9/11/14

Countershading Camouflage!

Many people are familiar with the “tuxedo” coloration of our African penguins. The white belly and black backs are distinctive and well known. But ever wonder why they have this coloration? Believe it or not, it’s a form of camouflage called countershading. And it's not just for penguins—many aquatic animals have this special coloration.

Formal dress is always in style in the penguin exhibit



Countershading refers to an animal as having dark coloration on the upper side of the body and a lighter color on the underside. If a predator swims above a prey item, like a penguin, and looks down, the dark back coloration blends in with the shadows or the dark ocean bottom. On the flip side, if a predator is underneath and looks up, the white or light colored underside of the prey blends in to the lighter colored sky/top of the water.

You can find examples of countershading throughout the Aquarium. And it’s not just for prey items—countershading works for predators too! Just as it allows prey animals to hide, predators take advantage of their countershading and become stealthy, blending into their surroundings. Take a close look at our sharks and their stingray cousins—lots of countershading examples here! Our leopard whiptail stingray even adds some fashionable spots, some disruptive camouflage, to the mix.

Blacknose shark cruising in the Giant Ocean Tank

Dark leopard spots add to the effect-very fashionable!

Want to take a nap undisturbed? Not a problem if you are a green turtle. The mottled color on their carapace blends in to their coral reef surroundings, while their light colored plastron protects from predators below while they are swimming. Even Myrtle can camouflage into the reef! Can you find her in her favorite napping spot?

Even Myrtle is countershaded!

The turtle version of hide-and-go-seek!

Green anacondas may grow to be over 25 feet long, but they still use countershading! When small, dark olive spots help juveniles blend in with tree bark and light belly spots blend in with the dappled sunlight and leaves. Once they move into their aquatic homes, anacondas benefit from this coloration as well. Dark backs blend in with dark riverbeds and light colors blend in with sunlight from surface of the water.

Olive and yellow spots-a perfect outfit for an anaconda

Countershading isn’t just for animals with backbones-some of our cephalopods are countershaded. Check out the nautilus and the cuttlefish in the Tropical Gallery! Nautiluses have dark stripes on the top curve of their shell to blend in with the dark ocean bottom. And while cuttlefish can instantly change their color to blend in with their surroundings, they often are countershaded to avoid predators!

Stripes on the nautilus shells help to blend in

Cuttlefish with some crazy countershading camouflage

Countershading—it’s not just for penguins! So next time you visit the Aquarium, take a closer look around you. See how many animals you can see with countershading-if you can find them. Happy looking!

8/18/14

A Most Unusual Lobster Larva

Recently Allison Langone, a summer intern with the New England Aquarium lobster lab, stumbled upon a very unique lobster larvae. Check out this newly-hatched conjoined twin!

Conjoined lobster larvae

The conjoined larvae seems to be conjoined on its back side only. Each “twin” has a full set of legs, which is four pairs of walking legs and a pair of claws. It looks like even more than the usual because larvae have extra appendages off their legs. It has two separate beating hearts. The intestinal tracts seem to function—you can see food in the right larva's intestine—though they seem to share stomachs (lobsters have 2 stomachs). These animals also share a set of eyes.



Interestingly, the larva seems to swim fine. In its holding tank, it swam around a bit before heading down to the bottom. Even with special care, an animal like this is never expected to live long. This animal died after a week or so.

This unique lobster hatched in the Aquarium's research lobster hatchery—the last year-round U.S. production facility for American lobsters. Our researchers are on the forefront of American lobster aquaculture research, investigating new and improved methods for raising lobsters in captive environments. Our scientists are investigating nutritional requirements and pigmentation in captive-reared American lobsters. They are also collaborating with fishermen and scientists to develop a greater understanding of Lobster Shell Disease.

A juvenile lobster in the nursery in a lovely shade of orange

Learn more about lobsters and their many shades of shell:



Now that you're all experts, come see traditional lobsters—with eight walking legs and a pair of power claws (one crusher and one pincer)! Plan a visit to the Aquarium! The Northern Waters gallery features several handsome adults scurrying around their cold-water exhibit. Look for wee juveniles in the lobster nursery at the Blue Planet Action Center. They're just tiny versions of the adults—complete with the unexpected colors!

