Introduction

The Blue Tang is part of the surgeonfish Family and is known by many different names; blue barber, blue doctor, blur tang, yellow barber and yellow doctorfish are a few examples.

Where Will I Find Them?

The Blue Tang can be found in tropical waters between 2 metres and 40 metres, between the latituted of 41 degrees N and 33 degrees S.  There are loads of them in Florida, the Bahamas and the Caribbean Sea.

They tend to live in holes and crevices on coral reefs, though the chances of finding a baby one is much less as they spend much of their time hiding from predators.

What Do They Look Like?

At 39cm in length at full maturity and blue colour with curious yellow bits, they are quite easy to recognise.  They are flat fish and have a pointed mouth.  The most obvious thing about them is the yellow spine at the base of the tale.  Young adults may still be more of a yellowy colour, which will darken to a blue as they reach full maturity.  At night the Blue Tang shows white stripes.

What Do They Eat?

The Blue Tang only eats algae from rocky areas.  The fish is very important when it comes to keeping algae levels under control, which if got out of control, could suffocate corals.

What is Their Usual Behaviour?

They can be found on their own, in pairs or in schools of 10 to 12, although occasionally you might find them in much larger groups.

What is Their Conservation Status?

Not listed on the IUCN Red List of Threatened Species.

References

www.marinebio.org

“Just keep swimming!” – Dorey

The air you breath from your cylinder (as you should remember from your initial dive training!) is about 78% nitrogen. As you dive and the ambient pressure increases, some of that nitrogen is absorbed into your cells (I’m not going into partial pressures here, I’ll save that for another day!). As you release the pressure again, the nitrogen will come back out of your cells, make its way to your lungs by your blood stream and you breathe it out.

However, there are several things you can do that will disrupt this process and instead of staying in solution in your blood, the nitrogen will exit from your cells as tiny bubbles. It is these little bubbles that cause all the problems in your body, which can be fatal.

What Causes the Bubbles?

- Over loading your cells with nitrogen either by not leaving a long enough surface interval between dives, or by doing something that pre-disposes your cells to take on more nitrogen (we cover that further down in the article)

- Surfacing too quickly or not completing sufficient deco-stops or safety stops, in other words you are forcing your body to off-gas much quicker than it should be.

- Flying or decreasing pressure beyond sea level (if you are lake diving in the moutnains – check out the deco rules for that!). Don’t forget that your body has not purged all the nitrogen by the time you surface, depending on how many dives you’ve done and the depth of those dives, you body could need another 3 to 12 hours to release all the nitrogen. It’s best to leave 24 – 48 hours before flying.

How will I know if I get DCI?

There are loads of symptoms you could experience all over your body, but they could include;
fatigue or a heavy body;
joint pains;
confusion or change in personality;
itchy or mottling skin;
vision or hearing problems;
balance problems;
shortness of breath or chest pains;
abdominal pains or nausea.

You could suffer from any or all of these and they could occur from 10 minutes after you get out the water, or not show themselves for 3 days. My advice if you get any of these symptoms is to get it checked out immediately as in some cases DCI can lead to death. I would rather hear I had pulled a muscle than find out too late that I was suffering from DCI.

How can I avoid DCI?

- Don’t do too much exercise before (will make your cells more hungry for oxygen, but they will take on more nitrogen) or after diving (you will increase the rate that your body tries to remove the nitrogen and cause bubbles).

- We all know that smoking is bad for you, but it will also increase the risk of DCI because of the nicotine (causes the blood vessels to constrict thereby slowing the release of nitrogen).

- Don’t allow your body to get dehydrated, be especially aware if you are diving on holiday in a hot country – you will dehydrate much more quickly than you would at home.  Don’t drink coffee or alcohol as that will dehydrate you further, and try to stay out the wind and direct sunlight while you are diving.

- We’ve already mentioned the risk of not leaving enough time between dives, make sure you know your timings; check your tables and know how long you need to leave between dives.

- Being cold will also affect your rate of off-gasing.  Make sure you are wearing the right equipment for the conditions you are diving in and don’t allow yourself to get too cold.  When you are cold, the blood vessels close to your skin will constrict to try to reduce the amount of heat you are loosing.  As with the effect of nicotine, the constricted blood vessels will slow the release of nitrogen.

- Nitrogen is 5 times more attracted to fatty tissues than to muscle; so the more fat you have on you, the more likely you are to have a problem with DCI.  Obviously every human has fatty tissues in our bodies, but the idea is to not let it get excessive .  Of course the fitter and healthier you are, the more you will enjoy the physical sport of diving anyway!

- I mentioned the risk of DCI during the female monthly cycle in the article “Diving with a Period“, but to cover it again – there isn’t really enough data to conclude either way whether we are more likely to get DCI at that time of the month than at any other time, so just be careful!  As more women get into diving, we learn more and more about the effect of pressure on the female physiology.

