Creature Feature: Wobbegong (or Carpet Shark)

Wobbegong is the common name given to the 12 species of carpet sharks in the family Orectolobidae. They are found in shallow temperate and tropical waters of the western Pacific Ocean and eastern Indian Ocean, chiefly around Australia and Indonesia, although one species (the Japanese wobbegong, Orectolobus japonicus) occurs as far north as Japan. The word wobbegong is believed to come from an Australian Aboriginal language, meaning "shaggy beard", referring to the growths around the mouth of the shark of the western Pacific.

Wobbegongs are bottom-dwelling sharks and spend much of their time resting on the sea floor. Wobbegongs are well camouflaged with a symmetrical pattern of bold markings which resembles a carpet, hence the name "carpet shark". The camouflage is improved by the presence of small whiskers lobes^[1] surrounding the wobbegong's jaw, which it uses to entice and catch fish. Wobbegongs are ambush predators. They use their relative invisibility to hide among rocks and catch smaller fish which swim too close. Most species have a maximum length of 4 feet or less, but the largest, the spotted wobbegong, Orectolobus maculatus, and banded wobbegong, O. halei, reach about nearly 10 feet in length.

Wobbegongs are generally not dangerous unless they are provoked. They have been known to bite people who accidentally step on them in shallow water; they may also bite scuba divers or snorkellers who poke or touch them, or who block their escape route. Wobbegongs are very flexible and can easily bite a hand that is holding on to their tail.^[2]  They have many small but sharp teeth. Their bite can be severe, even through a wetsuit.  Wobbegongs have been known to hang on once they have inflicted their bite and can be very difficult to remove.^[3] To avoid being bitten, divers should avoid contact.

Spotted wobbegong, Orectolobus maculatus,

showing the camouflage pattern and skin flaps

typical of wobbegongs.

Facts About Wobbegong Sharks

They are so flat in their shape that they look like the part of the sea floor.

They move slowly in water.

Diet: lobster, crab & octopus

They normally are not dangerous, but there have been 23 confirmed attacks.

Normally, it is not an aggressive creature.
Attacks only when provoked.

The females of these species can deliver around 37 young at a time.

^[1]^ "Wobbegongs - five species encountered in Queensland". Queensland Primary Industries and Fisheries. 2009-03-02. http://www.dpi.qld.gov.au/cps/rde/dpi/hs.xsl/28_12484_ENA_HTML.htm. Retrieved 2009-06-14.

^[2]^ Kuiter, Rudie (1999). Guide to Sea Fishes of Australia (amended ed.). New Holland Publishers (Aust.) Pty Ltd. p. 12. ISBN 1-86436-091-7.

^[3]^ "Shark sinks its teeth in for the long haul". The Sydney Morning Herald. 2004-02-12. http://www.smh.com.au/articles/2004/02/11/1076388440368.html. Retrieved 2006-06-14.

Chris' Dive Experiences: The Mythical So Cal Green Sea Turtle "Marine Room", La Jolla

Photo Courtesy of Virginia Hatter

Not all So Cal divers know that our temperate waters contain a couple of iconic animals. Animals that would normally conjure up thoughts of the warm, clear, tropical waters of the Caribbean and South Pacific. But there are a handful of lucky divers that have born witness to both Pacific seahorses and green sea turtles while diving here in San Diego. Lesley and I had heard a few stories over our 4 years of diving of divers seeing a green sea turtle, including Rod & Liz while diving at the Marine Room, but sightings remained extremely rare.

Our local dive site, The Marine Room, is named after the Marine Room restaurant sitting right on the beach, overlooking the ocean in La Jolla. Conditions at this site often vary more than other sites nearby primarily due to the coastal cliffs that surround it. During high tide, or if the surf is up a little, you’ll have waves not only rolling directly in toward the shore, but also waves cutting across as they bounce off the cliffs making it look like a big washing machine. The Marine Room offers two distinct dive options for a diver. You can kick out and to the left and enjoy rocky reefs with lots of life similar to diving La Jolla Cove, or you can kick straight out and catch the beginning of the same walls that you dive at La Jolla Shores.

