Sunday, 17 November 2013

Chromodoris kuniei - Hon Mun Nudibranch

Taken on the second dive near Hon Mun when we were diving from Debbie's Beach to Rainbow reef.  I particularly like the colouring on this  nudibranch.  Very attractive!




 



Saturday, 16 November 2013

Christmas tree worms - Spirobranchus giganteus

These little Christmas trees decorate the coral reef.  They seem like plants but are actually worms. 


 


Wednesday, 11 September 2013

Red Clown Fish - Nha Trang, Vietnam

Clownfish were brought to public consciousness the world over by Disney. They aren't particularly friendly fish and, unsurprisingly, are particularly aggressive towards strangers. They display erratic intimidating behaviour when approached, darting around hyperactively trying to scare potential invaders, predators or divers.


Like many sea creatures, clownfish exhibit interesting sexual characteristics.  They are all born male and later mature into females.  The largest most aggressive female is found at the top of the dominance hierarchy.  Once transformed this change is irreversible.  If a female clownfish is removed from the group, one of the larger male clownfish will move up the pecking order and become female.

Clownfish live in a symbiotic mutualistic relationship with anemone.  The clownfish are protected in the sea anemone from potential predators while the anemone benefits from regular preening of parasites and nutrients from fecal matter.  Clownfish are also extremely beneficial as they feed on small invertebrates that may harm the anemone.

By performing an elaborate dance with a chosen anemone, rubbing against its tentacles, the clownfish slowly acclimate themselves with their host.  A mucus layer on the skin of the clownfish confers immunity to the anemone's lethal sting.

Nha Trang Divin - Hon Mun Island, Vietnam


Nha Trang is the most famous dive location in Vietnam.  I went diving with Rainbow Divers Nha Trang, the best known dive centre and most well established of the Rainbow Divers centres.


Diving regularly take place around the island of Hon Mun which was declared a 'protected' Marine Park in 2003.  Hon Mun is located to the south of Nha Trang Bay and is characterised by cliffs, caves and numerous grottoes.


The island's excellent diving is largely due to its close proximity to warm sea-currents from the equator which are particularly favourable to the development of soft and hard corals whilst offering the ideal environment to an abundance of tropical sea creatures.




 




Lionfish - Nha Trang, Vietnam



Lionfish are native to the warm, tropical waters of the South Pacific and Indian Oceans




Mantis Shrimp - Nha Trang, Vietnam

Mantis shrimp are marine crustaceans that reach 30 centimetres in length and in rare cases have been recorded at up to 38 cm. The carapace of mantis shrimp covers only the rear part of the head and the first four segments of the thorax. Mantis shrimp appear in a variety of colours, from shades of browns to bright neon colours. 

Although they are common animals and among the most important predators in many shallow, tropical and sub-tropical marine habitats, they are poorly understood as many species spend most of their life tucked away in burrows and holes.  This one was spotted by the dive guide and 'enticed' out of its hideout.



 Check out this funny video for some facts (and fiction!) about the Mantis Shrimp:


Starfish - Nha Trang, Vietnam



Leatherjacket - Nha Trang, Vietnam



Nudibranchs - Nha Trang, Vietnam







Hard Coral, Nha Trang - Hon Mun Island, Vietnam


Hard corals are the reef builders. The hard coral polyp, such as those in Brain Coral, secrete a limestone skeleton cup around itself and live inside it for protection. When a polyp dies, its skeleton house remains intact.  The name "hard coral" derives from the skeleton which forms around the polyp.