In the waters off Gambell that year, a very large shark was reported by hunters as attacking a bull sea lion, weighing several hundred pounds, in the water. Brandon Ahmasuk, Subsistence Resources program director with Kawerak, said the hunters who witnessed the attack described the bull sea lion leaping out of the water and then making a beeline toward shore.
Next, they saw what looked like a huge shark before it dove below the surface. They soon saw a large pool of blood in the water and no sign of the sea lion. Currently, there is one record of a great white shark, at least 12 feet in length, caught in the central Bering Sea during August The fisherman cut open the stomach of the shark to see what it had been feeding on.
Large chunks of Steller sea lion fell out, according to Sheffield. Some coastal residents of western and northern Alaska began to report more unusual marine mammal sightings beginning in when over seals in northern and western Alaska beached themselves or were harvested. The seals were found to have skin lesions, hair loss, weakness or some combination of both.
Thus, estimates of biomass are not available for the stock assessments. This species is the primary species in the shark stock complex in the Bering Sea and Aleutian Islands. The life history of the Pacific sleeper shark is unknown. Of the animals that do get sampled, none have ever been mature. Parameters such as fecundity, age at maturity and natural mortality are unknown. Reproductive mode is speculated to be aplacental viviparity based on other species in the family. This species has proven very difficult to age, but research on a similar species Greenland shark, Somniosus microcephalus suggests that they are long lived.
Therefore little is known about their growth, longevity, or reproductive biology to inform the stock assessment. Our scientists are collaborating with our partners to fill some of these knowledge gaps. We are investigating the population stock structure through next generation genomics and examining alternative methods for age estimation, as well as collaborating with universities and other organizations on investigations of discard mortality and physiology.
Spiny dogfish are the primary shark species in the Gulf of Alaska. They are long-lived and slow growing species, living to years or more and not reaching sexual maturity until 36 years. Reproduction is also slow for this species: gestation takes nearly 2 years, with an average of about 9 pups per pregnancy, and recent studies have suggested that they can skip-spawn, further slowing the reproductive processes.
This species has been heavily fished in both British Columbia and Washington State, but other than a few sporadic attempts at directed fishing in the Gulf of Alaska, they are caught only as bycatch by fishermen targeting other species in the Gulf of Alaska. We have deployed satellite tags on spiny dogfish since to observe their migration and habitat use. Seals have turned up with chewed off flippers and large bite marks.
Some were beheaded. Brandon Ahmasuk is the subsistence coordinator at Kawerak, the nonprofit arm of the Bering Straits regional Native corporation. He says killer whales have been known to maim their prey, but the bite marks that have been showing up recently look clean. Killer whales tend to tear apart their food, which got Ahmasuk thinking about great white sharks. Eventually, with help from Alaska Sea Grant , the pictures were sent off to a shark expert in Hawaii.
About seven years ago, a couple of hunters spotted a large predator in the water on the south side of St. Lawrence Island in December.
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