As SeaWorld remains under scrutiny by the media — and increasingly state legislatures, like California, where a bill would ban orcas in entertainment — there continues to be a disconnect between the public image SeaWorld projects and the more complicated and controversial reality of keeping killer whales in captivity. Here’s just one telling example: SeaWorld often touts the high standard and quality of its killer whale “habitats,” noting on its new web pages that are dedicated to telling the “truth” about SeaWorld that:

Our zoological habitats are among the largest in the world today. They are multi-million-gallon environments of continually chilled and filtered saltwater. The killer whale habitat at SeaWorld Orlando, for example, encompasses more than 6 million gallons. We also have a dedicated team of water quality experts on call 24/7 to monitor this advanced system and ensure all water quality conditions meet or exceed federal standards

It is indeed true that great effort is made to maintain the water at just the right temperature and salinity for the animals. What is not mentioned is all the chlorine that is used to keep the water clear and sparkling (you can’t see Shamu clearly in a murky pool), and free of algae and bacteria. (Don’t even get a killer whale trainer started on what it looks like after a killer whale defecates in the pool, or produces any other bodily emissions.)

A number of former SeaWorld trainers I have spoken with about water quality have noted that captive killer whales routinely have mucus streaming from their eyes — an apparent protective mechanism that is considered “normal” at SeaWorld. Wild killer whale researchers like Naomi Rose and Ingrid Visser say that they have not seen similar, chronic, mucus weep from wild killer whale eyes, though it is of course a lot harder to see a wild killer whale’s eyes up close. According to Visser:

“I’ve spent a lot of time in the water with the orca and never seen mucus coming from their eyes when in the water with them, nor when photographing them up close from the surface — but then the orca are moving and the mucus is clear — so it would be hard to spot. However, I have seen it on stranded orca (and pilot whales, beaked whales, Bryde’s whales, bottlenose and common dolphins), which makes sense, because the eyes are then out of the water and they are trying to moisturize their eyes and expel dust and sand, for instance.”

Spikes in chlorine concentrations can be especially troublesome for both whales and trainers. Former Seaworld trainer John Hargrove spent time working at Marineland Antibes in France and told me about a chlorine overdose there that was so intense it seemed to prevent the killer whales from opening their eyes, and the skin on their heads and backs started peeling off. Another trainer’s eyes were burned so badly that he had to wear bandages that completely covered his eyes and shut out all light. According to Hargrove, he wasn’t allowed to open his eyes until more than a week had passed for fear he risked permanent blindness.

Trainer eye burns, it turns out, were not uncommon. Hargrove, who left SeaWorld in 2012 and worked at both SeaWorld California and SeaWorld Texas, explains in an email:

“There are dozens of documented reports of serious eye burns to trainers because there was an over-injection of chlorine in the pool, and as the whale underwater foot-pushed us through this cloud of intense chlorine, we had eye burns so severe we often couldn't even open our eyes. I was treated at least half a dozen times where I was I was sent off site for treatment, and could barely open my eyes because of the pain and wasn't allowed to do waterwork again for 2-3 days until they healed [enough] to swim again.”

“That was just from our brief exposure,” Hargrove says. “Imagine the whales always having to swim through it.”

The mucus secreted by the eyes of the killer whales -- whether it’s triggered by chlorine, more frequent exposure to the air, or other factors of captivity, like looking up into the sun more often, or even all of the above -- appears to offer some protection. There is no obvious trend (according to the trainers I have spoken with) of older killer whales predictably developing sight problems in captivity.

But that’s not true for all captive marine mammals, I learned. Pinnipeds, like sea lions and walruses, apparently do not have the effective eye protection sported by killer whales, and routinely suffer from premature cataracts, corneal disease, and lens issues. According to one study, chlorine and water treatment chemicals play a role, but sunlight is a key causative factor. The study explains:

“[C]aptive pinnipeds are frequently housed in pools painted a light blue color which is very effective at reflecting most of the UV light energy back towards the animals as they dive and swim. As well, captive pinnipeds are often housed in deep grottos or pools where they must look up frequently to see out of the exhibit or to catch fish.... When keepers, trainers, or members of the public feed the animals they may inadvertently force the animals to look directly into the sun to get their fish reward. These conditions may cause damage to the eyes of captive pinnipeds because they are forced to be exposed to far more UV light than their wild counterparts. This is supported by studies such as a recent publication that identified pinnipeds with no access to shade were 10 times more likely to develop cataracts or lens luxations.”