Sight Search

Sea Turtles of the World

 By Doug Perrine

They are all big, scaly air-breathers encased in streamlined shells, but don’t let that fool you into thinking that the seven living species of sea turtle are very similar animals. Having diversified for 200 million years, they have evolved different ways of surviving on a planet that has undergone massive upheavals during their tenure. Each species is a unique testament to nature’s inventiveness.

Green Turtles

I thought my opportunity had arrived. I needed a photo of turtles mating for my book, and just across a short stretch of glassy calm sea I spotted a pair of green turtles upright at the surface. I slipped into the water and snorkeled slowly toward the courting couple. Their belly-to-belly orientation was a clue that the female was not interested in the male. By facing off with a male, a female can prevent him from mounting her. This male was attempting to overcome her resistance by slapping her around with his large pectoral fins, each armed with a heavy-duty curved claw. These talons are used to hook onto the forward edges of the female’s carapace (upper shell) during mating, which enables the male to maintain his position for marathon coupling sessions that can last for hours or even days.
The two turtles were so intensely focused on their competition that they did not notice as I quietly finned up to within camera range. But when my shutter closed with a “clack,” the female turned to look at the strange creature that was now only 3 feet away from her. Deciding she wanted no part of me, she took one breath and dove for the depths. Male turtles in the mood, however, are notorious for their lack of discrimination. This one looked momentarily frustrated over the sudden disappearance of the object of his ardor, but then he turned to look at me with an expression that seemed to say, “It’s too bad she’s gone, but I guess you’ll do.”
Green sea turtles (Chelonia mydas) are cleaned of algae by yellow tangs and goldring surgeonfish (also known as kole tangs) near South Kohala, Kona, Hawaii.
The next thing I knew, those clawed flippers were smacking my face as I tried to push away the turtle with my camera and fins while waving frantically to the boat for a pick-up. My boat boys waved back happily, as if to say “Hello to you, too.” The few hundred yards separating me from sanctuary now seemed like the vast expanse of water between Moses and the Promised Land. I eventually climbed aboard with my virtue intact, but I resolved to never again underestimate the persistence and brute strength of this Don Juan of the animal kingdom.

I eventually succeeded in photographing green turtles mating in stacks of two, three and even four. Male sea turtles are rarely discouraged by the fact that another male has already mounted a female. Green turtles have distinguished their species not only with the longest recorded fornications but in many other aspects of their lifestyle and biology as well. Green turtles are the only sea turtles that are primarily herbivores as adults. On a diet consisting mostly of seagrasses and algae, they grow to the second largest size of any sea turtle, achieving a maximum weight of 517 pounds. They are also the only sea turtles that spend time ashore (beyond the time spent by egg-laying females). In a few locations and for reasons that have not been fully elucidated, green turtles of both sexes regularly drag themselves up onto the beach and spend hours basking on dry land.

Green turtles exist throughout the tropics and subtropics and are therefore perhaps the species most familiar to divers. They grow larger than hawksbill turtles, the other species most commonly seen on coral reefs, and have a shell with a smooth margin compared to the jagged edges of hawksbills’ carapaces. The plates that make up green turtles’ shells are smoothly joined rather than overlapping like the plates of hawksbills’ shells. Their beaks are blunter than the pointy, birdlike beaks of hawksbills, and the green is the only sea turtle with a beak that’s serrated. The jagged, toothlike serrations are useful for clipping off blades of seagrass. The green turtle is also the only sea turtle with a single pair of long scales on the forehead. Most other sea turtles have two pairs of round or square scales on the forehead.
Hawksbill sea turtle hatchling (Eretmochelys imbricate, critically endangered), Caribbean
Hawksbill Turtle

Hawksbill sea turtles are found on coral reefs and in other tropical habitats around the world. Their diet is even more unusual than that of green turtles: They feed primarily on sponges, which are full of noxious compounds and are often reinforced with needles of silica or other hard substances, which leads researchers to describe hawksbills as having a “diet of glass.” Hawksbills are sometimes seen tearing apart a section of reef to get at the sponges growing among the coral rubble.

