Coolest aquatic life.

 
I all ways get ask what the coolest things i have seen under water.
Well here is one.
 
Peacock mantis shrimp. these beautiful crustaceans are ferocious undersea predators that hunt with clubbed forelimbs, walloping their quarry with one of the strongest pound-for-pound punches on the planet.
               
The mantis shrimp can punch with the speed of a .22 caliber bullet strong enough to break the shells of its prey, as well as aquarium glass.
 
When a mantis shrimp hits its target, the velocity causes water to vaporize, then implode with a sharp bang, extremely high heat, and a flash of light   all of which is felt by the prey animal as an additional blow. 
   
When the striking limb of a mantis shrimp is not in use, it lies folded under the animal’s body, compressing a saddle-shaped spring that drives the animals stupendous strikes.
 
Some species of mantis shrimp wield spear like limbs that can impale their targets, instead of club-like limbs for bashing them. 
 
Their super-strong punches aren’t the only notable thing about the mantis shrimp. The animal’s eyes can see a huge variety of light wavelengths, including those in the ultraviolet spectrum.
 
 


"Why is the sea salty"

Yesterday a student completing a swim test mentioned to me 'the sea is so salty here' - a silly statement you may think, however it got me thinking - yes, we all know the sea is salty, but exactly why is the sea salty and why can it be more salty in some places than others? Well, here is the definitive answer as explained by the BBC. That's a lot of Salt!

Most of our planet’s surface is covered in water – salt water. The oceans that support so much of Earth’s life are around 3.5% sodium chloride – 50 million billion tonnes of salt.
But where does it come from? While some of it comes from volcanic vents or rocks on the seabed, most of it is actually from the land around us. Every time it rains, tiny amounts of mineral salts are washed into rivers, which eventually flow into the sea.
The salt in rivers is less than 1/200th the amount usually found in seawater. It becomes more concentrated in the ocean, as the Sun’s heat causes water from the surface to evaporate, leaving the salt behind. Extra salt added every year from rivers is balanced by salt which returns to the sea floor.
But salinity isn’t the same everywhere. Towards the poles, water is not as salty because it’s diluted by melting ice, while the extra heat in the tropics makes water there saltier – and denser. And that can affect how nutrients flow around the oceans.

 

A SELECTION OF KOH TAO’S BEST DIVE SITES

 
 
Southwest Pinnacles
Location: About 7 km Southwest of Koh Tao
Depth: Average 17 m / Maximum 28 m
Level of Diving: Beginner to Experienced Divers
A row of pinnacles offering wall dives and fantastic schooling marine life, such as snapper, trevally, and barracuda. The shallower points are carpeted with gardens of sea anemones and the deeper gullies are filled with healthy gorgonians and whip corals.
 
Chumphon Pinnacles
Location: About 5 km northwest of Nang Yuan
Depth: Average 20 m / Maximum 36 m
Level of Diving: Experienced Divers
This deep pinnacle is typically reserved for advanced divers, but can be accessed on your final open water training dives in good conditions. Majestic views, breathtaking rock formations and large marine life, with the increased chance of whale shark sighting.
 
Shark Island 
Location: 1 km off the southern tip of Koh Tao
Depth: Average 15 m / Maximum 28 m
Level of Diving: Beginner to Experienced Divers
Shark Island is named not for its carnivorous marine life but for the island’s resemblance to a shark fin from certain angles. The occasional currents bring in nutrient rich waters encouraging an abundance of marine life. Groupers, turtles and schools of raccoon butterfly fish inhabit the shallower depths, and nudibranch nurseries line the eastern coast.
 
Maarten. Padi Instructor.
Scuba Junction.


Cuttlefish facts

Cuttlefish are actually not fish but molluscs belonging to the order Sepiida and class Cephalopoda, which also includes squid, octopodes, and nautiluses.

Males have four pairs of legs, whilst females have three pairs. They also have two tentacles, with suckers, for catching prey.

Cuttlefish have three hearts and blue/green blood.

Cuttlefish spawn only once in a lifetime.

They have “W” shaped pupils, can’t see colour but can see forwards and backwards, with no blind spot.

Cuttlefish normally grow from 15-25cm, however the largest species (Sepia Apama) can reach 50cm.

