Cape Sharks and Seals [Archive] - Fly Fishing Forum

: Cape Sharks and Seals

09-29-2004, 11:50 AM
This article was posted by Bill Hubbard on a couple other forums and I am sure he will not mind me pasting the Newspaper article on this board... Thanks Bill...


CHATHAM - Shark scientists say that when great whites reach around 1,000 pounds, they switch from a diet of fish to marine mammals, largely whale carcasses and seals. At more than 1,700 pounds, the shark trapped near Naushon Island would prefer a big fat seal over a fish dinner.

A gray seal, one of more than 6,000 on the Cape, off the north side of Monomoy Island.
(File photo by KEVIN MINGORA)


Thanks to the Marine Mammal Protection Act of 1972, the seal population in New England and on Cape Cod has exploded. Gray seals alone have gone from less than 20 in Southern New England waters in the 1970s to more than 6,000 year-round residents on Cape Cod. Most of those are on Monomoy Island off the tip of Chatham.

With males weighing nearly 800 pounds and almost 8 feet long, they're hard to miss as they pop up in the summer surf off beaches all along the Outer Cape. The 3 million visitors who go to the Cape Cod National Seashore in the summer have gotten accustomed to seeing them a few feet from shore, near swimmers and surfers.

So, with evidence of a great white so close to shore and an ever-expanding seal population, should we be afraid to go in the water? After all, the West Coast has seen several great white attacks in which the shark supposedly confused a surfer or swimmer with seals.

"I don't think people have to be freaking out about that," said Lisa Natanson, a shark scientist at the National Oceanic and Atmospheric Administration Fisheries' Apex Predator Program in Narragansett, R.I.

Conditions different
Natanson said the conditions in both South Africa and on the West Coast, where many of the great white attacks have occurred, are very different from here. The seal population is higher and denser and located very close to where people swim and the water is much deeper close to shore, which allows sharks easier access to seals (and swimmers).
That doesn't mean a great white wouldn't be interested in catching a seal dinner just off the beach.

NOAA Fisheries mammal researcher Gordon Waring was off Monomoy recently when he noticed that harbor seals, who are normally skittish and jump into the water if anyone approaches, were keeping to the beach. That was when Waring noticed a large shark in the deeper channel just off the beach.

While Waring couldn't identify the species of shark, seal cruise Capt. Tom Newton had no doubt about what he encountered off Monomoy this summer.

Newton was skippering a seal cruise boat a month ago when he encountered a 14-foot great white shark that had been trapped by low tide in a 7-foot-deep tidal pool off Monomoy Island.

"The seals disappeared suddenly (off the beach), like throwing a light switch," recalled Newton. But the shark was less interested in hunting seals at that point and more intent on getting out into deep water.

With years of experience on dive boats and seal cruises, Newton had seen a lot of basking sharks, the plankton-eating cousin of the great white, with which it is most often confused, and this was definitely a great white.

"We rarely see them in there (Monomoy)," Newton said.

NOAA Fisheries estimates there may be more than 188,000 sea lions and 76,000 harbor seals off California, Oregon and Washington, with their numbers growing annually by 6 to 7 percent. Great whites are estimated at between 100 and 300. There is no shortage of seals in the Northeast, with more than 140,000 gray seals on Sable Island alone off Newfoundland. But the number of great whites, while unknown, is thought to be a lot fewer than out West.

Fall migration
Great whites also migrate out of our brutally cold winter waters. There are no swimmers or great whites here when migrating harbor seals come into our waters in the late fall and send the local seal population up to more than 12,000.
Waring pointed out that, unlike the West Coast, where people routinely see great whites eating seals, there is no documented evidence of that here. Cape Cod Stranding Network coordinator Kristin Patchett said the network can confirm two or three shark attacks on seals a year, but none that resemble the bite of a great white.

Waring said that, without great whites, there is no natural predator limiting the growth of the seal population on Cape. He said they don't know what the maximum sustainable seal population is because there are no historical records. So, could a big seal population ultimately attract the ocean's top predator?

"It might be possible, because of the increasing size of the seal population, but we don't have any evidence of it yet," he said.

(Published: September 29, 2004) "

Dble Haul
09-29-2004, 12:56 PM
My instincts tell me that the number of sharks in that general area is underestimated (not necessarily all great whites, either). Just because people on the water aren't seeing them doesn't mean that they aren't there. The food base is growing, and there's plenty of deep water.

And I've seen a few seals with bite marks on their flanks. Successful hunts will not leave any trace, except the loss of one animal among hundreds, and who's gonna really notice that? The article claims that there is no documented evidence of attacks on seals, but let's be realistic. There aren't cameras or eyes set up 24/7 on every piece of water, and many attacks happen underwater.

Do I think this is reason to not go in the water? Hell no. But we probably should have a deal of respect for the animals, because during any encounters we're in their environment.

09-29-2004, 01:08 PM
Well Mark.... all the more important for me to complete my project on Invisible Waders.....wouldn'd you agree??? :wink:

Dble Haul
09-29-2004, 01:55 PM
Yes, and drop the sealskin prototypes ASAP. :whoa:

09-29-2004, 02:38 PM
Mark is right.

There are a lot of references to shark encounters in Robert Posts book "Reading The Water" on Marthas Vineyard. Not just on the Vineyard but in one case at Matunuk (RI). No mention of Great Whites but lots of big sandsharks and bulls.

09-29-2004, 02:53 PM
You may want to work on an odor masking feature on those stealth waders too.