fishing hook
Enable an AI agent to recognise a fishing hook, assess its condition and compatibility, and decide whether it can be rigged, used, maintained or retired.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise a fishing hook, assess its condition and compatibility, and decide whether it can be rigged, used, maintained or retired.
A fishing hook is a terminal-tackle implement, almost always a bent length of steel wire with a sharpened point, optional barb, gape, shank and an eye or spade, whose job is to present bait, lure or fly, penetrate a fish (typically in the mouth) and retain that fish on a line or snood.
It can be Identify and compare a hook using its geometry, markings and documented product identity.; Inspect each point, barb, bend and attachment feature for damage or obstruction.; Attach or replace the hook in a compatible rig or lure assembly.; Assess whether bait or lure material leaves the required point exposure and clearance.; Evaluate sharpening or barb modification against hook condition and applicable constraints.; Protect exposed points, segregate damaged hooks and retire hooks judged unsuitable..
Distinguishing features
Look for a penetrating point leading into a bend that can retain a catch; a sinker or swivel lacks this capture geometry.
Check for an eye, spade or other provision for securing fishing line or a tackle connection; a bent needle alone does not establish fishing-hook identity.
Distinguish a hook incorporated into a lure from the complete lure by identifying the point-bearing component and its attachment boundary.
Distinguish it from a gaff head by establishing whether it functions as terminal fishing tackle or as part of a separate landing tool.
Do not require a barb for identification; inspect the point-and-bend configuration and intended fishing role even when no barb is present.
Scope
+ Hook point, bend, shank and line-attachment configuration
+ Single, double and treble forms, including barb configuration
+ Dimensions, material and surface treatment when known
+ Compatibility with a specified line connection, bait, lure or rig
+ Sharpness, deformation, corrosion and attachment integrity
+ Handling, modification and retirement decisions for the hook
- Complete fishing rigs and their overall performance
- Fishing line, leaders, knots and connectors as independently managed things
- Baits and lures beyond their interface with the hook
- Fish identification, biology and population management
- Fishing locations, permissions and regulations as independently maintained records
- Clinical treatment of hook injuries
Characteristics
- Hook configuration
- single, double, treble, other, unknown Establishes the number and arrangement of points that must be inspected and accommodated.
- Pattern designation
- Recorded manufacturer or supplier pattern name; unknown permitted Supports identification without treating a commercial pattern name as proof of geometry.
- Nominal size
- Marked size together with manufacturer and product series Allows catalogue matching while keeping nominal size distinct from measured dimensions.
- Gape
- mm, with measurement endpoints stated Helps assess clearance around bait or lure material and compare candidate hooks.
- Shank length
- mm, with measurement endpoints stated Helps assess bait support, lure fit and available space for attachment.
- Wire cross-section
- mm for diameter or principal thicknesses, with measurement location Describes hook bulk without inferring load capacity from thickness alone.
- Point orientation
- Description of inward turn and in-plane or offset alignment Separates visually similar patterns and informs intended-use matching.
- Barb configuration
- Per point: barbed, manufactured barbless, flattened barb, damaged, unknown; shank barbs recorded separately Supports retention, handling and rule checks while distinguishing original form from modification.
- Attachment interface
- eye, spade, integral mounting, other, unknown; geometry described Determines which line connections or tackle mountings can be considered.
- Material and finish
- Documented substrate and coating, or unknown Supports maintenance decisions without guessing composition from appearance.
- Point and body condition
- Per-feature observations of tip damage, wear, corrosion, cracking and deformation; uninspected permitted Provides the evidence needed to decide whether the hook remains usable.
- Installed relationship
- Connected line, leader, connector or lure, including attachment location and method Makes compatibility and replacement decisions specific to the actual assembly.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Hook identity and boundary Establishes what counts as this hook and how it is recognised within fishing tackle.
An agent must distinguish a hook from neighbouring tackle and know whether it is assessing a component or a complete assembly.
Capture form
Records the physical and intended-use evidence supporting identification as a fishing hook.
Fishing-hook recognition
Identify the penetrating point, retaining bend and fishing-tackle attachment role without making a barb mandatory.