Cuttlefish, like Octopus, release ink as a defence mechanism. This ink was formerly used as a dye, hence the name Sepia.

They live for approximately 1-2 years and inhabit mostly shallow tropical/temperate ocean waters.

The Cuttlefish ‘bone‘ is what controls their buoyancy.


Food

Generally Cuttlefish eat fish, shrimp, crabs, worms, molluscs but will also eat other Cuttlefish. They in turn are preyed upon by fish, seabirds, sharks, seals, dolphins and of course, Cuttlefish.

Intelligence

Cuttlefish have one of the largest brain to body size ratios and are thought of as amongst the most intelligent invertebrates. Cuttlefish cannot see colour but have highly sophisticated eyes, which are thought to give them sight even whilst in the womb. They are thought to learn their preferred prey in this way before they are even hatched.
Despite the fact Cuttlefish are colourblind, they are able to change their colour at will to match their surroundings.

Mating

Cuttlefish ratios mean there are usually 4-5 males for every female, which is a recipe for war. Males will either fight but more commonly trick each other, for the right to mate.
The most successful tactic is cross dressing! Males disguise themselves as females, by changing their colour, concealing their extra arms and even pretending to be holding an egg sack. The master of disguise can then sneak past the guarding male and mate with the female.
The successful male grabs the female with his tentacles, turns her face to face, then inserts a specialised tentacle into an opening near her mouth. He deposits sperm sacs there, fertilising the female, who he will guard until she lays their eggs only hours later. Check out this video of the dramatic event.
The female lays a batch of about 200 eggs and covers them with ink. After two to four months, they hatch out into perfectly formed little Cuttlefish with a yolk sac, to feed them until they make their first kill.

Threats

Cuttlefish populations are not well known, however, commercial fishermen in South Australia catch up to 71 tonnes during the mating season, both for human consumption and use as bait.
Because of their short life span and spawning only once in a lifetime, the threats of over-fishing are obvious. Currently there are no management restrictions in place to limit the numbers that can be taken but there is pressure to add the giant cuttlefish to the endangered species list.

Cheers,
Paul. Padi Instructor.
Scuba Junction.

 

Why I Love Teaching Scuba Diving 

 
My name is Natalie and I have been teaching people to Scuba Diving for over 11 years now.
 
I remember learning to dive myself – it is a very clear memory, I had many fears, struggles and problems to overcome during my Open Water Course and my Advanced Open Water too.
 
I believe that because of my fears of learning to dive, it has actually served me in teaching others to dive.
 
When I am teaching diving I get such a sense of achievement, I teach all levels of divers from beginners to professionals, my list of courses for myself to learn is endless too, if we believe we know everything that’s not true, its endless and a continual learning curve, everyday actually! Life is work in progress
 
When I see people learning to dive and continuing it fills my heart with joy, I really enjoy teaching Open Water and then to watch them grow and progress throughout the next courses. The pride and happiness each diver feels is intense, overwhelming, each course just feeding them more information and confidence, each course reminding them to take care and reminding them to be safe underwater! 
 
No question is too small, no question is stupid as we have heard them all before, I think it helps to really emphasise this, I also ask people to leave their ego and embarrassment at the door! This is necessary in any extreme sport! 
 
Because I was such a nervous and uncertain diver it helps me to really get inside my divers heads and thoughts, just by looking at someone you can really see and tell a lot of what is going on inside the mind.
 
Some people have never been in the ocean or have never even snorkelled, these are the guys I love to teach, they really get so much out of it, it’s very emotional at times, that’s what I love and that’s what makes me feel super happy about what I am doing in my life.
 
I prefer to teach in rough weather with low visibility, it really prepares the divers that the ocean needs to be well respected, it prepares them for wherever they will go next, the ocean is unpredictable, it can be rough and unforgiving, so we need to respect all the time where we are, underwater!! 
 
I just wanted to share what I love doing, what I get from teaching people to dive, when those feelings end I will hand my fins and mask up, but for now and the foreseeable future, I am excited to keep climbing the scuba ladder and to continue to learn and share all that I do with my students!
 
Scuba J all the way!
 
Natalie E Alderton. 
Partner/Instructor.
Scuba Junction.