight require special handling when they need medical care. To remove the eels from their exhibit, divers use a repurposed barrel with holes drilled into it. The eels are usually curious about the barrel and will swim right in, making it easy for the divers to secure the lid and carefully lift them out.
Lady Ray's size and weight require some out-of-the-box thinking for her medical care, too. Her caretakers used target training to teach her to approach a special bucket when it's placed in the water. This allows staff to ask her to move to specific locations—no lifting required!
