Pacific sleeper shark: new insights into mysterious ocean predator

Although the Pacific sleeper shark is one of the largest predatory fish in the ocean, with a range across the Pacific, little is known about it. To address the most pressing gaps in our knowledge and how to protect the species, a group of scientists stepped in to create a one-stop shop for information about the slow-moving shark species.

Pacific sleeper sharks are closely related to Greenland sharks and can interbreed, and from what we know or speculate about them, they share similar characteristics. They can reach lengths of up to 14.1 feet (4.3 meters), but it is speculated that adults living in the depths of the ocean may even reach 23 feet (7 meters). They are also suspected to be equally long-lived.

However, unlike their close relatives, they are notoriously understudied, which the study authors attribute to their lack of commercial value compared to Greenland sharks, the inaccessibility of their habitat, and the safety and security of capturing and handling such large animals. Logistics support. Finding adult Pacific sleepers is also rare.

Without a wealth of knowledge, it’s difficult to know how best to manage and protect sharks, which are currently listed as declining and near-threatened on the IUCN Red List.

We don’t have much to do in managing this species. Currently, they are managed based on historical catches. That’s not ideal, especially for a highly vulnerable species, study co-author Cindy Tribuzio said in a statement. The more information we gather, the better we can develop and apply alternative methods to better assess this and other species for which data are limited.

So the team began digging into the scientific literature on the mysterious shark species, borrowing some information about their close relationship along the way and making some new discoveries that could inform conservation.

One of the most important findings comes from genetic research, which suggests that there may actually be more Pacific sleeper sharks than previously thought, thanks to some camouflaged sharks.

Lead author Beth Matta said we once thought of three large species in the genus: the Pacific sleeper shark, the southern sleeper shark and the Greenland shark. We now know that southern sleeper sharks are not genetically unique.

They also found plenty of evidence about the potential lifespan of the sharks, supporting existing theories that they can reach impressive ages (although probably not as old as the 400-year-old Greenland shark).

For example, one study that used radiocarbon dating to analyze the lens of the eye found that they grew twice as fast as Greenland sharks, but still much slower than many other fish. Another capture and analysis of an immature female shark showed she was at least 35 years old. Tribuzio explained that this not only indicates extremely long lifespan, but also delayed maturity.

Through the results of this study, the team hopes to not only highlight the gaps that still exist in scientific knowledge, but also to exploit yes Known to help better manage this species.

“Based on the information we gathered in this study, we were able to demonstrate the need to prioritize Pacific sleeper shark assessment efforts,” Tribuzio said. Given the species’ vulnerability and the challenges of assessment, we need to think outside the box on how to manage this species.

For example, evidence suggests that Pacific sleeper sharks’ slow growth, delayed maturity, and long lifespan may make them more vulnerable to overfishing, providing targets for management.

Matta added that the more we learn about these sharks, the more concerned we are about keeping them alive in the future. There is still much to learn.

The research was published in Polar Biology.