Sadly, we are rapidly losing our chances of seeing a shark in the wild, because they are vanishing at an alarming rate. Each year nearly 100 million sharks are killed, largely for their fins, which are used to make shark fin soup.






Check out Brian's previous post about diving with mako sharks and this post he wrote about shark conservation.

Visitors to the Aquarium can experience what it's like to see sharks and rays up close in a new mangrove-themed exhibit, The Trust Family Foundation Shark and Ray Touch Tank.

Swimming with a whale shark is like being in the presence of a dinosaur. They are massive yet gentle, and mysterious. Their migrations and behaviors are not well understood; they move to ancient rhythms that we are not able to hear.

The great hammerhead is an elusive and solitary creature.

Although it appears prehistoric, science tells us that it is evolutionarily advanced compared to other sharks, since its nostrils have separated to either side of its hammer-shaped head, giving it stereoscopic smell.



Check out Brian's previous post about diving with mako sharks and this post he wrote about shark conservation.

Earlier this year, New England Aquarium explorers joined an expedition to Raja Ampat, Indonesia (this post by Dr. Mark Erdmann has more about the history of this region). The expedition members posted some amazing aerial photography, shared findings from Remote Operated Vehicle dives and reported on transects of coral reefs. Overall it was a fascinating expedition.

Last June, Photographer Ethan Daniels went on expedition to the same area, and he is generously sharing some of his images with the Global Explorers Blog. Check out the four images below and scroll through more of Ethan's images as they appear on the Aquarium's tumblr account. If you're in the Boston area you can meet Ethan and hear him speak about his work at a Boston Public Library lecture on Wednesday, July 27.

This is the eighth and final installment in a series of daily photo posts from an expedition to Tongass National Forest by Keith Ellenbogen, a photographer and frequent contributor to the Global Explorers Blog. He recently joined Philippe Cousteau on an expedition with The Boat Company to explore Southeast Alaska's abundant wildlife.  



[Note: In addition to being a popular fish for recreational anglers, Alaska salmon also supports a large commercial fishery starting each year in the spring and running through the fall. Alaska's commercial salmon fisheries are recognized as being environmentally responsible because of facets such as effective management, low rates of bycatch, and the use of fishing gear that does not cause substantial disturbance to marine habitats. These factors all contribute to the Alaska salmon fisheries being considered ocean-friendly.]

This is the seventh in a series of daily photo posts from an expedition to Tongass National Forest by Keith Ellenbogen, a photographer and frequent contributor to the Global Explorers Blog. He recently joined Philippe Cousteau on an expedition with The Boat Company to explore Southeast Alaska's abundant wildlife.  

This is the sixth in a series of daily photo posts from an expedition to Tongass National Forest by Keith Ellenbogen, a photographer and frequent contributor to the Global Explorers Blog. He recently joined Philippe Cousteau on an expedition with The Boat Company to explore Southeast Alaska's abundant wildlife. 

This is the fifth in a series of daily photo posts from an expedition to Tongass National Forest by Keith Ellenbogen, a photographer and frequent contributor to the Global Explorers Blog. He recently joined Philippe Cousteau on an expedition with The Boat Company to explore Southeast Alaska's abundant wildlife. 

This is the fourth in a series of daily photo posts from an expedition to Tongass National Forest by Keith Ellenbogen, a photographer and frequent contributor to the Global Explorers Blog. He recently joined Philippe Cousteau on an expedition with The Boat Company to explore Southeast Alaska's abundant wildlife. 

This is the third in a series of daily photo posts from an expedition to Tongass National Forest by Keith Ellenbogen, a photographer and frequent contributor to the Global Explorers Blog. He recently joined Philippe Cousteau on an expedition with The Boat Company to explore Southeast Alaska's abundant wildlife. 

This is the second in a series of daily photo posts from an expedition to Tongass National Forest by Keith Ellenbogen, a photographer and frequent contributor to the Global Explorers Blog. He recently joined Philippe Cousteau to explore this Southeast Alaska's abundant wildlife. 




Read more about the expedition on Philippe Cousteau's blog at EarthEcho.

This is the first in a series of daily photo posts from an expedition to Tongass National Forest by Keith Ellenbogen, a photographer and frequent contributor to the Global Explorers Blog. He recently joined Philippe Cousteau on an expedition with The Boat Company to explore Southeast Alaska's abundant wildlife. 

This post was written on July 13.

An early morning departure pays off big. In flat calm, we find a group of six Blainvilles at 6:59 in the morning, and follow them for over 7 hours. The group consisted of two mothers with calves, an adult female, and an adult male. One of the adult females, nicknamed chopper, was missing the top of her dorsal fin. The male was an old battle-scarred fellow, with a remarkable collection of deep gouges and scars all over the top forward half of his body.



