Before you spearfish — this comes first
- Get proper instruction before you spearfish. A recognised freediving or spearfishing course teaches the things that actually kill people in this sport, and reading about them is not the same as being taught them.
- Dive with a buddy, and dive one up, one down — one diver in the water, one on the surface watching them, every dive. A breath-hold blackout is silent and gives no warning; a watching buddy is the difference between an incident and a fatality.
- Stay inside your own training and experience. Depth and breath-hold times are personal, they change day to day, and nobody else's numbers apply to you.
- Understand the conditions before you enter the water: visibility, current, swell, tide, boat traffic and your exit. Conditions decide whether a dive is reasonable far more often than skill does.
- Use equipment you have been shown how to use, check it before every session, and be visible — a marked float and line are how boat traffic knows you are there.
- Never extend a dive for a fish. No catch is worth pushing a breath-hold, and the urge to take one more second is exactly what a blackout feels like from the inside — which is to say, like nothing at all.
Stalking
Method · Last reviewed 2026-08-10
Moving quietly over ground to find fish rather than waiting for them — the technique that covers water, and the one that costs the most oxygen for the least return if done badly.
Safety
Shallow water blackout and breath-hold loss of consciousness — Can cause serious injury or death
Stalking accumulates fatigue and oxygen debt across a session in a way that waiting does not. A diver who has been working hard has a shorter safe breath-hold than they had an hour earlier, and the sensation of comfort does not track the actual margin.
What reduces it: Rest on the surface for considerably longer than the dive took, and lengthen that as the session goes on rather than shortening it. Set dive times on the surface. Dive one up, one down. Never hyperventilate — the comfort it buys is exactly the warning that would otherwise arrive.
Worse when:
- Late in a session, when fatigue has accumulated
- When working against current
- On repeat dives with short surface intervals
Sun, dehydration and fatigue — Can cause injury needing treatment
Sustained swimming in a wetsuit is hard physical work, and dehydration through sweat inside a suit is invisible and substantial. Both degrade judgement and both make blackout more likely.
What reduces it: Drink before and between sessions rather than when thirsty. Treat a long swim as exercise and plan food and fluid accordingly. End the session on fatigue rather than on time.
Precautions that always apply here
- Never spearfish or freedive alone.
- Dive one up, one down: one diver down, one on the surface actively watching, every single dive.
- Never hyperventilate before a breath-hold. It delays the urge to breathe without adding oxygen, which is precisely the mechanism behind shallow water blackout.
- Tell somebody where you are going and when you expect to be back.
Stalking is the active counterpart to aspetto. Instead of settling and waiting, the diver moves — over reef, along a kelp edge, across a sand channel — looking for fish and closing on the ones worth a shot.
It exists because waiting only works where fish already are. On unfamiliar ground, on ground that holds fish thinly, or when the aim is to find out what is there, somebody has to go and look. Stalking is how the ground gets learned, and most divers spend far more of a session doing it than they realise.
The difficulty is that swimming is expensive. Every fin stroke costs oxygen, which shortens the breath-hold, which shortens the time available to do anything when a fish is found. A diver who stalks hard for twenty minutes has less left than one who has been resting between short dives, and the fish do not care.
So the technique is really about economy. Slow, long, unhurried fin strokes rather than fast ones; a route planned to use current rather than fight it; and the discipline to stop moving the moment something is seen, because a diver who is still swimming when a fish notices them has already lost the encounter.
What it is
Active breath-hold spearfishing in which the diver moves over ground searching for fish and closes on them, as distinct from descending to a fixed point and waiting. Covers surface swimming to locate ground and the descents made once something is found.
How it works
The diver works a route at the surface or at mid-depth, scanning for fish and for the structure that holds them, and descends when there is a reason to. The approach itself is oblique rather than direct and slows to nothing as range closes: a fish that sees a predator swimming straight at it leaves, and a fish that sees a large object drifting past frequently does not. Current is used rather than resisted wherever the ground allows, because a drift is free and a swim is not.
What it is for
To find fish on ground where none are known to be holding, to learn unfamiliar ground, and to cover more of it than any stationary technique can.
Setting it up
- Move slowly. Speed costs oxygen and buys nothing except distance you did not need.
- Plan the route so the current works for you, especially on the return leg.
- Approach obliquely and stop before you are close, rather than closing and then stopping.
- Look at structure, not at open water — fish are where the ground gives them a reason to be.
- Keep the gun forward and roughly aligned. Raising it as the fish appears is the movement that turns it.
Advantages
- Covers ground, which is the only way to find out what is on it.
- Works on unfamiliar water where there is no known holding spot to wait at.
- Builds the knowledge of ground that makes every later session better.
