Archive for the 'From the Curator' Category



The Life Cycle of Poison Dart Frogs Explained

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National Aquarium has had a long, successful history of breeding poison dart frogs. Here in the Upland Tropical Rain Forest exhibit, we have 16 species of poison dart frogs. Over the last few decades, scientists have become very interested in the reproductive strategies of these species and how they care for their young.

blue poison dart froglet

Dart frogs are incredibly intriguing animals. In addition to possessing toxins and bright colorations/patterns, they also have a fairly complex life cycle!

For most species, females will choose a leaf lying on the rain forest floor to deposit a mass of eggs, which the male will then fertilize. Males are oftentimes in charge of guarding the eggs while they develop.

poison dart frogs developing

Here at the Aquarium, most of our tadpoles develop behind-the-scenes in their own simulated bromeliad cup.

Once the tadpoles have developed, one parent will carry each tadpole to their very own pool of water held in a plant, known as a phytotelma. In the wild, some dart frog species (including many of the species we have in our collection) choose the water-filled cups at the base of bromeliads to safely store young.

Many tadpoles are omnivorous and most species will feed on algae and/or other small animal life (including other tadpoles). During their time in the bromeliads, the tadpoles will progressively metamorphose into full-fledged froglets!

The transition takes approximately two months, and they typically reach adult size and maturity within a year.

The normal life span for these animals in zoos and aquariums is about 10-15 years. Here at the Aquarium, we’ve had frogs live to be at least 23 years old!

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A Blue View: The Pollution We Cannot See

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 pm as John brings to the surface important issues and fascinating discoveries making waves in the world today.

March 13, 2013: The Pollution We Cannot See – Toxins in the Water

A Blue View podcast

Listen to John and Blue Water Baltimore’s, Halle Van der Gaag,
discuss how wastewater is polluting the Bay. 

When it comes to cleaning up the Baltimore Harbor, most of us think about trash cleanups. While keeping garbage out of our waterways is critically important, there’s another source of pollution infecting the Bay—bacteria from wastewater. Recently, Halle Van der Gaag, executive director of Blue Water Baltimore, sat with Aquarium CEO John Racanelli to talk about these toxins in our waters, and what needs to be done about them:

John: Tell me about what’s going on right now in our harbor in terms of bacteria and bacteria counts.

Halle: Well, unfortunately there’s way too much bacteria in the Baltimore harbors and our streams that feed the harbor. Though Baltimore has a separate sewer system, unfortunately we see huge amounts of wastewater entering our streams, not just from broken wastewater pipes but unfortunately through the storm drain system, where it’s not supposed to be coming from.

John: And that, I would guess, leads to higher bacterial counts, because these things kind of compound.

Halle: Absolutely. It’s unfortunate, but we have an aging system, on both the storm water and the wastewater side. So pipes are breaking. Raw sewage entering our streams contributes to bacteria, and everyone knows raw sewage in our waterways is not a good thing.

John: Absolutely. Where is this wastewater coming from?

Halle: It’s coming from our homes, our businesses, the places where we work. If you think about it, all our businesses are connected to the wastewater system, and it’s intended to go to the wastewater treatment site, but all along the way, there are opportunities for cracks and breaks and leaks, and that’s where we see the problems occur.

John: So it’s not really about the trash in this case, it’s about the waste stream.

Halle: And if you think about a fishable, swimmable harbor, it’s probably not the trash that’s going to keep you out of there, it’s going to be the bacteria.

John: What are the consequences of this dirty water in terms of how it affects humans and others?

Halle: We tend not to think about the harbor as a place where people recreate, but actually folks are out there in kayaks, paddleboats, on sailboats, and boating. Unfortunately, there are real significant public health risks if exposed. Skin infections, gastrointestinal issues, and even things like our pets getting sick when they run through the streams like the Jones Falls and the Gwynns Falls. So there are significant opportunities for folks to get sick and we are hearing more and more about those types of infections happening here in Baltimore.

John: I guess this must have an economic impact on our community too, eventually.

Halle: Absolutely. Who wants to sit at a restaurant along the Inner Harbor where there’s been a fish kill and where it’s very smelly and dirty? We’ve heard from restaurants last year during the June sewage overflow of how damaging it was to their bottom line.

John: So what’s being done out there right now to combat this overall issue of wastewater pollution?

Halle: Baltimore City is spending millions of dollars through something called the Consent Decree to actually upgrade and fix wastewater pipes and the streams. We hope in the next couple of years, we’ll see significant construction happening, and that should lead to a reduction in wastewater debris in the harbor.

John: Well then let me ask, what is the message we need to get out to really bring action on this critical issue?

