Scuba Cat Diving has been offering the Nitrox Enriched Air Specialty since ‘s introduction of the course in 1996. Once considered to be dangerous, it now is widely accepted and very accessible. Diving with Nitrox Enriched Air allows us to safely extend our bottom times and after all, time underwater is what it’s all about!

Since its introduction in recreational diving 1985, Nitrox Enriched air has slowly changed from being controversial to widely accepted. It is now our most popular Specialty Program and all our Daytrip boats are equipped with Oxygen Clean Compressors, which enables us to make Enriched Air available to all Nitrox certified customers.

Diving with Nitrox Enriched Air is most beneficial on dives between 18 and 30 meters. The reduced Nitrogen in the breathing gas means less Nitrogen loading and thus longer dive times.

What is Nitrox?

The air we breathe every day typically consists out of 78% Nitrogen, 21% Oxygen and 1% other gasses. In simple terms, Nitrox Enriched Air in Scuba Diving is any breathing max with an oxygen percentage exceeding 21%. The most popular mixes are EANx 32 (with 32% oxygen) and EANx 36. For recreational diving, breathing gases enriched to 40% oxygen are acceptable and up to 60% with Semi Closed Rebreathers.

Most scuba equipment, including regulators, BCD’s and dive computers are compatible with Nitrox Enriched Air up to 40% when they come from the factory, however you should check the manufacturer’s guidelines.

The normal air we use in scuba diving mainly consists out of Nitrogen (approx. 79%) and Oxygen (approx 21%)*.  Dive tables and computers are based on calculation of theoretical Nitrogen loading. This loading is expressed in Foot Sea Water (fsw), which is directly related to the Partial Pressure of Nitrogen. So, as most divers already know, the nitrogen loading is based on the depth of the dive and the amount of time we spend underwater. Besides these two elements, the third factor that determines our nitrogen loading is the percentage of Nitrogen in the gas we breathe.

In Scuba Diving, Enriched Air Nitrox is any gas mix with more than 21% oxygen. Our body doesn’t use the extra oxygen in the mix, but we do benefit from the reduced Nitrogen. The reduced nitrogen will reduce the partial pressure of nitrogen when we dive and reduce the nitrogen loading, thus extending our bottom time.

Nitrox Enriched air was first introduced as a recreational breathing gas in 1985, which caused major controversy among Scuba Diving experts. It took another 11 years before it became widely accepted with ‘s support of Nitrox Enriched Air as a recreational breathing gas and its introduction of Educational Material and the Nitrox Enriched Air Speciality course in 1996.

Most dive centres have Nitrox Enriched Air available and some boats have Nitrox available onboard.

Scuba Cat’s MV Scuba Adventure, includes several free Nitrox fills on every trip to allow longer dive times. MV Scuba Fun and MV Scuba Cat both have the facility for Nitrox on board meaning that you can take your Enriched Air Diver Specialty during your diving with us no matter which boat you are on. The course is available as a Elearning course, so you can complete the theory from your own home and enjoy the diving on your vacation.

A Surface Marker Buoy, also known as an SMB or safety sausage is an essential piece of kit for the safety conscious diver.

There are several types of surface marker buoys on the market including the open ended and self-sealing.  Scuba Cat has for several years, stocked a range from the Company “Surface Marker”. Udo Hartig, a diver himself, for optimum visibility, durability and ease of use, has designed this particular range.  It is a range that has proved popular amongst professionals and recreational divers.

"Surface marker"

An SMB is highly recommended in areas where there is boat traffic. The deployment signals to the boat Captain that there are divers completing a safety stop (5metres for 3 minutes) and are about to surface.  Deployment will also aid divers as it can be used as a reference to maintain the correct depth whilst on the safety stop.  An SMB is also essential when drift diving as it enables the boat crew to track the divers in a current.  Should the diver surface away from the boat the use of an SMB will minimize the wait on the surface, particularly in poor conditions such as high waves and poor light conditions. After all, it is so much easier to see a brightly coloured SMB at distance as opposed to a small head in a large ocean!!

