22 things scientists learned about sharks in 2022

2022 has been a weird year for humans, but it was a very interesting year for sharks! Shark species representing 90% of the global shark fin trade got listed on CITES Appendix II, which will require strict regulation, documentation, and dramatically improved sustainability of their fisheries. The once-every-four-years Sharks International conference was held in Valencia, Spain, and recordings of all talks are available until summer 2023. And sharks even made it into one of those “what Fox News is showing instead of current events that are bad for Republicans” memes!

There were also a lot of fascinating scientific discoveries, which this post will round up for you. As always, this is not meant to be a “best” or “top” list, so if your science isn’t included here please do not send angry letters. This is just some cool stuff I learned this year thanks to my amazing colleagues, in no particular order. Whenever possible I’ll also provide links to further reading on the topic. I hope you enjoy!

1 A genetic analysis found that endangered shark meat was found in pet food, and was poorly labeled in the ingredients section as “ocean fish.” Check out coverage of this study in Smithsonian Magazine.

2 A team of scientists released three decades of data showing how nurse sharks use the Dry Tortugas as a mating ground year after year… and hurricane Ian may have altered this vital habitat forever. Check out news coverage of this study here.

3 Speaking of nurse sharks, these sharks were observed following dolphins and feeding off the prey animals that were startled by dolphin foraging. If you’ve ever heard that it’s safe to go in the ocean if you see dolphins because sharks are afraid of dolphins, think again!

4 And speaking of shark mating, a fascinating behavior was described in basking sharks, the world’s second largest fish. They swim together in tight circles that are absolutely full of basking sharks, swimming very closely together. Check out the image below, and some media coverage in Newsweek.

Figure 1 from Sims et al.

5 Collisions with large ships are a major threat to whales. New research shows that this is also a threat to whale sharks, which have similar feeding behaviors as large baleen whales. Smithsonian Magazine covered this work.

6 Megalodon, which is definitely super-duper extinct despite being the subject of the internet’s weirdest conspiracy theory, still produces some fascating science. An analysis of well-preserved fossils shows that megalodon was a “super-predator,” able to fully consume animals that would be considered apex predators in modern times, and were likely faster than any shark species alive today. This story made CNN.

7 Shark scientists often want to perform research that helps to manage and conserve threatened species we love, but an analysis of shark research in India shows that most of it isn’t especially relevant to conservation. This story was covered in MongaBay.

8 Scientists who want their work to be more relevant to conservation and management could examine this new list of global research priorities. (And/or a list from a team I led that focuses on species in the United States).

9 One exciting discovery for shark conservation is the news that a new device keeps sharks away from tuna longlines, reducing the risk of bycatch. Media coverage of this discovery quotes me.

10 Great white sharks have fled from a known aggregation site, which has been home to some long-term wildlife tourism operations, due to orcas hunting and killing them. The drone footage of this is SO COOL.

11 Ocean acidification is a major threat to many species of marine life, so it’s good news to learn that sharks are resistant to some of the worst effects…their teeth become more elastic and therefore durable.

12 As an interdisciplinary scientist, I love seeing socioeconomic studies of shark conservation, and this one, showing how shark fishing is important for coastal Ghana’s fishing communities, is one I’ll share in my classes to show why we can’t just ban all shark fishing. It got covered in Forbes.

13 A team of scientists and conservationists introduced the Important Shark and Ray Areas framework, which will help shape global shark conservation and management for years to come.

14 Another tool that will help assess and improve shark management, M-Risk, was also introduced this year.

15 How smart are sharks? My neurobiologist colleagues hate that question, but a new review of shark cognitive abilities concludes that sharks have more complex brains and associated behaviors than most people think.

16 A global analysis of decades of IUCN Red List index data shows that even as tunas and billfish have improved their populations due to improved management, many sharks, caught as bycatch in those same fisheries, continue to face serious threats.

17 Greenland sharks, the world’s longest-lived vertebrate, have one of the slowest metabolic rates of any large marine animal.

18 A historical ecology analysis confirmed the long-term importance of some key habitat for critically eendangered angel sharks in the UK. I wrote about this for the Revelator.

19 A tagged scalloped hammerhead shark swam down to over 1,200 meters in depth, a new record for the species.

20 I’m sharing this analysis of a US Fish and Wildlife Service investigation into illegal shark fin shipments for the excellent title: “Sharks on a Plane,” but it’s also a really interesting look at how wildlife crime investigations occur.

21 Work on the potential conservation impacts of recreational fishing for sharks continues.

22 An analysis of sharksucker diet found that they primarily eat scraps of prey from their host shark’s messy eating.