What should I do if I get the Symptoms?!

1.  If it is available, breathe 100% oxygen and stay hydrated by drinking about 1 litre of non-alcoholic drink per hour.
2.  Lie down flat – don’t put the head lower than the body as this may cause the brain to swell.
3.  Arrange transport to the nearest emergency department or hyperbaric chamber.
4.  Keep all your equipment with you so it can be checked for problems that may have caused your DCI.

In Conclusion…

Learn to recognise what causes DCI and what the symptoms are so you can recognise in yourself, or others when you dive.  Think about investing in a dive computer if you haven’t already, they can tell you how long you have at your current dept before you go into a deco-dive, and if you do how long your stops should be.  Of course having a computer is no substitute for not checking your tables and planning your dive, but you it will make your dive more flexible and you can change your plan if you have to.  A computer will also tell you how long you should stay on the surface between dives – but don’t lend your computer to anyone else during your day of dives!

Now go and enjoy your diving!

About the Author: Elyse hopes to be an instructor soon, but until then she will write articles and visit as many different dive destinations in the world as possible. She is currently living in Malta, and loving the new diving on offer.

Introduction

Naturally this little silvery coloured seal lives to around 30 to 35 years, but they are commercially hunted for oil and fur.  They are usually hunted on their breeding grounds where they are at their largest concentrations which leads to the hunt as being the largest slaughter of marine animals in the world.

Where Will I Find Them?

There are 3 populations of this cute little seal; the northwest Atlantic population breeds in the Gulf of St Lawrence and off the coasts of Labrador and Newfoundland and is the biggest population of the three at between 4-6.4 million seals.  The Barents Sea population breeds in the White Sea and contains around 1.2 million seals.  The smallest population at around 300,000 seals is the east Greenland population which breeds near Jan Mayen Island.  They migrate huge distances after breeding- up to 2500km.

What Do They Look Like?

The Harp Seal gets its name from the harp-shaped pattern on the lower back of the adult seal.  Males and females are similar in size and average around 1.5 to 2 metres in length.  They are born with a yellow coat that changes to white after a few days.  After a few weeks they start to lose the white fur to get their adult coat of silvery-grey with irregular dark spots.  At sexual maturity the irregular dark spots start to change into the harp pattern well known on this species.

What Do They Eat?

The Harp Seal has quite a varied diet that includes capelin, polar and arctic cod, herring, halibut, plaice, krill, shrimps and prawns and many others fish and crustaceans.  They routinely dive to depths of 100 meters or more to feed, but they have been observed at depths of around 275 metres.

What is Their Usual Behaviour?

Generally they stay with their own population, and although juveniles have been known to move between populations, very little if any breeding occurs between the 3 populations.

What is Their Conservation Status?

Not listed on the IUCN Red List of Threatened Species.

References

www.marinebio.org

Couldn’t resist a baby picture!!

About the Author: Elyse hopes to be an instructor soon, but until then she will write articles and visit as many different dive destinations in the world as possible. She is currently living in Malta, and loving the new diving on offer.

The sculptures are sited in clear shallow waters to afford easy access by divers, snorkellers and those in glass-bottomed boats. Viewers are invited to discover the beauty of our underwater planet and to appreciate the processes of reef evolution.

About the Author: Elyse hopes to be an instructor soon, but until then she will write articles and visit as many different dive destinations in the world as possible. She is currently living in Malta, and loving the new diving on offer.

And this is why Microsoft hasn’t broken into the Scuba market…thankfully!

Introduction

The Marine Iguana is the only lizard in the world that takes to the sea.

Where Will I Find Them?

I can give you a pretty specific answer on this one because they can only be found in one place:  the Galapagos Islands off the coast of South America.  Populations are found throughout the islands and vary widely in size and colour, although they are considered to be one single species.

You will usually find them on rocky coasts and intertidal zones, although females can be found nesting up to 2km inland.

What Do They Look Like?

Generally they are grey to black in colour, although some may have coppery green or red patches.  The average length of the adult male is around 1.3 metres, while the female is a little smaller at 0.6 metres.  The main differences between the Marine Iguana and Land Iguanas are the short blunt snouts and the shape of the tail, which is squished slightly to help the animal navigate in the water.

What Do They Eat?

Marine Iguanas generally eat marine algae by diving to 2-5 metres during high tide, although they sometimes dive to depths of 20 or more meters.  Usually they only dive for a few minutes at a time, but they have been known to stay below the water for periods of more than half an hour.  Interestingly, the Marine Iguana must warm it’s body to around 36 degrees C before it eats by lying in the sun for long periods of time because when it dives in the water, it can lose as much as 10 degrees C in body heat.

What is Their Usual Behaviour?

They spend a lot of time sunbathing – lazy bums.

