Killer whales and dolphins can’t be kept for show in South Carolina, so the tragedies shown in the recent CNN documentary “Blackfish” aren’t likely to happen here — so far.

But the wording of the law banning the practice in the state was changed from “marine mammals” to “cetaceans,” or dolphins and whales, in 2011, because Riverbanks Zoo in Columbia plans a sea lion exhibit. That revision raises some concern.

“We will work very hard to defend the law if there’s any attempt to change it further,” said Mark Berman, of Earth Island Institute, who helped write it in 1992 before joining Earth Island.

The law was the first of its kind in the nation, and the original intent was to cover cetaceans, Berman said. He doesn’t like keeping sea lions for show either, but that animal can breed in captivity, he said.

“Blackfish” investigated the 2010 death of SeaWorld trainer Dawn Brancheau, pulled underwater by a performance orca named Tilikum that she worked with.

The report chronicles the four decades of keeping the 6-ton whales for show, which began with the death of the mother of Shamu when the popular performing orca was captured young. The documentary details trainer deaths and captive-animal horrors.

The 1992 law in South Carolina originally prohibited “the display of dolphins and porpoises.” It was approved after pressure by the South Carolina Humane Society to stop a dolphin park in Myrtle Beach.

After the 1992 law was passed, marine park developers pressured legislators to rescind it, unsuccessfully. Those interests are much better financed now, he said.

In 2000, the law was expanded to include all sea mammals because of jurisdiction conflicts between federal agencies.

Riverbanks Zoo declined to comment when asked about the 2011 change and the proposed exhibit.

Staffers of the South Carolina Aquarium toe the line when asked about marine mammals.

“That’s not something we’re debating or have any plans for,” said Jason Crichton, husbandry and facilities director. The aquarium stresses education and conservation.

“One of the best parts of the aquarium is you can look off the harbor terrace and see wild dolphins,” said Whit McMillan, education director. He saw one recently swimming upside down in circles, he said.

As for keeping creatures in captivity, aquarium staffers stress “an enriched environment,” in other words, providing opportunities for the animals to behave naturally, said curator Rachel Kalisperis. That includes such techniques as putting food for a lobster in a location where it must be sought out.

They counter visitor concerns about keeping animals in captivity by pointing out that the displays allow visitors to make a connection with the animal that “hopefully leads them up the ladder toward conservation,” McMillan said. “I can describe the giant spider crab all you want, but until you interact with the animal, you can’t experience it.”

Staffers are careful to stress that the aquarium belongs to the Association of Zoos and Aquariums, and must keep up a high level of care to be accredited. Riverbanks Zoo also belongs to the AZA, as does SeaWorld.

Public response to “Blackfish” was so strong that SeaWorld responded by saying in part that the marine mammal park in Florida is “one of the world’s most respected zoological institutions” that “rescues, rehabilitates and returns to the wild hundreds of wild animals every year,” commits millions of dollars to research and is committed to the safety and welfare of the audience, handlers and animals.

The Riverbanks sea lion project is a long-term renovation that would expand a former exhibit to an exhibit facility, including stadium seating and a platform over the pool, as well as a glass wall for underwater viewing, according to the zoo website.

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