Selectivity and what it is used for
Environment · Last reviewed 2026-08-10
Spearfishing is the most selective way of taking a fish that exists — which is an argument in its favour only if the selection is doing something defensible.
The conservation case for spearfishing is usually made in one line: it is completely selective, so there is no bycatch. That is true and it is not the end of the argument.
WHAT IS GENUINELY TRUE. The diver sees the animal before committing — species, size, condition — and can decline. Nothing is taken by accident. No undersized fish is landed and returned with an injury of unknown consequence. No non-target species dies in a net. There is no lost gear that goes on fishing. Measured per fish taken, the collateral cost is close to zero, and very few methods can say that.
WHAT COMPLICATES IT. Selectivity is a capability, and capabilities are neutral. What decides whether it is good is what it is used FOR, and the honest observation is that spearfishers, like everyone, tend to select for the largest fish available.
In a great many of the species spearfishers target, that has a specific consequence. Reef and rocky-ground fish are frequently long-lived, slow to mature and site-attached to a small area — and a substantial number of them, including wrasse and many groupers, change sex with age, so the largest individuals in a population are disproportionately the breeding males. Removing the largest fish from a small piece of reef, repeatedly, is a targeted intervention in that population's structure in a way that the same weight of randomly selected fish would not be.
So the useful conclusion is not that spearfishing is good or bad. It is that the method removes almost every source of harm EXCEPT the diver's own choice about which fish to take — and having removed the others, that choice is the whole thing.
What is genuinely true about the selectivity claim
The diver sees the animal before committing — species, size, condition — and can decline. Nothing is taken by accident. No undersized fish is landed and returned carrying an injury of unknown consequence. No non-target species dies in a net. There is no lost gear that goes on fishing after the session ends.
Measured per fish taken, the collateral cost is close to zero, and very few methods can say that. It is a real advantage and it should not be understated in the course of complicating it.
Authoritative guidance
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
- FAO fishing gear types and fishing technology information — Food and Agriculture Organization of the United Nations (Scientific institute)Relied on for: The classification of spear and harpoon gear and its selectivity characteristics relative to net and hook gear.States this directlyCitation checked — the work exists and is described correctly
- Good Fish Guide — Marine Conservation Society (Conservation authority)Relied on for: That gear selectivity is a component of fishery sustainability assessment.States this directlyCitation checked — the work exists and is described correctly
What complicates it, and why it is the diver rather than the gear
Selectivity is a capability, and capabilities are neutral. What decides whether it is good is what it is used FOR, and the honest observation is that spearfishers, like everyone else who fishes, tend to select for the largest fish available.
In a great many of the species spearfishers target, that has a specific consequence. Reef and rocky-ground fish are frequently long-lived, slow to mature and site-attached to a small area — and a substantial number of them, including wrasse and many groupers, change sex with age, so the largest individuals in a population are disproportionately the breeding males. Removing the largest fish from a small piece of reef, repeatedly, is a targeted intervention in that population's structure in a way that the same weight of randomly selected fish would not be.
So the useful conclusion is not that spearfishing is good or bad. It is that the method removes almost every source of harm EXCEPT the diver's own choice about which fish to take — and having removed the others, that choice is the whole thing.
Scientific evidence
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: That protogynous hermaphroditism is widespread among wrasse, groupers and other reef-associated genera, such that the largest individuals in a population are disproportionately male, and that several spearfishing target species are long-lived and slow to mature.States this directlyPassage read and verified
- Good Fish Guide — Marine Conservation Society (Conservation authority)Relied on for: That species life history — longevity, age at maturity, sex change — is material to whether a harvest is sustainable.States this directlyCitation checked — the work exists and is described correctly
What a diver can actually do about it
IDENTIFY BEFORE SHOOTING, every time, without exception. This is the capability that makes the method defensible, and declining to use it wastes the whole argument.
TAKE WHAT YOU WILL EAT AND STOP. A diver who is not taking a bag limit is not missing out on anything.
