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UF Veterinarian Develops Low-cost Feed For Rescued Manatees

Paul Cardeilhac, (352) 392-4700 ext. 5700

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GAINESVILLE, Fla. — Fifty pounds of romaine lettuce makes enough Caesar salad for a hundred people, but it’s merely a one-day food supply for a manatee in captivity.

To feed the endangered aquatic mammals more economically while they recover from injuries or medical treatment, a University of Florida veterinarian has developed a new manatee chow that costs one-tenth the price of lettuce.

The discovery comes at a time when manatee injuries and subsequent deaths have reached record rates. In 1986, 122 manatees died in Florida. Fifteen years later, that number climbed to 325.

“The manatees in captivity are there primarily because of injuries caused by humans,” said Paul Cardeilhac, a professor in UF’s College of Veterinary Medicine and Institute of Food and Agricultural Sciences who developed and is studying the manatee chow. “It’s our responsibility to take care of those animals. We don’t want the cost of feed to be prohibitive of keeping a manatee in captivity as long as needed.”

Using the new chow instead of a standard lettuce diet could result in savings of more than $16,000 annually per manatee. At $1 a pound, the yearly bill for one animal’s romaine lettuce often exceeds $18,000. The chow has 20 times the nutrient density of the salad green, so a manatee would need approximately two and half pounds of chow a day instead of 50 pounds of lettuce. A 365-day supply of the chow costs about $2,000.

A 2001 survey estimates 3,276 manatees remain in the wild, according to Chuck Underwood, a public information officer with the U.S. Fish & Wildlife Service.

Recovering the species is important, especially because the community of animals and plants coexisting in bodies of water in and around Florida is so closely tied together that no one knows how the loss of the manatee might affect the entire ecosystem, Underwood said. Rehabilitating manatees in captivity plays a vital role in species recovery.

“Every animal saved helps because each has the potential to reproduce and add to the population,” Underwood said.

The new chow is made from alfalfa, soybean meal and hulls, kelp, wheat, and a vitamin and mineral mixture and has a nutrient composition similar to romaine lettuce. The materials are cooked at high temperatures to kill pathogens and then formed into one-inch cylindrical pellets.

“The composition is designed to resemble natural forages that have been used to successfully grow and maintain rescued manatees,” Cardeilhac said. “We did nutritional analyses of romaine lettuce and water hyacinths and enlisted the expertise of those who feed manatees in order to ensure the animals get everything they need.”

The pellets float and absorb three to four times their weight in water. This prevents dehydration and constipation in manatees, which are thought to consume most of their water from food sources rather than drinking it directly.

Cardeilhac has developed two formulas. Critical care rehabilitation feed is used for manatees recovering from recent injuries or surgery, while a maintenance formula is fed to others in captivity.

“The pellets are convenient and easy to handle, plus they have a long shelf life,” Cardeilhac said. “They can be stored at room temperature for more than six months.”

So far, the new chow has been tested for a year at several sites in Florida: Sea World, Mote Marine Lab and Homosassa Springs Wildlife State Park. The chow will continue to be fed to manatees at these locations, and researchers hope to expand its use to other sites.

Cardeilhac has focused on Homosassa Springs, where nine female manatees live in captivity. Mark Lowe, the consulting veterinarian there, says the manatees are faring well so far.

“In the past, we tried feeding them monkey biscuits and elephant chow, but neither are geared for the manatee, as Dr. Cardeilhac’s formula is,” Lowe said. “We’re slowly increasing the amount of pellets we give them.”

At Homosassa Springs, the nine manatees now receive 11 pounds of pellets daily to supplement their lettuce diet. Cardeilhac’s three-year, $75,000 grant from the Florida Fish and Wildlife Conservation Commission covers the cost of pellets for the test facilities. If the Homosassa facility was paying for the chow, the savings from using the pellet-lettuce combination diet versus lettuce alone would be approximately $73,000 – money that can be used for other projects benefiting the manatees.

Those at Homosassa Springs – officially called Florida manatees, a subspecies of the West Indian manatee – are among 43 currently in captivity nationwide. Manatees, the only surviving herbivorous marine mammals, are protected under the U.S. Endangered Species Act of 1973.

These gentle, slow-moving creatures can grow to 13 feet and weigh more than 3,000 pounds. They spend most of their time eating, resting and traveling. Nearly all manatees in the wild stay in Florida’s fresh and saltwater environments year-round. In summer, as water temperatures increase, however, they move as far west as Louisiana and as far north as Virginia.

Manatees may be injured or killed by cold temperatures or red tides, which are higher-than-normal concentrations of microscopic algae that produce toxins and may be ingested by manatees. But the biggest problems they face are from people. Population growth leads to development, which results in destruction of manatee habitats. Speeding boats hit manatees, crab trap lines get tangled around their flippers and floodgates crush them. Already this year manatee deaths in Florida due to watercraft collisions have reached a record 83, according to the Florida Fish and Wildlife Commission.

“Rescue, treatment and rehabilitation are viable options to reduce human-related manatee deaths and even some natural mortality of manatees,” Cardeilhac said. “Feeding them while they’re being treated and maintained in captivity can be extremely expensive. The more economically we can do this, the better.”