While green turtles can also have beautifully patterned shells, it is the carapace of the hawksbill turtle that provides the easily worked material for tortoiseshell jewelry. In young hawksbills, the scutes (scalelike plates) that make up the carapace overlap and produce a very jagged margin, especially at the rear of the carapace. In older hawksbills, however, the carapace margin can be smooth, and there is little overlap of scutes. Hawksbills can be recognized by their slender heads and pointy, birdlike beaks.

Loggerhead Turtles


The third species of sea turtle likely to be seen by divers is the loggerhead. The big, blocklike head of this species distinguishes it immediately from other sea turtles and provides a clue about its feeding habits. While the serrated jaws of the green turtle are designed for snipping off blades of grass and strands of algae, and the sharp, narrow beak of the hawksbill is well adapted for reaching into crevices in the reef to scrape off sponges, the massive jaws of the loggerhead enable it to crush shelled invertebrates such as crabs, lobsters, scallops, conchs and urchins. An adult loggerhead can crack a thick conch shell that is difficult to chip with a hammer.
Loggerhead turtle (Caretta caretta), Bahamas
Naturally you would not want to have the industrial-strength feeding apparatus of a 400-pound loggerhead closing around any of your body parts, which is why I once found myself swimming as fast as I could in tight circles around the wreckage of an old ship with a large turtle in hot pursuit. I had violated one of the two cardinal rules of wildlife interaction — don’t touch and don’t feed — and I was paying the price. To facilitate the filming of the feeding behavior of this species for a documentary on marine wildlife, I had pulled some hidden shellfish out of the wreck and placed them on the seafloor in front of the turtle. The technique worked well for a few takes, but then the pea-sized reptilian brain of the turtle made the connection between tasty food and the guy in the red wetsuit. Soon the cameraman and lighting assistant were laughing too hard to operate their equipment as they watched me over-breathing my regulator in a panic while trying to outmaneuver the hungry giant.

Another distinguishing characteristic of loggerheads is the color of their shells and skin, which tend toward shades of brown with tones of orange, red or yellow. This is in contrast to the more green, gray and brown color schemes of hawksbill and green turtles. If you are in doubt, the species identification can be confirmed by counting the large scutes on either side of the carapace. There are five lateral scutes on the shell of a loggerhead but only four on green and hawksbill turtles. The loggerhead’s carapace is also longer and more spindle-shaped than the rounder shells of greens and hawksbills.

While all sea turtles are migratory to some extent, loggerhead turtles are simply phenomenal in this regard, regularly crossing the Pacific Ocean between breeding and feeding areas. This is one of the longest migratory paths known in the animal kingdom — about one-third of the distance around the earth.
Type your new text here.
Leatherback Turtles

Leatherbacks are champion swimmers, wandering thousands of miles as they hunt for dense concentrations of drifting jellylike organisms in the open ocean. Because leatherback turtles feed in deep water and usually approach shore only to nest, divers rarely see them. For anyone lucky enough to see one, the huge size and unusual appearance of the leatherback should leave little doubt about its identity. The shell is covered with smooth skin rather than hard scutes, and it has seven prominent longitudinal ridges on the upper surface. The body is nearly black with irregular white splotches, and it’s even more spindle-shaped than the loggerhead’s. The flippers are enormous, spanning up to 9 feet. Instead of a hard beak, like other sea turtles, the leatherback has a muzzle with an M-shaped opening, suitable for slurping down large quantities of gelatinous prey. Spiky projections inside the mouth and throat keep the jellies from swimming back out again.