THINK ABOUT THE LARGEST FISH. In protogynous species it is likely to be a breeding male, and it will not be replaced quickly on a small piece of reef.
SPREAD THE PRESSURE. Diving the same small area every week has a different effect from diving it twice a year, whatever any individual session looks like.
KNOW WHAT IS PROTECTED where you are, and treat it as a floor rather than a target.
DO NOT SHOOT WHAT YOU CANNOT RECOVER. A shot fish lost into structure is this method's one genuine welfare failure, and it is entirely within the diver's control.
WHAT REMAINS UNKNOWN is worth stating too. The population-level effect of recreational spearfishing specifically — separated from commercial and subsistence pressure on the same stocks — is not well quantified for most fisheries. Whether size-selective removal meaningfully shifts the age at sex change in protogynous species is an active research question rather than a settled one. This record does not pretend otherwise.
Practitioner consensus
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.
- Good Fish Guide — Marine Conservation Society (Conservation authority)Relied on for: That consumer and harvester choice is treated as a meaningful lever in sustainability frameworks.FishingHQ's interpretation of what it saysCitation checked — the work exists and is described correctly
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: Species-level life history underpinning the size-selection argument.Background and mechanism onlyPassage read and verified
Where to go next
Species affected
What these connections rest on (1)
Scientific evidence — 1 connection
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
Dusky grouper
A conservation claim resting entirely on verified life-history figures rather than on advocacy, which is why it is the catalogue's worked example.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: That Epinephelus marginatus is a protogynous hermaphrodite with females maturing at about five years and changing sex to male at about ten, has low resilience, a minimum population doubling time of 4.5 to 14 years and a vulnerability score of 64 out of 100.States this directlyPassage read and verified
- Good Fish Guide — Marine Conservation Society (Conservation authority)Relied on for: That life-history traits including longevity, late maturity and sex change are material to whether a stock can sustain harvest.States this directlyCitation checked — the work exists and is described correctly
Practices involved
What these connections rest on (1)
Scientific evidence — 1 connection
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
Spearfishing
A conservation claim resting on documented life history rather than on advocacy, which is why it is held to a scientific standard.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: That protogynous hermaphroditism is widespread among wrasse, groupers and other reef-associated genera such that the largest individuals are disproportionately male, and that several spearfishing target species are long-lived and slow to mature.States this directlyPassage read and verified
- Good Fish Guide — Marine Conservation Society (Conservation authority)Relied on for: That gear selectivity and species life history are both components of fishery sustainability assessment.States this directlyCitation checked — the work exists and is described correctly
Authoritative guidance — 1 connection
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
Spearfishing
Selectivity is the discipline's central environmental argument.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Diver safety guidance underlying this connection. Selectivity is the discipline's central environmental argument.States this directlyPassage read and verified
Where this applies
- The Coral TriangleA diver choosing an individual fish is the most selective method available here, which is also why spearfishing on an aggregation is so damaging when it happens.
- The Croatian AdriaticA spearfisher selects a specific fish rather than accepting what takes a bait, which is the discipline's great strength for avoiding bycatch and its great danger for a slow-growing site-attached species whose largest individuals carry the population's reproduction.
What these connections rest on (2)
Scientific evidence — 2 connections
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
The Coral Triangle
An environmental pressure that is specific to this place rather than general to fishing, joined so the issue record carries a real example.
- The IUCN Red List of Threatened Species — International Union for Conservation of Nature (Conservation authority)Relied on for: Assessment of the species and habitats affected, and the pressures acting on them, including habitat change and exploitation.States this directlyCitation checked — the work exists and is described correctly
- Code of Conduct for Responsible Fisheries — Food and Agriculture Organization of the United Nations, Rome, 1995 (Standards body)Relied on for: Principles for responsible fisheries management, precaution, gear selectivity and the treatment of shared and small-scale fisheries.Background and mechanism onlyCitation checked — the work exists and is described correctly
The Croatian Adriatic
A claim that a place raises a particular environmental question, resting on the scientific and conservation literature for the system rather than on angling practice.
