Getting Ready To Dive In

It’s more than just gear that gets you out there when you begin harvesting and hunting underwater on one breath. You need a respect for the ocean and the risks associated with what we do as underwater hunters. Before you even entertain going on a shopping spree and loading up with all the flashy spearfishing and freediving equipment you can find, there are a few things you should be asking yourself.  

Before the equipment…

Firstly, Ask yourself.. “Am I equipped with the knowledge to avoid getting into trouble and endangering the lives of myself, of my dive buddies and of other mariners?”… At a bare minimum you should be doing an extensive amount of independent research online and from proven publications. Freediving is not without its own risks and combined with spearfishing and hand harvesting, it can be a risky pastime. Ideally, one should start by taking a course and seeking instruction from a professional freedive instructor. There is no better investment for someone who is looking to get into freediving and spearfishing. You can have all the best gear in the world but having a solid foundational knowledge of freediving and risk management that goes with it will give you the keys to the ocean you desire! 

You can have all the best spearfishing and freediving equipment in the world but having a solid foundational knowledge of freediving and risk management that goes with it will give you the keys to the ocean you desire! 

What equipment do I really need?

The next question is…do I really need that? You can spend a lot of money on all of the best gear out there, which is great if you can afford it, but you may in the long run end up with gear that you don’t really need. On the flipside, don’t buy junk. You’ll just have to replace it later as you progress as a Spearo. Find the happy middle ground in all of this. Try and think about purchasing your gear in stages.  

Focus on your ‘Essentials’: 

Buy the best equipment you can afford. This will be the gear you depend on to build the foundation of your skills and grow your bottom times. There’s no point in buying a speargun and all the trimmings if you haven’t yet become a proficient and competent freediver. Get to know and depend on your ‘essentials’ first. These are the pieces that will keep you in the water longer, insulating you, conserving your oxygen while maximizing your efficiency on the whole.  

Riffe International Products can be found in our Spearfishing and Freediving Equipment stock at

Next up…

Next, you should add in your ‘Safety Kit’

Having a proper ‘safety kit’ will enhance your diving in many ways, most of all keeping you safer. The float setup will help mark your position to others in the area and can provide emergency floatation in a time of need. The dive watch/computer will allow you to easily track you and your buddies’ surface intervals and bottom times with the automated functions that these devices provide. In addition there are other obvious utilitarian benefits to these items as well. Your float becomes your pack mule for harvesting carrying all your bits, bobs and catch while your dive watch will help you mentally map the bottom contours and locate those reefs you painstakingly researched… 

Finishing the equipment puzzle…

Lastly, build your ‘harvesting kit’

These are the tools of the trade. The options seem and are indeed limitless. By the end of your journey, I can assure you that you will own a tool for each job and always be looking for that next little gadget to help do the job better!  

Is it feasible to set yourself up for a full kit in one fowl swoop? If you’ve got the budget, for sure! Why not?! In doing so just remember to use the same mentality and approach discussed above. Be mindful of where you allocate your funds and prioritize what’s most important. For example, invest more of the allocated budget into your essentials and safety kit rather than your harvesting kit if your funds are finite. At the end of the day, we’re just trying to help shed a little light on what really counts with your spearfishing and freediving equipment when you’re starting out. 

Mindset for the Lifestyle

The final, and second most important element to becoming a competent and responsible underwater hunter (aside from the safety of yourself and others) is founded around being ethical in your marine harvesting. Take only what you need and respect the ocean which gives us so very much. Educate yourself on the marine biodiversity of your area and gain an understanding for the quarry upon which you prey. We recommend reaching out to Bottom Dwellers Freediving or the Ucluelet Aquarium for any programs they may have running that can help get you out there more sustainably and ethically Spearfishing and gathering marine life by hand and spear is amazingly rewarding and fulfilling. Become a steward of the ocean and do your best to foster this same outlook in others.  

Stay safe and make good decisions. – Mick 

Hypoxia in the Community: Episode 1 – Blackout

Author: Chris Adair
Contributions by: Brad Johnson

Our first blackout of the accounts in this series to share is that of Brad Johnson’s. Brad’s contribution to this 3 part series and this episode will be addressed as an interview more so than a written story of the events. The reason for this is one that’s relatable to the scenario and the impact these events can play in people’s lives. “I have anxiety even talking about it,” Brad says. Even though Brad was enthusiastic and keen to be included in this series and to share his story with the community he found that as he tried to put words to paper he would get emotional and mentally lock up through the anxiety that reliving the scenario would create for him.  