Leatherbacks are so different from all other sea turtles that they are classified in a separate family. Incredibly for an animal whose diet consists of creatures that are 95 percent water, they grow much faster and larger than other sea turtles, attaining lengths of nearly 10 feet and weights of up to a ton. They achieve this prodigious growth by feeding around the clock, whereas most sea turtles are active by day and rest at night. To find dense concentrations of sea jellies, leatherbacks dive to depths of more than 3,900 feet, which rivals the capabilities of sperm whales and elephant seals.

Unlike other sea turtles or any other living reptiles, leatherbacks are semi-warm-blooded, able to maintain a body temperature at least 32°F higher than the surrounding water temperature. This enables them to withstand the near-freezing temperatures of the dark depths where they hunt and to feed in frigid, high-latitude waters where other turtles cannot survive. A higher internal temperature facilitates faster digestion and a higher metabolic rate, which fuels their fast growth and early maturation. Leatherbacks are estimated to begin breeding at an age of 13 to 14 years, compared with 20 to 50 years for green turtles.
Female olive ridley sea turtles (Lepidochelys olivacea) come ashore at sunset to nest during an “arribada” (mass nesting event) at Ostional, Costa Rica.
Olive Ridley Turtles

Divers do not often encounter olive ridleys, as these turtles do not frequent coral reefs but usually feed either in soft-bottom areas or in open ocean. However, they can be viewed on shore in one of nature’s greatest spectacles. While other types of sea turtle may share preferred nesting beaches with other members of their species, the act of nesting is a solitary event; not so with the two species of ridley turtles, which coordinate their nesting in mass events known as arribadas. During an arribada, which may last for days, hundreds of thousands of female turtles may come ashore on a single stretch of beach with hundreds or thousands digging nests simultaneously. Eggs may go flying through the air as turtles dig up nests previously laid by other turtles.

Olive ridleys are the smallest sea turtles, reaching a maximum weight of only 106 pounds. Adults have a nearly round carapace that is gray, brown or olive in color. The carapace has five to nine lateral scutes (usually six or seven), compared with four or five in other species.
Type your new text here.
Kemp’s Ridley Turtles

Kemp’s ridley turtles are very similar to olive ridleys, growing only two pounds larger, but they are usually lighter in color and have only five lateral scutes. Historically, Kemp’s ridleys also nested in large arribadas, but this occurred at only one remote beach in the Gulf of Mexico — a location unknown to turtle researchers until 1963, by which time the population had been nearly wiped out by egg collectors.

Kemp’s turtles are currently the rarest and most endangered of all sea turtles. Before 1963, scientists were not even sure that this was a valid species, as they were not known to reproduce. Adults are found almost exclusively in the Gulf of Mexico, although juveniles may travel to the North Atlantic. An unknown number were killed in BP’s 2010 Deepwater Horizon oil spill in the Gulf of Mexico.

Sightings by divers are very rare, although a very small number have been spotted on Florida reefs. Kemp’s ridleys specialize in feeding on crabs, unlike olive ridleys, which feed on a wide variety of marine organisms. Kemp’s ridleys are the only sea turtles that nest more often by day than by night.
A female Australian flatback sea turtle (Natator depressus) comes ashore to nest, leaving tractorl-ike tracks behind her, at Crab Island, off Cape York Peninsula, Queensland, Australia.
Australian Flatback Turtles

Australian flatback sea turtles are considerably more abundant than Kemp’s ridleys, but are even less likely to be seen by divers. The first underwater photographs of an adult flatback were published in 2012. The distribution of this species is even more restricted than that of Kemp’s ridleys. Because they have a life history that is drastically different from other sea turtle species, flatbacks are found only in the tropical and subtropical areas of the Australian continental shelf.

 All other sea turtles swim out to sea after hatching from eggs laid on a beach, and they spend years drifting and swimming in the open ocean before most settle into coastal habitats as juveniles (though leatherbacks and some olive ridleys and loggerheads stay in the open ocean). Flatbacks, however, stay in coastal waters after hatching and never disperse to the open sea.

