Sight Search

On a Mission: Critter hunting in Washington’s Salish Sea

Elusive and enigmatic, sixgill sharks grow to more than 15 feet long. Millions of nondivers in the Seattle–Tacoma area are blissfully unaware of these magnificent monsters in their midst. Photo by Brandon Cole
CREDITS | Text and Images By Brandon Cole

Critter hunting in Washington’s Salish Sea

 There’s a big difference between casual, submerged sightseeing — happy-snapping pictures of whatever you run across while blowing bubbles — and diving dedicated to carefully searching select sites, sometimes during a particular season or time of day, to find and photograph predefined species. It’s possible to luck out while wandering about, but success more often involves a plan.

 The Salish Sea crosses the U.S.–Canada border, but its Washington portion encompasses Puget Sound, Hood Canal and the Strait of Juan de Fuca, which connects everything to the vast Pacific Ocean. It is also my local diving headquarters. The cool, plankton-rich waters hold a wealth of critters that underwater image-makers consider high-value targets. When something’s hot, it pays to devote bottom time to marine life currently basking in the limelight.

 Let’s survey an eclectic mix of five portfolio-worthy photo subjects beneath the waves of the Evergreen State. Along the way, I’ll drop hints on where, when and how to prosper in this living treasure scavenger hunt.

 Giant Pacific Octopus

 Some years are better than others for critter hunting. Animal populations boom and bust, and ocean conditions vary widely. The winter of 2020–2021 was excellent for giant Pacific octopus (Enteroctopus dofleini).

 I observed them out of their dens at Sunrise Beach Park, Day Island Wall and many spots in Hood Canal. The number of female octopuses brooding eggs made it extra special. To have a surplus of them at the same time on the same reef, tenderly caring for their offspring and valiantly guarding them against predators, was extraordinary. I executed six dives to document the mothers cleaning their eggs with tentacle caresses and oxygenating them with jets of water from their siphons.
An octopus is out for a stroll.
Flagpole, Octopus Hole and Sund Rock in Hood Canal proved to be octopus gold mines. Having a slate to map den locations and note information was helpful, as were the generous local divers who shared their sightings.

Bluntnose Sixgill Sharks

Hexanchus griseus favors very deep water, but you can encounter this prehistoric shark (modern shark species have five gill slits) at a few venues in the Salish Sea. Encouraged by social media reports of recent sightings, I prepped my gear and drove 300 miles from my landlocked home in eastern Washington to Puget Sound.

It took three long decompression dives over three nights until a 7-foot adolescent bluntnose sixgill shark materialized from the blackness 95 feet down and southwest of the “deep line” at Redondo Beach. The creature transfixed me — utterly alien, graceful and ponderous at the same time. I stared in amazement through my camera into its metallic eyes. Three more sharks made brief appearances on that dive. It had been years since I had last seen a sixgill, and here I was in the presence of multiple.

The sharks’ seasonal appearance here in July and August may relate to salmon fishing and crabbing in the area. Divers have also seen sixgills at Rosie’s Ravine in Hood Canal.

Pacific Spiny Lumpsuckers

Never underestimate the excitement that weird little fish can generate. During winter, a hard-core subset of Seattle- and Tacoma-area divers schedules regular nighttime shore dives that feature the bug-eyed, pouty-lipped Pacific spiny lumpsucker (Eumicrotremus orbis). Ranging from pea-sized to as big as a jumbo tater tot, they are covered with conical protuberances — the lumps — instead of scales and have a suction-cup disc — the sucker — on their undersides to stick to algae and rocks. Their colors range from yellow to green, brown or red.
Cuteness personified, lumpsuckers are comically inept swimmers that feed on tiny crustaceans.
Finding lumpsuckers can be difficult due to their size, camouflage coloration and the wide-bladed kelp and tufts of algae in which they lurk, but practice helps you develop a knack for spotting them. In the words of one regular eagle-eyed shooter, Redondo Beach in central Puget Sound is “primo lumpy land.” She kindly taught me to get low and go slow while exploring the sandy slope south of the boat ramp. The sweet spot is between 10 and 15 feet deep, and winter delivers the most sightings and larger fish. Three Tree Point is another smart choice for a lumpsucker quest.

Wolf Eels

Wolf eels share local celebrity status with the eight-armed invertebrates mentioned above. It’s not uncommon to encounter both animals on the same dive while exploring rocky reefs and walls at many locales in Washington. Wolfies have a panache that more than compensates for their shortcomings in the beauty department. Like frogfish in the tropics, wolf eels entice me to photograph them even when not on my agenda.