Rock, Paper, Scissor, Blackout…: 

Brad is a Concrete Contractor in town. He works hard, long hours and enjoys freediving and spearfishing as a meditative and mental escape from the noise and stresses of life. “It’s like a weekend of hedonistic pleasures,” Brad boisterously jokes about the joy that freediving brings him. Brad is a PFI Intermediate Certified Freediver with 30m depths under his belt on the line. He has a son and a partner that are his world and since his hypoxic event (blackout) in Mexico in March of 2020 have become even more so. 

Blackout Management Practice with Bottom Dwellers Freediving

Brad was heading down to Mexico with his partner Shannon to celebrate the completion of her 2nd year of Carpentry schooling. There were no real plans for freediving on this trip except to snorkel with Shannon when they felt like getting wet. Otherwise the two were planning to enjoy a few too many pool side tequilas and umbrella drinks in a relaxing week to get away from life’s stresses. 

One morning, well into the week of celebrations, Brad received a message from a friend and dive buddy from back home whom they happened to bump into at the airport on the way down to Cabo. Kevin was organizing a boat charter and wanted to know if Brad was keen to join too. Did that fish look bigger underwater?… Game on! Brad pauses on the holiday celebrations for a day and connects with Kevin at the boat the following morning. The boys are comfortable diving together already. They already know the gear provided by the charter and with the guides finding this out the boys get thrown right at it. Starting shallow in the ten meter zone they warm up. Deeper drops to twenty meters feel great. The water is glass, the sun is shining and the vis is all-time for the Canadian green water duo. The guide then spots a forty pound pargo at twenty meters. “Let’s get after it!” Brad’s body vibrates as he tries to contain his excitement. 

The conditions are perfect. There’s fish on the reef and excitement is high. Kevin and Brad wind up for an epic siege of Rock, Paper, Scissor to decide who gets the glory of making the first drop to the holed up pargo below. Ten bouts later Brad finally prevails. His heart is pumping from the adrenaline fuelled by the desire to get the fish in the hole twenty meters below. Without skipping a beat, Brad lays flat, takes a peak inhale and drops to the reef to hunt. He pokes around a bit and is feeling great on bottom. He can’t see/find the fish and decides to ascend. Brad gives an okay signal on the way up, hits the surface, starts going through his recovery breaths, then “whoooomph!”… peripheral collapses. 

Video of Brad’s Blackout caught on film by his dive buddy Kevin…

Brad comes around and starts making sense of what’s gone on. The in-water charter guide is holding him vertical under the arm keeping his airway above water. Brad composes himself and gets out of the water and up onto the boat. Brad had blacked out. His dive day is done and his body needs time to recover. On the boat he’s offered a cold coca cola to get some sugars in him and they recount what happened with the crew.  

Brad kicked to the surface rather hastily but was still cognitive when he hit the surface. As he hit the surface and began going through his recovery breaths Brad blacked out which most likely was from a pulmonary dump due to low oxygen levels created by pressure change. The guide being right there caught Brad and the gun and quickly flipped Brad onto his back. He removed Brad’s mask to allow him to breathe as Brad appeared to have reverted back to nasal breathing. Nasal breathing is our most natural form of breathing and is our dominant form during a blackout and other hypoxic events. Once the mask was off, Brad began breathing. He came around and was taken aback. “I was surprised and in shock”.  

I remember when I first heard about the blackout from Brad’s lips what had happened to him. I was incredibly relieved that he was okay as he is my friend and a former Bottom Dwellers student. I also remember how it felt when he first told me what had happened and how he said he was embarrassed to tell me about it. I told Brad at the time that sharing these stories will only help a freediving community grow safer and stronger. I continue to stand by my comment to Brad and it is the goal of a safer and stronger community that has prompted this series. We can learn alot from each other’s experiences and these are the types of stories that help spread awareness of the risks in freediving.  

Nothing that happened to Brad that day was anything to be embarrassed about. Brad had done what he could to rest and recover the day before and on that particular dive he had a hypoxic event. The scenario was managed well enough by the guide that was at his side when he blacked out and ultimately Brad and Kevin came out of the scenario with a learning experience and a story to tell and share.  

The question to ask here is what factors contributed to Brad’s blackout as he did on that dive? He was feeling fine on the dives and warm ups. So why did things turn so fast? Let’s take it back to the beginning to break this down a little deeper. 

The Breakdown: 

Previously when Brad has prepared for courses or trips he has made sure to put his health first. He would dedicate to cutting out bad foods, stop drinking and focus on health to get his stamina up. This trip with the charter was unplanned and last minute. With Brad going all Ricky Martin and having lived the ‘la vida loca’ lifestyle for the week prior to the dive day the first contributing variable came into play. Brad was automatically starting at a deficit which with freediving can hugely play into one’s abilities to perform. How we fuel our bodies and manage our intake and hydration levels greatly affects our performance in freediving all the way down to our oxygen efficiency.  

