Sea Stars – Because “Starfish” Aren’t Really Fish At All

For years, scientists have been trying to get us to stop calling these wonderful creatures “starfish.” Relatives of the sand dollar, sea urchin, and sea cucumber, a better name would be “sea stars.” There are almost 2,000 species of identified sea stars in the oceans and they vary widely in color, texture, size and shape. Sea stars normally live to be anywhere between 5 to 35 years old in the wild.


Red Starfish

Sea stars are marine invertebrates and typically have a central disc and five arms; however, some species have as few as four arms and others have as many as 10, 20, or even 40. They live in all of the oceans in the world and have adapted to both very warm and very cold climates. Sea stars only live in salt water though, if you put a sea star in fresh water it would die.

The main predators of sea stars are sea otters, rays, sharks, seagulls and different types of fish. They do have some pretty cool defenses though, they use camouflage to blend in with their surroundings, they can drop an arm to escape and then grow a new one in it’s place, and they have armor which protects them from many attackers. Sea stars armor consists of a tough covering on their upper side, which is made up of plates of calcium carbonate with tiny spines on the surface.

These marine animals feed on common ocean creatures like clams, mollusks, coral, and dying fish, they have a very unusual method of eating them. They eat clams and other shelled creatures by prying the shell open and then pushing their stomach out through its mouth and into the bivalve’s shell. Once it has digested its food, the sea star will slide its stomach back into its body. This strange way of eating enables sea stars to eat prey that are larger than their mouths.

Star Fish

Star Fish

Sea stars move using hundreds of tube feet, which are located on their underside. Some sea stars, like the adult sunflower sea star, can move at an incredible one meter per minute using its 15,000 tube feet. These tube feet are also used by sea stars to hold their prey.

Did you know that sea stars don’t have blood in their bodies? Instead of blood, they use seawater to pump nutrients through their bodies via a water vascular system. The sea star pumps seawater through its sieve plate, or madreporite, into its tube feet to extend them and then muscles within the tube feet retract them.

While sea stars aren’t totally blind, they can’t see anywhere near as well as humans. They have something called an eyespot on the tip of each arm, which allows them to sense light and shapes. If you look carefully at the tip of a sea stars leg, you might notice a red or black dot – that is its eyespot.

Next time someone talks about “starfish,” you can tell them that they aren’t really “fish” at all; they don’t have gills, scales or tails like fish do. These complex and beautiful animals are considered threatened by scientists due to pollution and loss of habitat, so we need to work together to keep our oceans clean, healthy, and thriving.

Watch Sea Stars move in this timelapse video.

Stars of the Sea from Karin Brussaard on Vimeo.

10 Cool Facts about Manatees

Marine & Oceanic Sustainability Foundation fan, 7-year-old Ava, asked us to write about her favorite underwater animal, the manatee. When we asked Ava why she liked manatees, she told us, “I like their cute faces and want to know why they are vegetarians like my momma.” Well, we don’t know why they are vegetarians, but we love their cute faces too and we’ve dug up 10 cool facts about manatees for you.

  1. ManateesManatees are large, gray mammals that live in the water. They have a flat, paddle-shaped tail and have two flippers. Manatees can grow to be up to 13 ft. (4 m) long and weigh as much as 1,300 lbs. (590 kg).
  2. Even though they live in the water, manatees are more closely related to elephants and hyraxes than sea lions and whales. (Hyraxes are small, thickset animals that resemble gophers. They don’t look anything like elephants or manatees. Crazy, huh?)
  3. Just like all marine mammals, manatees have to come to the surface to breathe air. A resting manatee can hold its breath for up to 15 minutes, but when it’s swimming, it must surface every 3 or 4 minutes.
  4. Manatees have good eyesight even though their eyes are pretty small. Also, you can’t see any ears on the outside, but manatees also have good hearing. This is because they have large inner ear bones.florida-manatee
  5. Manatees can be found in shallow, slow-moving rivers, estuaries, saltwater bays, canals, and coastal areas – especially where seagrass beds or freshwater vegetation thrive. Manatees are most commonly found in and around the Caribbean Sea, the Gulf of Mexico, the Amazon Basin and West Africa.
  6. Although manatees typically swim at about 3 to 5 mph (5 to 8 kph), they have been known to swim for short bursts at 19 mph (30 kph).  They are acrobatic and graceful swimmers and can do somersaults, rolls, and swim upside down.
  7. Manatee moms are pregnant for about 11 to 13 months and their babies, called calves, weigh about 60 pounds (27 kg) when they are born. The mothers must take their newborn calves to the water’s surface for their first breath, but the little ones can usually swim on their own after about an hour. Calves are dependent on their mothers for about two years.
  8. Adult manatees have a big appetite – they eat LOTS of water grasses, weeds, and algae. In fact, a manatee can eat a tenth of its own weight in just 24 hours – that a lot of plants!
  9. Manatees can live up to 60 years, but their average lifespan in the wild is about 40 years.many_Manatee
  10. Manatees are a federally listed endangered species in the United States. In other words, there aren’t a lot of them left in the wild. One reason for this is that manatees reproduce very slowly – in fact, the time between generations is about 20 years. Humans need to be very careful around manatees. These gentle animals are often injured during collisions with speedboats and by accidentally getting caught in the nets of fishermen. Fortunately, we are learning more about them every day and teaching others how to live near them while ensuring their safety and health.
Learn More About The Crystal River Manatee

