Discover the mysterious world of the Pacific sleeper shark. These elusive creatures have been keeping secrets from us for far too long, but now, thanks to some dedicated researchers at the National Oceanic and Atmospheric Administration (NOAA), we’re finally starting to unravel their mysteries.
First things first, let’s talk about where these sharks hang out. Pacific sleeper sharks are the ultimate deep-sea dwellers, spending most of their time chilling at depths of up to 6,600 feet below the surface. That’s like living in a completely different world!
The truly fascinating part is that these sharks are believed to be among the planet’s longest-living creatures. We’re talking about centuries. But here’s the problem: according to a new NOAA Fisheries study published in the journal Polar Biology, these ancient sharks are facing a serious threat from overfishing.
Beth Matta, a research fisheries biologist at the NOAA Fisheries Alaska Fisheries Science Center, put it bluntly: “We still know little about even its most basic biology.” She’s right, and that’s a big problem. As Matta says, “We can’t manage what we don’t understand.” That’s why she and her colleagues set out to create a comprehensive resource on Pacific sleeper sharks so that we could start protecting these incredible creatures.
So, what do we know about these sharks? Well, for starters, they can grow up to a whopping 23 feet long. That’s like having a small submarine swimming around in the ocean! But despite their impressive size, these sharks are in no hurry. They move at a glacial pace, taking their time to mature. It can take them decades just to reach sexual maturity.
And when it comes to having babies, Pacific sleeper sharks are pretty chill about that, too. They have very few offspring throughout their long lives, which means that if we overfish them, their populations could take a serious hit. In actuality, fishing boats merely accidentally catch the majority of Pacific sleeper sharks that humans encounter.
Cindy Tribuzio, another researcher at the NOAA Fisheries Alaska Fisheries Science Center and a co-author of the study, put it into perspective: “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. Pacific sleeper sharks could potentially take that to extremes.”
Despite their size, extensive habitat range, and vulnerability, Pacific sleeper sharks have only recently become the focus of scientific research. Why? Well, they don’t have much commercial value; they’re really hard to study in their deep-sea homes, and safely catching and handling these giant sharks on ships is no easy feat.
“A large portion of the population remains unseen and unsampled,” Tribuzio explained.
In their paper, the researchers made some fascinating discoveries. They found that the number of Pacific sleeper shark sightings has gone down off the coasts of Taiwan and Alaska but has increased in Russian waters. They also used genetic data to show that all the Pacific sleeper sharks out there likely belong to just one species, not three like we previously thought.
“We used to think there were three large species in the genus: Pacific sleeper shark, southern sleeper shark, and Greenland shark,” Matta said. “Now we know the southern sleeper shark is not genetically distinct.”
The researchers also identified a potentially crucial habitat in the Bering Sea where these sharks seem to grow into adults. In the summer of 2023, they even had the opportunity to study a 14-foot female shark. Guess what? She was at least 35 years old but still not ready to have babies.
“That indicates not only extreme longevity but also delayed maturity,” Tribuzio said. “All those pieces together suggest a high susceptibility to becoming overfished.”
The goal of this Polar Biology paper was to gather all the available knowledge about Pacific sleeper sharks from a wide range of sources. The researchers hope to use this information to better understand the risks these sharks face and figure out how to manage them effectively.
“We don’t have much to go on for managing this species.” Right now, they are managed based on historical catch. That’s not ideal, especially for a highly vulnerable species,” Tribuzio said. “The more information we can gather, the better we can develop and apply alternative methods that will do a better job of assessing this and other data-limited species.”
To make this study possible, the researchers teamed up with the Alaska Fisheries Science Center, Fisheries and Oceans Canada, and fishing industry partners. “Almost all of the research we have done and are doing is highly collaborative.” We especially work with fishing industry partners a lot,” Tribuzio said. Without their support and the measurements and samples they collect, we could not have accomplished much of our research.”
The ultimate goal? To prove that Pacific sleeper sharks desperately need our help and conservation efforts.
“With the information we compiled in this study, we were able to demonstrate the need to prioritize Pacific sleeper shark assessment efforts,” Tribuzio said. “And that we need to think outside the box on how to manage this species, given its vulnerability and challenges to assessing it.”
Matta couldn’t agree more. “The more we learn about these sharks, the more we care about keeping them around into the future,” she said. “And there is so much more to learn.”
So there you have it, folks. The Pacific sleeper shark may be a mystery, but it’s a mystery worth solving. These ancient, slow-moving, deep-sea giants need our help, and thanks to the hard work of researchers like Matta and Tribuzio, we’re one step closer to giving them the protection they deserve. Who knows what other secrets these sharks will reveal as we continue to study them? One thing’s for sure: the more we learn, the more we’ll care about keeping these incredible creatures around for centuries to come.
