CHATHAM — In the tale of the return of the seal population to Cape Cod, the point where a positive becomes a problem depends on how you look at a colony of seals. Fisherman look at them as competition. Sharks look at them as calories. And the public looks at them in all sorts of ways, from a reason to go to a particular beach, to a reason not to.
On Saturday in the auditorium of the high school in Chatham, the various stakeholders in the seal story gathered for what was billed as the Outer Cape Seal Symposium — scientists, fishermen, and captains of seal tourism boats — to discuss what is known about the animals’ exploding population, what needs to be known, and what can or should be done about it.
At the moment, not much can be done. Bounties ended in the early 1960s, and the animals have been protected by the Marine Mammal Protection Act since 1972. Any efforts to thin the population would require a change in federal law that allows for the killing of a much-adored animal.
“It would be political suicide for anybody to say, ‘We’ve got to get rid of them, we’ve got to cull them out,’ ” said Ernie Eldredge, a weir fisherman in Chatham who watches more and more seals steal more and more fish out of his traps each year. “But I don’t think we can allow the population to go unchecked. We can’t just resolve ourselves to the idea that nothing will be done about it and we’re going to have to go out of business.”
But if reduced fish hauls weren’t enough to make people pay attention to the seal population boom, the accompanying surge in the shark population in Cape waters has been quite good at generating publicity.
The summer of 2012 was the summer of the shark on Cape Cod. It started in early July with a photo of a kayaker being tailed by a shark in Orleans, which was determined to probably be a harmless basking shark. But people were alarmed, and when a Great White bit a bodysurfer in Truro at the end of that month, fingers pointed to the exploding seal population.
There are no solid numbers for the total seal population in Massachusetts, but on Muskeget Island off Nantucket, six seal pups were counted in 1991 and 2,096 in 2008. With those seals have come sharks, according to Greg Skomal, the principal investigator of the Massachusetts Shark Research Program.
The one thing all Great White hot spots around the world have in common “is food shaped like this,” Skomal said as he displayed a photo of some seals to the 200 people in the auditorium. “If you open up the cafe, the predators will come. And that’s exactly what’s happened off the east coast of Cape Cod.”
Skomal said the Cape used to get one or two, maybe three confirmed Great White sightings a year. Last year it was more than 20.
But the central question, according to Greg Early, a marine biologist, is how much is too much.
“We talk a lot about what we mean by ‘over-abundant,’ ” Early said. “Clearly, that’s what’s in the back of everyone’s mind.”
Early said the issues surrounding the seals involve regulation, ethics, and science, all must be considered at once.
Thanks to generations as star attractions in aquariums, seals have good PR. Even the fishermen who compete with them acknowledge they are clever opponents, capable of adapting to almost anything designed to foil them.
Some think the only solution is a cull. But the scientists who spoke Saturday, including Betty Lentell, a biologist contracted by the Cape Cod Commercial Fisherman’s Association, said an enormous amount of data would need to be gathered before it could even be determined if that would be beneficial.
One person who wants to see nothing happen to the seals is Keith Lincoln, owner of Monomoy Island Ferry, who has been taking tourists out to see the seals since 1989. He is now one of four seal cruise operators in Chatham, and he estimated that they recently have been taking a total of about 20,000 people a year out to see the pinnipeds.
His prediction was that nature would find some way to thin the population, but until then seals — and sharks — were great for business.
“As soon as that first shark of the season makes the media, we can’t keep up with the phone calls,” he said. “I only wish it would happen a month earlier.”
Correction: Because of incorrect information provided to the Globe, an earlier version of this article incorrectly identified marine biologist Greg Early as an employee of the New England Aquarium. Mr. Early previously worked at the aquarium but now works at Integrated Statistics on Cape Cod. Also, because of incorrect information provided to the Globe, an earlier caption accompanying the photo at the top of this story misidentified a group of seals on North Beach Island. They were harbor seals.