Surface Marker have produced two open ended SMB’s that are compact and come complete with a carry pouch that can easily be attached to the BCD. The SMB’s are made from very durable 210D Nylon and are dual coloured, orange one side and neon yellow on the other. This is the best colour combination for a recreational diver. The orange is bright in strong sunlight and significant glare, whereas the neon yellow is excellent for diminishing light conditions. They also have “Diver Below” written in bold letters. The open-ended SMB’s come in two sizes 145cm and 175cm. The latter is a deluxe model and also has a reflective strip, which increases the visibility of the diver.

"Surface Marker"

The one component that sets these buoys apart from other products on the market is the innovative Webbing Deployment System in also known as WDS. This system is simple to use and minimizes risk of entanglement, which is common when SMB’s are used with string. The webbing system folds neatly and is secured with a small bungee cord. As the SMB goes to the surface the webbing unravels easily and it can be effortlessly gathered on ascent.  This particular system eliminates the use of a reel, which can be daunting for some divers. It is definitely a simplistic system that is proven to work. The ideal depth to release the SMB is at 5.5m, which is ideal for the safety stop. The diver can easily maintain contact with the webbing by using the stainless steel thumb ring. This can easily be released should the need arise.

The Surface Marker Pro is a self-sealing SMB, which is commonly used by professionals and technical divers. These buoys are designed to be inflated at depth. The self-sealing internal baffle ensures that the SMB remains fully inflated on the surface. Self-sealing SMBs are fitted with an over pressure release valve, which allows expanding air to escape as it ascends. This particular SMB comes in three colour combinations that cover all requirements. Technical divers on ascent and decompression stops normally use the orange. This colour signifies that all is well. However, should a problem arise then a technical diver will deploy neon yellow which indicates to the surface support that a problem has arisen and that maybe immediate assistance is required. It is also possible to attach a diver’s slate to the SMB, so communication with the surface is possible.   Instructors tend to favour the dual coloured SMB, which offers optimum visibility in all surface conditions. The range of self sealing SMBs are also furnished with the highly visible SOLAS tape and an attachment for strobes or a cyalume stick.

It is possible to encounter problems when deploying an SMB.  One problem that may arise is a jamming reel when using a self-sealing SMB, which does not have the WDS system.  It helps to have a simple reel or use a finger reel that will not jam.  Surface Marker has finger reels available that will fit snugly into the carry pouch of the SMB, which reduces the bulk of equipment.  The finger reels come complete with 30m of line, a stainless steel double ended snap hook and a thermoplastic spool for durability. When using any reel system be mindful of the possibility of entanglement and do not attach the reel to diver. If the SMB is dragged for any reason and you are attached then a rapid ascent may result.

"Finger Spool"

When inflating the SMB it is recommended to keep your regulator in your mouth at all times. If you use the primary air source and problems enfold then it is difficult to resolve them. It is important to remain calm and in control. When inflating the SMB it is advisable to use one of two methods. Firstly, the alternative air source can be held under the open end of the buoy and air can be purged inside. However, be mindful that in cold conditions this may result in a free flow. The second method of inflation is open the buoy above the primary demand valve and exhale allowing the air to enter the SMB.

"Thank you"

Surface Marker also supply 25kg and 65kg lift bags. Scuba Cat has been loaned several by Surface Marker for use on the clean-up events that are held at least bi-annually. The main events are Earth Day and International Clean-Up. The latter event is a extended to a weekend accommodating participants on one of the two liveaboards, MV Scuba Cat and MV Scuba Adventure.  The loan of the lift bags has proved invaluable over the years for lifting various objects varying in size. They are also ideal for marking objects that need lifting on subsequent dives. The lift bags are available in orange and neon yellow and are made from the very durable 210D Nylon, the same material as the SMB’s. The bags are furnished with a top handle and dump valve, which allows the diver to make a controlled ascent rate when surfacing. They also have a strong stainless steel ring for attaching rope. The self-sealing system ensures that the lift bag will remain inflated on the surface.

One of the latest products is the signal mirror. This is compact and can easily be slipped into a BCD pocket. Should you find yourself in the daunting position of not being seen by a boat the mirror comes into it’s own. The unique feature of the mirror is that it can be directed at a specific target and can be visible for 32km!!!!! You could even signal to a passing aircraft…

"Signal Mirror"

Signalling devices are a must. If you would like to become more confident deploying an SMB then why not do the Distinctive SMB Deployment Speciality or The Drift Diver Speciality.