Halle: So I think sometimes people can be frustrated about paying into fees to upgrade these systems, but in this case, there’s really nothing citizens can do. This is about city government doing what it needs to do to repair critical wastewater infrastructure, and it’s nobody’s fault the pipes are a hundred years old. We have pipes from the 1800s that are still functional. And so we just need to get behind the city and support these upgrades.

John: Okay, well thank you, Halle, very much for coming to talk about this important issue.

About Blue Water Baltimore
Blue Water Baltimore’s mission is to restore the quality of Baltimore’s rivers, streams and harbor. From organizing trash cleanups and planting trees to monitoring streams and advocating for stronger clean water laws, Blue Water Baltimore is hard at work in communities around the state. Learn more at bluewaterbaltimore.org.

The Health Harbor Report Card
The recently released Healthy Harbor Report Card 2012 contains Blue Water Baltimore’s annual assessment for the Baltimore Harbor. This year the Harbor received an overall grade of C-. The Harbor’s grade, which is based upon 2012 monitoring data collected by the Baltimore Harbor Waterkeeper, was higher than expected. Still, the Harbor met ecological health thresholds only 40 percent of the time, which is just barely a C-.

To view the complete Healthy Harbor Report Card, click here.

To see the Baltimore Harbor’s bacteria monitoring results for yourself, click here.

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A Blue View: Rising Seas

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 pm as John brings to the surface important issues and fascinating discoveries making waves in the world today.

June 26, 2013: Rising Seas

A Blue View podcast

Click here to listen to John discuss the impact
climate change is having on rising sea levels. 

On these hot summer days, our thoughts tend toward ice cream cones and tall glasses of ice water on a sweltering afternoon rather than the melting of ice sheets around the world. But just as the ice melting in your glass causes the water level to rise, so too does the melting of the world’s ice shelves.

Perhaps you’ve seen the incredible videos of massive chunks of ice breaking away from a glacier, causing crashing impressively into the sea. Until recently, it was thought that this was the primary cause of ice loss in Antarctica. But in fact, a study by NASA and university researchers indicates that warming oceans are also dissolving the ice from underneath the ice shelf at unprecedented rates, causing the greatest loss of Antarctic ice shelf mass. Scientists plan to use these data to help determine how ice shelves melt, improving projections of how the ice sheet might respond to a warming ocean and contribute to sea level rise.

Ice loss is not just occurring at the poles: NASA researchers have discovered that glaciers outside of the ice sheets of Greenland and Antarctica lost an average of 571 trillion pounds of mass each year during the six-year study period, causing sea levels to rise almost two-tenths of an inch during that time. This actually matches the sea level rise attributed to the combined ice loss of the Greenland and Antarctica ice sheets.

Ice melting isn’t the only contributor to sea level rise. Warming temperatures cause waters to warm and expand. In turn, warming waters take up more volume. This phenomenon is called thermal expansion. The combination of ice melting and thermal expansion means that sea level rise is not just a possibility…it is happening now, and the only question is how fast it’s going to rise.

Many scientists now believe that sea levels will rise by no less than one to two feet by 2100. And without dramatic reductions of greenhouse gas emissions, the threat could be much more substantial.

The East Coast in particular is at greater risk from sea level than other areas of the world, mainly due to ocean currents and differences in seawater temperature and ocean salinity, according to climate scientists. The U.S. Geological Survey found that sea levels from North Carolina to Boston climbed by about 2 to 4 millimeters a year between 1950 and 2009 as compared to a global average of one-half to 1 millimeter.

These amounts may seem small and unimportant, but the repercussions from these rising levels are anything but. Imagine increased coastal flooding, shoreline erosion, loss of wetlands, and destroyed homes and businesses on the order of superstorm Sandy. Sea level rise does affect us all.

We need to take steps to control warming, as sea surface temperature and sea level rise are inextricably linked. According to the EPA, sea surface temperatures have risen at an average rate of 13 one-hundredths of a degree per decade since 1901. As small as that may sound, over 112 years, that’s an increase of one and a half degrees, which is already impacting not only sea level, but also coral reefs and other essential ocean habitats, migration and breeding patterns, the intensity of storms, and the spread of invasive species and marine diseases.

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Sawfish Granted Endangered Species Protection

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Earlier this month, the National Marine Fisheries Services granted sawfish protection under the Endangered Species Act (ESA).

largetooth sawfish

Sawfish are one of the most, if not the most, imperiled groups of cartilaginous fish. Like most sharks and rays,  late maturity and low reproduction rates make these animals vulnerable to over-exploitation. Additionally, their toothed “saw” often gets caught in fishing gear and nets, making them susceptible to bycatch. As a result of these threats, populations of sawfish have reportedly declined by as much as 99 percent in recent decades.

