Sharks: the actual risk picture, and the behaviours that matter

Almost everyone who spends time in the ocean has thought about sharks, and almost nobody has adjusted their behaviour in ways that meaningfully change the odds. That gap is worth closing in both directions: the fear is disproportionate, and the small number of things that do matter are worth knowing.

Calibrating the risk

Shark bites are rare events. Across the enormous number of hours humans spend swimming and surfing worldwide, the number of incidents is very small, and the number of fatal incidents smaller again.

For essentially any ocean user, the drive to the beach carries more risk than the water does. Drowning, sun exposure and being hit by your own board are all far more likely to hurt you.

None of that means the risk is zero, or that it is uniform. It varies enormously by location, season, time of day and what you are doing, which is why blanket reassurance is unhelpful and so is blanket fear.

What raises the risk, concretely

Time of day. Dawn and dusk are when many species feed and when visibility in the water is poor. Low light reduces a shark's ability to identify what it is approaching, and misidentification is the mechanism behind most bites on humans.

Murky water. Same reason. River mouths after rain, sediment-heavy water, and surf full of sand all reduce visibility.

River mouths and channels, particularly after heavy rain, which flushes organic material and attracts fish.

Bait activity. Diving birds, fish jumping, seals working a school. That is a feeding environment, and being in the middle of one is genuinely a poor idea.

Seal colonies. In regions with large predatory species, proximity to seal populations is the single most significant location factor. A person on a surfboard in a seal area is in the habitat of an animal that hunts things roughly that size and shape.

Being alone, and being far from shore.

Bleeding, including from a fresh reef cut — worth avoiding on principle regardless.

What actually reduces it

Swim and surf during the middle of the day, in clear water, with other people, at patrolled beaches where there is monitoring.

Get out if you see bait fish being worked, or if birds are diving, or if seals suddenly leave the water.

Avoid the mouths of rivers after rain.

Do not wear shiny jewellery, which flashes like fish scales in the water.

Pay attention to local information. Regions with genuine shark activity have monitoring, tagging alerts, spotter programmes and local knowledge. Use them — they exist because the local risk is real enough to justify the infrastructure, and the same infrastructure tells you when it is fine.

Deterrent devices, honestly

Electrical deterrents that produce a field around the wearer have the best evidence base of the available options, with published testing showing a reduction in interactions for some devices in some conditions. They are not a guarantee, the evidence is species-specific, and effectiveness varies considerably between products.

Magnetic and chemical deterrents have weaker support. Patterned wetsuits intended to disrupt recognition are an interesting idea with limited independent evidence.

If you surf somewhere with a genuinely elevated risk and it affects your enjoyment, a well-evidenced deterrent is a reasonable purchase. Treat it as a marginal improvement, not as protection.

If you see one

Do not panic and thrash — erratic splashing resembles a distressed animal.

Keep it in sight. Sharks are far more likely to approach something that is not looking at them, and maintaining eye contact and turning to face the animal is standard advice from people who work around them.

Move steadily and deliberately toward shore or a boat. Get onto your board if you are surfing, which puts more between you and the water.

Stay vertical in the water column if you can, and back away rather than turning your back and swimming.

In the extremely unlikely event of a bite

Fight back, aggressively, targeting the eyes and gills. Playing dead does not help; sharks generally release when they encounter strong resistance.

Get out of the water immediately and control bleeding. Massive haemorrhage is the cause of death in most fatal incidents, and it is the thing bystanders can actually address — direct pressure, a tourniquet on a limb if available and trained, and rapid transport.

This is a strong argument for beach-based groups knowing basic bleeding control regardless of the cause.

The honest framing

Fear of sharks is not irrational — it is a response to a genuine predator, and the consequences of a rare event are severe. But it is disproportionate to the frequency, and the disproportion has costs: people avoid the ocean, and people focus on sharks while ignoring rip currents, which injure and kill vastly more ocean users every year.

Spend your attention where the risk actually is. Learn to read a rip, swim between the flags, and go surfing in the middle of the day.