Search and Recovery is the ideal Speciality if you would like to learn how to use lift bags.

It is almost guaranteed that when you dive on coral reef from Phuket, Thailand  you will encounter the vibrant coloured Parrotfish.

"Hello"

Parrotfish are abundant and range in size from 30cm to 1.4m. How did this family of fish (Scaridae) derive the name Parrot?  Just have a look at the dentition; numerous teeth are fused to form a beak, much like a parrot’s beak. The teeth aid feeding activity as the Parrotfish eats algae from coral and rocky substrates, often leaving teeth scars behind. Parrot fish are considered to be herbivores, but they are not necessarily vegetarians as the large Green hump head parrot fish is known to include coral polyps in it’s diet.  The feeding activity of the parrotfish is important in the production and distribution of coral sands. If you watch Parrot fish excrete you will notice that it is fine white sand. This has been responsible for helping create small islands and beaches worldwide. It is estimated that a Parrotfish is capable of producing 90kg of sand per year!!! How is this possible? The beak takes the coral or rock and then it is pulverised by a set of grinding teeth located in front of the oesophagus. The digestion procedure gives sand as the end product. The Parrotfish eating habits are paramount in controlling algae growth resulting in a thriving reef. Another little fact about the Parrotfish is that their teeth continuously grow and by chomping on rock keeps the growth in check!!

"Parrotfish"

Parrotfish are known to reproduce throughout the year, but more predominantly during the summer months. This family are generally sequential hermaphrodites starting their life as female then change to male. However, one exception to this is the Marbled Parrot fish, which is known not to change sex.  Parrotfish are pelagic spawner’s. This means that the eggs are spawned in mid water and are buoyant, the eggs float freely eventually resting on the coral where they stay until they hatch. The Parrotfish larvae appear not to have any characteristic facial features or colouration for the first few days after hatching.

Juveniles have a different colour pattern to the adults and it is possible for juveniles of some tropical species are capable of changing colour temporarily to mimic other species. It is not unusual to see “flocks” of juveniles swimming en mass over a coral reef. Often they are dark in colour and occasionally an individual can be seen changing it’s pigmentation.

The Parrotfish are unique in that they are able to secrete a mucus cocoon from a gland near the mouth. This provides protection from nocturnal predators. Also, it can act as an early warning system allowing the fish to flee if the protective cocoon is disturbed. The Parrotfish is only able to produce this cocoon once during the night, so it is important when night diving not to disturb the sleeping Parrot fish.

The Parrotfish skin is covered in a mucus substance that is believed to have antioxidant properties that can help repair any damage that may occur to the skin. Also, the mucus has anti parasitic properties, repelling potential parasites.

There are approximately 80 identified species of Parrot fish, which are abundant in and around coral reefs worldwide. They are a close relative to the Wrasse family, but there are some distinctive features that help with identification. When trying to identify a parrotfish look for an elongated, blunt head. The body of the fish is deep and brightly coloured with defined large scales and finally look for the unique bird like beak.

"Hump Head Parrotfish"

If you would like to know more about the identification of species why not sign up for on a Aware – Fish Identification Specialty Course, which will enhance your knowledge and highlight the key things to look for.

Initially when people start diving on reefs they are appreciative of the beauty of the corals and marine life that inhabit the area. However, once you become familiar with the reef the finer details of the eco-system and relationships of the organisms become more apparent.

"The reef"

There are many different types of relationships that we see on every dive probably without even realizing it. One of the most famous relationships is the symbiotic one between Clownfish and the Anemone. The clownfish has a protective mucus on the body, which enables it to shelter in the tentacles of the anemone without being stung. The presence of the clownfish helps to defend the anemone, particularly from polyp eating fish. The Clownfish, also known as Anemone fish, of which there are varies species, keep the anemone clean by eating morsels that are left over from fish as well as eating parasitic critters and algae, for example, copepods, isopods and zooplankton. They also aid water circulation within the anemone as it swims amongst the tentacles. The fecal matter from the Clownfish acts as nutrients for the host anemone.