- Keeps a diver warmer than sitting still, which matters in cold water.
Limitations
- Expensive in oxygen, which shortens every breath-hold that follows.
- Announces the diver's presence across a wide area rather than a small one.
- Less effective than waiting on ground already known to hold fish.
- Fatigue accumulates, and fatigue is a safety variable rather than a comfort one.
Conditions
Stalking needs visibility good enough to see fish at a range where an approach is still possible — in poor visibility a diver is on top of a fish before either knows it, which wastes the encounter and occasionally alarms both. Manageable current is essential, because working against it is where sessions are lost. It suits varied ground with structure to work along; over featureless bottom there is nothing to search and waiting is usually better.
Common mistakes
- Swimming too fast, which is the single commonest error and the most expensive.
- Approaching head-on, which reads unambiguously as hunting.
- Continuing to move after a fish has been seen.
- Working against the current on the way out and having nothing left for the way back.
- Treating the surface swim as travel rather than as part of the session's workload.
Why a stalking diver runs out of margin differently
Waiting and covering ground can both end in a blackout, and they arrive there by different routes. The distinction is worth making because the countermeasure differs, and because the route this technique takes is the less obvious one.
ASPETTO'S ROUTE IS THE EXTENDED DIVE. The diver is comfortable, still, and watching a fish approach, and the decision to stay a few more seconds arrives exactly when the oxygen margin is smallest. The countermeasure is a time decided on the surface and honoured in the water regardless of what is swimming towards you.
STALKING'S ROUTE IS ACCUMULATED DEBT, and it is the trap because every individual dive feels safer. Movement raises oxygen consumption and carbon dioxide production, so recovery takes longer than it used to; a diver who keeps the surface interval constant while working harder arrives at each dive with less than they had at the last. The deficit builds ACROSS a session rather than within a dive, and the blackout, when it comes, comes on a dive that felt entirely ordinary.
SO THE SURFACE INTERVAL IS THE CONTROL, AND IT HAS TO LENGTHEN as a covering-ground session goes on rather than stay constant. The instinct is the opposite: the ground has not been covered, the light is going, and the obvious economy is to get back down sooner. That economy is the mechanism.
AND THE BUDDY PROBLEM IS SPECIFIC TO THIS TECHNIQUE. One-up-one-down assumes a diver on the surface can see the diver below and reach them. Two divers covering ground drift apart within minutes without either noticing, and at that point there are two solo divers who both believe they have a buddy. The countermeasure is a pattern agreed on the surface — who leads, how far apart, and how often contact is re-established — settled before the entry rather than negotiated by hand signals afterwards.
WHAT THIS PAGE WILL NOT DO IS TELL YOU HOW LONG TO REST. Recovery is individual, changes with the day, the temperature and the work done, and a published interval would immediately become a number to beat. That is what a recognised course is for, and it teaches it with somebody watching — which is exactly what a website cannot do.
THE ONE RULE THAT IS SAFE TO PUBLISH: if the question 'should I surface now' has occurred to you, it has already been answered. Surface, rest longer than you think you need, and go again.
Authoritative guidance
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Freediving safety practice: hypoxic blackout, its absence of warning symptoms, the ascent as the highest-risk phase, and the surface supervision that addresses it.States this directlyPassage read and verified
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Diving safety guidance covering buddy protocol, shore and boat diving practice, entanglement and the incident patterns behind them.States this directlyCitation checked — the work exists and is described correctly
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Technical and sporting standards for underwater activities, including spearfishing conduct, technique convention and the safety expectations set by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
The identification cost of a shorter look
There is a selectivity cost to covering ground that is rarely stated, and it matters because selectivity is the argument this whole discipline rests on.
A WAITING DIVER WATCHES A FISH APPROACH for several seconds, from a fixed position, with time to see the flank, the fins, the size and the condition. That is an unusually good look by the standards of any fishing method, and it is what makes the claim 'a spearfisher can decline the fish' true.
A MOVING DIVER FREQUENTLY GETS ONE LOOK AT AN ANGLE, in worse visibility, with the fish already reacting. The pressure to decide quickly is real, and it is the pressure that produces shots at unidentified fish, at undersized fish, and at fish presented where the tip cannot hold.
THE STANDARD DOES NOT RELAX BECAUSE THE ENCOUNTER WAS BRIEF. `lookalike-species-and-why-uncertainty-means-do-not-shoot` states the rule and it is not conditional on how good the look was: uncertainty means the shot is not taken. In practice that means DECLINING MORE SHOTS while covering ground than while waiting, which feels like the technique working badly and is the technique working correctly.