Excess stress on the body can lead to Blackout

Leading up to the drop where Brad had his blackout that put him on the boat there were a huge amount of psychological factors and stresses that came into play in the form of excitement. Ten rounds of the most epic Rock, Paper, Scissor game you’ve ever seen, while you’re waiting to see who gets the chance at getting that trophy fish, in a setting that you only get to dream about and visit so often in your life is more than enough to get your heart rate up and have these peer pressures and psychological stresses ramping up against you. This was even more obvious once Brad won the game with the ever coveted and powerful rock where he then proceeded to lay flat, take a peak inhale and begin his drop… without even doing a proper breathe up. Excitement had gotten the best of him. Amidst his excitement on the drop, he trips up slightly on his float line detracting from the efficiency of his descent. He reaches bottom and is hyper-focused and distracted on finding the prized fish. As he turns and begins his ascent he is already in trouble but he just doesn’t know it yet. Adrenaline, psychology, peer pressures, physical ability and lack of preparation all culminated into this scenario occurring as it did. Until Brad was able to step back, remove himself from the scenario and look at it objectively, he was unaware of how things were stacking up against him. Brad actually was “feeling great”… until he wasn’t. Another potentially deadly factor that could have gravely worsened things in this scenario was that in all the excitement throughout the day the crew had completely forgotten to do a proper buoyancy check. “I was wearing too much weight for too little wetsuit.” Brad knows how to manage his weight and understands the repercussions even more so now but the excitement of the day got the best of him and if his guide and buddy hadn’t been right there this could have been a completely different outcome. Overweighting is a common mistake many spearos make and this shows that even certified freedivers can get caught up in the excitement of things and get complacent. Being over weight when a blackout occurs is a lethal combination.

Asides from Brad’s weighting in this scenario and to take the time to do a proper breathe up there were a few other things he could have done to better his performance and lessen the risk of a hypoxic event, however, it again comes back to the fact that he was “feeling great” until he blacked out.  

I asked Brad how he has managed dealing with this event and how it shifted his mindset with freediving since. Brad had this to say: 

“It was a very humbling experience and I put the brakes on hard with freediving,” he said. “Even with all the work I’ve done with you and the goals I set, I’m now stepping back and giving the sport even more respect where it’s owed.” Brad continued “It’s not that I wasn’t as strong a diver as I was, this experience showed me how serious the repercussions can be and how important having the safety in place is… Never dive alone… You start getting cocky and that’s when you get caught. I almost got caught.”  

Blackout Preparation requires planning

Brad found he began to push freediving further aside due to the anxiety and stress it caused for him and his partner.  He was pushing away dive buddies and using work as a scapegoat to avoid getting out. A big driving factor in his desire to temporarily disconnect from the sport after this blackout experience was his love for his son and his partner whom the experience had rattled fairly hard. 

“I haven’t really been diving since. I got busy with work and the times I did get out I was really in my head. My bottom time was cut drastically and every time I’d get that ‘kick’ in the gut it would throw my whole game off.” 

Brad’s not done just yet. He’s leaving the white noise behind and getting back out there.  

“I don’t want to give up on the sport… I love it… I’m missing it big time… I get out in the water and I relax… Work and life is busy. I’ve been resetting, putting family, the girlfriend and work first and easing back to it. Lately I’m just super tentative with getting back at it but I’ll get there again soon. I’m going to leave the line and the gun at home….leave all that bullshit behind and just get out there and dive… just enjoy it again.” 

Hypoxia in the Community: Episode 2: Preview 

“Other than luck, the only thing that saved my life from this blackout was making sure I was properly weighted at the beginning of the trip. Had I been overweight and sunk no one would have been close enough to help me and I’m certain given the tide and swell that were running I would have drowned.” 

Foraging from the sea: Thinking Sustainably, Acting Ethically

Staying up too late in the darkness of your bedroom. The glow of Navionics on your phone as you scouting out those new potential zones and bottom structure. Obsessively cross checking weather patterns and systems. Checking tides, currents and visibility reports for when everything might align for that window to get you and your crew out there again. Traveling and going the distance to get a little further to that new spot, that next zone. Plunging beneath the liquid curtain and laying eyes on that new reef and what it holds in the hunt for that sustainable harvest.

Driving the sustainable mindset…

The mind of the freedive harvester is ever working and focused on that sensation and that addiction that keeps drawing them back to the sea for that shared adventure and experience. The draw to this is not only fuelled by the hunt and experience within the adventure itself. It’s fuelled by the culmination of these events bringing friends and family together around the fire and around the table to enjoy the bounty retrieved from the ocean that day. 