Lesley and I awoke early on Friday the 13th to meet a group for a dive at Marine Room. When we arrived, we were greeted with clear skies, no surf and picture perfect surface conditions. We kicked out toward the rocky reefs on the left side of the dive site, enjoying the normal chit chat and joking that we had come to enjoy from this group of divers. Previously, Lesley and I had dove the Marine Room, but had always kicked out to dive the walls instead of the reef, so we were excited to see a new area and compare the two. We dropped down and kicked toward the kelp and reefs and I was amazed at how much life there was to see. We enjoyed loads of Calico bass, big and small, coming right up to our mask to check us out. Under almost all the rocky overhangs we found lobster peeking out at us waving their antennae. Spanish shawl nudibranchs and pipefish were found in and on the blades of eel grass. As we continued on we had a big school of jack smelt swim right in front of us.

Photo Courtesy of Virginia Hatter

At this point all of us were having a great dive stuffed with lots of cool sitings. I decided to head for a clump of kelp in front of me, passing just to the left of a huge patch of eel grass, when I heard Lesley’s quacker (which sounds like a duck call underwater) going off right behind me. I turned around to see Lesley frantically waving her hands around telling me to get over and look at something. As I made my way over to the eel grass patch that I just passed, I saw from a distance what I thought was a big halibut or electric eel sitting in the grass. As I got a few feet closer to Lesley I couldn’t believe what she had found, the mythical green sea turtle!

I think all of us were initially stunned by seeing the turtle sitting in our cold green water chomping on eel grass, instead of warm clear water chomping on the green growth found on coral as we were accustomed to. Unlike other green sea turtles that I have seen in warmer waters with their beautiful shiny shells, this one had a thick layer of sand and dirt with a group of barnacles growing on its shell. This certainly worked in its favor as camouflage in the So Cal environment.

We each moved in closer, one at a time, for a good look at the turtle that continued to sit there eating and looking at us. We stayed with the turtle for a good 5 minutes, with divers taking pictures and video before he tired of us and moved on his way. As I looked around with a smile I could tell that this special moment wasn’t lost on this group of experienced divers with high fives and dancing taking place around me.

Seeing special things like this brings a smile to a diver's face and renews the saying, "you never know what you will see”. The pictures you see here are the very pictures taken that day at the Marine Room.

Tips for Basic Regulator Maintenance

Today let’s focus on regulator care. I have seen many regulators come in for service that just make my skin crawl. I just don’t understand how some people do not take care of equipment on which they depend so completely while diving. Regulators with corrosion in the first stage can be avoided with regular care. The gritty sand which gets into your second stage and seems impossible to avoid, especially when diving La Jolla Shores, can also be removed with regular care.

I will give you some tips on how to take care of your life-preserving regulators. I would also like to dispel some of the misunderstandings on the auto closure devices (ACD) on the Aqua Lung regulators and a tip on a relatively unknown fact about the Atomic regulators.

We all know we need to test our equipment before we use it diving. For those of you who have taken a class at The Dive Shack, hopefully you remember when testing a regulator you need to breathe on it. Pushing the purge valve on the regulator to ensure it is working, in fact does nothing to test its proper functioning. When you push the purge valve, yes you make air come out, but that does not test the integrity of the diaphragm. When the reg is in your mouth and you inhale, the diaphragm collapses onto the purge valve which opens the regulator to allow air to flow. Testing your reg by actually breathing on it not only checks the valve, but also the condition of the diaphragm, and the way the regulator will be operating during the dive.

When putting your gear together for a dive, here is a helpful tip to care for your reg. Before you put your regulator onto your tank valve, blow a puff of air out of the tank. This will clean out the tank valve, which will ensure no water or other debris gets into your regulator.

Now let’s talk about post-dive care.

After your dive, when you take the reg off the tank valve, make sure the dust cap is clean and dry before you put it back into place and secure it with the yoke screw. Just remember you do not need to crush the dust cover, finger tight always works here.

Now let’s talk about that ACD (auto closure device) on your Aqualung regulator. Some people think that because of the ACD located on your first stage, the dust cap is no longer needed. This is not true. You should still use the cap, just don’t install it to where you are pushing in on the ACD causing it to open. The reason for using the cap is, even though water is not going to get into the regulator, it will collect in the face of the ACD and if you put the reg onto the tank you are now allowing water to drip into your first stage which leads to corrosion.