- Which visible features establish a point-and-bend capture form rather than a needle, clip or connector? definition
- What evidence establishes its role as fishing tackle rather than a gaff component or another kind of hook? boundary
Component and product identity
Separates the physical hook from its host assembly and links product claims to their origin.
Hook unit and designation
Record the managed hook unit, its point arrangement and any supported manufacturer designation.
- Does the assessed unit comprise one single, double or treble hook, or several hooks connected by a larger assembly? boundary
- Which markings, packaging or product documentation support the recorded pattern and nominal size? provenance
Point, bend and shank geometry Captures the hook-specific geometry needed to compare forms and assess physical fit.
A size label alone does not describe point orientation, bait clearance or the hook's shape.
Dimensions and alignment
Records dimensions with explicit measurement conventions.
Measured hook profile
Describe gape, shank length, wire section and point alignment using reproducible observations.
- What are the gape, shank length and wire thickness, and which endpoints or locations define each measurement? measurement
- How does each point align with its shank and bend, including inward turn and any out-of-plane offset? measurement
Barbs and retention features
Distinguishes point barbs from features intended to hold bait along the shank.
Retention feature configuration
Record the location, form and modification state of each barb or bait-retaining projection.
- Which points carry barbs, and are there separate bait-retaining barbs on the shank? definition
- Is an absent or flattened barb an original design feature, a documented modification or an unresolved observation? provenance
Rig and bait interfaces Describes how the hook connects to tackle and accommodates bait or lure material.
An intact hook can still be unsuitable if its connection is insecure or its capture geometry is obstructed.
Line and lure connection
Assesses the hook-side interface for a specified line connection or mounting.
Attachment fit and security
Record eye or spade geometry, contact surfaces and the fit of the proposed connection.
- What attachment feature is present, and what are its opening, orientation and relevant contact-surface dimensions? measurement
- Can the specified connection seat and remain retained without an observed gap, sharp edge or restricted movement compromising it? action
Bait clearance and hook movement
Evaluates the hook in its proposed baited or lure-mounted configuration.
Working point exposure
Record how bait, lure bodies and adjacent hardware affect point exposure, gape and movement.
- With the intended bait or lure fitted, how much gape remains and where is each point exposed, covered or deliberately embedded? measurement
- Does the installed hook move as the intended rig requires without fouling the lure, leader or another hook? action
Hook condition and serviceability Assesses the penetrating tips, load-bearing body and attachment surfaces.
Small local defects can affect hook function, and multi-point hooks require point-by-point inspection.
Point and barb inspection
Records tip and barb condition separately for each point.
Point readiness
Distinguish an inspected point from an assumed sharp point and record the assessment method.
- For each point, what inspection method and observations indicate sharpness, rounding, rolling, breakage or obstruction? measurement
- Does tip or barb damage warrant further inspection, supported maintenance or retirement under the chosen acceptance criteria? action
Body and attachment integrity
Assesses the shank, bends, joints and line-contact features for deterioration.
Structural condition
Record observed deformation, corrosion, cracks and joint or eye defects without assigning an unsupported strength rating.
- Where are deformation, corrosion, cracking, joint movement or eye-opening defects visible, and how extensive are they? measurement
- What known snagging, overload, straightening or other use history could affect the decision to retain this hook? provenance
Use, modification and retirement Connects the hook's recorded configuration and condition to a specific proposed action.
Suitability depends on intended use, supporting evidence and applicable constraints, rather than appearance alone.
Intended-use constraints
Links the hook to the fishing task and externally maintained requirements.
Hook selection decision
Assess the proposed hook against the intended method, rig demands and verified hook restrictions.
- What evidence supports this hook's suitability for the specified method, bait or lure, target catch and expected rig demands? provenance
- Which applicable requirements concerning point count, barb state, pattern or dimensions must be checked before use? action
Maintenance and point control
Governs hook-specific maintenance, modification and handling of exposed points.
Maintain, protect or retire
Choose a supported next action and preserve evidence of changes to the point, barb or body.