 


We put swimmers on both sides of the boat, but discovered a new twist in the fecal collection game. A rare bloom of plankton in the region lowered visibility to below 40 feet, making following the whales underwater difficult. In fact, for the swimmers, the whales remained distant shadows and dark shapes for most of the morning, on the edge of our ability to see them. Our hopes of collecting feces improved later in the morning as the whales moved into clearer water, when visibility improved to over 70 feet. Sure enough, Roz got a terrific sample from one of the adult females at 12:38.




The long follow also allowed us to watch the interactions of the whales underwater. Calves stayed close to their moms, tucked either directly underneath her, or directly behind her dorsal fin, appearing to coast along in her wake. The male usually stayed behind or off to the sides of the group, and at one point came up behind Roz in the water, startling her as he swam by within 6 feet! Checking her out--prey? Predator? Threat? Apparently finding her benign (but scaring the daylights out of her in the process), he resumed patrolling the edges of the group.

We stayed with them another hour, then lost track of them on a long dive, as the wind picked up and made sighting conditions difficult. The entire follow lasted over 7 hours, and the whales travelled over 9 miles to the southeast. At 4 p.m. we headed back north, went for one more look offshore from Sandy Point, with no luck. Home by 6 p.m. and off to dinner at a local joint, where the local whist championship was underway. A perfect Bahamian ending to our trip here.


We return home tomorrow, but this work will continue for at least another month here. We want to thank our collaborators at the Bahamas Marine Mammal Research Organization, especially Diane Claridge, Charlotte Dunn, and Kendria Ferguson, for their cheerful, dedicated, and hard-working efforts on behalf of this program and all the marine mammals found here. Thanks also to Mike Wiese and the Office of Naval Research for supporting this and other efforts to unlock the mysteries of the elusive beaked whales of the Bahamas.

-Scott

At sea well before 7 a.m., with light winds and calm seas, we head to Cross Point, the location of last nights beaked whales. Early en-route, we encounter several pygmy sperm whales (Kogia sima) a species the NEAq team had never seen from a boat before (blunt headed small whales, ca 9-10 feet). [Note: the Aquarium's rescue team has responded a deceased pygmy sperm whale, shown in this post.] Remarkably, even less is known about this species (and its close relative the dwarf sperm whale) than the beaked whales, and every sighting is a treat. These whales are also deep-diving squid eaters, but spend little time at the surface, and are extremely wary of boats.


But onward. Beaked whales, almost in the same spot as last night! Diane spots them early, but they prove elusive, with long dives and short surfacing periods. And the wind starts picking up, eventually making sight conditions impossible. Then one of our motors starts smoking and has to be shut down. We retreat to a nearby cove to anchor, check the engine, and see if the wind drops. Our refuge is home to a local reef, so several of our crew slip over the side to have a look around. This reef is at risk by a proposal for building a channel to develop a limestone quarry just behind the beach, so it was interesting to see the diversity of coral and fish in the area. [Note: The Aquarium's teen divers posted their observations from threatened mangrove habitats along the coast of Bimini last year.]



The engine does not appear to be damaged, but needs some attention, and the wind increases. Yikes! We retreat for home on one engine, with Diane on the phone to the mechanic. He suggests a simple temporary solution, and we are back in action (sort of), but the wind gives us no breaks, and we continue homeward. A greeting committee of the local bottlenosed dolphins interferes with a direct transit, and we identify 21-22 of them before continuing on, arriving at the field station in mid-afternoon.

-Scott

An early morning departure by one boat gets beaten back by high wind and seas. But the wind dies throughout the day, and we try again around 2 p.m., working the edge of the shelf south to Cross Harbor Point (about 16 miles southeast of the field station). Finally at 4 p.m., we sight a group of Blainvilles beaked whales, five of them including and mother and calf, an adult female, and two adult males. Diane and Charlotte were particularly excited about this sighting because it was the first time they had seen two adult males together in a group in the long term study here. Swimmers went in the water nearly immediately, and we collected a sample at 4:30. The whales were very calm, allowing relatively close approaches, but the visibility was extremely poor, only about 40 feet.


One of the males had a cluster of stalked barnacles surrounding his left tooth (see photo) – also visible in this whale is a pronounced hump behind the head, a feature that Diane believes is age related, and that appears to be are of most scarring in males. The other male (also quite scarred up) was missing the tip of his dorsal fin. All in all, it looks like being a male beaked whale is a rough life! Whales dove deeply around 5:30 p.m., and with light diminishing, we head for home rather than wait the hour or so for them to re-appear.
As a last hurrah, as we round rocky point for home, we encounter the resident bottlenosed dolphins again, who want to play. A couple of identification photos, and then a few sunset shots (art, not too much science), and we arrive home after 7.

