Charles Wickersham was spearfishing off Florida's Anna Maria Island last weekend when he saw something swimming toward him. Moments later, a 10-foot-long bull shark had grabbed his thigh. The 21-year-old doesn't remember a great deal of what happened next, but the shark swiftly let go, and Wickersham, thanks to swift action from his fishing buddies, was rushed to a hospital, where, 800 stitches later, he has recovered strongly.

For Wickersham, the attack, while frightening, ended well — or at least, far better than it might have.  For People for the Ethical Treatment of Animals, it presented an opportunity.

Apparently finding inspirational irony in the notion of "man spears fish, big fish bites man," PETA announced this week that it had prepared a billboard advertisement featuring a picture of a shark with a human leg (or "drumstick" in PETA's parlance) in its mouth next to the words: "Payback is Hell. Go Vegan." The group said it aimed to place the billboards on and around Anna Maria Island, where Wickersham was attacked.

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To emphasize the organization's sensitivity, an accompanying PETA blog post was headlined "Spear-Fisher Becomes Live Bait" and, with an intentional wink to the audience, referred to the ad as "biting."

Not altogether surprisingly, this news was not especially well-received. In a remarkably understated response, Wickersham's mother said simply that the campaign was "over the top" before adding that she didn't wish to dignify it with any further comment. A local angler said that if he saw one of the billboards, he would "burn it down."

Contacted by the New York Daily News, PETA's Ashley Byrne pointed to the fact that "Americans alone kill 12 billion fish for food every year," before adding, "We are glad that Mr. Wickersham will be OK. We hope that after this painful and horrible experience, he and other fishermen will consider the pain that fish feel, and we hope they will consider taking up another pastime."

That didn't go down too well, either.

"If you want to lead a campaign saying humans should value and protect the natural environment and use resources more wisely, or that we should cause less suffering, I'm onboard with that," David Shiffman, a shark conservation biologist and blogger who has launched a Twitter campaign urging PETA to withdraw the ad, told Discovery News. "But if you want to argue that humans and fish are somehow morally equivalent, stay the hell away from my family."

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PETA insists that the purpose of the campaign is to "make the point that the deadliest killers in the water aren't sharks — they're humans." But Shiffman, who is a Ph.D. student at the University of Miami and blogs as WhySharksMatter on Southern Fried Science, argues that it does the opposite, that as well as being offensive to families of victims, the ad demonizes sharks and perpetuates their image as man-eaters.

That view was forcefully articulated by Kevin Zelnio, a blogger at Deep-Sea News, who argued that "the real whammer for this ad is that it vilifies and plays on our existing fears of sharks as evil, man-eating, ocean-fun killers. This makes it harder for those people who work tirelessly in shark conservation to ACTUALLY save animals' lives and educate people about … unsustainable harvesting and an unfounded perpetuation of a damaging stereotype."

Photograph of bull shark by Albert Kok. (Wikimedia Commons)