What is Their Conservation Status?

Marine Iguanas are listed as Vulnerable on the IUCN Red List of Threatened Species because:

“The marine iguana Amblyrhynchus cristatus is endemic to the Galápagos Islands, Ecuador. The population occurs as ten subpopulations on separate islands in the range. Total extent of occurrence is less than 5,000 km² and area of occupancy is estimated to be less than 500 km². Total population size is unknown, however, El Niño effects are known to cause periodic declines in population (at least 85% mortality). In addition to this, the population is threatened by pollution (e.g., oil spills) and predation by exotic species on the islands.”

References

www.marinebio.org

Is it just me, or does this one look like it it smiling?!

About the Author: Elyse hopes to be an instructor soon, but until then she will write articles and visit as many different dive destinations in the world as possible. She is currently living in Malta, and loving the new diving on offer.

Wetsuits are usually made of neoprene, which has loads of little bubbles of nitrogen trapped in the material.  It is these bubbles that give the suit thermal insulation, but also give the suit positive buoyancy, or in other words; it floats.

Semi-dry suits are just wetsuits with seals at the ankles, wrists and neck, which helps prevent the water escaping from your wetsuit once your body has warmed it up!  If you are buying a new wetsuit, I would advise finding a semi-dry suit as this will keep you more insulated than a normal wetsuit.

The thicker the wetsuit, the more positively buoyant you will be, so bear that in mind if you dive with a thicker suit.  You might need to add some extra weight to counter the extra buoyancy, but also remember that as you go deeper, gases compress, so your suit will lose some of it’s buoyancy and thermal properties.

Wetsuits need to be quite snug in order to work effectively, so although it would be tempting to go a size bigger in order to make it easier to get on, make sure there aren’t too many “baggy bits” – you will just get cold.  You’ll know when you get the right size for you as you will have found the balance between being not too difficult to get on, but still quite snug around most body parts.

I would highly recommend finding a big dive shop or water sports shop that has plenty of choice of wetsuits, try different brands and different sizes – and don’t be afraid to ask the guys in the shop for help.  I bought mine off the internet, and although I was incredibly lucky getting the suit I did because it fits so well, it wasn’t actually the suit I ordered!  First time they sent me the wrong size, then I sent it back asking for the right size, and they said they didn’t have one left in stock – but they did have another one in my size.  It was a slightly more expensive one that they were planning on replacing mine with – bonus!!  I was lucky – but next time I will definitely go to a shop!

A little tip for getting into wetsuits a little easier is to use talcum powder – sprinkle some on the wrists and ankles and your skin will just glide through!  Of course this only works if the suit isn’t wet!!  Another tip I’ve heard that might benefit the ladies more than gents (well the gents can try it if you want…) is to put a pair of pop socks on before slipping into your wetsuit.  Not personally tried it, but might be worth a try!

Right, so I think we’ve covered everything of importance regarding wetsuits, probably not a huge amount there that was completely foreign to you…but what about dry suits?

There are two types of drysuit, Neoprene drysuit and Membrane drysuit.  You can see from the pictures below how they differ:

So you can see here that the neoprene drysuit has a layout very similar to the neoprene wetsuit, in that there is 1 layer of foam neoprene as protection.  This big difference is that with the wetsuit, it keeps a layer of water next to your body.  In a drysuit, the neoprene is waterproof, so instead a layer of air is next to your body.  The drysuit will have waterproof seals on the  wrists and neck to stop the water getting in, and most drysuits have built in boots.

The membrane drysuit works in a slightly different way.  For insulation, you use a thermal under-suit, or just normal clothes – any tracksuit – or depending on the water temperature just a T-shirt and trousers will be fine!  The membrane layer acts only as the waterproof layer, to stop the water getting in.  Obviously on the rare occasion the water does get in – you will probably want to get out the water ASAP, because you will have lost all your thermal protection!

The biggest thing though, when it comes to diving in a drysuit, compared with a wetsuit, is the extra bag of air you are swimming around with.  As we know, the more air in the suit, the more positively buoyant you are, so you need to take that into account when you first dive with a drysuit.  The other thing is making sure there is some air in your suit at the surface, or that you put some in as you go down because the air that is in there will compress and can cause pinching.

It is a bit of a skill to dive with a drysuit, not difficult to acquire, but it is definitely worth getting an instructor, or someone who has dived with drysuits a lot to talk you through what to expect and to give you tips etc.

When it comes to buying a drysuit – again there is no better way that getting people’s opinions – instructor, club members or the guys in the shop – and making your own decision.  If you can try one before you buy, then great – but that isn’t possible for everyone – so you will just have to make the most informed decision you can!

Have fun!

About the Author: Elyse hopes to be an instructor soon, but until then she will write articles and visit as many different dive destinations in the world as possible. She is currently living in Malta, and loving the new diving on offer.