 All sizes of these strange turtles prefer silty, nearshore waters inhabited by saltwater crocodiles and deadly jellyfish — environments not conducive to in-water observations. Apart from their nesting behavior, little is known about them, including when and where they mate. Some researchers have never even seen a male. Their dietary preferences are unknown, although the few stomachs that have been examined contained a variety of marine invertebrates.

 Flatbacks grow to about twice the size of ridley turtles, maxing out at 213 pounds. They are generally lighter in color than other sea turtles and have a carapace with a distinctive upturned brim. Researchers believe flatbacks can move faster on land than other sea turtles, as survival of the nesting females sometimes requires them to outrun saltwater crocodiles.

Astonishing Variety


The world’s sea turtles are a far-ranging, deep-diving, long-enduring and truly diverse group of animals. Some are carnivores; others are herbivores. Some are pelagic, while others are coastal. Most are cold-blooded, but some are partially warm-blooded. They represent not only different species but also different genera and even different families.
The sea turtles inhabiting today’s oceans aren’t different from each other like Hereford cows are different from Jerseys; they’re as different as cows are from dogs. Don’t be content just to see “a turtle” — I hope you see a hawksbill or a loggerhead or, with a bit of luck, something as rare as a leatherback.
© Alert Diver — Q3 Summer 2013

