Diving then and now - Part 1

by B. N. Sullivan

One of the earliest posts in The Right Blue tells about our training as divers. In the post I mentioned that I first learned to dive in 1970. That's right -- 38 years ago!

Diving has changed a lot since 1970, mostly because of improvements in equipment. We decided it would be fun to review the progression of those changes for our readers. This exercise will take several posts, so bear with me.

To start things off, have a look at the picture at left. That's me, in 1970, when I was a newly minted diver. (No, I wasn't angry -- the sun was in my eyes!)

When we first unearthed this old photo, I had to laugh. That red thing I'm wearing looks like a life vest pilfered from an airliner, but it's not. Known as a 'horse-collar' vest -- for reasons I'm sure are apparent! -- it was used primarily for surface flotation.

Dive gear is very heavy, and can be cumbersome. Swimming on the surface with, among other things, a metal tank on your back, and lead weights arrayed around your waist can be incredibly daunting at times. When the flotation vest was inflated, it helped counteract that weighed down feeling, and enabled divers to keep their heads above water while waiting for a boat, or swimming to shore. Those horse-collars were not very comfortable, however.

The vests had little CO2 cartridges inside. The CO2 could be released to rapidly fill the vest in an emergency, but most of the time, we blew the things up by puffing into the little inflator hose. The CO2 cartridges were single-use only, and it was expensive to replace them all the time, so we really did restrict ourselves to using them only when we were struggling or in a jam.

Fortunately those dopey horse-collar vests with the CO2 cartridges are no longer used by sport divers. They've been replaced by buoyancy control devices (BCDs for short), in the form of vests, jackets, or pouches (called 'wings') attached to a harness. These days, BCDs are inflated at the push of a button, with air supplied from the scuba tank through a special low-pressure hose. Divers can and do still use the BCD for flotation on the surface, but they also make use of the device underwater. By adding a little puff of air to the BCD at depth, divers can adjust their buoyancy, compensating for the weight of their gear.

The next thing I spotted in the photo was the tank -- or rather the valve on the tank -- and the regulator. We were using "J-valves" on scuba tanks at that time. There was no such thing as a submersible pressure gauge, so we could not monitor how much air we had left in our tanks once we entered the water. Tanks fitted with "J-valves" had a mechanism that blocked the diver's air supply at a certain (low) pressure level. The valve had a lever on it that the diver could pull to release the remaining air, known as the 'reserve' air. Believe me, that reserve wasn't much, but it would provide a few more breaths -- usually enough to get to the surface (we hoped!).

The regulator in the photo is a single-hose demand flow regulator, which was a pretty sophisticated rig at that time -- compared to, say, a double-hose regulator. Those old double hose regs required the diver to sort of suck the air out of the tank! We still use single-hose demand flow regulators, but the ones we have now have numerous ports on the first stage -- the part that attaches to the tank valve. To those ports we attach various pieces of gear, including power inflators for our BCDs, submersible digital pressure gauges so that we can continuously monitor our air supply, and one or more extra second stages -- the part of the regulator that has the mouthpiece -- to facilitate sharing air with a dive partner if need be.

Note the clunky old analog depth gauge that I'm wearing on my wrist in that photo. Key pieces of dive management gear in those days were the depth gauge and the dive watch or timer. Those relics now have been replaced by digital electronic decompression computers which continuously sense depth, keep track of elapsed time, and recompute every few seconds how long we can safely remain at a given depth -- as well as many other bits of information that I won't go into until another time.

Even our wetsuits have changed. The one I'm wearing in the photo had no lining and was extremely difficult to get into -- just rubber against skin. Everyone carried a box of cornstarch or a can of talc in their gear bags then. We applied it liberally before donning our suits, but it made quite a sticky mess, and often didn't help the process all that much. These days our suits are lined with Polartec or other soft materials that make them as easy to slip into as a pair of jeans.

Ahh, the good old days!

Wordless Wednesday #20 - Happy Valentine's Day

[Click photo for larger view.]

My previous Wordless Wednesday posts.

Wordless Wednesday home page.

Do Not Disturb: Sleeping Fish

by B. N. Sullivan

We all need our rest, and so do the fish in the sea. Fish don't sleep exactly like we do. For one thing, they don't have eyelids, so they can't close their eyes. Nevertheless, most fish we know about do take their rest for some part of the day or night, on a fairly regular schedule.