- JNCC species and habitat conservation advice — Joint Nature Conservation Committee (Conservation authority)Relied on for: Habitat classification and description for the intertidal, coastal and freshwater habitats named, and the species characteristically associated with them.States this directlyCitation checked — the work exists and is described correctly
- ICES Advice on fishing opportunities, catch and effort — International Council for the Exploration of the Sea (Scientific institute)Relied on for: Ecoregion description, nursery function and the hydrography of the European sea areas assessed.States this directlyCitation checked — the work exists and is described correctly
Related reading
- Competition spearfishingScoring by weight concentrates removal on the largest fish in a defined area on a single day — which in protogynous reef species means the breeding males, deliberately and at scale.
- Corrosion, maintenance and pre-dive inspectionA corroded hinge pin that stops a barb deploying, or a frayed cable inside a crimp, produces a fish that is shot and not recovered. Maintenance is therefore a welfare practice as directly as it is a safety one.
- Deciding not to shootThe decision not to shoot is where selectivity actually happens, because there is no release and no gear change that reduces impact. In this discipline the diver's own limits are the management system.
- Fish growth, age and what a big fish representsSelective removal of the largest fish is the counter-argument to selectivity.
- Floppers, slip tips, and holding a fishA fish that tears off is a wounded animal that is not recovered, which is the failure mode this component exists to prevent. That makes tip choice a welfare question before it is a recovery one, and it is decided when the diver decides what they are hunting.
- How fish respond to a diverA method that removes the individuals which allow close approach is applying selection pressure to behaviour, which is a real and under-discussed effect of it.
- Identifying fish underwaterSelectivity is realised only where the diver can actually identify the fish.
- Scuba spearfishing, and why it is treated separatelyEffort and catchability rise sharply, particularly for deep, site-attached, slow-growing species breath-hold diving cannot reach.
1 more
What these connections rest on (9)
Scientific evidence — 4 connections
Supported by peer-reviewed research or fisheries science. The sources are listed and can be checked.
Competition spearfishing
A conservation claim resting on documented reproductive biology rather than on objection, which is why it is held to a scientific standard.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: That protogynous hermaphroditism is widespread among wrasse, groupers and other reef-associated genera, such that the largest individuals in a population are disproportionately male.States this directlyPassage read and verified
- Good Fish Guide — Marine Conservation Society (Conservation authority)Relied on for: That size-selective removal and the concentration of fishing effort are components of sustainability assessment.States this directlyCitation checked — the work exists and is described correctly
Fish growth, age and what a big fish represents
Selective removal of the largest fish is the counter-argument to selectivity.
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: Species and habitat data underlying this connection. Selective removal of the largest fish is the counter-argument to selectivity.States this directlyPassage read and verified
How fish respond to a diver
The selectivity argument, extended to the trait the method actually selects on.
- Fear of fishers: human predation explains behavioral changes in coral reef fishes — PLoS ONE 6(8): e22761, 2011 (Scientific literature)Relied on for: Flight initiation distance in targeted reef fishes is greater in fished areas than in protected areas and is attributed to human predation including spearfishing.States this directlyCitation checked — the work exists and is described correctly
Spawning aggregations, and why they are vulnerable
The case that shows exactly what the selectivity advantage does and does not consist of.
- Reef Fish Spawning Aggregations: Biology, Research and Management — Springer, Fish & Fisheries Series vol. 35, 2012 (Scientific literature)Relied on for: That spawning aggregations concentrate reproductive output, are disproportionately vulnerable because catch rates mask decline, and have in documented cases ceased to form after being fished.States this directlyCitation checked — the work exists and is described correctly
Authoritative guidance — 5 connections
Stated by a fisheries authority, scientific institute or recognised angling body. Authoritative, but summarising rather than demonstrating.
Corrosion, maintenance and pre-dive inspection
A claim that a piece of equipment participates in an environmental argument, resting on the responsible-fishing and welfare literature rather than on practitioner preference.