Categories

 2021
 April
Aqua Pool Noodle ExercisesUnderwater Photographer and DAN Member Madelein Wolfaardt10 Simple Things You Can Do to Improve Your Underwater PhotographyCOVID-19 and Diving: March 2021 UpdateDiver Return After COVID-19 Infection (DRACO): A Longitudinal AssessmentGuidelines for Lifelong Medical Fitness to DiveExperienceFitness Myth or Fitness Fact?The Safety of Sports for Athletes With Implantable Cardioverter-DefibrillatorsCardiovascular Fitness and DivingHypertensionPatent Foramen Ovale (PFO)Headaches and DivingMiddle-Ear Barotrauma (MEBT)O’Neill Grading SystemMask Squeeze (Facial Barotrauma)Sinus BarotraumaInner-Ear Barotrauma (IEBT)Middle-Ear EqualisationAlternobaric VertigoDecompression IllnessOn-Site Neurological ExaminationTreating Decompression Sickness (The Bends)Top 5 Factors That Increase Your Risk of the BendsHow to Avoid Rapid Ascents and Arterial Gas EmbolismUnintended Rapid Ascent Due to Uncontrolled InflationUnexpected Weight LossFlying After DivingWisdom Tooth Extraction and DivingYour Lungs and DivingScuba Diving and DiabetesDiving after COVID-19: What We Know TodaySwimmer’s Ear (Otitis Externa)Motion SicknessFitness for DivingDiving After Bariatric SurgeryWhen to Consult a Health-Care Provider Before Engaging in Physical ActivitiesFinding Your FitnessHealth Concerns for Divers Over 50Risk Factors For Heart DiseaseJuggling Physical Exercise and DivingSeasickness Prevention and TreatmentMember to Member: Guidelines for SeniorsHigh-Pressure OphthalmologyOver-the-Counter Medications
immersion and bubble formation Accidents Acid reflux Acute ailments Aerobic exercise After anaesthesia Aged divers Air Quality Air exchange centre Air hose failure Air supply Airway control Air Alert Diver Magazine Alternative gas mix Altitude changes Altitude diving Altitude sickness Aluminium Oxide Ama divers Amino acids Anaerobic Metabolism Animal life Annual renewal Apnea Apnoea Aquatic life Aquatics and Scuba Diving Archaeology Argon Arterial Gas Embolisms Arterial gas embolism Arthroscopic surgery Aspirin Audible signals Aurel hygiene Australian Flat backed BCD BHP BLS BWARF Back adjustment Back pain Back treatment Backextensors Badages Bag valve mask Bahamas Balancing Bandaids Barbell back squat Barometric pressure Barotrauma Basic Life Support Batteries Beach entry Becky Kagan Schott Bench press Benign prostate hyperplasia Benzophenones Beth Neale Beyond Standards Bilikiki Tours Biophysics Black Blood flow Blood thinners Blue Desert Blue Wilderness Blue economy Blurred vision Boat safety Boesmans gat Boesmansgat Bone fractures Bouyancy compensators Bouyancy controls Boyle's Law Boyle\'s Law Bradycardia Brain Breast Cancer Breath Hold Diving Breath holding Breath hold Breath-hold Breathing Gas Breathing gas contamination Breathing Breathold diving Bright Bank Broken bones Bruising Bubbleformation Buddy Exercise Buddy checks Buoyancy Burnshield CGASA CMAS CO2 COVID-19 Updates COVID-19 COVID CPR Cabin pressure Caissons diseas California Camera equipment Camera settings Cameras Cancer Remission Cancer treatments Cancer Cannabis and diving Cannabis Cape Town Dive Festival Cape Town Dive Sites Cape Town CapeTown Carbon Monoxide Carbon dioxide Cardiac research Cardio health Cardiological Cardiomyopathy Caribbean Carmel Bay Catalina Island Cave diving Challenging Environments Chamber Safety Chamber science Charging batteries Charles' Law Charles\' Law Charles\\\' Law Charles\\\\\\\' Law Charles\\\\\\\\\\\\\\\' Law Charlie Warland Chemotherapy Chest compressions Children diving Chiropractic Chlorophll Christina Mittermeier Citizen Conservation Cleaning products Closed Circuit Rebreathers Cmmunity partnership Coastal diving Coastalexcursion Cold Water Cold care ColdWater Cold Commercial Fishing Commercial diving Commercial schools Composition Compressed Air Compressed gas Consercation Conservation Photographer Conservation photography Conservation Contact lenses Contaminants Contaminated air Coral Conservation Coral Reefs Coral Restoration Coral bleaching CoralGroupers Corals Core strength Corona virus Coro Costamed Chamber Courtactions Cozumel Cristina Mittermeier Crohns disease Crowns Crystal build up Crystallizing hoses