Honouring and respecting one’s catch through the process from start to finish. Descending into the depths on one breath. Observing, understanding and making the appropriate choices before selecting the harvest. Returning to the surface and being granted that gratifying breath as the surface tension breaks in accomplishment. The connection one feels from this is undeniably strong and beautiful. It’s this underlying gratitude and respect for the liquid environment and the resources pulled from within it that cultivates and guides the thoughts and actions of the sustainable mind in ethical ocean harvesting. 

Where it begins…

Ethical and sustainable harvesting begins with the education and knowledge to support the choices that lead to the end game you are desiring to achieve. Making decisions in the hunt that will promote the long term health of the reefs from which we are harvesting drives the mindset of most freedive-harvesters, especially of those who can truly identify as sustainable and ethical hunters. This title isn’t earned by owning a speargun alone. In fact, spearfishing can have adverse effects on a reef if the wrong choices are being repeatedly made once someone becomes proficient at freediving and hunting. Where then do these ethical and sustainable choices start? 

Identifying your Target: 

A hunter should always have a strong knowledge base of species identification. This is even more important with regards to the species being harvested. Knowing the specific species you are targeting and the physical traits to identify them is where to start with this. Once you have learnt how to identify between the specific species it’s important to learn more about each of these species before you begin your hunt. Consider what facts and traits about this species make them a sustainable and ethical choice or not.

Species identification does not start and stop with the ability to distinguish between different species however. There are decisions to be made surrounding each species’ specific characteristics which take the decision making process even further. Species specific size characteristics, rate of maturity (Baby making prowess… cue the Marvin Gaye), overall knowledge of life spans of the species and seasonal habits such as nesting and mating. These pieces of information among others all play into the choices of ethics and sustainability in freedive-harvesting and spearfishing.

I.D. Resources

Some fantastic hardcopy resources to check out to get more informed are available from Harbour Publishing who have a selection of different books and field guides relevant to our waters. Another fantastic way to learn a little more about your local species would be to check out a local aquarium. The Ucluelet Aquarium, the Shaw Centre for the Salish Sea and the Vancouver Aquarium all hold exhibits which can inform you and show you real life examples of specific species you’re interested in learning about. 

This title isn’t earned by owning a speargun alone. In fact, spearfishing can have adverse effects on a reef if the wrong choices are being repeatedly made once someone becomes proficient at freediving and hunting.

Is there anybody home? 

Being present and spending time on the reefs we’re harvesting from allows us the opportunity to physically observe the state of the reef we’re hunting before making any decisions on what we’re removing. We generally have a good idea of what we’re after and the goals of our harvest before we even get in the water, however, being able to lay eyes on the reef and see the diversity in species and the population density of specific species allows us to momentarily gather information to better assist in more sustainable and ethical choices. If you are noticing an abundance of fish of a certain species on the reef, ask yourself why. Should you notice that the reef only has limited numbers of specific species, again ask yourself why and then consider if taking any of those species would be a sustainable and ethical choice.

Ongoing questioning allows us to take a step back, create correlations, make better decisions and ultimately learn from our experiences. We can learn a lot by observing from even one drop to a reef. The more drops we make in a zone, the more we learn about the area and general trends.  The more knowledgeable we become, the better decisions we will make. 

It was ‘thiiiiiis’ big… 

For freedivers that are spearfishing or hand harvesting the ultimate goal is to get out and collect what’s desired and needed for the table. We do, however, sometimes get caught up in our natural competitive tendencies which may guide and steer us further away from our ultimate goal than we’d like. Beating your own personal best (PB) or pulling out a bigger fish than your buddy did last season are some examples of the mentality that can get us caught in this scenario.

Throughout the Freedive-Harvesting courses with Bottom Dwellers Freediving we address this social dilemma and age old story as “the hunt” and acknowledge how easily it is that we can get caught up in it. The fact of the matter with fish is that with most fish species bigger fish are better and more successful breeders. There is a-lot to be said for leaving the bigger fish to swim another day to allow them to continue breeding and help sustain the reefs’ populations. Ultimately, the most sustainable and ethical choice would be to select a fish that is large enough to warrant the purpose of taking for your meal/meals but that is also not in the biggest class of fish on that reef. Limited time on each drop and that competitive edge engrained in many of us can affect our ability to make clear decisions under pressure.

Checking in… Ego or Sustainable?

It’s important to check in and remember the reasons as to what brought you to the reef, the goals you had before getting there and staying true to these as best you can. I’ve been in the position before where I have regrettably taken big fish off reefs I had said I wouldn’t anymore after having imposed my own size restriction caps on certain species for myself’. In this particular instance I ended up taking a fish that I truly didn’t want for any reason other than to attempt to beat out my previous best.

There there were plenty of other options around on the reef to put fish tacos on the table that day but the hunt got the best of me. In the end I was rewarded with nothing but a heart sinking feeling with the decision I made in taking this fish. It was exactly the same weight as my previous best. That lapse in judgement was enough to bring me back into check about where my intentions really were at the time of that dive and how I now operate on that particular reef to this day.  