When rinsing your regs, slosh your second stage around in fresh water and move any parts that are movable (i.e. adjustment knobs). It’s not a bad idea to use a cleaner like the one sold at TDS, it helps dissolve salts and chlorine. Rinsing will also help get the sand out. Some people like to soak their regs, this is really not needed, and in fact if the dust cover is not on properly water may enter the hose and trickle back into the first stage. After you rinse the reg let it hang to dry. You should make sure to drain any water that collects inside the second stages and in the ambient chamber of the first stage.

Atomic regulators are designed with a small leaf spring in the second stage. The purpose of this spring is to take the pressure off the rubber seat in the inlet valve when there is no air pressure coming down the hose. The up side to this leaf spring is it takes some of the wear away allowing a longer life for your reg. However, the down side to the leaf spring design is, even with the dust cap on, water can get into the hose from the second stage. This is why you should never soak an Atomic Regulator.

For storage, keep your reg in a cool, dry place; never in direct sunlight for an extended amount of time. Some people like to spray their gear with conditioner. It is fine to be one of those people, just make sure you use a food grade silicone (sold at The Dive Shack) and never, ever use an oil. Spray some silicone onto a dry rag and wipe it on the hoses, mouthpiece, and even the reg body if you like. This will keep it looking shiny and new. But remember don’t spray it into the reg; just wipe it on the outside with a clean cloth. You want to avoid getting any silicone on the diaphragm.

The last thing to keep in mind when caring for your regulator is to take your gear in annually to TDS for service to make sure it is clean inside, and that it is working within factory settings. Also, during the service overhaul we freshen your regulator by changing out all its o-rings and seats.

So in closing, to keep me happy and you safe during your dives, make sure you follow the proper assembly and disassembly of the gear. Test your equipment the way it is meant to be used. Clean your equipment thoroughly while ensuring you take care not to allow water into the first stage or the hoses. Store your equipment someplace where it will not get dried out. And finally, make sure your gear is serviced regularly according to the manufacturer’s recommendations.

If you ever have any questions regarding the care and maintenance of your gear, read the user’s manual and or give us a visit at The Dive Shack.

Enjoy your regulator and happy diving.

Humility Expounded

There have been some very significant Rods in my life. Many of you know Rod Tuttle, owner of The Dive Shack. Rod Deutschmann is probably a new character to you though. Rod D. (this could get confusing, huh?) and his wife Robin are amazing photographers and the instructor staff for San Diego In Focus Learning Center (http://www.iflcsandiego.com/). From the beginning my classes with them were mind blowing. They were able to simplify all of the confusing terms and settings for manual photography into simple concepts. They then had you apply these simple concepts to your own camera, in class. Each class was spent outdoors moving all over and shooting. You would concentrate on changing the settings until you achieved the image that you had pictured in your mind. Classes were fun! I learned so much each session, and was excited to come home and apply what I had learned. I was willing to shoot a piece of gravel in the driveway just to perfect these concepts.

Pinhole Camera Image Courtesy of Wikipedia

One of the first things that Rod D. taught me was that all a camera consists of is a box with a hole. In photography, we are just using the camera to capture light. We control the hole or aperture - how large it is and how long it is open - to make our images. That is it! A pinhole camera is the most simple of cameras, and perfectly illustrates the "box with a hole" concept.

Rod D. then simplified things even further for us. He said controlling a camera is as easy as filling a glass with water. The glass in this illustration is your camera sensor. You choose the size of the glass by choosing your ISO. The higher the ISO,1600 for example, the smaller the glass is and the faster it fills. A lower ISO like 100 fills more slowly.

It's your choice

The aperture would correlate with the faucet you are using to fill your glass. You choose how long it is on by choosing your shutter speed which shows up as a number. On my camera that ranges from 60" (60 seconds) to 4000 (1/4000th of a second). You also choose how fast the water is coming out of the faucet by how high you turn it on. On your camera, that correlates with your aperture or f-stop. The lower the f-stop is the bigger your aperture is. A bigger aperture lets light in more quickly so it fills your sensor up faster.

Take some time to find each of these settings on your camera. Get comfortable changing them all. Once you have done this, you have started down the path of taking full control of your images. You are going to love where this path leads you. We will explore each of these settings individually in future posts.

Creature Feature: Cuttlefish



Ngerchong Inside dive site (Palau)
Photo courtesy of Liz Tuttle



Often called the "chameleon of the sea" because of its ability to change the color of its skin at will, the cuttlefish is actually not a fish at all, but really a mollusk. Belonging to the class Cephalopoda (which means head-footed), they are the cousin of the squid, octopus, and nautilus.

