Monday, October 27, 2008

Puffer Fish

Puffer fish have a very unique defense mechanism. They are able to swallow water to inflate their bodies like balloons. Most fish will eat anything that will fit into their mouth, and avoid anything bigger than themselves. By puffing up like this, a puffer fish quickly jumps to a much bigger size, and becomes inedible to most fish.

A puffer fish spends most of its time deflated. In this state, it is much more streamlined and can swim unhindered in search of food. When it puffs up, it moves extremely slowly. I used to catch puffer fish by startling them into puffing up. This made them suddenly almost immobile. I could then easily pick the little ball up with my hands.

If I caught them in a net before they managed to puff up with water, they would fill up with air. This turned them into little living balloons. I would put them on the surface and they would float down the beach until they relaxed and deflated.

Puffer fish come in many colors, shapes, and sizes. Most can easily fit into the palm of your hand, but some grow as big as a person. Some species are decorated with beautiful colors as well.

Friday, October 24, 2008

Jellyfish


Jellyfish are cnidarians, related to sea anemones and sea slugs. They consist of a dome-shaped body and tentacles that trail behind them. Jellyfish are able to swim through the water by pulsing their jelly-like bodies. Their tentacles are covered in poisonous stinging cells called nematocysts. These tentacles can paralyze or kill fish. Some jellyfish, like the box jellyfish below, are powerful enough to kill humans. The venom in a box jellyfish can stop a person's heart in less than 3 minutes.

While most jellyfish are relatively small, some can grow to enormous sizes.

During certain times of year, jellyfish can be found in huge numbers, clouding the seas with their pulsating forms.

Some jellyfish can even glow in the dark.

Wednesday, October 22, 2008

Crabs

Crabs are Crustaceans and members of the Arthropod phylum. They have a hard exoskeleton surrounding their entire bodies which acts as a suit of armor. Most crabs use their powerful claws to fend off attacks and capture prey.

Some species such as the hermit crab scoot into empty snail shells and carry the shell on their backs. When threatened, they can disappear into the shell.

Other species rely on camouflage to hide from predators.

Most species of crabs can survive for short periods of time outside the water. Their shells hold enough water to keep their gills moist, therefore allowing them to breathe on land. Some crabs spend most of their lives on land.

Crabs range in size from barely visible to the giant coconut crab pictured here. Crabs can be found all over the world in a staggering variety of shapes and colors.

Monday, October 20, 2008

Mandarin Goby

One of my favorite fish in the whole ocean is the Mandarin Goby. Its lifestyle and behavior are much like any other goby, but its colors are absolutely stunning.

These vibrant and flashy fish can be found as the centerpiece of many saltwater aquariums. They are heavily sought after because of their beautiful display.


Friday, October 17, 2008

Great White Sharks

Great White sharks are among the fiercest and most deadly predators in the world. They are among the few species of sharks that have a reputation as man-eaters. They are some of the most efficient and powerful predators in the world. Here is some breathtaking video footage of great white shark attacks from the series "Planet Earth".

[WARNING: Not safe for small children or people who love seals]

video

Wednesday, October 15, 2008

Dinoflagellates: Bioluminescent Algae

In some oceans when the night is dark enough, you can see the waves glow as the water stirs. This is caused by phytoplankton called dinoflagellates. They give off a soft blue glow when disturbed. The chemicals they use are similar to the ones causing lightning bugs to glow.


When a person swims through the algae, the motion gives off a glow all around them, looking like angel's wings. Boats and wave action can also cause ripples of light to cascade in their wake. This video was taken at a dock in Australia where this algae is plentiful. People throw water on it to cause it to glow in amazing patterns.

Monday, October 13, 2008

Planet Earth Echinoderms Video

video

This is a clip from the amazing Planet Earth series that aired on the discovery channel. It shows the behavior of some of the echinoderms in the California oceans. You will see starfish, brittle stars, sea urchins, and sand dollars. All of these are members of the echinoderm family. The stop motion photography allows you to see the behavior of these slow moving creatures.

Friday, October 10, 2008

Flying Fish

Flying fish are some of the most amazing organisms in the ocean, and believe me there are lots of amazing creatures in the sea. Flying fish have a very unique defense mechanism for escaping predators. They have found that the best way to avoid other fish in the water is to get out of the water. As their name suggests, flying fish can actually leap out of the water and fly short distances.

Flying fish have very specialized pectoral fins (the fins on their sides) which can actually function as wings. While underwater, they fold the fins close to their bodies so they can swim just like normal fish. When a flying fish feels threatened, it will take a running start and jump out of the water.
Some flying fish have been clocked to fly for over 45 seconds, but most flights are relatively short. Like all fish, flying fish still breathe through gills, and must return to water before they run out of oxygen. Still, that quick flight is plenty of time to escape most predators. As far as most fish are concerned, if their prey leaves the water, it is out of reach.

