April 15, 2024 — The Pacific sleeper shark is the largest shark in Alaska, and possibly the largest predatory fish in the ocean. It is also one of the most vulnerable of all managed fish stocks in Alaska waters.
“Yet we still know little about even its most basic biology,” said Beth Matta, research fisheries biologist at the NOAA Fisheries Alaska Fisheries Science Center.
A new collaborative NOAA Fisheries study takes an important step toward better understanding and managing the Pacific sleeper shark. Researchers compiled knowledge from a wide variety of sources to provide important new insights into its biology and ecology. They identified and prioritized research needs to better assess and manage this species.
“We can’t manage what we don’t understand,” said Matta, who led the study. “We wanted to create a one-stop shop for information on Pacific sleeper sharks—a resource that others can use.”
Slow Growth and Low Production Lead to Vulnerability
The Pacific sleeper shark, named for its sluggish nature, lives throughout the Pacific Ocean. It has been found in shallow intertidal zones, and sighted by submersibles at depths beyond a mile underwater. It is encountered by humans most often as unwanted bycatch on commercial fishing vessels.
Like many other sharks, the Pacific sleeper shark likely grows slowly, matures late, and has a long lifespan and low productivity. These qualities make it highly susceptible to overfishing.
“Sustainable fishing rates for long-lived sharks are very low. For example, the spiny dogfish, a Pacific sleeper shark relative with a lifespan of 100 years, can tolerate harvest rates of only about 3 percent,” said study coauthor Cindy Tribuzio, NOAA Fisheries Alaska Fisheries Science Center. “Pacific sleeper sharks potentially take that to extremes.”
In Alaska waters, the majority of Pacific sleeper shark mortality is due to fisheries bycatch. Observed declines in certain parts of its range, coupled with its low productivity, have led to conservation concerns. The North Pacific Fishery Management Council highlighted conservation concerns in its most recent stock assessment review.