Cutaneous decompression Cylinder Ruptures Cylinder handwheel Cylinder valves DAN Courses DAN Profile DAN Researchers DAN medics DAN members DAN report DCI DCS Decompressions sickness DCS theories DCS DEMP DM training DNA DReams Dalton's Law Dalton\'s Law Dalton\\\'s Law Dalton\\\\\\\'s Law Dalton\\\\\\\\\\\\\\\'s Law Danel Wenzel Dangerous Marinelife Dauin island Dean's Blue Hole Dean\'s Blue Hole Deco dives Decompression Illness Decompression Sickness Decompression Stress Decompression illsnes Decompression treatment Decompression Decorator crabs Deep diving Deep water exploration Deepest SCUBA Dive Delayed Offgassing Dental Dever Health Diaphragms Diopter Diseases Disinfection Dive Buddy Dive Chamber Dive Computer Dive Destinations Dive H Dive Industry Dive Instruction Dive Instructor Dive Medical Form Dive Medical Dive Practices Dive Pros Dive Research Dive Safety Tips Dive South Africa Dive Training Dive Travel Wakatobi Dive Travel Dive accidents Dive buddies Dive computers Dive courses Dive excursions Dive exercise Dive exeriences Dive experience Dive fitness Dive gear Dive heallth Dive health Dive medicals Dive medicines Dive medicine Dive operators Dive opportunities Dive planning Dive procedures Dive safety 101 Dive safety Dive safe Dive skills Dive staff Dive travels DiveLIVE Diveleader training Diveleaders Diver Health Diver Profile Diver infliencers Diver on surface Diver recall Diverover 50 Divers Alert Diversafety Divesites Diving Divas Diving Kids Diving Programs Diving Trauma Diving career Diving emergencies Diving emergency management Diving fit Diving guidelines Diving injuries Diving suspended Diving Dizziness Dolphins Domestic Donation Doug Perrine Dowels Dr Rob Schneider Drift diving Drysuit diving Drysuit valves Drysuits Dyperbaric medicines EAPs EAP Ear pressure Ear wax Ears injuries Eco friendly Education Electronic Emergency action planning Emergency decompression Emergency plans Emergency underwater Oxygen Recompression Emergency Enviromental Protection Environmental factors Environmental impact Environmental managment Equalisation Equipment care Equipment failure Equipment inspection Evacuations Evacuation Evaluations Even Breath Exercise Exercising Exhaustion Exposure Protection Extended divetime Extinguisher Extreme treatments Eye injuries FAQ Factor V Leiden Failures FalseBay Diving Fatigue Faulty equipment Female divers Fetus development Fillings Fire Coral Fire Safety Firefighting First Aid Equipment First Aid Kit First Aid Training First Aid kits First Aid Fish Identification Fish Life Fish Fit to dive Fitness Levels Fitness Training Fitness evaluation Fitness to dive Fitnesstrainng Fitness Flying Focus lights Foundations Fractures Francesca Diaco Francois Burman Fredive Free Student cover Free diving Free flow Freedive INstructor Freedive Training Freediver Freediving Instructors Freediving performance Freediving Gar Waterman Gas Density Gas consumption Gas laws Gas mixes GasPerformance Gases Gass bubbles Gastoeusophagus Gastric bypass Gastroenterologist Gear Servicing Germs Geyer Bank Giant Kelp Forest Giant Kelp Girls that Scba Gobies Gordon Hiles Great White Sharks Green sea turtle Guinness World Record Gutt irritations HCV HELP HIRA HMLI HMS Britanica Haemorhoid treatment Hand signals Hawaii Hawksbill Hazard Description Hazardous Marine life Hazardous marinelife Headaches Health practitioner Heart Attack Heart Health Heart Rate monitor Heart fitness Heart rates Heart rate Heart Heat stress Heliox Helium Hepatitis C Hepatitus B Hiatal Hernia High Pressure vessels High temperatures Hip strength Hip surgery Hippocampus History Hot Humans Hydrate Hydration Hydrogen Hydroids Hydrostatic pressure Hygiene Hyperbaric Chamber Hyperbaric research Hyperbarics Hypothermia Hypoxia I-52 found INclusivity IdentiFin Imaging Immersion Immine systems In Water Recompression Indemnity form Indian Ocean Indigo SCuba Indonesia Inert gas Infections Infra red Imaging Injections Inner ear Instinct Instruction Instructors Insurance Integrated Physiology International travel International Internship programs Internship Interval training Irritation Irukandji Syndrome Isotta housing Joint pain Junior Open Water Diver KZN South