Keep it diverse, Keep it Sustainable

You’re now identifying the species you’re after. You’ve made the effort and taking the time to get educated on the specific characteristics of those species. You’re observing the state of the reef and its overall composition. The next step in sustainable and ethical harvesting is to remember to switch the focus of your targets and to keep your catch bag diverse. Being diverse in your harvest takes the pressure off the specific species that you focus on and target more regularly. Taking the time to learn new species that are edible and that you can enjoy will go a long way with keeping your reefs healthier in the long run.

We’re incredibly fortunate in the Pacific North West to be able to enjoy the abundance of edible harvest accessible from our ocean. Lingcod, rockfish, greenling, crabs and prawns are the top taco contenders but by diversifying and moving away from the common targets the world becomes much more than just your ‘oyster’. Learning to enjoy sea urchins, gooseneck barnacles, sea cucumbers, sea weeds, kelp, a variety of bivalves and univalves unfolds a smorgasbord of bountiful beautiful harvest accessible with the right knowledge, understanding, skill sets and a Tidal Water fishing license.


Over Sharing…

We’ve already mentioned the negative effects that social media can have with the effects of peer pressure and competitive edge. Location mapping and landmarks however are by far the worst side effect social media has on a reef and adventure sports in general. The physical pressure that gets put on a reef as knowledge that it holds good fish spreads can have terrible side effects. Even more so as it gains popularity as a productive hunting site. For these reasons, and as my own general rule, I do not share locations on public forums, including this article.

We’ve seen reefs with once good fish populations that are now suffering due to geographic location and ease of accessibility. The unceasing and relentless pressure put on these common knowledge locations by different groups of divers being the primary cause for this. There’s nothing wrong or rude about not sharing a spot over social media. In fact, I applaud people on holding those spots close and keeping them sacred. By sharing locations I’m not just talking about saying the location name or area, it also comes down to being flagrant with your use of landmarks in social media posts.

Blowing up your spot

People are generally pretty smart. By knowing the general area you were in, using a few extra digital tools and a little local knowledge it can be pretty easy to pick spots out for their location. Prior to social media, people had to explore and find their own locations for whatever activity they were doing. The only way they found out where spots were was by word of mouth and maps. Everyone wants the quick fast track to that next best spot and keeping those spots close to you is the best way to preserve them.

I’m a big advocate of this approach with locations. Even with some of our closest dive buddies there is a “you know when you go” mentality that we run with for some locations and pride is held in keeping those zones undisclosed. The best part is that your true dive buddies will understand and respect this if they’ve ever had to work for spots of their own at some point. It’s about protecting those spots that you care about from the devil that is social media when it comes to geo-tagging and locations.

You owe it to that reef that’s provided you with those bowls of ceviche, those fish tacos and those sensual scallop medallions. You owe it to the reef and all the species on it. As sustainable as freedive-harvesting and spearfishing can be it can have negative effects. If too many people are hitting the same spot it will undoubtedly have negative side effects on those heavily targeted species if it’s easy enough to access. 

Sustainable and Ethical Mindset

There’s a lot that comes together to own the title of a sustainable and ethical harvester. This mindset and lifestyle is more than just freediving and spearfishing. It’s about utilizing knowledge and understanding so that one can make the right choices while on the hunt to promote sustainable and healthy reefs for the future. It’s about respecting and cherishing that environment and what it provides. We’re always learning, improving and bettering ourselves. Being open to conversation, and being humble and respectful of each other is what will continue to grow a healthy, positive and sustainable freedive-harvesting community. Enjoy those experiences. Enjoy those fires and meals with friends and family and do so in a way that will allow for the next generations to come to do so as well. 

Dive Safe and enjoy those bigger picture tacos,

Author: Chris Adair

Hypoxia in the Community: Prologue

The topic of blackouts is a common discussion throughout freediving communities. Risk management, awareness and preparedness are vital components to competently and safely managing these scenarios when they occur. Management of these hypoxic events begins with being educated on the subject of hypoxia, understanding why these events occur and learning how best to manage them.

There is no ignoring that hypoxia and in turn hypoxic events occur in freediving. Turning a blind eye to the reality of this is one of the more reckless things that one can do in this beautiful sport. A hypoxic event is a response our body has due to the depletion of oxygen in the cells, tissues and/or body as a whole. This is known as hypoxia. Hypoxic events are more commonly described as ‘blackouts’ and ‘near blackouts’ which are also known as Loss of Motor Controls (LMCs) and Sambas. It’s very likely that if you stick with this sport long enough you will witness one of these events at some point first hand.  