All seven recognized species of sawfish are considered critically endangered by the International Union for Conservation of Nature (IUCN).  Nationally however, earlier petitions to grant sawfish similar protection under the ESA have not been successful. The first listing, of the smalltooth sawfish, occured in April of 2003. The largetooth sawfish was listed under the ESA in August of 2011. With the freshwater and largetooth species recently being synonymized, all are now protected under the ESA, including the two living here at the Aquarium.

largetooth sawfish

One of the largetooth sawfish that live in our Shark Alley exhibit.

The designation to list all species of sawfish is a positive step forward for these animals. The hope is that through collaboration with other aquariums, research biologists, conservation groups and NGOs we can assist in the recovery of sawfish populations worldwide.

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A Blue View: Dolphin Earthquake Study

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 pm as John brings to the surface important issues and fascinating discoveries making waves in the world today.

June 19, 2013: Dolphin Earthquake Study

A Blue View podcast

Click here to listen to Dr. Mark Turner discuss how
our dolphins reacted to last year’s earthquake.

On August 23, 2011, a magnitude 5.8 earthquake occurred with its epicenter approximately 118 miles from the National Aquarium, Baltimore. A short time before the dolphin pavilion started shaking from the earthquake, an Aquarium volunteer logging the activities of four dolphins noticed that they all started to swim very quickly in close formation, something she could not recall ever having seen before. She had enough time to note this behavior in her handwritten log before the building suddenly started shaking. At the same time all this was happening, the underwater sounds in the dolphin pools were being recorded using a pair of hydrophones (i.e., underwater microphones). The combination of the in-person observation and the hydrophone recordings provides valuable insight into dolphin behavior.

When an earthquake occurs, seismic waves radiate out from the focus of the earthquake at different velocities. The fastest of these, called the primary wave or P-wave, can travel at speeds of 15,000 miles per hour. However, although very fast, P-waves often are unnoticed by humans. The S-wave and surface waves, the ones that shake everything and cause the worst destruction, travel at much slower speeds.

Although no humans at the Aquarium that day reported feeling the P-wave, its trace did show up in our hydrophone recordings almost 22 seconds before the arrival of the S and surface waves. In view of the P-wave’s appearance in the recordings and the dolphins’ behavior, marine mammal researcher Mark Turner believes the dolphins felt the P-wave, and the volunteer observed their reaction to it. Listen to the hydrophone’s recording: 

This is a clip of the underwater sounds in the dolphin pools when the August 23, 2011, Virginia earthquake occurred. Two hydrophones were recording at the time. The left stereo channel is the recording from the hydrophone in the front pool where a dolphin presentation was in progress. The right channel is from the back holding pool where fast swimming in an unusual configuration was observed. In the video that accompanies the sound clip, the top two panels show the raw signal picked up by each hydrophone. The top panel is from the front pool and the bottom one is from the holding pool.

The bottom two panels are spectrograms. A spectrogram is a visual representation of sounds in which the x-axis is time and the y-axis is frequency. In a spectrogram a dolphin whistle will appear as a dark, wavy line, and a squawk can sometimes appear as a stack of parallel wavy lines.

The sound clip begins at almost exactly the time the earthquake started in VA. The various seismic waves traveled from the earthquake’s focus to Baltimore at different velocities, with the P-wave arriving first, 27 seconds into the clip. Although the very low frequency vibrations induced by the P-wave are visible in the upper panels, they are inaudible, although you might hear some water splashing. The S and surface waves (the ones that are very loud and shook everything) did not arrive until almost 22 seconds later, 49 seconds after the beginning of the clip.

You may hear some of the presentation music, a bit louder in the left channel. If you listen carefully you will also hear (and see in the spectrograms) dolphin clicks, squawks and whistles. And, of course, you will hear the loud noises made by the earthquake surface waves as they sounded underwater.

An excellent overview of the different seismic waves with animations can be found by clicking here.

All signal displays were generated using Raven Pro, Interactive Sound Analysis Software, Bioacoustic Research Program at the Cornell Lab of Ornithology.

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How the Global Pet Trade is Impacting the Survival of Many Exotic Species

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When it comes to pets, most people are content keeping traditional cats and dogs while others desire animals with a more exotic flair. Pet stores and online vendors offer the potential exotic pet owner an abundance of wildlife, ranging from parrots and marmosets to cobras and scorpions. Sadly, many recipients of exotic wildlife are unaware that their purchases may support a trade that is often illegal, inhumane, or detrimental to wild populations.

It may come as a surprise to many that the United States is one of the largest importers of live animals in the world with over one billion live animals imported since the year 2000. Various regulatory agencies strive to control this trade. The US Fish and Wildlife Service is responsible for enforcing not only its own internal regulations but also those regulations that fall under the auspices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

In addition, the U.S. Public Health Service and the U.S. Department of Agriculture enforce various aspects of live animal importations that seek to prevent the introduction and spread of emerging diseases that affect the health of both humans and domestic livestock. Imports of pet Bell’s Hingeback Tortoise’s were banned when tortoise borne ticks were found to contain Heartwater Disease, a serious threat for wild and domestic ruminants.