"Anemone"

The Anemone fish is an all year breeder. The nest for the eggs is found very close to the host anemone on the reef in nooks and crannies, so the eggs are protected from predators. At any one time there are between 100 and 1000 eggs laid and external fertilization takes place. Spawning normally occurs on a full moon. It is the role of the male to protect the eggs, which hatch within 4 to 5 days often 2 hours after dusk.

"Nemo"

The anemone can host many fish. If multiple fish are present then there is a distinct hierarchy with the dominant fish being the largest and most aggressive female. Should there be a reason this fish leaves the anemone, for example, death, then the largest male will turn into a female. Clownfish are hermaphrodites and are born male. Within a multiple colony there is only one breeding pair.

"Hello"

The main predator of the clownfish unfortunately is man. They are harvested for the aquarium trade.  A clownfish in the wild can live between 6 and 10 years, but this is reduced once the fish is placed in captivity. One of the most common mistakes is placing the fish in the wrong anemone. They are only ten anemones that can accommodate the fish. So, it really beneficial for the fish to stay in the natural environment.

"Look at me!"

Anemone fish can be found in the warmer waters of the following regions NW Australia, SE Asia, Japan, Pacific, and Indo Malaysia region. Surprisingly, they are not found in the Caribbean.  There are varies species of clownfish include Clarkson, Skunk, Tomato, Saddle, Yellow and False to name a few.

"Skunk Anemone Fish"

If you would like to expand your knowledge of marine relationships then why not take the Underwater Naturalist Specialty course.

Night diving is something that divers seem to love or hate, just like marmite!!! Night diving offers an experience that is completely different to day diving.  First and foremost it’s dark and a torch is a must. The torch gives light, but it is concentrated, so you only get to see what is in the beam.  If anything, this lets you focus more on the marine life that is highlighted.

Diving in the Dark

It’s incredible to see the difference in life. The day shift is going to bed and the night shift is coming out. You will find fish tucking themselves into cracks in the rocks for protection against the nocturnal predators. Parrotfish, for example, can be seen with a protective mucus bubble surrounding them. This can only be produced once during the night, so it is important not to disturb the fish when shining the light.

If you should be lucky enough to see a turtle sleeping then just say “hi” and “goodbye”. When a turtle sleeps it lowers it’s heart rate, so that it is able to sleep without having to go to the surface for air. If the turtle is disturbed then it may become disorientated and doesn’t know which way up is.

Also, the shock of being woken could induce a heart attack, which is not a good scenario!! So it is important to show respect for the sleeping creatures and not shine the light directly into their eyes. Can you imagine what it is like when you are fast asleep and someone walks into your bedroom and puts the light on?

Predators, like moray eels looking for a midnight feast can often be seen free swimming at night. They look amazing as their undulating bodies move across the reef. During the day morays tend to hide in rocks, so it is hard to appreciate their size and beauty. Barracudas are really quiet cheeky and often use the torch light to locate their next meal. So, if you don’t want to be responsible for fish becoming a meal then don’t shine you torch on it!

The night shift includes crabs in all different shapes and sizes. Have a look in finger corals to find small porcelain crabs, look under coral blocks to find the larger ones. Decorator crabs, with their legs covered in camouflage are difficult to find as they look like the coral surrounding them.  Sponge crabs are amusing to watch as they try and merge with the rocks, so they can’t be seen.

Lobsters can be seen walking around the reef and are very good rock climbers and they don’t even need crampons!! It’s amazing how quick these cumbersome creatures can move. Look in coral blocks and you will be able to see red dots, like little rubies. These are the eyes of shrimps, many different species in all shapes and sizes.  Again, a lovely sight as they dance around.

There is just so much to see on a night dive, but the key is to move slowly and concentrate on a small area. Always take the opportunity to blank out your torch by placing it against your body (don’t switch it off) and wave your arms around. If the Bioluminescence are in full swing then you will create a magical moment as they sparkle around you.

Night diving is an experience not to be missed ………………………

Why leave it all to chance……….. enjoy your first night dive experiences with a Professional, so you can enjoy the wonders anytime day or night.