By John Lippmann
Executive Director
DAN S.E. Asia-Pacific

Copyright: John Lippmann

During diver training, dive students are normally drilled to avoid diving beyond 130 feet / 39 meters. However this depth limit recommended by most of the training agencies is not forged in stone. Historically, it appears that it probably emerged from the U.S. Navy, possibly as a result of equipment limitations at that time, and the work restrictions imposed by the relatively short no-stop times available at greater depths.

An increasing number of divers dive beyond the 130-foot limit, some routinely and others occasionally. The advent of dive computers has negated much of the decompression penalty and dive restrictions previously associated with deep diving, and has no doubt encouraged the current trend. In addition, the increased availability of a variety of gas mixtures has enabled more divers to venture deeper and deeper.

The loss of sharks could contribute to the destruction of one of the planet’s most under-appreciated sources of carbon storage — seagrasses, according to FIU researchers. Not that sharks eat the seagrass, they don’t, but they do eat the turtles which feed in the seagrass meadows. Add this to the problems of pollution, mooring and destruction of seagrass, means this vital habitat – and the sharks – need help.

An online “citizen-science” project called “Plankton Portal” has been created by researchers at the University of Miami in collaboration with the National Oceanic and Atmospheric Administration (NOAA) and the National Science Foundation (NSF). The Plankton Portal lets you explore the open ocean from your own home. You can dive hundreds of feet deep, and observe the unperturbed ocean and the myriad animals that inhabit the earth’s last frontier. The Plankton Portal is at http://www.planktonportal.org/.

SCUBA Travel are pleased to release their annual list of the diving best-selling books and DVDs.

Most of the books are either diving area guides – to specific locations or dives around the world – or sea life guides. One breaks the trend though: Simon Pridmore’s Scuba Confidential. This tells readers how to be a better diver.

One DVD makes the list, showing the best diving locations in world.

Here are the top ten: figures in brackets show the previous year’s position.If positions change (and some are very close) this page will update with the new best-sellers.

As you can see, many books continue to be in the top ten year after year. Coral Reef Fishes: Indo-Pacific and Caribbean has not been out of the top ten since we started publishing the list in 2002! But then, it’s a great little book.

The Okeanos is equipped with real-time broadband satellite communications that provide the ship with telepresence -- meaning the video and photos collected with underwater robots known as remotely operated vehicles, or ROVs, are shared on the internet in real time. So scientists, teachers, students, and you can watch the dives as they happen. With the ship currently exploring Papahānaumokuākea Marine National Monument in the Northwestern Hawaiian Islands and Hawaiian Islands Humpback Whale National Marine Sanctuary, there’s no time like the present to tune in and check out the action.

“But it's so difficult here! The water is only ten feet deep!” It seems that I hear this from about fifty percent of my cave diving students. We train basic cave skills in the open water area of cenotes, where the depth tends to max out at about fifteen feet and we do the skills hovering neutrally buoyant mid-water. The truth is, that pretty much every type of control is more difficult in shallow water, and that is precisely why shallow water makes for such an incredible practice environment – if you can control yourself in shallow water, you can control yourself anywhere.

So grab your fins and head out to the shallow end of the smallest pool you can find, here are five things that you can improve by practicing your diving skill in shallow water.

Feeding sharks for the benefit of divers is becoming more and more common, but is controversial. New research suggests that feeding in areas with several different sharks, over time, leads to one species increasing in numbers at the expense of the others. Published in PLOS ONE⁽¹⁾, the study looked at the Shark Reef Marine Reserve feeding site in Fiji from 2003 to 2012.

Eight species of shark regularly visited the site in 2003: bull shark (Carcharhinus leucas), grey reef shark (Carcharhinus amblyrhynchos), whitetip reef shark (Triaenodon obesus), blacktip reef shark (Carcharhinus melanopterus), tawny nurse shark (Nebrius ferrugineus), silvertip shark (Carcharhinus albimarginatus), sicklefin lemon shark (Negaprion acutidens), and tiger shark (Galeocerdo cuvier). By 2012, there were more individual sharks visiting, but fewer species. The winner was the bull shark. The smaller tawny nurse shark, silvertip shark and sicklefin lemon shark became very rare visitors.

A quarter of sharks, rays and chimaeras are threatened with extinction, according to a new study by the International Union for Conservation of Nature. Large, shallow-water species are at most risk.

The group found that only 23 percent of these fish is listed as “least concern” on the IUCN Red List of Threatened Species. Of the 1,041 known species, 25 are listed as critically endangered, 43 are endangered, and 113 are vulnerable to extinction. This is the worst reported status for any major vertebrate group except for amphibians.