THE PRACTICAL CONSEQUENCE for a diver learning ground: the first passes over unfamiliar water are for finding out what is there, not for shooting. A diver who treats a survey swim as a hunt takes the marginal shots, and the marginal shots are where the wounded fish, the undersized fish and the protected species come from.
AND WHERE COLOUR HAS GONE, SHAPE IS THE ANSWER. `why-colour-disappears-with-depth` and `identifying-fish-by-shape-when-colour-is-gone` cover the mechanism; the point here is that a moving diver loses colour cues and time cues at once, and shape and behaviour are what remain.
Spearfishing is regulated differently in every jurisdiction and frequently differently within one — on equipment, on areas, on seasons, on species, on minimum sizes, on the use of any breathing apparatus and on who may do it at all. Those rules change. Check the current rules with the authority for the water you are diving before you go.
Authoritative guidance
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Technical and sporting standards for underwater activities, including spearfishing conduct, technique convention and the safety expectations set by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- BlueWater Hunting and Freediving — BlueWater Freedivers, Ventura, California, 1995 (Practitioner report)Relied on for: Established practitioner description of spearfishing technique, ground selection and rigging, recorded as practitioner literature rather than as scholarship.FishingHQ's interpretation of what it saysCitation checked — the work exists and is described correctly
- General angling website restatements of established technique — Various (Credible secondary source)Relied on for: Widely restated descriptions of established spearfishing practice and equipment convention, recorded as practitioner consensus rather than as scholarship.Background and mechanism onlyCitation checked — the work exists and is described correctly
Where to go next
Related techniques
What these connections rest on (1)
Authoritative guidance — 1 connection
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
Spearfishing
A technique claim with a safety consequence — accumulated exertion shortens every subsequent breath-hold — which is why it is held above practitioner level.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: That exertion and accumulated fatigue increase hypoxic blackout risk, and that surface intervals must be proportionate to the workload as well as to the dive.States this directlyPassage read and verified
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Dive planning and buddy protocol for breath-hold activity.FishingHQ's interpretation of what it saysCitation checked — the work exists and is described correctly
Skills behind it
- How fish behave towards a diverApproach angle is the whole technique: a diver swimming straight at a fish reads as a predator hunting, and one drifting obliquely past frequently does not.
- Shallow-water blackout: what it is, and why it gives no warningExertion raises oxygen consumption, so an active approach shortens the available margin without changing how the dive feels.
What these connections rest on (2)
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
How fish behave towards a diver
A behavioural claim at practitioner level, with the underlying biology supported separately on the concept record.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: General in-water conduct and its effect on marine life encounters.Citation checked — the work exists and is described correctly
- General angling website restatements of established technique — Various (Credible secondary source)Relied on for: Widely restated practitioner accounts of fish flight response to divers.Citation checked — the work exists and is described correctly
Scientific evidence — 1 connection
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
Shallow-water blackout: what it is, and why it gives no warning
Technique bears directly on the rate at which the margin is spent.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: The physiology of hypoxic blackout, including the carbon dioxide basis of the urge to breathe and the ascent-related fall in oxygen partial pressure.States this directlyPassage read and verified
Compared with
What these connections rest on (1)
Practitioner consensus — 1 connection
Widely and independently recommended by experienced anglers and specialist sources. This is real angling knowledge, not proof: controlled evidence for it is limited, and FishingHQ records it as convention rather than as a demonstrated effect.
Aspetto (waiting)
A comparison a diver makes on every session, and the trade — energy against search — is the substance rather than the technique descriptions.
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: In-water conduct and energy management for breath-hold divers.Citation checked — the work exists and is described correctly
- General angling website restatements of established technique — Various (Credible secondary source)Relied on for: Widely restated practitioner accounts of the trade-off between waiting and searching in spearfishing.Citation checked — the work exists and is described correctly
A comparison a diver is genuinely choosing between, joining two records that resolve one another.
- CMAS technical and sporting standards for underwater activities — Confédération Mondiale des Activités Subaquatiques (Standards body)Relied on for: Breath-hold spearfishing as a defined discipline with its own technical, equipment and safety standards, set out by the international underwater federation.States this directlyCitation checked — the work exists and is described correctly
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: That the safety requirements of breath-hold diving apply across the discipline rather than to particular equipment or techniques within it.States this directlyPassage read and verified
Sources for this page
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: That exertion and accumulated fatigue increase the risk of hypoxic blackout, and that surface intervals must be proportionate to the dive and the workload.States this directlyPassage read and verified
- BSAC diving safety guidance and annual incident report — British Sub-Aqua Club (Water-safety or diver-training authority)Relied on for: Buddy protocol and dive planning for breath-hold activity.FishingHQ's interpretation of what it saysCitation checked — the work exists and is described correctly
How FishingHQ labels evidence is explained in the evidence policy.