Acknowledging the Disconnect: 

It is apparent that there can, at times, be a disconnect between recreational freedivers and the reality of blackouts and LMCs. It can be easy to remove ones’ self from the fact that events like this can occur until a hypoxic event has either been experienced or witnessed.  Free divers generally acknowledge the risks of hypoxia but at times there is a lack of respect when it comes to embracing the protocols and management systems that were created and designed to be implemented to help minimize the dangers and risks associated with these events. Unfortunately, it often takes this first hand experience before many freedivers acknowledge the reality of the risks associated with the sport. To help bridge that gap with this disconnect we have asked a few local freedivers to share their first hand experiences with hypoxic events for us.

Our hope, through this, is to allow the lessons learned from some of our community members’ experiences to shed light on the reality of this subject. Before diving into the dirty details of these stories with our local community members we need to bring it back to our two previous questions. Why do these hypoxic events occur and how do we manage the scenario at hand when they do occur? 

The basics of a blackouts hypoxia

Having a proper understanding of the physics and physiology of freediving is beneficial on many levels in this sport. One of the ways it will benefit you is by allowing you to better understand hypoxia and why these types of hypoxic events occur. Nerding out on the science and having a full understanding of Boyle’s Law and Dalton’s Law of Partial Pressure will help you better understand the relationships between pressure, volume and density. It is within the scientific relationships guided by these 2 laws that we become more susceptible to hypoxic events as we freedive.  

The purpose of this blog post isn’t to give you a full lesson on the science behind hypoxic events as there is a lot of great instructional material, programs and courses out there that fulfill that need. The general basics however can be broken down as follows to help you better understand hypoxic events. 

Hypoxia and the types of blackouts

There are two main types of blackouts in freediving that we will focus on. Performance Freediving International (PFI), which is the instructional system that I instruct at Bottom Dwellers Freediving, classifies these blackouts as ‘ascent’ and ‘recovery’ blackouts. The type of blackout is defined by the mechanisms that contribute to the blackout itself. In general, when blackouts are discussed in freediving they get tossed under the veil of ‘shallow water blackout’. Scientifically there are ways to distinguish between the mechanisms which create those blackouts and in this blog we’ll focus on the two mentioned above. 

Boyle’s Law

Water is dense… much more dense than the air of our atmosphere. Salt water is even more dense than fresh water but, for these general purposes, it’s not enough to make a notable difference and we’ll just focus on the salty brine that we all love and enjoy so much. As we freedive and move deeper through the water column, pressure increases fairly rapidly.

Pressure is measured in units known as Atmospheres of Pressure (ATA). For every additional ten meters of depth in this salt water environment, an additional 1 ATA will be felt. Thus, by ten meters of depth we will already be subjected to a second ATA of pressure doubling the amount of pressure that was exerted on our bodies while at the surface. This change in pressure is shown as 1 ATA at the surface and changes to 2 ATA at ten meters of depth. According to Boyle’s Law and assuming that temperature remains the same (which we will for these basic purposes) there is an inversely proportional relationship between volume and pressure. This indicates that at ten meters of depth (and now 2 ATA) our lung volume would already now be half (i.e. 1 over 2, ½ or 50%) of what we had at the surface. Now that’s a pretty drastic change in your lung volume and we’ve only descended ten meters! As we continue to dive deeper pressure continues to increase by 1 ATA for every ten meters of depth, while volume continues to show the inversely proportional relationship to pressure.

Have you ever been freediving and felt like you’re out of air at fifteen meters even though you only left the surface fifteen seconds prior? This is due to the relationship between volume and pressure, the reduced volume of air that is now occupying your lungs and how the autonomic functions of your body are responding to this volume decrease. At twenty meters of depth and 3 ATA your lung volume will now be one third (33%) of what it was at the surface. You might assume that this would indicate lower oxygen levels at this depth but that would be incorrect. This is where Dalton’s Law comes into place.  

Ascent Blackouts

Although increased pressure results in decreased volume, this reduction in volume actually increases gas density. This relationship allows your body to access more oxygen for cognitive behaviour under the added pressure than you would otherwise have access to at the surface. Pretty amazing right!? That same amazing relationship between physics and our physiology is actually the reason we are so susceptible to blackouts and LMCs while freediving. By pressurizing our body and utilizing the oxygen (which we would only realistically have access to while at depth under pressure) we subject ourselves to a scenario where we’re able to utilize more of the oxygen we would require for cognitive and conscious behaviour at the surface while operating at depth without even knowing we are doing it.