The cuttlefish can range in size from 1 inch to 3 feet (and even bigger in the case of the giant Australian cuttlefish which may grow to the size of a small man). It possesses eight sucker-lined arms and two prehensile tentacles (which can be withdrawn into pouches under the eyes) and a sharp, beak-like mouth which allows it to cut open flesh like a pair of scissors, so it can use its tentacles to tear out meat. It hunts during daylight, feeding primarily on small fish, crustaceans and other mollusks.

It moves about in the water by way of a complex propulsion and bouyancy system (much like a submarine). "The cuttlefish propels itself using a series of spurts, drawing water into a compression chamber which it squeezes to jet the water out a funnel under the head. Direction changes can be made by swivelling the nozzle of this funnel, and narrowing the funnel controls speed. Like a submarine, the cuttlefish fills tiny compartments in its cuttlebone with gas to help maintain neutral buoyancy. This helps the cephalopod hover above the ocean floor, because although it has a sophisticated propulsion system its large cuttlebone does not allow it to be overly active, or quick in the water. " [1]

Staying Neutral

Redrawn after Clarkson, E.,
Invertebrate Palaeontology and Evolution,
George Allen and Unwin, London,
1979 (Seventh impression 1984), p.167.

The cuttlefish is a bottom-dweller which often lies in ambush for smaller animals. For this way of life, it needs to keep itself at neutral buoyancy, so that it neither sinks nor rises...in order to be able to operate at varying depths and water densities, cuttlefish need to be able to adjust their overall density so as to always remain ‘neutral’ in the water. The cuttlefish does this by an ingenious mechanism. The bony shell actually has many narrow chambers. If these were all filled with gas, they would give a lift of up to 4% of the animal’s weight. However, they are only part-filled with gas—the darker areas shown are where it is part-filled with liquid. The cuttlefish is able to pump liquid in and out of that section as needed to keep the buoyancy ‘just right’. [1]  

The cuttlefish actually has 3 hearts - one for each set of gills and one for the remaining body. Unlike our own blood which gets its red color from the pigment hemoglobin, the cuttlefish's heart pumps blue-green blood which uses hemocyanin pigment to carry oxygen. Its skin is comprised of 3 layers of color pigment cells called chromatophores. These cells are controlled by the nervous system which signals them to expand or contract at a remarkable speed allowing for the hypnotic transformation of the cuttlefish's coloration and pattern.

"A strange fact about the cuttlefish is that it can adopt the female coloration along one side of the body as well as retain the male coloration on the other side. Male cuttlefish are extremely alert when it comes to the females, especially if she is laying the eggs. The male will guard aggressively over the female and this is when another approaching male will use his ability to have a dual look to access the female and trick the male." [2]



Close-up of a cuttlefish eye
Photo courtesy of Wikipedia



Oddly enough, even though it can put on a spectacular color display, the cuttlefish does not see color. Its w-shaped pupil only perceives polarized light which enhances its perception of contrast. Their retina has two areas of concentrated sensor cells called foveae, one to look forward and one to look more backward. There is no blind spot like we have because the optic nerve is positioned behind the retina. The eye changes focus by reshaping the entire eye, instead of reshaping the lens as in mammals.

Cuttlefish are considered to be highly intelligent, like their cousin the octopus. In fact, they have one of the largest brain-to-body size ratios of all invertebrates. Cuttlefish have ink, like squid and octopuses, which they use as a last resort to help evade predators when their camoflague fails. Their predators include dolphins, sharks, fish, seals, seabirds and other cuttlefish. Their life expectancy is about one to two years.

They are mostly shallow-water animals which inhabit tropical to temperate waters, although they have been know to descend to depths of 2,000 feet. Cuttlefish are generally found along the coasts of east and south Asia, western Europe, the Mediterranean, as well as all coasts of Africa and Australia.

[1] Weston, Paula, ‘Fascinating Cuttlefish', answersingenesis.org, March 1, 1997.

[2] Lad, Kashmira, ‘Cuttlefish Facts', buzzle.com. 