8/14/14

The ins and outs of lobster molting

You can find American lobsters (Homarus americanus) on exhibit at the Aquarium every day. From the tiny juveniles in the Blue Planet Action Center to the heavy-weights carving out territories in the chilly habitat of the Northern Waters Gallery. Plan a visit today to see New England's favorite crustacean. 

Here's a story of a lobster rite of growing up—molting—brought to you by guest blogger and volunteer Daire Gaj.

What do you do if you're a lobster and you're growing too big for your shell? Climb out of your shell and grow a new one! That's what one of our lobsters behind the scenes did a couple of weeks ago.

Scroll through these pictures to see how molting happens!





















A lobster will undergo many molts in the process of growing up. It's not often that we get to see a lobster molt, though Anita Kim caught it on video back in 2009.

Anita, manager of the Aquarium lobster lab, has watched hundreds of lobsters grow up. She says that lobsters will molt most frequently when they are young, approximately once every two weeks. As they grow older, their growth slows and they may molt once a month. The oldest lobsters will molt once every few years. How long can they continue? Anita says their natural lifespan is unknown. With a tree, you can measure its age by counting the rings in its trunk; with a fish you can count the rings in its ear bones, but lobsters offer no visible indicator of age. It's possible they may be able to reach a hundred years or more.

Lobsters have an advantage when it comes to longevity, because they can regenerate body parts when they molt. “It's like getting a fresh start,” Anita says. This lobster was in the process of regrowing lost claws when it molted. You can see one of its partially grown claws in this photo from early in the process.

The highlighted version shows where the tiny regrown claw was

Sadly this lobster is now clawless again. It appears the molt did not go perfectly, and the lobster had to leave its claws inside the exoskeleton. Anita says it will happen from time to time that lobsters eject their claws while molting. “The claws are typically the difficult part,” she says, picking up a model of a lobster, and pointing to the complicated joints in the feeding claws. So imagine trying to take off a pair of tight-fitting gloves, both at the same time.

The good news is that it will have plenty of time to grow its claws again. While its brothers and sisters in the open ocean are using their claws to break open mollusks, this lobster will be getting chopped shrimp delivered via room service in its home behind the scenes.   

And if you think that's cool, you might be interested in this video of a juvenile lobster molting behind the scenes in our lobster research lab!

Juvenile lobster in the nursery

See lobsters like this juvenile at the Aquarium's lobster nursery! Imagine how many molts are ahead of this little guy. Plan a visit today.

8/5/14

Feeding Time: Shark and Ray Touch Tank

How do you feed a shark or a stingray? Very carefully! That’s a joke that we hear (and tell) a lot at the Trust Family Foundation Shark and Ray Touch Tank. And while it might be a joke, feeding our animals is something we take very seriously at the Aquarium!

Everyone looks forward to breakfast!

The topic of feeding (and eating!) comes up a lot throughout the Aquarium. It makes sense—eating is one of those universal things that all of us organisms need to do. With over 100 animals in the touch tank, visitors often are curious to learn how we feed so many animals in one place.

The first question many people ask is what do we feed the animals in the exhibit. Fortunately, all of the different species of sharks and rays eat the same types of food. So what’s on the menu? Mealtime usually includes squid, small fish, clams and shrimp. The diet is prepared first thing in the morning and then fed to the exhibit throughout the day.

Breakfast!

As feeding time arrives, food is simply scattered on the sandy bottom of the exhibit. Both sharks and rays will cruise over the sand, picking up pieces of food as they go. To ensure that everyone has the opportunity to get something to eat, the exhibit has food added to it a couple of times a day. But the animals never know when it’s coming—we change the times slightly each day to keep them guessing!

Making sure everyone gets something to eat

Food sinking to the bottom

As the food sinks to the bottom, animals come from all over the exhibit to the two main sandy areas. Even those animals that usually hide during the day, including the sharks, will come out for a snack! In a flurry of fins, tails, and mouths, the food is gone in no time!





With a keen sense of smell, these animals can locate their prey easily. And as their mouths are located on, or near, the bottom of their body, scooping up food from sand is no problem. Both the rays and sharks will eat when they are hungry, so it's possible that every animal might not eat at each meal. But with feedings happening throughout the day, everyone has the opportunity to find a yummy snack when they want one.