 

The weather is supposed to be calm for tomorrow, so we rushed to get the samples labeled and frozen, photos and data downloaded, cameras and binoculars cleaned and re-packed, so we can go to sea at the crack of dawn tomorrow.

-Scott

This photo was taken during the Bahamas whales expedition yesterday.


Catch up with the Aquarium's Bahamas whale expedition.
Learn more about the purpose of this expedition with this introductory post.
Get some more background on Blainvilles beaked whales in this post.
Browse all of the expedition posts here.

The weather called for light winds, so both boats left the beach just before 7 a.m. We decided to look for sperm whales, surveying about 24 miles north-south in the deep waters offshore, using both hydrophones and binoculars.


No luck on the sperm whales, with silence everywhere on the hydrophones (sperm whales announce themselves by clicking pretty clearly if they are in the area). No luck on the weather either, as we found ourselves in a sea state of beaufort 4+ by 11 a.m. (3- to 4-ft. seas with constant whitecaps). We finally ran inshore into calmer waters, and found some bottlenosed dolphins over Rocky Point bank that Diane and Bahamas Marine Mammal Research Organization (BMMRO) had been following for years. That was fun, but it was not our mission. And, as all marine biologists know, when the weather kicks you, there is only one thing to do--eat. So we had lunch.


Then we tried offshore for sperm whales again, but once again, no sounds, and the wind, while subsiding, was still unpleasant. Heading south once more, the winds finally dropped to about 10 knots, and the seas died out. Kendria and Roz spotted beaked whales off to one side, a large male and another animal. Shortly later we found three more, juveniles or females. Towing divers on both sides, Roz and Diane finally got samples of a defecation around 4:30 in the afternoon. Then the wind started picking up, so we headed for home--refueling for tomorrow, and we are ready for another early day tomorrow.



-Scott

Blainville's beaked whale (Mesoplodon densirostris), our other study species, is a member of an especially poorly understood and fascinating group of animals, the Ziphiidae or beaked whales. I used to tell my university students "If you're looking for a sense of mystery in life, study beaked whales. Because the Ziphiidae is hands-down the most poorly understood family of mammals on the planet." (I had no idea at the time that one day I'd be studying them myself!)  At the time I was teaching, the Ziphiidae section in the textbook was full of phrases like "No data." "Data deficient." "Has never been seen alive." "Range unknown." "Social structure unknown." "Diet unknown." "More research needed."



We know a bit more about beaked whales today, but still not much. Beaked whales are a group of about 21 species of mid-sized toothed whales, most of which are still, to this day, very poorly known. Their name comes from the pointy "beak" shape of the front of their heads, rather like a dolphin's beak. A real oddity of beaked whales is that males of most species (but not the females) have a pair of unusually shaped teeth that stick out of their lower jaws. It's thought that they use these tusks for fighting other males, because only males have the teeth, and adult males are often criss-crossed with scrape marks that they've presumably acquired while fighting other males. The species that we're studying, the Blainville's beaked whale, has a peculiarly shaped lower jaw that seems to have evolved to support these short teeth. The "cheeks" of the lower jaw extend high above the face on both sides, and each side of the lower jaw is topped by a short, stout tooth (see photos).

 


All the beaked whales are deep divers that tend to be rather shy, diving when a ship comes near them and then staying underwater for a long time.... during which the ship at the surface usually loses track of them. That makes them pretty difficult to study! Fortunately, our colleagues at the BMMRO have developed the snorkeler-towing method (see our first post), allowing them to follow a group of Blainville's for short periods of time. Their research shows that the Blainville's are usually in small groups of 3 to 7 animals. Each group usually has one adult male accompanied by a few females and younger animals. They tend to do a long, deep dive of almost an hour, then a series of shorter, shallower dives while they're getting ready for the next long deep dive. It's during the shorter, shallower dives that we can follow them. Furthermore, the BMMRO researchers can individually identify the different Blainville's whales by means of the scrape marks on the males, and scars from cookie-cutter sharks. And they've realized they see the same individual whales again and again. In other words, the whales are local residents, staying within a relatively small area. "We're actually on our third generation of beaked whales," says Charlotte (of our BMMRO), meaning that they've followed some individual beaked whales so long that they've seen whales raise offspring to adulthood, and then seen those offspring have grand-offspring of their own.


Year by year, thanks in large part to researchers at the BMMRO, our picture of beaked whales is getting clearer. But there's still a lot of mystery remaining, and a lot more to learn.

-Kathleen Hunt