- Code of Conduct for Responsible Fisheries — Food and Agriculture Organization of the United Nations, Rome, 1995 (Standards body)Relied on for: That gear selectivity and the avoidance of unrecovered mortality are central to responsible fishing, and the framework within which those obligations sit.Background and mechanism onlyCitation checked — the work exists and is described correctly
- Humane Harvesting of Fish: percussive stunning and percussive equipment — Humane Slaughter Association (Angling or fisheries organisation)Relied on for: Humane harvesting practice for fish, including the obligation to render a fish insensible promptly and the consequences of failing to.States this directlyNot yet checked
Deciding not to shoot
A conservation consequence of the method, joined to the environmental topic that frames it, rather than a hazard to the diver.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Freediving safety, the mechanism of hypoxic blackout, and the requirement for direct supervision by a competent buddy on every dive.States this directlyPassage read and verified
- AIDA International freediving education and safety standards — AIDA International (Water-safety or diver-training authority)Relied on for: Recognised freediving education and safety standards, including buddy procedure and the one-up-one-down principle.States this directlyCitation checked — the work exists and is described correctly
Floppers, slip tips, and holding a fish
A claim that a piece of equipment participates in an environmental argument, resting on the responsible-fishing and welfare literature rather than on practitioner preference.
- Code of Conduct for Responsible Fisheries — Food and Agriculture Organization of the United Nations, Rome, 1995 (Standards body)Relied on for: That gear selectivity and the avoidance of unrecovered mortality are central to responsible fishing, and the framework within which those obligations sit.Background and mechanism onlyCitation checked — the work exists and is described correctly
- Humane Harvesting of Fish: percussive stunning and percussive equipment — Humane Slaughter Association (Angling or fisheries organisation)Relied on for: Humane harvesting practice for fish, including the obligation to render a fish insensible promptly and the consequences of failing to.States this directlyNot yet checked
Identifying fish underwater
Selectivity is realised only where the diver can actually identify the fish.
- DAN guidance on freediving safety, hypoxia and shallow-water blackout — Divers Alert Network (Water-safety or diver-training authority)Relied on for: Diver safety guidance underlying this connection. Selectivity is realised only where the diver can actually identify the fish.States this directlyPassage read and verified
Scuba spearfishing, and why it is treated separately
The argument regulators actually act on, kept apart from the ethical one.
- Code of Conduct for Responsible Fisheries — Food and Agriculture Organization of the United Nations, Rome, 1995 (Standards body)Relied on for: Expectations for gear selectivity, minimising waste and lost gear, and managing total removal from a stock.States this directlyCitation checked — the work exists and is described correctly
How this compares
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.
Bycatch and discards
A gear-selectivity comparison held to an authoritative standard because it underpins most of the public argument about fishing methods.
- FAO fishing gear types and fishing technology information — Food and Agriculture Organization of the United Nations (Scientific institute)Relied on for: The classification of spear and harpoon gear and its selectivity characteristics relative to net and hook gear.States this directlyCitation checked — the work exists and is described correctly
- Good Fish Guide — Marine Conservation Society (Conservation authority)Relied on for: That gear type is a principal determinant of a fishery's sustainability rating.States this directlyCitation checked — the work exists and is described correctly
Sources for this page
- FishBase: a global information system on fishes — Froese, R. and D. Pauly, eds. — FishBase Consortium (Scientific institute)Relied on for: That protogynous hermaphroditism is widespread among wrasse, groupers and other reef-associated genera, such that the largest individuals in a population are disproportionately male, and that several spearfishing target species are long-lived and slow to mature.States this directlyPassage read and verified
- Good Fish Guide — Marine Conservation Society (Conservation authority)Relied on for: That gear selectivity and species life history are both components of fishery sustainability assessment.States this directlyCitation checked — the work exists and is described correctly
- FAO fishing gear types and fishing technology information — Food and Agriculture Organization of the United Nations (Scientific institute)Relied on for: The classification of spear and harpoon gear and its selectivity characteristics relative to net and hook gear.States this directlyCitation checked — the work exists and is described correctly
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