Some fish -- especially pelagics -- hunt at night, and rest during the day. Most reef fish are very busy during the day, so they rest at night. They stop moving about and enter a sleep-like state. While they are resting, they are generally sluggish and not very alert. We try our best not to startle them or disturb their rest during our night dives.

Some fish lie on the bottom to rest, while others hang motionless in the water column. Small fish, in particular, often hide while they are in their somnolent state so that their predators can't find them and eat them. Staying out in the open to rest definitely would give their predators an unfair advantage. In the first photo on this page, a tiny fish called a Pygmy Toby (Canthigaster pygmaea) has snuggled itself amongst corals and sponges to "sleep."

In the second photo, a small fish has chosen to settle into a stand of fire coral to takes its rest. We're not sure what species of fish this is, although the shape suggests that it is some kind of Damselfish.

In addition to hiding, another strategy that many fish use to discourage predation while they rest is to change color. Their color may darken or become mottled during periods of rest, helping them to blend in with their environmental background.

Some species of Parrotfish hide themselves by spinning a slimy cocoon around themselves. The mucous cocoon is secreted from an organ in the head of the Parrotfish. (Sorry, I don't have a photo handy.) It is thought that, in addition to hiding the fish, the cocoon also masks the animals' scent, making it harder for predators to locate them.

Both of the images on this page were captured during night dives in the Red Sea, along the coast of the Sinai Peninsula.

The Leaf Scorpionfish

by B. N. Sullivan

Meet the Leaf Scorpionfish (Taenianotus triacanthus). This little fishie is one of the smallest members of the Scorpionfish family. This fish family, Scorpaenidae, gets its name from the venomous spines that most of the fishes in the family bear. (Regular readers of The Right Blue will recall our posts about the Turkeyfish/Lionfish -- another member of the same family.)

The Leaf Scorpionfish gets its name from its appearance. When you see one in its natural environment, it really does look like a leaf, rather than a fish -- until you spot its eye! Members of the Scorpaenidae family tend to be "lie-and-wait" predators. They tend to stay still in one spot until their prey happens past, and then they pounce very suddenly. They rely on camouflage so that they can blend into their surroundings, making it easier for them to surprise their prey.

The bodies of Leaf Scorpionfish are laterally very flat, which certainly contributes to their leaf-like appearance. This little fish not only looks very much like a leaf, it also behaves like a leaf! If you stay still and watch one for awhile, you'll see the little guy rock back and forth every once in awhile, just as a leaf or a stray piece of seaweed would do if it had settled on the reef. This, too, seems calculated to trick potential prey.

The Leaf Scorpionfish is a small species -- maximum length is about four inches (10 cm). They come in lots of colors -- yellow, reddish, purple, brown, pale pink, and off-white. They often have blotches, which enhance their camouflage, and they sport little fleshy appendages on their heads and chins that look like little weeds growing on them.

The photos on this page show examples of some of the color variations of the Leaf Scorpionfish. Despite the range of colors, they are all the same species. (Click on the photos to enlarge.)

The first photo on this page shows a purple Leaf Scorpionfish. You can see that this individual has a lot of blotches. If you see a scuzzy-looking Leaf Scorpionfish, he's probably getting ready to molt, which they do periodically. Soon after they molt they look much less blotchy. Sometimes the color looks a bit different after molting, too.

The second photo is a 1:1 macro shot of a Leaf Scorpionfish that we watched over a period of many months. In the second photo, you can see the little fleshy appendages on the fish's chin quite clearly. It's all part of the disguise.

We've noticed that when one of these fish finds a good spot on the reef, they tend to stay put in the same small patch of real estate for a long time. Once one is located, it's a safe bet that a diver will be able to return to the same spot again and again, day after day, month after month, and see the same little fish. Good dive guides know this, and that is why they can reliably lead divers and underwater photographers to a Leaf Fish almost at will.

The final photo on this page shows one more color variety. This yellow Leaf Scorpionfish is perched on a coral head. We have noticed that smaller Leaf Scorpionfish often tend to hide in the coral this way, while the larger ones seem to prefer a spot on a rocky bottom. We don't know why this is so, but we surmise that the little ones may feel safer in the coral, since it affords them some protection. They can hunker down if there's a lot of surge, for instance.

I took all of the photos on this page at Puako, Hawaii, at depths ranging from less than 20 feet (6 m) to about 125 ft (38 m).