The Fishes In the Deep Blue Sea

they-glowOceans cover more than 71% percent of our planet – and those oceans contain 97% of all the water on Earth. More than half of that water is deeper than 1 km (that’s only about ½ mile down.) Scuba divers and explorers have never explored most of the water this deep because it would kill them. There are several reasons why deep water is so dangerous for humans: 1) It’s cold – really cold, 2) There’s no air – without air, you’d pass out in about 5 minutes; 3) The water pressure gets stronger the deeper you go – the water pressure would squish you and collapse your lungs; and 4) This one is a little more confusing, but basically all the pressure on the body causes something called “nitrogen narcosis” and it would cause you to suffocate.

barreleye2-350For all those reasons, we don’t really know much about the fish and other creatures that live in our deep oceans. We know that they don’t get much light from the sun, that they can handle lots of pressure, and that they can survive in very cold temperatures. Most of these fish also don’t have skeletons, their skin is jelly-like, they grow very slowly and live longer, they don’t reproduce as quickly as fish closer to the surface, and there are not as many of them. All these things make them very different from the fish we normally see and find in seafood restaurants.

So, why does this matter? It matters because the Earth’s population is growing every day and today more than 1 billion people depend on fish as their main source of protein. With so many people eating fish, fishermen began running out of fish that that they could catch close to land and near the surface. Naturally, they moved further out to sea, but those fish populations started to get low too. Eventually the fishermen had to try new ideas and began fishing in deeper waters. Fish like mackerel, which live close to the surface can reproduce 50% of their population in a year, but these deep see fish can only reproduce 6% of their population in that same time. Through research, we can learn more about these fish and how to fish them at a rate that keeps them from being overfished and disappearing.

fish lightHave you ever heard of aquaculture? It is the farming of fish and other underwater plants and animals. It’s a lot like agriculture, which is the farming of plants and animals for food and other products on land. Aquaculture is one important way in which we can make sure that there are enough fish for people to eat and that the fish in our oceans aren’t overfished and have time to reproduce. In the last couple of years, aquaculture has become a big business. In fact, 50% of the world’s supply of seafood today already comes from fish farms across the planet. Aquaculture is one way in which scientists and fishermen are working together to figure out how to keep our oceans healthy and our population fed.

Watch MinuteEarth’s wonderful video on this

Galapagos Penguins

I don’t know about you, but when I think of penguins, I think of cute little birds in tuxedos playing in the snow. I recently learned that there are actually penguins that live in the tropics, right near the equator in the Galapagos Islands.Tropical Penguin

There several islands in the Galapagos archipelago (a group of islands), but the penguins seem to stay mostly on the western islands of Fernandina and Isabela. They probably stay on these islands because there is a current of colder water that runs along their shores called the Cromwell Current.

Galapagos Penguin SwimmingA survey done in the 1970s estimated that there were around 10,000 of these penguins, but current surveys show that there are only about 1,000 breeding pairs left. Scientists think that about 77% of the population died in 1982 and 1983 when the islands experienced unusual weather, which caused a food shortage for the penguins. They seem to be slowly rebuilding their population.

Galapagos penguins are pretty small, they only weigh about 2 kg (4.5 lbs.) – about the weight of a pineapple. They only get to be about 49cm tall, that’s less than 2 feet. They have a large bill and a narrow white line around the face. Their backs are grey and black and their belly is white.

