genetics

In search of scalloped hammerheads

Mission Overview

Thanks to the Moore Charitable Foundation and Paul G. Allen Philanthropies, we headed to San Salvador in the Bahamas in search of endangered scalloped hammerhead sharks. Although a shark sanctuary, there are few data showing the existence of scalloped hammerheads in Bahamian waters. On 840 baited remote underwater video surveys (BRUVs) previously completed in the Bahamas by our team, no scalloped hammerheads were documented. Anecdotal accounts of scalloped hammerheads from local dive shops and fishers sparked our interest to investigate further.  From our core research team were Florida International University’s Dr. Demian Chapman and Gina Clementi, as well as Dalhousie University’s Taylor Gorham. Joining them were FIU researchers Dr. Yannis Papastamatiou, Dr. Bautisse Postaire, and Megan Kelley as well as photographer Andy Mann, free-diver Trevor Bacon, Captain Scott Genereux, first mate Joey Salomone, journalist Amaro Pablo-Gómez, and Pew Charitable Trusts conservationist Maximiliano Bello. Using BRUVs, dive surveys, and environmental DNA (eDNA) collection, the team had their sight set on confirming the presence of scalloped hammerheads in San Salvador.

Day 1

With energies still high, we decided to start the trip off with BRUVs. After completing eight deployments, we headed in for the night to enjoy dinner together and test out our new eDNA sampling equipment. But, as luck would have it, the boat we were using to set BRUVs had a mechanical issue, taking away dinner while it was practically right under our noses. That feeling must be what it’s like to be a shark not able to get the bait in our cages! After a couple of hours waiting safely at sea for assistance, we finally returned to our home boat, the Lady G. With full stomachs, we headed to the deck to collect eDNA samples. After spotting lemon sharks and one southern stingray swimming around the boat, we decided to call it a day – a very successful one!

Dr. Postaire (left) carefully drops the Niskin bottle over the side of the boat to collect water that was later filtered for eDNA. Back in the laboratory he will use genetics to try to look for sharks and rays. He will likely find the lemon shark that was swimming around the boat, pictured on the right.

Day 2

Today, it happened! Yannis and Megan spotted a scalloped hammerhead immediately after a dive and right before a BRUV retrieval. Although not filmed by the BRUV, Yannis was able to capture a video of it pooping, seen below. We completed nine BRUVs today and sampled for eDNA at three sites.

Day 3

Diving and BRUVs continued, with our second scalloped hammerhead sighting.

Diver Megan Kelley seen with a Nassau grouper. Photo credit: Andy Mann

Day 4

Taylor and Bautisse sampled another four sites for eDNA while the rest of the team went to explore a seamount. Sighted were silky sharks, oceanic whitetip sharks, three whales, and a tiger shark on a drifting pelagic BRUV.

A curious silky shark investigates the team. Photo credit: Andy Mann

Day 5

Edd Brooks from the Cape Eleuthera Institute joined the team. We were slowed down by strong wind and rain today, but we didn’t let that dampen our spirits. Three BRUVs were completed and a pod of dolphins swam around us for 30 minutes, playing with corals, eating gobies in the sand, and chasing barracuda.

Day 6

The talented Andy Mann filmed a few staged BRUVs today (check out some of the resulting footage on our homepage), while the science team completed three BRUVs and sampled five sites for eDNA. Edd took some of the team to the mangroves where they successfully caught a juvenile lemon shark for a tissue sample.

A Caribbean reef shark swims past our staged BRUV, allowing photographer Andy Mann to capture this stunning moment on camera.

Day 7

Our trip has come to end. Due to prevailing winds and because both our Niskin bottle and pump for filtering water broke, we decided to end the trip early. After 26 coral reef BRUVs completed, one pelagic BRUV set, two deep BRUVs set, 21 eDNA samples collected, and sightings of scalloped hammerheads, we can call this a successful mission!

And we’re off! Photo credit: Bautisse Postaire 

These single ladies don’t need a man

Publication specs

Title: Facultative parthenogenesis in a critically endangered wild vertebrate

Authors: Andrew Fields, Kevin Feldheim, Gregg Poulakis, Demian Chapman

Journal: Current Biology

Year: 2015

The Internet exploded last year with news of a vertebrate capable of producing offspring without sex. Billions of people across the globe tuned in to learn about the smalltooth sawfish’s newly discovered ability. The study was led by our lead principal investigator, Dr. Demian Chapman, and his Ph.D. student, Andrew Fields. This ability, scientifically known as facultative parthenogenesis, where animals that generally need a male to produce offspring can do so without one, is not a new scientific concept. In fact, it has been discovered in many captive vertebrates like birds, reptiles, sharks, and more recently rays. So what’s so novel about it? Smalltooth sawfish are a type of batoid, or ray, that are critically endangered and in 2007 were among the first elasmobranchs to receive international trade regulations by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Since the 1960s, these rays have seen a population decline of about 95% due to habitat loss, overfishing, bycatch, and target capture – where their rostrum, or snout, was sold as curio, aka a bizarre object usually used for home decoration. Smalltooth sawfish are currently only found in Southwest Florida and parts of the Bahamas. This study provided the first evidence of facultative parthenogenesis in the wild and it may be more common than previously thought, particularly in populations on the verge of extinction. But don’t get too excited – there is no scientific evidence of this phenomenon occurring in mammals.

White sharks: finding mates nearby

Photo: Yannis Papastamatiou

Photo: Yannis Papastamatiou

Publication specs

Title: Genetic Diversity of White Sharks, Carcharodon carcharias, in the Northwest Atlantic and Southern Africa
Authors: Shannon J. O’Leary, Kevin A. Feldheim, Andrew T. Fields, Lisa J. Natanson, Sabine Wintner, Nigel Hussey, Mahmood S. Shivji, and Demian D. Chapman 
Journal: Journal of Heredity
Year: 2015

Would you want to swim across the ocean to find a mate? Probably not, and neither do great white sharks. A recent study showed that white sharks are breeding on the side of the Atlantic Ocean where they were born despite their tendency to venture into the open ocean. The results revealed two distinct populations of white sharks, separated by the vast Atlantic Ocean. This implies that effective conservation measures would be separate and local, both in the Southern African nations and in the Northwest Atlantic. Luckily, white sharks are federally protected in both locations, which means this study’s findings validate current protection measures.

Photo: Katie Flowers

Photo: Katie Flowers