Blue Whale (Balaenoptera musculus), aerial view of an 80 foot individual, Sea of Cortez, Mexico. © Flip Nicklin/Minden Pictures

Don’t forget to read Part 1 of this post, Ocean’s largest inhabitants under the radar…until now

It’s hard to believe that an animal could dwarf the basking shark, but try to imagine an animal whose heart is the size of a car, whose tongue weighs as much as an elephant, and who has blood vessels wide enough that a grown man could swim through. Can you picture it? If so, you’re imagining the mighty blue whale (Balaenoptera musculus), the largest animal that has ever lived on Planet Ocean. (Planet ‘Earth’ for all you land-lubbers; I am a marine biologist after all.)

Like the basking shark, however, we know shockingly little about how many are left, about its migrations, and even about where it goes to breed and birth its calves.

Most populations of the “great whales,” including blue whales, suffered massive declines due to commercial whaling during the first half of the 20th Century. Historically, blue whales in the North Pacific Ocean were frequent visitors to British Colombia, Canada, and the Gulf of Alaska, but by the 1960s, had virtually disappeared. Meanwhile, large concentrations of blue whales off California and Baja California, Mexico, have been documented since the 1970s, but the relationships between these observations – and the whale populations themselves – had been unknown.

In a recent study, researchers from British Colombia, Washington and California reported numerous sightings in the last decade of blue whales in their former northeastern Pacific stomping grounds, suggesting that the elimination of whaling has allowed blue whales to reclaim old territory. Most interestingly, the scientists used photo identification to confirm that the whales venturing north belonged to the California feeding population.

Blue Whale (Balaenoptera musculus) tail, Sea of Cortez, Mexico. © Flip Nicklin/Minden Pictures

Whale biologists had feared that ‘memory’ of historical feeding areas like B.C. and the Gulf of Alaska might have been lost by area-specific intensive whaling activities, but these new findings show that tragedy might have been averted in this case. However, the true causes of this re-expansion in blue whale ranges are unclear; the study’s co-authors suggest that fluctuations in favorable environmental conditions could be driving the perceived changes in blue whale movements.

Nonetheless, although there is still cause for concern about the future of blue whales in the North Pacific, we can be happy to see that they are finding their way back to places they once called home.

As impressed and intrigued as I am with the things that we scientists have learned, it’s what we don’t know that continues to capture my interest and imagination.

The fact that colossal creatures like the basking shark and the blue whale could be in any way mysterious to curious scientists and awestruck observers speaks to nature’s complexity and to our meager understanding of it. These cases show that if we stay in pursuit of the answers we need to know and to protect nature’s wonders, they will reveal themselves to us in time. What we do with this newfound knowledge is up to us.

Fun Blue Whale Links:
National Geographic Blue Whale Size Comparison
Whale and Dolphin Conservation Society Life-Size Blue Whale

References:
Skomal et al., Transequatorial Migrations by Basking Sharks in the Western Atlantic Ocean, Current Biology (2009), DOI:10.1016/j.cub.2009.04.019

Calambokidis et al., Insights into the population structure of blue whales in the Eastern North Pacific from recent sightings and photographic identification. Marine Mammals Science (2009), DOI: 10.1111/j.1748-7692.2009.00298.x

Multitudes of animal species continue to evade detection by science, mainly because they are really hard to find. Many are tiny, or well-hidden, or live in places that people have a hard time getting to (or escaping from). While roughly a couple of million species have been officially catalogued, perhaps tens (hundreds?) of millions of species remain undiscovered.

So you would figure that we know just about all there is to know about the planet’s biggest species – the ones that rival monster trucks and ocean liners in size…but you’d be wrong. In fact, scientists are still uncovering secrets as to the whereabouts and wanderings of two of the largest animals that have ever lived.

Basking Shark (Cetorhinus maximus) © Alan James/Minden Pictures

The basking shark (Cetorhinus maximus) is the world’s second largest fish; only the appropriately named whale shark (Rhincodon typus) is larger.