I have a handful of go-to sites for dedicated eel searches. Skyline, south of Anacortes, is typically home to strikingly orange juvenile wolf eels measuring 1 to 2 feet long. Look for them snaking about in the sea cucumbers and algae above 30 feet. I have also found little guys peeking out of holes in Keystone Jetty’s wooden pier pilings and coiled up inside old glass bottles at Redondo.
Adult male wolf eels are usually gray to white with a large fleshy face, while females are darker, smaller and more svelte.
You’re almost guaranteed to spy numerous adult wolfies in the rock piles at Sunrise Beach Park, Flagpole and Sund Rock. During winter, you might spot females wrapped around a volleyball-sized clutch of pink eggs. My favorite spot for quality encounters with wolf eels is Day Island Wall, which you can reach by shore or boat. The ledges and walls between 40 and 100 feet accommodate many wolf eels. Be sure to go during slack tide, ideally on a small exchange of less than 3 knots, to avoid the strong currents in the Tacoma Narrows.
Rock Greenlings

The rock greenling (Hexagrammos lagocephalus) is another critter that, like the sixgill shark, appears more frequently on bucket lists than in logbooks. Few divers have seen one, even though the species is not rare. They are simply hard to find and live where most divers never explore. They prefer shallow, rocky habitats battered by waves and surge and overgrown with thick, mixed kelp, eelgrass and algae. Their colors and patterns help them blend masterfully with the surroundings. Some rock greenlings may reside in the same area for years, which is one of the few advantages searchers have. The Strait of Juan de Fuca, specifically Salt Creek Recreation Area and Sekiu Jetty, have resident greenlings just waiting to be discovered in only 5 to 15 feet of water.
Calm days with minimal swells and wind chop are best to search for rock greenlings.
Even if you don’t see one, you’re sure to enjoy the abundant and diverse marine life on these stellar Washington shore dives. Monitor weather forecasts for calm conditions, and be prepared for a serious search once submerged. It took me two two-hour dives to find a greenling last year. Marking its location with a small surface marker buoy allowed me to easily return with my third tank to the exact spot in the bewildering maze of algae-covered rocks to photograph this spectacular fish in earnest. All the shivering, hard work and planning to reach this moment faded away.
An aerial view of Tongue Point at Salt Creek Recreation Area in the Strait of Juan de Fuca
How to Dive It

Conditions: Washington is a year-round diving destination. Puget Sound’s inland waters are sheltered from the Pacific Ocean’s storms and swell, while the Strait of Juan de Fuca is more exposed. Strong winds can develop throughout the region. Currents can be nonexistent to strong, depending on location and time of year. Some sites can be dived almost any time, while others require slack on small exchanges for safety and comfort.

Water temperatures range from the low-40s°F at depth in winter to the mid-50s°F in late summer. Thermoclines and freshwater layers can be present, especially after heavy rains. Drysuits allow you to customize undergarment thickness to your thermal tolerance. Water clarity is best in late fall and winter, with visibility between 20 and 50 feet. In spring and summer, plankton reduces the visibility, but the water may be clear beneath a murky surface layer.

There are dive sites suitable for all skill levels and interests: deep walls, shallow bays, muck dives, rocky reefs, jetties, pier pilings, purpose-sunk artificial reefs, seamounts and pinnacles. Many dive sites are accessible from shore.

Support: Many full-service dive shops in the region offer gas fills, gear and training, and area dive clubs and informal groups meet up for fun dives. The local diving community is active, supportive and willing to introduce visiting divers to the Salish Sea. Boat charters and private guide services are available.


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 AGE Accident management 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 Brandon Cole 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 Envenomations 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 Greenlings 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 Oxygen 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 Jellyfish 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 Lionfish Live aboard diving Liver Toxicity Liver diseas Liz Louw Lost at sea Low blood pressure Low pressure deterioration Low volume masks Lumpsuckers 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 Menopause Menstruation 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 Nichola Bird 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 Oral contraseptives 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 Potuguese man-of-war 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 Remote islands 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 Salish Seas Salty Wanderer Sanitising Sara Andreotti Sardine Run Saturation Diving Save our seas Schrimps Science Scombroid Poisoning Scorpion Fish 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 Sixgill Sharks 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 Thermoregulation Thomas Peschak Thunder Bay National Marine Sanctuary Tides Tips and trick Tonga Tooth squeeze Transplants Travel destinations 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 Wolf Eels 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