A white-spotted bamboo shark and her squid snack!

Perhaps next time you visit the Aquarium, you might just be in time to see the shark and stingray touch tank exhibit animals get something to eat. Consider buying your tickets online and printing them at home so you can zip in the door when you arrive. Here's where to start planning your next visit!

And in case you're hungry for a snack of your own, head over to the New England Aquarium's website for environmentally friendly seafood options and seafood recipes. Bon appetit!

7/12/14

Plankton: They're kinda a big deal

Ever wonder why the murky, green waters of the northern latitudes are different than clear, blue waters of the tropics?

The murky green waters of Boston Harbor contain lots of life!

Or why New England had such large cod populations when the colonists arrived? Or why coral comes in so many beautiful colors?

Vibrant colors of a tropical reef

One reason: plankton! Well... so if plankton is such a big deal, why doesn't the Aquarium have a plankton tank? Well, one could argue that we do. Every tank in the aquarium is interconnected with plankton.

What are plankton? 
Like the term “cat,” plankton is an umbrella term used to describe a diverse set of organisms. The name plankton is derived from the Greek word planktos, meaning wanderer or drifter. Any creature carried by the ocean currents is considered plankton, from microscopic bacteria and algae to gelatinous siphonophores that grow in colonies longer than a blue whale.

 

Phytoplankton like diatoms, dinoflagellates, and coccolithophores are photosynthetic. They not only provide the base of the ocean food web, they also provide up to half of the oxygen that we rely on to breathe on land! But not all plankton photosynthesizes. Zooplankton feed on other organisms. Some plankton, called holoplankton, spend their whole life at the whim of ocean currents. These creatures
include copepods, brine shrimp, and sea jellies. Other plankton, called meroplankton, grow out of their drifting phase and embrace a more benthic or pelagic form. Lobsters, crabs, urchins, sea stars, barnacles and many fish all start their life as plankton!

Plankton…. They’re Kinda a Big Deal 
Phytoplankton are the base of the food web. These organisms convert the sun’s energy, along with carbon dioxide and water, into chemical energy and oxygen through photosynthesis. Because they are the first link between the sun’s energy and the rest of the food web, they are referred to as “primary producers”. This chemical energy, in the form of carbohydrates, is the fuel that helps to power the rest of the food web.

A right whale skim feeds on copepods. Watch video of a right whale feeding in Cape Cod Bay!

As the major primary producer of marine environments, phytoplankton provides the fuel for the rest of the system. Though some of the food webs they fuel are complex, some of them are relatively simple! One such food connection can be found right off the coast of New England. Phytoplankton feeds zooplankton, which feeds whales. From one of the smallest organisms to the biggest in only two
steps!

That water off New England is also very different from the sparkling turquoise waters you might see in the tropics—because of plankton. You see, the cold, nutrient rich water travels up to the surface of the ocean and hits sunlight, sparking a bloom of phytoplankton. The nutrients and blooms cause the waters here to appear murky and green. Tropical waters, however, have very few nutrients and thus phytoplankton blooms can’t occur. Without the phytoplankton and nutrients, the water is super clear. This abundance of phytoplankton supports the food web that is responsible for the iconic fisheries of New England. (Check out some of the tiny planktonic animals that appear in Boston Harbor!)

Cod is a cold water fish with iconic status in this region 

Corals, along with some other marine animals like upside-down jellies and giant clams, rely on photosynthetic organisms most commonly referred to as zooxanthellae. Zooxanthellae help create food for their host. The zooxanthellae, mostly planktonic dinoflagellates (see the sketch above), are ingested by the host, encased in a membrane to protect then and then they go to work. The carbohydrates they create fuel the corals (and give them beautiful colors) while the zooxanthellae get a home and needed nutrients. Everybody wins!

So from the cool dark depths of our Gulf of Maine exhibits to the sparkling Giant Ocean Tank, these marine ecosystems are teeming with life that can all be traced back to the humble plankton. Keep that in mind the next time you visit the Aquarium and see our 600-lb fur seal lounging on the deck! (Pick up your timed ticket and print at home and you'll breeze right into the Aquarium!)

This post comes to us from Aquarium educator Kim McCabe.