Cuttlefish are renown for their tremendous camouflage capabilities – changing the color and texture of their skin to match their surroundings. They have another weapon in their hide and seek armory though – electric cloaking.

It is well known by SCUBA divers that many parrotfish and wrasse sleep soundly in mucous cocoons during the night. Until now the reason has not been known, but has been thought to be some sort of protection against predators. New research by scientists at the University of Queensland, Australia has found that the cocoons actually act as a kind of “mosquito net”.

The air around here is growing increasingly chilly and I think a nice, warm blanket to hide under is called for. All sorts of animals have lovely fur you can make one out of, but you have to do all the work yourself. Unacceptable! There is a very strange answer to this problem, so long as you can tolerate your blanket being soaking wet. The Blanket Octopus has come to tuck you in. I hope she's brought some hot chocolate along, too.

Blanket Octopus are 4 species of the genus Tremoctopus. They are found throughout the world's tropical and sub-tropical oceans, from the surface to moderate depths. I usually think of octopods crawling around on rocks and such but the Blanket Octopus is pelagic, living life out in the open ocean with no need for coasts or the sea floor at all.

The vast open ocean presents an especially challenging environment for its inhabitants since there is nowhere for them to hide. Yet, nature has found a remarkable way for fish to hide from their predators using camouflage techniques. In a study published in the current issue of Science, researchers from Harbor Branch Oceanographic Institute at Florida Atlantic University and collaborators show that fish scales have evolved to not only reflect light, but to also scramble polarization. They identified the tissue structure that fish evolved to do this, which could be an analog to develop new materials to help hide objects in the water.

Once you do your first ocean dive something inside of you changes. You form a connection to the ocean. You start to care about the sea and begin thinking about what you can do to protect it.

We all know some basic things that we can do to reduce our carbon footprint, for example, stop using single-use plastic and recycle as much as possible. But have you ever thought about sustainable shopping while travelling?

As ocean-loving scuba divers, we should not buy souvenirs from anyone exploiting ocean wildlife.

Being a scuba diver is awesome. You breathe underwater, identify fish and experience weightlessness on every vacation. You have designated yourself as an ocean activist, and you’re well on your way to achieving Master Scuba Diver. Being the scuba diver in your group of friends is a big responsibility, but you handle it with grace and ease.

Did you know that as a scuba diver, you’ve developed skills that also make you rule at life? It’s true!

Published by R. Cilveti, B. Osona, J.A. Peña, L. Moreno, O. Asensio, en representación del Grupo de Técnicas de la Sociedad Española de Neumología Pediátrica (the Spanish Society of Pediatric Pulmonology)

 

Abstract

The increase in recreational scuba diving in recent years, including children, involves risks and the possibility of accidents. While legislation, conditions and risks of scuba diving are well documented in adults, scientific evidence in scuba diving by children and adolescents is sparse and isolated. Furthermore, existing guidelines and recommendations for adults cannot be transferred directly to children.

In this photo provided by the Florida Keys News Bureau, artist David Dunleavy, puts finishing touches on a huge mural entitled "Dolphin Rodeo" at an Islamorada, Fla., marina. The 252-foot-wide by 33-foot-high artwork features two dolphin, also known as mahi-mahi, that are popular ocean gamefish caught off the Florida Keys and other regions of the world. It took the New Jersey artist a month to paint his 62nd larger-than-life SeaLife Mural. Andy Newman AP

Valparaiso, CHILE—The Chilean government on Monday announced that it has created the largest marine reserve in the Americas by protecting an area hundreds of miles off its coast roughly the size of Italy.

One in four people have an opening between the left and right chambers of the heart – called a Patent foramen ovale or PFO. Normally this is not a problem, a flap covers the opening and generally remains closed because of greater pressure in the left chamber than the right. In scuba divers though, it is a worry.

After and whilst ascending from a dive, nitrogen bubbles are formed in the blood of a diver’s veins and carried back to the heart. In a diver with a PFO, the bubbles can pass to the left chamber of the heart and be carried in the arteries back around the body. If they get into the tissues then the diver might get decompression sickness (the bends), even when diving within the normal decompression limits.

One of the treatments for a PFO is to close it using a catheter based procedure. A catheter is a flexible hollow tube which can be used to move a closure-device in place in the heart. In a study available this week in the journal, JACC: Cardiovascular Interventions, doctors report that closing a PFO in this way completely eliminates arterial bubbles after a dive. This compares to a control group where after an 18 m dive 32% of them had bubbles in their arteries, and after a 50 m dive 88% exhibited arterial bubbles. No difference was found in the presence of bubbles in veins in either groups.

The dives were simulated in a hyperbaric chamber: 34 divers “dived” to 18 m for 80 min, and 13 divers to 50 m for 20 min.