Tag Archives: Animalia

THE BIZARRE AND COLOURFUL WORLD OF SEA STARS

Starfish, also known as sea stars are a ubiquitous ocean species, with around 1,800 living species occurring in all the world’s oceans, and can be found at ocean depths greater than 6,000 meters.

“The Sunflower Sea Star”  is one of OceanFutures Society’s many videos ~ Uploaded on Oct 27, 2009 – When people think of sea stars, they don’t typically think of voracious predators scouring the seabed, leaving carnage and fear in their wake, but this may simply be a matter of perspective. To the scallop or clam, this sea star is a pure nightmare. This whimsical look at one of the ocean’s less known predators may change your perception of sea stars forever. For more unique insights into the ocean realm, watch America’s Underwater Treasures, a two-hour episode of the PBS series Jean-Michel Cousteau: Ocean Adventures

Some 2,000 sea star species live throughout the world’s oceans. Some weigh as much as 11 pounds (5 kilograms) and stretch more than 2 feet (65 centimeters) across, but others are only half an inch (1 centimeter) in diameter. These animals reproduce prolifically, and some sea stars can release millions of eggs into the water for fertilization at the same time.

Starfish can go from soft (able to squeeze into small spaces) to rigid in a split second. In fact, their entire anatomy is surprisingly complex, including their nervous system.

The undersides of starfish have many tube feet capable of grasping on to things with amazing force. They work on a hydraulic water vascular system which aid the starfish’s movement – some species very slowly while others can move up to 9 feet in one minute. The tube feet are also used to grasp and deal with food.

Uploaded by on Mar 13, 2011 ~ This star fish is walking around my tank all the time, it just cruises the entire tank. Excellent to watch.

Secondly, the underside is where their mouth is located. They can swallow their prey whole and down it goes in a short esophagus to a cardiac stomach, and then on to a second pyloric stomach. But they don’t have to swallow… when dealing with prey larger than its mouth, many species of starfish can also spit out their stomachs to engulf the food and begin to digest it before pulling everything back into its body – eueew! (In this photo the sea star is eating a clam!)

Green Brittle Star at feeding time ~ Uploaded by on Nov 8, 2008.  This is my 2 year old green brittle star at feeding time.

Starfish species don’t all come with five arms. Several species have 10 to 15 arms, and some other species have as many as 50.

These bottom-dwellers play important roles in the ocean ecosystem, including keeping populations of shellfish in check, and, according to recent studies, absorbing large amounts of carbon in the world’s oceans.

Ever wonder what happens to a starfish when it is flipped upside down? ~ Uploaded by on Jun 8, 2010

NUDIBRANCHS – “SAY WHAT?”

 I really don’t know what I’d do without my e-mail account.  I’ve just discovered interesting information that I’d like to share with you about another amazing colourful mollusc-like marine creature, known as a “nudibranch” (pronouced NEW-dih-bronk) 

“Just what are nudibranchs?”, you might ask.

The nudibranchs are ocean bottom-dwelling, shell-less mollusks featuring featherlike gills and horns mostly found on their backs and are part of the sea slug family. They are noted for their often extraordinary colors and striking forms.

Nudibranchs are usually oblong in shape and measure anywhere from ¼ inch to 12 inches.

Nudibranchs are carnivores that graze on corals, anemones, algae, barnacles and sponges. To identify prey, Two extremely sensitive tentacles (‘rhinophores’) on top of their heads help them locate their food sources., called rhinophores, located on top of their heads.

The colour of the nudibranchs is retained from the food they digest.  This colouring and poisons they keep from their prey help the nubdibranchs protect themselves from predators.

Nudibranchs lifespans vary with some living under a month, and others living up to one year.



Related links -

SMH article ‘Underwater Wonders on Mail Run':

http://www.smh.com.au/victoria/underwater-wonders-on-mail-run-20120507-1y7vw.html

Aquatic Community.com:

http://www.aquaticcommunity.com/sw/nudibranch.php

Article in National Geographic:

http://animals.nationalgeographic.com/animals/invertebrates/nudibranch/