Chris' Dive Experiences: "Blue Corner", Palau, Micronesia (Part 2)

As we approached the dive site, "Blue Corner", our divemaster, Steve, jumped into the water to check the current. I found out he did this in order to check the direction of the current so that we could start our dive along the wall at the right spot and easily drift to the corner of the reef.

After a thorough dive site briefing which included a quick lesson on how to use our reef hooks, we back-rolled off the boat and descended onto a nice wall. As we drifted along this wall, enjoying visibility that was around 100 feet, we saw lobster, turtles, large schools of fish, colorful sponges and corals.

Photo Courtesy of Rod Tuttle

As the dive time lengthened the current picked up, pushing us along. Steve signaled that "Blue Corner" was just ahead and we should prepare to use our reef hooks. As I neared the point, the current was ripping, making it easy for me to ascended to the top of the reef. There I turned to face the edge of the wall, quickly securing my hook into the reef, I then inflated my BCD. Hooked in with my BCD inflated allowed me to stay in one spot while I floated in the water above the reef. Without a reef hook, it would have been impossible to stay in one spot because the current was so strong.

Now what makes this one of the top 10 dive sites in the world is the view. Imagine you are floating above a cliff and looking out and down on hawks flying below you and other animals moving around on the ground. Now place yourself underwater. As I looked out into the water column, there were huge schools of barracuda and trevally moving with the current. The next thing I saw was my first shark - a big grey reef shark, and then another and another. The water was just teeming with life moving by us. Everywhere you looked, underwater life was passing right by us as we floated and watched.

Photo Courtesy of Liz Tuttle

Camera strobe lights were firing every few seconds, as divers filled their memory cards with wide angle shots overflowing with life. Out of the corner of my eye I saw something  coming near me. I turned and saw the friendly, HUGE, resident napoleon wrasse that Steve had mentioned in our briefing. He was very curious. He came right up to me and checked me out. I swear he was almost as big as I was.

Too soon Steve our dive master signaled to unhook. We had been at the site for 30 minutes and it was time to go. We unhooked and were pushed by the current away from the edge of the point and into shallower water for our safety stop. Even as we drifted up and away from this top dive site we saw tons and tons of life everywhere we looked.

Back on the boat, divers were hooting and hollering and giving high fives as our boat cruised to our lunch and surface interval destination. The boat neared a couple of the rock islands and turned into a little cove where we saw a picture perfect little sandy beach. As we sat eating our lunch, we talked at length about the fantastic dive we just completed, all the while being the only people enjoying this perfect little island.

This is diving in Palau!

Chris' Dive Experiences: "Blue Corner", Palau, Micronesia (Part 1)

Photo Courtesy of Lesley Alstrand

After an overnight trans-Pacific flight, our plane touched down after midnight in a torrential downpour. Even if we could have kept our eyes open during the bus transfer to the resort, we wouldn’t have been able to see anything through the rain. It was not long before we reached our destination of the beautiful Palau Pacific Resort (often referred to as PPR). After being greeted and checking into our rooms, our heads thankfully hit our plush pillows.

We awoke later that morning to the ringing of the phone. It was Rod (owner of TDS) wanting to know if Lesley and I were ready to go diving. We couldn’t wait!

This was my first time out of the states, and I will never forget my initial feeling as we went to meet up with the rest of the group for breakfast. I was so impressed by the peace and quiet, the scenery of the island, and the beach. It was everything you would imagine when you think of an exotic and tropical location! Now on to the best part - the diving! If the view from the resort was considered beautiful and exotic, the boat rides to the dive sites would be described as absolutely stunning!

Palau is made up of over 200 rock islands. For me, the closest thing that I can compare these islands to are the floating islands in the movie Avatar. Your dive boat speeds in and around these islands on the way to your dives, and if you aren’t careful, you could fill your camera's memory card just on the way to your dive site with the topside scenery. As we neared "Blue Corner", one of the world’s top dive sites, we sped through another great dive site, "German Channel".



Photo Courtesy of Liz Tuttle

"German Channel" was an access channel created by the German military for their ships during World War 2 by dynamiting through a shallow reef. As we approached this channel the first time, all you could hear were ooh’s and aah’s from all the divers on the boat. The water displayed every single hue of blue, green and turquoise you could ever imagine as you cruised along this very shallow to deep dive site. It is just impossible to fully capture the channel's beauty in pictures. This is another one of those things you just have to see for yourself at least once in your life!