Topic: Rural Living
These guys are out in our waters also.
Photo: fishingmag.co.nz. This sevengill shark taken surfcasting from the beach at Birdlings Flat , just south of Banks Peninsula, took over an hour to land. It measured 8'3" in length.
"Sevengill sharks have broad heads, small eyes and teeth like jagged saw blades. They can grow up to 800 pounds and 10 feet long. While they're not abundant off the Oregon coast, Washington's Willapa Bay supports a healthy concentration and may be a breeding ground, said Debbie Farrer, a scientific technician with Washington Fish and Wildlife who helped coordinate the catch for the aquarium.Sevengills can be aggressive: They commonly snatch seals from sandbars and have been known to attack dogs in shallow water, Farrer said. Her research turned up one documented attack on a human." - Oregonlive.com
[Excerpt] Click here to read the entire Oregonlive.com article
Thursday, June 28, 2007
LORI TOBIAS
The Oregonian StaffNEWPORT -- For nearly a month, Jim Burke carefully choreographed the introduction of five new sharks at the Oregon Coast Aquarium. From their capture at Willapa Bay to their planned release in the Passages of the Deep tank, he rehearsed every step, knowing a mistake could prove disastrous.
But even a perfectly executed plan couldn't control what would happen when the sharks slipped into their new home:
Would the broadnose sevengill sharks swim peacefully with the other fish? Would the males mingle curiously with the female shark already there? Or would the release end with blood in the water, halting the entire plan?
For more about our friends out there in our waters, click here to go to Baynature Magazine (San Francisco) article from 2001
Sevengill Cowshark
In the waters of San Francisco Bay, the deceptively slow-moving, but powerful, sevengill cowshark (Notorynchus cepedianus) is the top marine predator. It feeds mostly on smaller sharks, as well as on other fishes and young harbor seals. It is named for the seven gill slits on each side of its head. (Most other sharks have five gill slits on each side.) The sevengill reaches 10 feet in length and can exceed 250 pounds.
Sevengills are masters of stealth and constantly test the water for electrical pulses from potential prey; once the signal of a distressed or feeding shark has been picked up, the black-speckled, gray body appears to come out of nowhere. These opportunistic hunters will routinely take advantage of any shark caught on a fishing line or focused on feeding. In the course of our research, we have pulled up long lines set over deep-water channels patrolled by sevengills, only to find well over half of the hooks sporting little but the heads of the smaller prey sharks. Sevengills have even been observed attacking mating leopard sharks in narrow, shallow marsh channels. While no attacks on people have been documented in open water, sevengills held in captivity have attacked divers.
Although sevengills are found in temperate seas of both the Pacific and southern Atlantic oceans, they are most common along the Pacific Coast in Humboldt, Tomales, and San Francisco bays, which serve as primary nurseries for the species. Large individuals generally patrol the deep-water channel in the South Bay, as well as other deep areas of the Bay. Their newborn offspring, however, are found in the shallows near marshes. The 17-inch long sevengill pups are born in late spring or early summer, timed to coincide with the birth of their main prey—the pups of other shark species.