These relationships in Boyle’s and Dalton’s laws are why we become so susceptible to hypoxia and blackouts while freediving, in particular, on our ascents where the relationships are reversed. As pressure decreases, the volume of air in our body begins to increase. The density of oxygen in the blood, cells and tissues then in turn begins to decrease. As a result, our cells and tissues are spontaneously robbed of the oxygen we now require for cognitive behaviour, resulting in an ‘ascent’ blackout due to critical hypoxia.. The mechanisms to create an ascent blackout and the partial pressure of oxygen (PO2) flip, described above, is directly related to these laws and the relationships between pressure, volume and density as well as the rate of oxygen consumption by the freediver. 

Recovery Blackouts

Recovery blackouts have slightly different mechanisms in place but are as directly related to the affects pressure has on our body as ascent blackouts. During recovery blackouts critical hypoxia is reached upon surfacing and is correlated to blood pressure disruption which occurs due to the reduction in pressure on ascent. This is why recovery breathing is implemented in freediving. It combats the blood pressure disruption which, if left unchecked, can result in the recovery blackout which accounts for the majority of blackouts in freediving. 

Now that we have a solid understanding of the basic science behind hypoxia and the reason these two most common types of blackouts occur it is also important to consider what types of scenarios lead us to these situations. Regardless of how well trained an individual is in freediving, we are all susceptible to hypoxic events. This is why the number one rule in freediving is to never freedive alone.

Education and Training

The most valuable training accessible to anyone starting out in this sport is the training one gets from a basic level certification from a credible agency and certifying body. These certifications instruct you in the fundamentals of freediving with a focus on proper buddy system diving. There are many credible agencies out there to choose from, including but not limited to: PFI, AIDA, SSI, and Molchanov. The most important thing when starting out is to get some formal training right out of the gates. Having the proper training under your belt will set you up to be a safer, more proficient and more confident freediver.  In the event that a blackout or LMC should occur in front of you in a live diving environment you will have been prepared with hands-on experience in the motions of managing someone through some of these potential scenarios. Regardless of how well trained you are, if you’re diving alone you will be rolling the dice on your well being. It’s as simple as that. 

“I know my limits and dive within them… I’m fine…” is a sing-song we hear all too often in the world of freediving.

The variables with hypoxia

Now let’s brush the surface on what types of scenarios and variables contribute to hypoxia or increase the likely-hood of a blackout or LMC. General health, physical ability, physical environment, stress levels, peer pressures and the psychology behind freediving as well as general diet and habits all play into each and every dive we take. Freediving is an extremely mental sport and one of the most beautiful moving meditations one can experience. Finding the beauty in the ‘flow state’ which freediving provides is what draws many individuals deeper and deeper into the sport. It is used for cross training amongst many high level athletes to sharpen and strengthen the mind as well as train oxygen efficiency and carbon dioxide (CO2) tolerance. The mental aspects of this sport can, however, play against us and undermine us at the worst of times.

All of the variables mentioned above can play into our dives and our ability each and every day. “I know my limits and dive within them… I’m fine…” is a sing-song we hear all too often in the world of freediving. The fact of the matter is that there are just too many variables involved to always be in control and that’s why having a buddy there can mean the difference between diving another day or not. Some simple things you can do to enhance your abilities, performance and safety with freediving are the following: Dive in buddy systems with proper freediving supervision (i.e. one up, one down). Always complete your recovery breaths. Have a clear mind. Dive rested. Eat well/healthy, hydrate and follow surface-interval protocols. Being in-tune with yours and your dive buddies’ health and well-being will provide awareness that can benefit and add to the enjoyment and safety of your dives. 

Risk Management: Learn it to Execute it 

So what do you do if a hypoxic event affects your buddy during a dive? How do you properly manage this scenario? Unfortunately, this isn’t a topic that is easily and fully coverable in a blog but we have a valuable resource that we will provide you with to help get you a better understanding of the ins and outs of these processes. Ted Harty is owner of Immersion Freediving out of Florida and is a veteran PFI Freediving Instructor. In recent years he has created an online self paced instructional resource called . This website was designed and created by Ted to help raise awareness on the subject of hypoxic events in freediving due to demand with regards to the ever growing number of cases in the sport. provides a free online safety course. You will learn the truth about blackouts, how to minimize your risk, how to potentially save your buddies life should a blackout occur, as well as how to tell if you are wearing too much weight (you likely are…). While this online course is not a substitute for the hands on skills you learn in an in-person freediving class, it’s an excellent starting point from a trusted and reliable source.

We highly recommend that if you’re practicing breath holding in a liquid environment while freediving or snorkelling to any capacity, head over to the link provided and take the Freediving Safety program online. This program will virtually run you through basic freedive safetying protocols and techniques with a goal to make this basic knowledge more accessible to the general freediving community. This online course is not a replacement for the formal and hands on training you will get in a certifiable freediving course, however, it’s great knowledge to have access to if you’re getting out there before getting the chance to get a course under your belt. 

