Spanish dancer and 'Naked gills'

The most fascinating and colourful creature on earth has to be the nudibranchs or sea slugs. Always fascinated by the array of colour combination they demonstrate and the ability to camouflage. Almost a new species is found everyday. Up till now there are more than 3000 species known to human. Sorry for those who misread the title of this post, but this is a perfectly healthy page dedicated to the marine animals. Come on…

Nudibranchs or sea slugs represent fascinating and colourful life form. Their name is pronounced nudi - brank and it means "naked gill". As the name suggests the vast majority have gills outside their body and they have evolved without the protection of a shell. In all nudibranchs the shell is only present in the larval stage. As adults, the mantle replaces the shell.
They can be found throughout the world's oceans at all depths. The only place you will not find them are high energy areas, such as heavy surf close inshore where their soft body could be damaged.

Anatomy of Nudibranch


The mantle.

The surface of the mantle may bear tubercles which vary in size, shape and number and are often a character used to identify nudibranchs. Acid glands and/or spicules are incorporated in the mantle tissue and it is thought that these are mainly defensive in function.
Processes found in some species have coloured tips and contain defensive glands and have been shown to produce chemicals distateful to fish.




Cerata

The cerata contain branches of digestive gland.


The rhinophores.

The head region of nudibranchs bears a pair of sensory tentacles called rhinophores. These structures are primarily chemosensory (smell, taste) in function. In many dorid nudibranchs the rhinophores can be retracted into a basal sheath. The shape of the rhinophores varies greatly from one species to another and a table showing the different types of rhinophore found in British nudibranchs is provided to help identification.

The gills.

In nudibranchs the gills are probably the most important respiratory organ, however gaseous exchange also occurs over the entire body surface. In dorids the gills consist of several feather-like structures that encircle the anus. The gills can be retracted into a gill-pocket.

The oral tentacles.

Many nudibranch species have a pair of processes, one on either side of the mouth, which are probably involved in identifying food by taste or touch.

Feeding
Nudibranchs feed on other invertebrates such as sponges, soft corals,
anemones, sea pens, Portuguese man-of-wars and hydroids.
Certain species are specific about their diet and feed only on a single or small selection of hosts, others are generalised browsers.
Certain species eat the eggs of other nudibranchs. These tend to be pale in colour so that they can go unnoticed on the egg masses. Sneaky!

Defence
Nudibranchs have an amazing array of defences. Colour is believed to be an important defence in many species. Others ingest and utilise the stinging cells from soft corals.
Particular species bury themselves in the sand and others hide during the day coming out at night.

They do not have shell for protection, but they use highly sophisticated chemical warfare. When distressed, some species secrete toxins so deadly that it could kill marine animals within 50cm radius.

They obtain this toxin from their food source containing chemical compounds which they store. Some species accumulate the poison in their Cerata, tentacle type sacks located along their backs away from their head, others store in the dorsal body wall.

The striking colour is for camouflage and as a warning to predators not to eat them because they are poisonous or pretending to be.


They travel by producing slimey mucus and using muscle or hair movement on the fleshy foot.

Reproduction

They are hermaphroditic possessing both male and female reproductive systems. Their gonad is located on the right side of their body close to the head as shown below.


Each nudibranch is both male and female producing sperm and eggs. To mate, two nudibranchs come together side by side and pass sperm sacs through a tube in their 'neck' to each other as shown in picture below.




Both then go their own way and lay egg masses that may contain millions of eggs.
The egg mass, which in most cases is laid in an anticlockwise spiral is made up of thousands of small eggs giving a speckled appearance.




Nudibranchs life span vary from 4-5 weeks to one year.

Spoil yourself with the beautiful colours of nudibranchs!




Spanish Dancer

One of my favourite nudibranch is the Spanish dancer.




This is the largest species of nudibranch, which can grow to as much as two feet in length. This specimen is about a foot long. Spanish Dancers are often seen swimming through the water in peculiar movement which is fascinating for divers to watch, as they simultaneously bend their body up and down, and move the edges in a wavelike motion.







The Spanish dancer dances as the diver gazes…



They definitely have the nicer costume than the Spanish dancers I paid through my nose to watch them do the flamenco dance in Barcelona, Spain!

See what I mean? OL attire for Flamenco dance...
No offense to the dancer cause her flamenco dance was really skilled.

But I'd rather gaze at the spanish dancer nudibranchs as they grace through the water. =)

That is what makes our marine lives so precious.

I would like to dedicate this post to my friends who are troubled with unhappy things in their lives at the moment. Hope that you will be strong in this difficult phase of your life and paint your life with beautiful colours of joy and happiness once again. God bless you.