Coast Karen van den Oever Kate Jonker KateJonker Kidneys Kids scubadiver Komati Springs KwaZulu Natal Labour laws Lake Huron Laryngospasm Lauren Arthur Learning to dive Leatherback Legal Network Legal advice Legislation Lembeh Straights Lenses Leukemis Liability Risks Liability releases Liability Life expectancy Lifestyle Lightroom editing Live aboard diving Liver Toxicity Liver diseas Liz Louw Lost at sea Low blood pressure Low pressure deterioration Low volume masks Lung Irritation Lung function Lung injuries Lung squeeze Lung surgery Lung MOD Macro photography Maintenance Malaria Mammalian Dive Response Mammalian effect Mandarin Fish Marine Biology Marine Science Marine Scientists Marine conservation Marine parks Marine plants Marinelife Marinescience Masks Master scuba diver Maximum operating depth Medical Q Medical emergencies Medical questionaire Medical statement Medicalresearch Medicalstudents Medication Mehgan Heaney-Grier Membership benefits Mermaid Danii Mesophotic Michael Aw Middle ear pressure Mike Bartick Military front press Misool Resort Raja Ampat Mixed Gas Mono Fins Mooring lines More pressure Motion sickness Motionsickness Mozambique Muscle pain Mycobacterium marinum National Geographic Nausea Nautilus Ndibranchs Neck pain Neoprene layers Neuro assessments Neurocognitive research Neurological assessments Nitrogen Narcosis Nitrogen build up Nitrox No-decompression Non-nano zinc oxide Non-rebreather Mask Nonrebreather masks Normal Air North Sulawesi Nosebleeds Nuno Gomes O2 providers O2 servicing OOxygen maintenance Ocean Projects Ocean Research Ocean animals Ocean pollution Octopus Oil contamination Olive Ridley Open Ocean Open water divers Optical focus Orbital implants Oronasal mask Osteonecrosis Out and about Out of air Outer ears Outreach Overhead Envirenments Oxygen Administration Oxygen Cylinder Oxygen Units Oxygen deficit Oxygen deicit Oxygen dificiency Oxygen ears Oxygen equipment Oxygen masks Oxygen providers Oxygen supplies Oxygen supply Oxygen systems Oxygen therapy Oxygen P J Prinsloo PADI Freedivers PFI PFO PJP Tech Paralysis Parentalsupervision Part 3 Partner Training Patent foramen ovale Perspective Peter Lindholm Philippine Islands Philippines Phillipines Photographers Photography tips Photography Physical Fitness Physioball Physiology Physiotherapy Pills Pilot Whale Pistons Planning Plastic Plimsoll Interface Pneumonia Pneumothorax Poison Pollution Pool Diving Pool workout Post-dive Pre-dive Predive check Pregnancy Pregnant divers Preparation Prepared diver Press Release Preventions Professional rights Provider course Psycological Pulmanologist Pulmonary Barotrauma Pulmonary Bleb Pulmonary Edema Pulse Punture wounds Pure Apnea Purge RAID South Africa RCAP REEF Radio communications Range of motion Rashes Rebreather diving Rebreatherdive Rechargeable batteries. Recompression chamber Recompression treatment Recompression Recycle Reef Chcek Reef Conservation Reef safe Reef surveyors Refractive correction Regulator failure Regulators Regulator Remote areas Renewable Report incidents Rescue Divers Rescue Procedure Rescue breathing Rescue breaths Rescue skill Rescue training Rescue Research Resume diving Return To Diving Return to diving Risk Assessments Risk assesments Risk assessment Risk elements Risk management Roatan Marine Park Roatan SABS 019 SMB SafariLive Safety Gear Safety Stop Safety SaherSafe Barrier Salty Wanderer Sanitising Sara Andreotti Sardine Run Saturation Diving Save our seas Schrimps Science Scombroid Poisoning Scuba Air Quality Scuba Guru Scuba Injury Scuba Instructor Scuba children Scuba divers Scuba dive Scuba education Scuba health Scubalearners Scubalife Sea Horses Sea Turtles Sea slugs Seagrass Sealife Seasickness Seaweed Sea Shallow dives Shark Protection Shark Research Shark conservation Shark diving Sharks Shipwrecks Shore entries Shoulder strength Sideplank Signs and Symptoms Sit-ups Skin Bends Skin outbreak Skin rash Snells Window Snorkeling Snorkels Social Distancing Sodwana Bay Solomon Islands Sonnier bank South Africa Sperm Whales Spinal Bend Spinal bends Spinal cord DCS Spinal pain Spinner dolphins Splits Squeezes Squid Run Stability exercise Standars Stay Fit Stents Step