Wednesday, October 8, 2008

World's Deepest Fish

video

Scientists have discovered fish living nearly 5 miles below the surface of the ocean. There is no light at this depth, and the pressure is enough to easily crush nearly any living thing. The pressure is about as much as the weight of 1,600 elephants. The water temperature is nearly freezing. It seems impossible that anything could survive in these conditions, yet there is life here.

This species of snailfish is able to thrive in large numbers in this extreme environment. Scientists had to specially design the camera equipment so it wouldn't be destroyed by the crushing pressure. It was previously inconceivable that anything could live at such depths, but it seems that no matter where we search on earth, there is always life.

Monday, October 6, 2008

Sea Anemones

Sea anemones resemble flowers, but they are actually cnidarians, related to coral and jellyfish. They spend their lives rooted to surfaces using a big sticky foot. Their tentacles wave in the currents and catch any pieces of food or animals that pass by.

Sea anemones spend their larval stage as zooplankton floating in the currents. When they reach maturity, they settle on the sea bottom and anchor themselves.

The tentacles of a sea anemone are lined with tiny cells called nematocysts. These cells contain a microscopic spring loaded harpoon. When an unfortunate animal brushes by, the harpoon fires, ensnaring the victim and delivering deadly poison. Once the hapless victim is entangled, the anemone pulls it into its mouth. It digests the food in its stomach and excretes the waste back out through its mouth.
Sea anemones are often sought out as partners for other organisms which use their powerful poison as defense. Hermit crabs will often uproot small sea anemones and stick them on their backs. This serves the anemone well because it is now mobile and can more easily catch bits of food. It also gets to snack on any of the crab's leftovers. The crab benefits by having added protection from predators. Anything trying to eat the crab gets a powerful sting.

Another animal that uses the sea anemone as protection is the clown fish. These fish are adapted to keep the sea anemone from stinging them, and spend their entire lives nestled safely in their deadly tentacles.

Sea anemones come in many shapes, sizes, and colors, and can be found throughout the world, from the cold oceans of North America to tropical Australian coral reefs.

Friday, October 3, 2008

Sea Slugs Part 3

Yes, I have even more amazing sea slug photos. There are so many diverse and unique species of sea slugs. These are just a few of the most colorful.






Wednesday, October 1, 2008

Sharks

Sharks are the most effective and deadly predators in the oceans of our world. Sharks are perfectly designed aquatic killing machines. There are over 360 known species of sharks, ranging from the tiny dogfish to the massive whale shark.

The bodies of sharks are perfectly designed for quick and decisive strikes. They are streamlined for speed and power in swimming. A shark's skin is covered in tiny teeth which face forward, causing a layer of turbulence around their bodies and making them even more streamlined. The high tech racing suits worn by many swimmers in the Olympics were designed to mimic a shark's skin.

Most sharks are colored to help them disappear into the water. They are a dull gray and darker on top to blend into the deep waters when looking down at them. Their undersides are light, blending in with the light water above.

Sharks have heightened sense organs to help them find prey. These sense organs are packed into their snouts. This causes their noses to be very sensitive. Sharks can often be warded off by a sharp blow to the nose, which causes them great pain. They can smell even a drop of blood in the water for miles, which is why you should never swim when you are bleeding. When sharks smell blood, they often go into a frenzy, lashing wildly at anything that moves. Sharks also have electric receptors and can sense the tiny electric fields emitted by living things. When an animal panics or is afraid, their electrical signals increase and sharks can sense it. This is why it is said that sharks can sense fear. In a way, they can. They can read the heightened electrical activity in terrified prey, and it makes them more likely to attack.

Sharks have massive jaws that actually unhinge to allow them to take huge bites. When a shark bites, its eyes actually sink back in their head to protect them from thrashing enemies and their sharp claws or fins. Their strong jaws are lined with rows of thousands of razor sharp teeth which continually fall out and are replaced.

Man has always feared sharks, but they actually don't normally hunt humans. A shark prefers oily, fatty fish and seals for a meal. Sharks also tend to feed on weak or injured sea creatures. They rarely bother attacking healthy animals unless they are very hungry. Sharks are attracted to blood, splashing, and fear. Each of these things tells a shark that the animal is hurt, and will be an easy meal. If you ever see a shark, stay calm and relax. It will usually just check you out, then leave you alone.
Most shark attacks are a case of mistaken identity. Humans surfing in wetsuits look very similar to seals, which are some of their favorite prey. In the entire world, there are an average of only about 50 shark attacks each year. Only about 5 of these are fatal. On the other hand, there are an average of 520,000 murders worldwide each year. We are over 100,000 times more likely to be killed by a human attack than a shark attack, and we go out in human infested areas each day. So don't let sharks scare you out of the water.