Galápagos Penguin Galápagos IslandsThe penguins mostly eat small fish like mullet and sardines. Unfortunately, because they are so small they have many predators. On land, crabs, snakes, owls, and hawks pick on the little penguins; in the sea, sharks, fur seals, and sea lions can attack them. It can be a rough life, but these penguins seem to enjoy their tropical paradise.


Click here for a link to a teacher resource on the Galapagos Penguin.


Watch to learn more about the Galapagos Penguins


Galapagos Penguins trying to catch dinner


Fireflies of the Sea

Have you ever seen a firefly? It glows due to something called bioluminescence. Our oceans are full of creatures that use bioluminescence. Why are these creatures glowing? There are actually many different reasons why they glow or flash. They could be calling for help or trying to attract a meal – they might even be trying to lose a predator. Different creatures use bioluminescence in different ways; squids spray bioluminescent ink, whereas other creatures have bioluminescent cells the glow or flash.



There are many different types of animals that glow and for all different reasons. For example, the deep sea angler fish has a small rod above its mouth with a “lightbulb” to attract fish near its mouth so it can eat them. There’s also the vampire squid that shoots out a glowing liquid when escaping a predator to shock it. As a last resort, the deep sea jellyfish flashes when it’s attacked, it does this to call larger predators in hopes they will eat it’s attacker.

Bioluminescence is created by a chemical reaction. This reaction involves at least three ingredients: an enzyme called luciferase, oxygen, and luciferin. The luciferase helps the oxygen bind to the organic molecule called luciferin. The high-energy molecule created by the reaction releases energy in the form of light. To be able to do this it took 50 evolutions or more!



Bioluminescent are found throughout marine habitats, they can be found in the deepest parts of the ocean all the way to the surface. There are so many more types of these creatures that have not been discovered yet. Humans have only explored 5 percent of our oceans and have barely touched the deepest parts. Scientists discover new fish everyday and there are thousand or even millions more to be found.

Click here for a link to lesson plans and activities on bioluminescence.

See bioluminescence in action.

Learn more about bioluminescence in this talk.

The Mystery of the Ocean

giantsquitgraphicfactf320x301You would think an animal the size of a school bus would be easy to find. Yet the giant squid, which weighs over a ton and is over 42 feet in length, is still one of the biggest mysteries of the ocean. Scientists all over the world are trying to learn more about this elusive animal. Part of the reason that so little is known about them is because they live in the deepest parts of the ocean. They are so deep that it takes about 2 hours to go up and down in a submarine. It has only been recently that they have had technology advanced enough to go that deep and it is still very expensive.

A giant squid’s body may look pretty simple – like other squid and octopus, it has two eyes, a beak, eight arms, two feeding tentacles, and a funnel. The eye of a giant squid is a big as a dinner plate. The main part of the body is called the mantle. On the underside of the body is the funnel. The squid pumps water through the funnel to move through the water, to lay eggs, and to squirt ink. Feeding tentacles can catch prey up to 330 feet away. They also have sharp tooth suckers at the end of their tentacles.


Giant suckers

Giant squid feed on deep-water fish and other squid. Once they catch food with the suckers and teeth on their feeding tentacles, they pull it back to their body and their beak. The beak breaks the food down into smaller pieces first and then they use the radula, a tongue-like organ with teeth, to grind it up more. The food then goes into the esophagus, which travels through the squid’s brain, to the stomach. Although giant squid do not have many predators, remains of them have been found in the stomachs of sperm whales.

architeuthis beak 32xx258


It is believed that giant squid live for 3 to 5 years, but this is just an educated guess by scientists. During their life, giant squid only reproduce once. Females release millions of tiny, transparent fertilized eggs into the water in a jellied clump called an egg mass. They need to make lots of eggs because other marine animals quickly eat most of the eggs that are released.

It is believed that the giant squid live in all four of our oceans, but none have ever been seen in tropical or polar regions. They are usually found near continental and island slopes. Although there is so little known about the giant squid, there are multiple studies in progress right now. In 2012, researchers in Japan were able to capture video of a living giant squid for the first time. Using flashing lights to mimic bioluminescent jellyfish, they were able to attract a giant squid to the camera in a submarine. Scientists are learning more and more about these mysterious squid every day.


Architeuthis distribution

Click here for a link to lesson plans and activities on Giant Squid (Architeuthis dux).

The first video of a giant squid ever!

How they found the giant squid.