Basking sharks can reach lengths of 10-12 meters (33-40 feet), and are known for swimming with their cavernous mouths – big enough to swallow a person whole (theoretically speaking) – wide open to take in and sieve tiny plankton from the water.

They inhabit mostly temperate (higher-latitude) waters around the world where oceanographic conditions are right for feeding, but they seem to disappear from these areas in the winter.

Where do they go? Do they hibernate? Do they ‘fly south’ like migratory birds and elderly Americans from northern states?

To solve this mystery, marine biologists from Massachusetts and Maine deployed sophisticated satellite-linked archival tags on two dozen basking sharks from off the coast of Cape Cod. To the scientists’ surprise, the sharks crossed 2000 km (more than 1,200 miles) of ocean to previously unknown locations throughout the sub-tropical and tropical western Atlantic. This is also the first ever use of this type of technology to record a fish species crossing the equator.

This expanded knowledge of basking shark geographic range shines new light on many aspects of this species’ biology, particularly reproduction, but also demonstrates the importance of tropical as well as temperate waters to these far-ranging behemoths.

Check back later this week for Part 2 of Bryan’s consideration of these colossal ocean mysteries…

Take the following steps and show our leatherback champs that you care. Bring a friend or two along for the ride and multiply your impact.

• Keep up with what’s happening with sea turtles around the globe at www.SeaTurtleStatus.org.
• Learn more about what conservation groups are doing to save leatherbacks in the Atlantic Ocean at www.FreeTheLeatherback.com, and in the Pacific Ocean at www.leatherback.org.
• Of course, keep checking www.conservation.org for the conservation stories, photos and the latest news and events.

MINIMIZE FISHERY IMPACTS
GET SCHOOLED

Smart seafood choices are good for everyone: sea turtles, oceans, fishermen, you, and your family. Learn about the impacts of different fishing and fish farming methods and use your purchasing power to promote responsible stewardship of marine resources.

Online? Check out www.blueocean.org/seafood for more information.

On the go? Text FishPhone™ to get instant information on a fish you’re considering. Text FISH and the name of the species you would like to learn more about to 30644 (e.g., FISH SHRIMP, or FISH MACKEREL); in under ten seconds Blue Ocean will send you a recommendation and the reason for it.

REDUCE POLLUTION
DISPENSE WITH DISPOSABLES

Pollution affects sea turtles in many ways, both directly and indirectly. Take stock of the goods that you use and learn what you can substitute for more environmentally friendly products, and what you can do without altogether.

Start by replacing the single-use plastic bags, bottles, and utensils in your life with reusable ones and join the Bring Your Own movement.

Learn more at http://www.bringyourown.org/.

Find what you need at http://www.reusablebags.com/.

KEEP OCEANS CLEAN
JOIN OR ORGANIZE A COMMUNITY CLEANUP

Even if you recycle what you can and properly dispose of what you can’t, your waste can sometimes end up in the wrong place – on the street, in they sky, and on the water. No matter how it gets there, loose waste can end up in the ocean.

Don’t let it get that far. Join the annual International Coastal Cleanup or bring your community together independently to collect trash along the shores of a local waterway, park, or street.

Wawa Bear
Turtle Stats
Wawa Bear nested on the same beach she has nested on since 1993 in French Guiana in the early morning of 22 March 2009. She laid 95 billiard ball-sized eggs, weighed 560 kg, and still had her transmitter attached, so the scientists actually were able to track her right to the nesting beach all the way from Nova Scotia.
Listen to Dr. Mike James from the Canadian Sea Turtle Network describe their experiences watching Wawa Bear’s migration to her nesting beach and waiting for word that she had been spotted.

Billy
Turtle Stats
We actually got a faint hit from Billy’s transmitter about a month after it went silent, but after the Race had ended. Although the location was of limited accuracy, it appeared that Billy had crossed the finish line after all, and was hanging out off of Galera Point, Trinidad. This is typical behavior for an adult male in a breeding season (i.e. hanging out in waters off nesting beaches), and Billy’s choice of location was strategic, as Trinidad hosts one of the largest leatherback nesting colonies in the world, with thousands of females coming ashore to lay eggs each year.