Making the Connection

Now let’s make the connection of the knowledge learnt here to real life events by showcasing real community members’ stories and scenarios. To do this we’ve reached out to 3 local Vancouver Island freedivers who have all experienced hypoxic events and blackouts in live diving environments in the last few years. These are real life examples and stories from our small and ever growing freediving community on the west coast of Canada. Brad Johnson, Galyn Franklin and Josh Marek have all shared their stories with one communal goal. The hope is that through bringing these stories from our local waters into perspective for the readers that we will shed a little more light on the reality of blackouts in freediving and the scenarios that surround them. Join us for Hypoxia in the Community: Episodes 1-3 for the first hand stories, emotions felt from the events at hand and the experiences learnt throughout these endeavours. 

Dive Safe,
The Spearfishing Canada team

Author: Chris Adair

The Inception of Spearfishing Canada: The Very First Breath Hold

Spearfishing Canada believes in the concept that freediving and spearfishing is for everyone. Our dream is to share that idea and the sport which has given us so much with all Canadians through our online community. We launched Spearfishing Canada (SFC) in June 2020 though the inspiration and journey started way before SFC was live. 

Where it began…

SFC was founded by three friends who crossed paths in a variety of different ways. Via an interwoven path created by the freediving and spearfishing community we became friends, business partners and fellow Canadian freedivers. We hold these labels thanks to the ocean and everything within it including the surrounding community fuelled by the love of exploring and preserving our local liquid environment. 

Mick Sheinberg – Operations

The story really starts With Mick Sheinberg. Mick grew up in Australia diving and spearfishing with friends on the Sunshine Coast. His Passion for the sport grew as he travelled around the globe diving in various locations. Mick didn’t however get serious about diving until moving to Canada to live on Vancouver Island. This is when Mick Joined HTO Surf Shop which gave him a vessel to pursue diving and spearfishing as an occupation and as a lifestyle. HTO began stocking freediving and Spearfishing equipment which immediately attracted likeminded aquatic-enthusiasts and sustainable marine harvesters. After Exiting the retail game to pursue a career as a firefighter with the city of Victoria. Mick at this point endeavoured to continue supporting the local spearfishing community by supplying high quality gear to eager divers. Through his desire to educate divers on the importance of sustainability, safety and the best equipment to use, Mick founded the vision for Spearfishing Canada.    

Chris Adair – Freedive Pro

In 2013 Chris Adair found out HtO was carrying Spearfishing gear. He hadn’t been spearfishing since he was 16 in the Mediterranean, but it was something that had always captivated his interest. Chris has always thrived in a liquid environment. Growing up surrounded by the waters of Vancouver Island made his upbringing semi-aquatic. Taking the values instilled by his family throughout his childhood, he found himself enjoying the principles associated with hand harvesting and spearfishing in the local ocean environment. As his addiction grew, Chris took his first recreational freediving course through PFI international. Chris is now an Intermediate PFI Freediving Instructor and owner of Bottom Dwellers Freediving. Bottom Dwellers offers Freediving Courses teaching students to freedive up to depths of 40m/135’ as well as Sustainable and Ethical Harvesting Programs. With the retirement of HtO Surf Shop (RIP) in July 2019 there was a void in respects to the accessibility of freediving and spearfishing gear locally. Since that day Spearfishing Canada and this local online community has been in the works to facilitate the need. 

Iwan Williams – CFO

In 2013 Iwan Williams started snorkeling and diving with friends in the pursuit of hand-picking Dungeness Crabs. This quickly spiralled into Iwan buying his first Riffe speargun from HTO and Mick Sheinberg. This took Iwan on a 3-year adventure throughout Vancouver Islands coastal regions in the pursuit of underwater exploration. In 2017 he took his first freediving course with Bottom Dwellers where the passion only continued to grow. Later that same year with a few of his aquatic brethren Iwan started, “Whistle Buoy Brewing Company”, a brewery in Victoria BC. The brewery’s name itself coming from a reef that these friends would regularly dive in Bamfield known by the locals as “Whistle Buoy Rocks”. These experiences and relationships propelled Iwan towards being part of the SFC concept.   

Big things to come!

Through the years, the trips and the adventures together. From HTO to Bottom Dwellers, to Whistle Buoy Brewing Company, to the Canadian Spearfishing Association and now Spearfishing Canada, the part we’re playing in the freediving and spearfishing community continues to grow. As exciting as this is for us all it’s great to be part of something so inclusive and so much bigger than ourselves. We all feel incredibly lucky to be where we are right now and growing with the community we’re proud to call ourselves a part of. 

It’s a great time to dive! Just as the title implies, we were addicted from the very first breath hold. 

Author: Iwan Williams

@spearfishingcanada on Instagram #spearfishingcanada