Discovery of a Great Hammerhead Nursery

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).

Fun Science FRIEDay – A fish without blood

Amidst all the hysteria surrounding the seemingly unstoppable COVID-19, we bring you a story of a fish without blood. In 1928 a biologist sampling off the coast of Antarctica pulled up an unusual fish. It was extremely pale (translucent in some parts), had large eyes and a long toothed snout, and somewhat resembled a crocodile (it was later named the “white crocodile fish). Unbeknownst at the time, but the biologist had just stumbled on a fish containing no red blood pigments (hemoglobin) and no red blood cells – he iron-rich protein such cells use to bind and ferry oxygen through the circulatory system from heart to lungs to tissues and back again. The fish was one of  sixteen species of what is now commonly referred to as icefishes that comprise the family Channichthyidae, endemic around the Antarctic continent.

The Antarctic ice fish on the seafloor surrounded by brittle stars. (Photo credit:  E Jorgensen/Alfred Wegener Institute)
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Cut rock samples from the Rio Grande Rise show Fe-Mn crusts (black and gray) growing on various types of iron-rich substrate rocks (pale to dark brown). Photo credit: Kira Mizell, USGS.

A lost continent, rich in cobalt crusts, could create a challenging precedent for mineral extraction in the high seas.

[This article originally appeared yesterday in the Deep-sea Mining Observer. ~Ed.]

The Rio Grande Rise is an almost completely unstudied, geologically intriguing, ecologically mysterious, potential lost continent in the deep south Atlantic. And it also hosts dense cobalt-rich crusts.

The Rio Grande Rise is a region of deep-ocean seamounts roughly the area of Iceland in the southwestern Atlantic. It lies west of the Mid-Atlantic Ridge off the coast of South America and near Brazil’s island territories. As the largest oceanic feature on the South American plate, it straddles two microplates. And yet, like much of the southern Atlantic deep sea, it is relatively under sampled.

Almost nothing is known about the ecology or biodiversity of the Rio Grande Rise.

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37 things I learned about shark ecology and conservation for my dissertation

The fam attending my dissertation defense

The fam attending my dissertation defense

After a little more than 5 years of hard work, I’ve officially completed my Ph.D.! You can read my dissertation (“An Integrative and Interdisciplinary Approach to Shark Conservation: Policy Solutions, Ecosystem Role, and Stakeholder Attitudes”) online here in its entirety.

In case there are some among you who don’t really want to read a 281 page dissertation but are curious about what I found, I’ve prepared this blog post to summarize my key conclusions. (Note: this does not include every conclusion. Some are aggregated together, and some more technical conclusions are omitted for this summary).

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Fun Science FRIEDay – Visualize the Seafloor

Happy FSF! As some of you may know (and for those who don’t), I study the bottom of the ocean, and I do so primarily using innovative technology to image the seafloor (e.g., Wormcam). The interesting work I’ve conducted has resulted in me having the opportunity to present my work to a larger lay audience, in the form of a TEDx presentation.

(Photo Credit: TEDx Newport)

(Photo Credit: TEDx Newport)

I am giving my TED talk with my good buddy and colleague Steve Sabo.  In our talk, “A Picture is Worth a Thousand Worms”, Steve & I will illustrate the significance of the ocean floor through advancements in underwater camera technology and data visualization, making complex science more accessible for everyone.

Our TED photo (Photo credit: Meg Heriot)

Our TED photo (Photo credit: Meg Heriot)

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Fun Science FRIEDay – Underwater World of Pollination

Pollination. I think most people understand why this is important (or maybe I should say, I hope). To put it simply, the process of pollination facilitates reproduction in plants by transferring pollen from one plant to another. In the terrestrial world, this can be mediated by physical forcing (e.g., wind) or by animals (e.g., insects) – and its why people are freaking out about the loss of bees due to pesticides (because they are a primary pollinator), but I digress. Until relatively recently, pollination by animals was not thought to occur in the ocean. Unlike on land, where most flowering plants rely on creatures to carry pollen, plant reproduction in an aquatic world was surmised to rely exclusively on currents and tides. However, a team of researchers led by marine biologist Brigitta van Tussenbroek revoked the long standing paradigm that pollen in the sea is transported only by water, discovering and documenting the process of zoobenthophilous pollination (a term they coined).

Gamarid amphipod feeding on pollen or mucilage of a male flower of the seagrass Thalassia testudinum at night. (Photo credit: Tussenbroek et al. 2012)

Gamarid amphipod feeding on pollen of a male
flower of the seagrass Thalassia testudinum at night. (Photo credit: Tussenbroek et al. 2012)

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Fun Science FRIEDay – Shark Daycare

A great white shark nursery in the North Atlantic that was discovered in 1985 south of Cape Cod in the waters off Montauk, New York  has received renewed attention due to the increased activity of white sharks off cape cod in recent years. The nursery was first documented in 1985 by Casey and Pratt who deduced the presence of a nursery based on the number of juvenile sightings and landings in the area. This work was followed up recently  by OCEARCH (an organization dedicated to generating scientific data related to tracking/telemetry and biological studies of keystone marine species such as great white sharks), which tagged and tracked nine infant great whites to the nursery, located a few miles off Montauk.

