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Making Waves: Episode 7 (Dec. 12, 2008)

... Red tide toxins are showing up in bottlenose dolphins in higher-than-expected amounts. A new study finds out what’s going on.

...And coral jewelry. It’s a popular holiday gift. It looks pretty .... but we’ll tell you why you should cross it off your list.

Those stories are coming up today on Making Waves from NOAA’s National Ocean Service.


A new study by NOS researchers finds that harmful algal bloom toxins are transferred to dolphins through the fish they eat.

What’s a harmful algal bloom? You probably know them better by the popular name ‘red tide.’ Scientists call them harmful algal blooms, or HABS, and they occur when colonies of algae grow out of control while producing harmful toxins. They happen each year around the nation in coastal waters ... and when they hit, it often means we humans can’t eat the shellfish in the area for a while. That’s because the shellfish filter the ocean water to get their food, so they eat the algae that carry the toxins.  And it takes a while for those toxins to get out of their system.

In the same way, fish also accumulate toxins from eating algae during red tide events.

And what the new study shows is that the primary prey fish of dolphins in Florida carry the toxins for longer than expected -- long after a bloom is over.

Scientists from the NOS National Centers for Coastal Ocean Science found high amounts of  brevetoxin in the food web of Florida bottlenose dolphins. Brevetoxin is produced by one type of toxic algae called Karenia brevis - and that’s one kind frequently found in red tides in Florida.

What the study points out is that coastal managers need to be aware of this long-term, repeated dietary exposure to algal toxins when considering threats to marine mammal health.

Previous NOS studies have found that HABs play a big role in unusual deaths of marine mammals like seals, sea lions, dolphins, and whales. Scientists call it UME, or unusual mortality events ...  and it’s defined as an unexpected marine mammal stranding, or significant die-off of any marine mammal population. Of all the unusual standings and deaths that occur in our waters, it’s estimated that over 50 percent are caused by algal toxins.

In recent years, there have been increased efforts to take a closer look at carcasses and live stranded animals to help us better understand what’s going on. By knowing more about marine mammal deaths ... their causes and the rates ... we can help to better protect them. And it will give us a better idea about what is normal and what is an unusual when marine mammals strand themselves or die in large numbers.

Understanding unusual marine mammal events is important because they can serve as indicators of ocean health, and this in turn can give us insight into bigger environmental issues with implications for human health.

All marine mammals are protected under the U.S. Marine Mammal Protection Act.

Corals are popular as souvenirs, for home decor, and in jewelry, but many did you know that these beautiful structures are made by living creatures. And even if you do know this, you might not be aware that corals are dying off at alarming rates around the world.

That’s why it’s better to leave the corals in the ocean where they belong. Corals are already gifts.

Coral reefs are made from the calcified skeleton of tiny sea creatures called coral polyps. These skeletons can grow in a wide range of shapes and sizes, including formations that resemble the branches of a tree. These skeletal structures come in a wide range of shapes and colors

Our coral reefs are some of the most biologically rich and economically valuable ecosystems on Earth. Some people call the reefs the rain forests of the oceans, others say the reefs are the medicine cabinets of the oceans. Both are good analogies.

 Coral reefs are home to millions of species of plants and fish that people depend on for food and tourism. In fact, NOAA estimates the commercial value of U.S. fisheries from coral reefs is over $100 million per year. Local economies also receive billions of dollars from visitors to reefs through diving tours, recreational fishing trips, hotels, restaurants, and other businesses based near reef ecosystems.

Coral reefs also serve as barriers or buffers near shorelines to protect against waves, storms and floods. This helps to prevent loss of life, property damage and erosion.

Coral reef plants and animals are also a critical source of new medicines being developed to treat illnesses ranging from cancer to heart disease. Some coral reef organisms produce powerful chemicals to fend off attackers, and scientists continue to research the medicinal potential of these substances.

But corals are in real danger. They are threatened by pollution, invasive species, fishing, disease, bleaching, and global climate change.

And they’re threatened by consumer demand for coral jewelry.

So you can help protect the reefs by marking anything made of coral off of your holiday shopping list.

Now let's take a closer look at one type of coral that’s prized for it’s beauty.

The U.S. is the world’s largest documented consumer of Corallium. This is a red and pink species of coral often used to create jewelry. Finished pieces of jewelry and art crafted from this type of coral can fetch anywhere between $20 and $20,000 in the marketplace.

By some estimates, the U.S. imported over 26 million pieces of Corallium between 2001 to 2006.

Commercial harvesting to satisfy the demand for coral jewelry has reduced colony size, density, and age structure of Corallium over time. Harvesting is also lowering the reproduction capability of this species and is decreasing its genetic diversity.

Research indicates that removal of red and pink corals for the global jewelry and art trade is also leading to smaller and smaller Corallium in the wild. The average base diameter of Corallium is has shrunk over the past few decades from an average of about four inches to less than an inch because so much of it is harvested. 

Since corals grow at rates of much less than inch, they live for an extremely long time, and they don’t even reach a mature stage until they are between seven to 12 years old. But once this coral is harvested for jewelry and other uses—especially when it’s pulled out at a young age—surrounding coral beds often don’t recover.

The good news is that all of us can help reduce the demand for coral jewelry, art, and decorations by refusing to by them.

You can appreciate the beauty corals on our web site. We’re at From there, you can surf to NOAA’s Coral Reef Conservation Program  web site, or you can visit NOAA Coral Reef Watch to see how researchers are monitoring these living structures from space.

That's all for this week. If you have any questions about this week’s podcast, about the National Ocean Service, or about our ocean, send us an email at
A reminder that you may see a short survey pop up while visiting the NOS site. We’d love to get your feedback! It’ll only take a few minutes, and your comments will help us make our site better.

Let's bring in the ocean ... This is making waves from NOAA's National Ocean Service. See you next time.


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