Happy Shark Week (if you celebrate), and I’m so excited to share our newly published open access paper about our research on juvenile great hammerheads (Sphyrna mokarran) with you! (It’s been hard to keep this one to ourselves).
Great hammerheads are an iconic shark species which have undergone significant population declines globally. In 2019, they were assessed as Critically Endangered by the IUCN Red List, which reported overfishing as the greatest threat to their survival. Great hammerheads are known to make incredible long-range migrations and cross state and international boundaries, making them challenging to protect as adults. Little is known about where they are born or where they spend their early years of their life, although there have been scattered reports of juveniles from the Gulf of Mexico, the Florida Keys, and one report from Georgia.
Identifying habitats that are important to juvenile sharks matters because young sharks are often the most vulnerable individuals in a population, and their survival is vital to the future of their species. Many juvenile sharks spend time in “nursery areas”—places where they are less likely to be eaten by predators, or where food resources are abundant. They then expand their ranges as they age, covering more distance as they grow larger. Identifying nurseries has long been a conservation priority for managers and scientists. After several years of research, our team has collected the first scientific evidence of a nursery area for great hammerhead sharks on the Atlantic coast of the United States—within sight of the skyline of Miami, Florida.
There’s a three-part established test for an area to be identified as a shark nursery: 1) Juvenile sharks are more commonly encountered in that habitat than elsewhere; 2) they remain in the area for extended periods; and 3) The area is used repeatedly over years. Our results demonstrate that this area definitely meets two of these criteria, with preliminary evidence that it also meets the third. We’ve found the same habitat may be a nursery area for several other shark species too, including scalloped hammerheads, another Critically Endangered species!
Although great and scalloped hammerheads are protected in Florida waters and must be released if caught, hammerhead sharks often die or suffer serious harm from capture stress. Some of these juvenile individuals were caught with hooks from prior encounters with recreational anglers still embedded in their jaws. We hope learning more about this nursery can help us reduce threats to and better protect these small sharks. We can’t wait to share further updates as new results come in from the project’s telemetry expansion, supported by the Nature Trust of the Americas and a National Geographic Explorer Grant.
Our short scientific paper documenting this work is available open access through the journal Conservation Science and Practice, you can visit the project website here, or I hope you will watch the incredible video (also embedded at the top of the post).
This article originally appeared in the June/July 2020 issue of the Deep-sea Mining Observer. It is reprinted here with permission. For the latest news and analysis about the development of the deep-sea mining industry, subscribe to DSM Observer here: http://dsmobserver.com/subscribe/
For over 50 years, deep-ocean explorers have been able to claim that more people have walked on the moon than have dived to the deepest point on the Earth. Only two men descended into Challenger Deep in the 20th century–Don Walsh and Jacques Piccard–they were joined in the early 2010s by director James Cameron. Earlier this year, Victor Vescovo became the fourth to reach the bottom of Challenger Deep and, over the course of several subsequent dives this summer, the ranks of those who’ve reached the deepest ocean has swelled.
Astronaut, oceanographer, and former NOAA Administrator Kathy Sullivan and explorer and mountaineer Vanessa O’Brien became the first and second woman to dive to the bottom of Challenge Deep aboard the privately owned HOV Limiting Factor, piloted by Vescovo and his team.
[The following is a transcript from a talk I gave at the 2019 Minerals, Materials, and Society Symposium at the University of Delaware in August, 2019. It has been lightly edited for clarity.]
Good afternoon and thank you all for
coming. I want to change tracks for a bit and scan the horizon to think about
what the future of exploration and monitoring in the high seas might look like
because ocean and conservation technology is in the midst of an evolutionary
shift in who has access to the tools necessary to observe the deep ocean.
This is the Area. Areas Beyond National
Jurisdiction, International Waters, the High Seas, the Outlaw Ocean. It’s the
portion of the ocean that falls outside of national EEZs and is held in trust
by the UN under the Convention on the Law of the Sea as the Common Heritage of
Humankind. It covers 64% of the ocean and nearly half of the total surface of
the Earth. It’s also the region in which most major deep-sea mining ventures
intend to operate.
Pirates! Robots! Meteors! A team of plucky teenage explorers! If this doesn’t end up as a feature film, I’ll eat my red watch cap.
On Monday, February 6, 2017 a meteorite dropped out of space and dropped right into Lake Michigan. Since then, a team of young explorers sponsored by the Shedd Aquarium and the Adler Planetarium have been combing the lake for the lost meteorite. Catch up with this epic adventure through their podcast and on OpenExplorer. The search continues into 2019.
Not all hydrothermal vents emerge in the deep sea. Of the coast of Iceland, shallow water vent spew forth their hydrothermal plumes in the shallows, where small underwater robots can easy access. You’d think we’d know more about them than their deep ocean counterparts but we actually know less.
On a hot summer day in the murky waters of the man-made Millbrook Quarry in Northern Virginia, a group of about 25 people outfitted in scuba gear take turns going down to a depth of 30 feet, testing their compass reading skills, flooding their masks and practicing emergency ascents without air. The sight is not so unusual since Millbrook is the main training and certification site for scuba divers in the DC/Maryland/Virginia area and often hosts such groups. What might give folks pause, however, is that upon closer look they may notice that all 25 of the divers are African American. And if they chat with this unexpected bunch, they might also find that a majority are certified and qualified to search for, document and help excavate slave trade shipwrecks.
Divers with Purpose and the Slave Wrecks Project will be traveling across Africa and the Caribbean documenting the stories of underwater archaeologists working to preserve the history of the Atlantic slave trade buried at sea.