Lindblad
Turtle Stats
Despite the transmitter ceasing to function while Lindblad was still out in the central Atlantic, the tag kicked on again about a month later, and Lindblad is now northwest of where she was previously, about 500 kilometers off Puerto Rico, but still not in the Caribbean. Our Costa Rican colleagues are waiting for her to come to nest if not this year, maybe next.

Nightswimmer
Turtle Stats
Despite going as far south as the other turtles, Nightswimmer turned around and is still heading northwest, but not very quickly. It appears that Nightswimmer might be in a non-reproductive year. Adult turtles that are not ready to reproduce in a given year still make long migrations to find food, but instead of going into the Caribbean like the other turtles, they often remain in deeper waters far out in the open Atlantic.

Grembo and Searcher
Turtle Stats: Grembo | Searcher
It might look like they are lost and stuck out in the eastern Atlantic, or maybe even that they’re heading to Africa to nest. However, we know from previous years that turtles will travel from Canada over to the eastern side of the Atlantic possibly to feed in the Mauritania upwelling off Africa, which supports a productive marine foodweb. These turtles are probably chowing on jellies for a while longer before they’ll make their way toward the Caribbean or the northeast coast of South America. It is also possible that they are in a non-reproductive year and will begin to head back to Canadian waters in the next few months.

Cali
Turtle Stats
It seems that Cali’s run-in with the fishing gear really did have a big impact on him. First, he began his migration much sooner than the other turtles – almost immediately after he was entangled and then released. Then, although it seemed like he was steaming toward the Caribbean, he suddenly hit the brakes and turned around. We think he did this because he didn’t have enough energy to make the full migration to breeding areas in tropical waters, so had to turn around and go back to ‘refuel.’ Although this is just our speculation about what happened, it definitely shows that even a relatively minor, non-lethal interaction with fishing gear can interrupt natural behavior of leatherbacks and affect whether they reproduce in a given year. Cali’s experience is very important for us to understand how influential fisheries bycatch can be to leatherbacks and other animals.

Backspacer
2009 Turtle Race Winner!
Turtle Stats
Shortly after crossing the finish line and doing a few more loops, Backspacer’s transmitter stopped signaling. We hope that she is spotted in the coming months by nesting beach colleagues.

Nueva Esperanza
Turtle Stats
She has kept her momentum and is still moving inside the Caribbean. She was moving close to the coast of Colombia, possibly headed toward Panama or Costa Rica. However, the last we heard from her, she was in the into the Gulf of Urabá, Colombia, close to several large nesting beaches! We hope to hear very soon from our Colombian colleagues about her nesting.

Estéban
Turtle Stats
He continues to hang around the Windward Islands, probably still trying to find females to mate with. As demonstrated by some of the turtles in the Race, many females have to cross this area to reach their nesting beaches on the mainland Caribbean, so Estéban has put himself in a great position. He has stuck pretty close to the coasts of St. Lucia and St. Vincent since crossing the finish line. This behavior is very typical of male leatherbacks.

Seabiscuit
Turtle Stats
He is still off the coast of French Guiana, likely still seeking opportunities to mate. The leatherback population that nests on the Guiana Shield (Suriname, French Guiana, Guyana) is one of the largest populations in the world, with thousands of females nesting each year. So, like Estéban (and possibly Billy), Seabiscuit has found a very good spot to spend the next month or so.

Can’t get enough turtles? Check out these stories and features for more shells and science.
FEATURE: Now or Never: Eastern Pacific Leatherbacks Face Extinction
DISPATCHES: Tagging Hawksbill Turtles in Ecuador
FEATURE: TurtleFest: An Odyssey Begins
RESEARCH: Persistent Leatherback Turtle Migrations Present Opportunities for Conservation
FEATURE: Communities and Sea Turtles