ups Stephen Frink Stepping up Strobe Lighting Stroke Submerge tech Submerged Sudafed Sulawesi Sun protection Sunscreen Supplemental oxygen Surface Marker Buoys Surface supplied Air Surfaced Surgeries Surgery Suspension training Swim Fitness SwimmingIn wateractivities Swimming Symbiosis TRavel safety Tabata protocol Talya Davidoff Tattoes Tec Clark Technical Diving Technical divng The Bends The greatest Shoal The truth Thermal Notions Thomas Peschak Thunder Bay National Marine Sanctuary Tides Tips and trick Tooth squeeze Transplants Travel smarter Travel tips Travel Tropical Coastal Management Tunnelling Turtles Tweezers Ultrsound Umkomaas Unconsciousness Underground work Underseaa world Underwaater Photos Underwater Photographer Manirelife Underwater Research Underwater floral Gardens Underwater hockey Underwater photographer Underwater photography Underwater pho Underwater sound Underwatercommunications Underwater University of Stellenbosch Urinary retention. Vacations Vaccines Vagus nerve Valsalva manoeuvers Valve stem seals Vape Vaping Vasopressors Vasvagal Syncope Venting Verna van Schak Virus infections Volatile fuels WWII wrecks War stories Washout treatments Wastewater Watchman device Water Resistance Water Weakness Weigang Xu Weights West Papua Western Cape Diving Wet Lenses Wet diving bell Wetsuit fitting Wetsuites Wetsuits White balance Whitetpped Sharks Wide Angle Photos Wide angles Wildlife Winter Wits Underwater Club Woman and diving Woman in diving Womans health Woman Women In Diving SA Women and Diving Women in diving Womens Month Womens health Work of Breathing Workout World Deeepst Dive Record World Records Wound dressings Wreck divers Wreck dive Wreck diving Wreckdiving Wrecks Yoga Youth diver Zandile Ndholvu Zoology Zooplankton abrasion absolute pressure acoustic neuroma excision adverse seas air-cushioned alert diver altitude alveolar walls anemia antibiotics anticoagulants antiseptics bandages barodontalgia bent-over barbell rows bioassays biodiversity bloodcells body art breathing air calories burn carbon dioxide toxicity cardiovascular career developments cerebrospinal fluid cervical spine checklist chemo port children child chronic obstructive pulmonary disease clearances closed circuit scuba corrective lenses currents cuts dead lift decompression algorithms decongestants decongestion dehydration dive injuries dive medicing dive ready child dive reflex dive tribe diver in distress diver rescue diver training dive diving attraction doctors domestic travel dri-suits drowning dry mucous membranes dry suits dry e-cigarettes ear spaces elearning electrolyte imbalance electroytes emergency action plans emergency assessment emergency training environmentally friendly equalising equalizing exposure injuries eyes fEMAL DIVERS fire rescue fitnes flexible tubing frediving freedivers gas bubble gas poisoning gastric acid gene expression health heartburn histidine hospital humidity immersion and bubble formation immersion pulmonary edema (IPE informal education isopropyl alcohol jaundice join DAN knee laparoscopic surgery longevity lower stress malaise marielife marine pathogens medical issues medical procedures medical risk assesment medications mental challenge mental preparedness micro-organisims micro minor illness mucous membranes multilineage dysplasia myelodysplasia nasal steroids nasal near drowning nematocysts neurological newdivers nitrogen bubbles off-gassed operating theatre operations orthopeadic otitis media outgas pain perforation phillippines phrenic nerve physical challenges pinched nerves plasters pneumoperitoneum polyester-TPU polyether-TPU post dive posture prescription mask preserve prevention proper equalization psychoactive pulmonary barotrauma. pulmonary injury. pulmunary barotrauma radiation rebreather mask rebreathers retinal detachment risk areas safety stops saturation scissors scuba equipment scuba single use sinus infections smoking snorkeling. spearfishing sterilising stings strength sub-aquatic sunscreen lotion swimmers ears tattoo care tecnical diver thermal protection tissue damage toxicity training trimix unified standards upwelling vision impaired vomiting warmers water quality zinc oxide