May your life be as colourful as the living colour of the ocean, nudibranchs. Love you all.

Love the Ocean. Protect the Ocean.

Please leave comments and thoughts in the chatbox at bottom of page. Thank you.

For more information, visit :

http://www.downbelow.co.uk/nudibranch.html

http://www.reefed.edu.au/home/explorer/animals/marine_invertebrates/molluscs/nudibranchs

http://www.seaslug.org.uk/nudibranchs/anatomy.html

Acrobats and singers of the deep..

As we ascend from the deep, on our way up, we hear beautiful echoic singing voice and trails of bubbles brush through our feet… it’s the Humpback whales come to say hello!

Humpback whales are my favourite whale species of all time.. they are the most acrobatic animal in the ocean and loves hurling their massive bodies out of the water in different styles and postures called breaching and fall back into the sea with much grace.. They have massive tail fin, called a fluke, which helps them propel the body through the water and breaching. This behaviour is believed to be involved with courtship, removing pests or parasites from the body or they simply do it for fun!

Enjoy this video and feel the excitement of whale watching!!




Humpback whales are great singers of the deep.. they are well known for their magical songs, which travel for great distances through the world's oceans. These sequences of moans, howls, cries, and other noises are quite complex and often continue for hours. Scientists are studying these sounds to interpret their meaning. It is most likely that humpbacks sing to communicate with others and to attract potential mates.



These whales are found near coastlines, feeding on planktons, tiny krills(shrimp-like crustaceans) , small schooling fish such as herring and mackerel. A humpback consumes between 2,000 and 9,000 pounds of fish and krill a day. Humpbacks sometimes engage in social hunting in which several whales encircle a school (group) of fish and blow bubbles that form a "net" around the fish, then move in with their mouths open to devour their prey.





Humpbacks migrate annually from the tropics to polar regions. They swim enormous distances during migration, sometimes as much as 4,000 miles each way! Mothers and their young swim close together, often touching one another with their flippers with what appear to be gestures of affection. Females nurse their calves for almost a year, though it takes far longer than that for a humpback whale to reach full adulthood. Calves do not stop growing until they are ten years old.




The humpback whale is capable of living up to 95 years

Humpbacks are distinguished by the markings on the underside of their tails (also known as flukes). The patterns can range from all black to all white, with most having a mix.

Fluke pigmentation may be influenced by inheritance from the parents. Superimposed on the basic pattern are scars from injuries acquired during fights with other individuals, attacks by killer whales or sharks, or attachment of parasites such as barnacles.

Evolution ....


Scientists believe the ancestors of whales were land animals that crawled into the sea to escape predators or seek food.

The mammals gradually lost their limbs and became fully adapted to living in the ocean.




According to new evidence, published in the journal Nature, one of the secrets to adapting to a marine environment was a scaled-down inner ear.

This semi-circular canal system gives land mammals, including humans, a sense of balance.

We only become aware of its role when something goes awry - such as feeling drunk, sea sick or riding a rollercoaster.

These are smaller, size-for-size, than land-dwellers. Our inner ears, for example, are bigger than those of the blue whale.

A whale can make acrobatic leaps and turns without experiencing vertigo.
This is thought to be because its smaller inner ear is less sensitive.

Fossils show that the inner ear of early whales evolved rapidly after they entered the sea. The adaptation enabled early whales to swim without becoming dizzy.


Threats to the Humpback whales and Interventions…


1. Humpback whales were nearly hunted to extinction for their oil and meat by industrial-sized whaling ships well through the middle of the 20th century.
But the species has been bouncing back since an international ban on their commercial whaling in 1966.

2. The US government is considering taking the humpback whale off the endangered species list in response to data showing the population of the massive marine mammal has been steadily growing in recent decades. It is the first review for humpbacks since 1999.

3. The global humpback population is estimated to be about 60,000, according to the Swiss-based Conservation of Nature union.


As the Humpback whales sing their way back into the deep, we head back to the boat and have some sweet dreams of our gentle giants of the deep...

Love The Ocean. Protect The Ocean.

Which marine animal will we meet in our next diving trip? Join me next time to find out!

Please leave your comments or thoughts in the chatbox on the bottom of the page.

For more informations, visit :

http://animals.nationalgeographic.com.au/animals/mammals/humpback-whale.html

http://www.wcs.org/saving-wildlife/ocean-giants/humpback-whale.aspx

http://news.bbc.co.uk/1/hi/sci/tech/1974869.stm