In 2003 African Monkey Pox was introduced when shipments of Gambian Pouched Rats, destined for the pet trade, were imported into this country. The scale of the global wildlife trade, both legal and illegal is staggering. It has been estimated that the illegal wildlife trade ranks just behind the trade in illegal arms and narcotics in terms of scope and finances. Earlier this year, 54 critically endangered Madagascar Plowshare tortoises were confiscated by authorities in Thailand. Destined for the high-end illegal pet trade, an adult tortoise of this species might sell for $50,000 – this one shipment represented approximately 10 percent of the world’s remaining population of plowshare tortoises.

plowshare tortoise

A plowshare tortoise.

For those who still wish to maintain non-traditional pets, know that these non-traditional pets require a substantial commitment. The desire to own an exotic pet often clouds ones judgment. Rescue groups are overflowing with unwanted parrots and other exotic animals, relinquished because former owners underestimated the time, money, and commitment it requires to adequately maintain these animals within their homes. In many cases exotic pet owners, ignorant of state or local laws that prohibit the keeping of certain species, have had their animals seized by law enforcement or been forced to surrender them. Responsible and successful maintenance of an exotic pet requires careful sourcing along with substantial research, finances, time commitment, and an honest discussion as to one’s ability to meet the requirements, both physical and psychological, of the species in question.

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A Blue View: Explore A Shore Responsibly

A Blue View is a weekly perspective on the life aquatic, hosted by National Aquarium CEO John Racanelli.

From the smallest plants and animals invisible to the human eye to entire ecosystems, every living thing depends on and is intricately linked by water.

Tune in to 88.1 WYPR every Tuesday at 5:45 pm as John brings to the surface important issues and fascinating discoveries making waves in the world today.

June 12, 2013: Explore the Shore

A Blue View podcast

Click here to listen to John discuss the importance
of responsibly enjoying the shore!

Whether boating, fishing, or just walking along the sandy shore, spending time on the water is a classic summer pastime. For many of us, these visits are an opportunity to explore. From birds, crabs, and fish, to the occasional dolphin and seal sighting, an amazing diversity of life lives in harmony along the shore. It is critical, though, as many of us make our way to the water, that we take responsibility for the ways that our actions impact the environment.

When we get too close to certain wildlife, for example, we can unintentionally cause a nest failure or force an animal to flee, putting its survival at risk. Never feed wildlife, not even the bread scraps from your beach picnic, and avoid sensitive sand dunes by sticking to walkways. And when boating, obey posted speed limits and slow down while motoring through shallow waterways. Respect these natural habitats by observing wildlife from a distance—close enough to appreciate the beauty of these incredible ecosystems but far enough away to leave wildlife and plants undisturbed.

It’s also essential to dispose of trash properly. Every summer, people leave their footprints—and a whole lot of trash—along our coasts. From fishing line to plastic bags, our throwaways can throw our oceans into turmoil if we don’t dispose of these materials responsibly.

Fishing line is particularly dangerous to animals. Wildlife often eat or become entangled in monofilament line, which is practically invisible. One unfortunate sea turtle was found with an astounding 590 feet of fishing line in his gut. One study showed that more than 50 percent of sea turtles stranded on a beach contained traces of debris in their digestive tracts. Sixty-five percent of those animals had ingested plastic bags, and it’s no wonder: the U.S. International Trade Commission reported that 102 billion plastic bags were used in the United States in 2008 alone—that’s a bag a day for every woman, man and child.

Though there are many statistics citing the numbers of animals that die as a result of marine debris each year—one estimate in fact is 100,000 marine mammals and millions of birds and fishes—this area of study is evolving. The National Oceanic and Atmospheric Administration’s Marine Debris Program is taking essential strides in supporting efforts to research, prevent, and reduce the impacts of marine debris, but it’s clear that we can’t afford to wait to take action. The bottom line is that even one piece of garbage on the beach is one too many.

This year, think about your impacts as you pack for your day at the beach. A great place to start is reusable goods. It’s often windy by the shore, so keep your trash and belongings from blowing into the ocean. Some popular fishing areas provide safe recycling containers for monofilament line. You can also ship monofilament to the Berkley Recycling Center in Iowa. This company will use your line to create Fish-Habs, which are four-foot underwater habitat structures made from recycled fishing line, milk cartons, and soft drink bottles. These cubes attract fish and encourage plant growth, providing natural cover necessary to maintain healthy habitats.

Whatever you do, follow this one essential rule when you’re at the shore this summer: When it’s time to go home, leave nothing but your footprints!


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