Great White Shark. Image courtesy animals.NationalGeographic.com

Great White Shark. Image courtesy animals.NationalGeographic.com

Photo of a great white shark in Mexico by Terry Goss, WikiMedia Commons. http://commons.wikimedia.org/wiki/File:White_shark.jpg

Photo of a great white shark in Mexico by Terry Goss, WikiMedia Commons. http://commons.wikimedia.org/wiki/File:White_shark.jpg

 

 

 

 

 

 

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Seagull swallowed by tuna

The tuna that ate a seagull, and other bird swallowing marine megafauna

Once again, the internet is in a fervour over a rarely documented, but pretty common, animal interaction.  The video below shows fishermen at a pier in L’Escala, Spain tossing small fish to a tuna.  A nearby seagull went for the same fish and was ingested by the tuna, much to everyone’s surprise.  Naturally, the tuna spat out the seagull, luckily uninjured, and it flew away to dive another day:

Seabirds are often ingested by marine megafauna since both groups forage in the same areas, often on the exact same prey.  This video was an artificial overlap of foraging animals created by the people tossing fish from the pier, but in natural settings where two animals feed on the same prey and one of those animals is considerably larger than the other, the smaller animal faces a pretty high risk of being swallowed.

This is especially true for lunge-feeding whales that take in large mouthfuls of fish, water, and anything else at the surface.  Haynes et al. identified three Glaucous-winged gulls in the fecal remains of foraging humpback whales in Glacier Bay, Alaska.  The birds were mostly intact, suggesting that humpback whales aren’t capable of digesting birds well (we’ve all been there).

All of the examples above are accidental ingestion, but some marine animals deliberately target birds for food, too.  Tiger sharks seasonally aggregate at the Hawaiian Islands of French Frigate Shoals to forage on albatross fledglings.  Fledglings are fat, slow, and naïve, making them easy and profitable prey.  This foraging strategy is common among sharks and is the same reason white sharks target seal colonies during South African winters.

The alien giant catfish of the river Tarn in southwestern France is an aquatic example.  They have also acquired a taste for feathered food and learned to ambush aloof pigeons, with a success rate of 28%:

Although not mega- megafauna, the Hilaire’s Side-necked turtles of Brazil have been documented consuming pigeons in a scene that honestly rivals Jaws.  Who’s slow now? (Edit: Thanks to @mattkeevil for the reference!)

Marine and aquatic animals do indeed eat birds, accidentally and deliberately.  Exactly how regularly this happens is unknown, but this antipodean pairing is essentially the chocolate shake and fries of the natural world.  The bottom line is, if you are in the same space where something bigger than you is foraging, you might get swallowed.  Birds, and humans, alike:

Fun Science FRIEDay – Osprey Version of the Truman Show #ospreycam

Do you ever get that feeling that you are being watched? I imagine that is what the ospreys at the nesting platform at the Virginia Institute of Marine Science (VIMS) must feel, if they notice at all. These birds have a camera that is trained on their nest 24/7 during the osprey breeding season (generally from mid-March to October).

Osprey in a nest on the campus of the Virginia Institute of Marine Science (Photo Credit: VIMS)

Osprey in a nest on the campus of the Virginia Institute of Marine Science (Photo Credit: VIMS)

Ospreys are unique among North American raptors for their diet of live fish and ability to dive into the water to catch them. As a result of their life history strategies, osprey nests occur around nearly any body of water: saltmarshes, rivers, ponds, reservoirs, estuaries, and even coral reefs. The placement of OspreyCam at VIMS provides us with an around-the-clock window into the world and “family” dynamics of these amazing birds. We are able to watch as a mating pair cohabit their nest and use it to rear their young. As you can imagine, once the chickies hatch, things get quite interesting in the osprey nest!

Checkout the addictive live feed below, and happy FSF!!

One of the world’s rarest birds is also the squee-est

Introducing the spoon-billed sandpiper:

(c) Roland Digby/WWT/PA Wire, originally published http://www.westerndailypress.co.uk/world-s-rarest-birds-hand-reared-experts-returned/story-27630995-detail/story.html#ixzz3jFOW6Q43

(c) Roland Digby/WWT/PA Wire, originally published here.

Spoon-billed sandpipers are migratory wader birds that breed in the sub-Arctic and winter in southeast Asia.  Best estimates point to less than 100 breeding pairs left in the wild due to a decrease of breeding habitat in the Arctic and increase of bird-hunters in Asia.  Don’t worry, this is a story about #OceanOptimism…

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