- Is sharpening, cleaning or barb flattening supported for this hook, and what inspection must follow the proposed change? action
- How will every exposed point be contained during storage, transport or disposal, including points on a damaged multi-point hook? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- J-hook (standard bait hook, including Aberdeen, Carlisle, O'Shaughnessy and baitholder patterns)
- Circle hook (non-offset and offset/kirbed)
- Treble hook
- Double hook
- Octopus hook
- Worm / extra-wide-gap (EWG) hook
- Jig hook
- Fly hook (dry, wet, nymph and streamer irons)
- Which of these kinds and varieties hold for the sense of fishing hook this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q18367 - Item labelled fish hook / fishhook; confirm the Q-id against the current sitelink if using it as a primary key.
- Harmonized System / Combined Nomenclature - 9507.20 - Fish-hooks, whether or not snelled; parent heading 9507 covers rods, reels and other line-fishing tackle.
- Manufacturer pattern + trade size - {brand pattern} {size}, e.g. Mustad 92668 #4, Owner 5111-131, Gamakatsu Octopus 2/0 - The practical SKU in tackle trade; size is a dimensionless series (#22…#1 then 1/0…n/0), not millimetres.
- Which of these identifiers and schemes hold for the sense of fishing hook this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- World Customs Organization Harmonized System heading 9507.20 (classification of fish-hooks, whether or not snelled).
- NOAA Fisheries / 50 CFR Part 635 - circle-hook and related gear rules for U.S. Atlantic highly migratory species.
- Florida Fish and Wildlife Conservation Commission - non-offset circle hooks required when using natural bait for reef fish in Gulf state waters.
- ICCAT, IATTC and WCPFC conservation measures on circle hooks (and related bait/gear rules) to reduce sea-turtle and other bycatch on pelagic longlines.
- Inland and recreational byelaws requiring barbless or single hooks on designated catch-and-release waters (UK Environment Agency and many U.S. state wildlife agencies).
- Lead-tackle restrictions in some jurisdictions (U.S. states, parts of the EU/UK) that mainly hit jig heads and weights rather than the hook wire itself.
- Which of these standards and regulation hold for the sense of fishing hook this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Tied or snelled to a recreational line as the point of a bait, lure or fly presentation.
- Fished in thousands on commercial pelagic and demersal longlines, each hook on a snood.
- Used in pole-and-line, handline, drop-line and ice-fishing.
- Factory-fitted to hard baits as trebles, or as siwash singles replacing trebles on spoons and plugs.
- Sold loose in size/pattern boxes, and packed in military and survival fishing kits.
- Preserved as archaeological and ethnographic objects in bone, shell, wood, bronze and iron.
- Which of these real-world use hold for the sense of fishing hook this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- trade size - #22 (tiny fly) through #1, then 1/0 to about 20/0 (tuna/shark) - dimensionless (hook-size series)
- gape (gap) - 2-60 - mm
- wire diameter - 0.3-4 - mm
- shank length - 8-80 for most recreational patterns; longer on Aberdeen and some bait hooks - mm
- mass - 0.05-25 for typical recreational singles; heavier on large commercial and shark hooks - g
- point offset (kirb/reversed) - 0-15 - degree
- Which of these typical measurements hold for the sense of fishing hook this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wire yield: the bend opens or straightens under a fish or a snag.
- Point rolls, chips or dulls on bone, enamel or rock.
- Carbon-steel corrosion and later fracture in salt water; stainless can still fail at the eye or barb.
- Eye deformation or cut-through of the knot or snell.
- Deep-hooking and post-release mortality, especially swallowed J-hooks with bait; circle hooks are used to shift hook-ups toward the jaw corner.
- Tissue tearing from barbs; barbless hooks drop fish more easily and are mandated on some waters.
- Puncture wounds to anglers and subsequent marine infection.
- Longline bycatch of sea turtles, seabirds and sharks, sensitive to hook type, size and offset.
- Foul-hooking or dedicated snagging, often illegal.
- Galvanic corrosion when a carbon or stainless hook is moulded into a lead jig head.
- Which of these failure modes and hazards hold for the sense of fishing hook this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- North America uses aught sizes (2/0, 5/0, …) in everyday speech and has pushed circle hooks into many saltwater bait fisheries by regulation.
- Japan and East Asia keep a dense named-pattern catalogue, often default to kirbed (offset) bait hooks, and dominate fine-wire manufacture; China is a major OEM source.
- United Kingdom and Ireland still sell named long-shank patterns (notably Aberdeen) and require barbless hooks on many stillwaters.
- Scandinavia and much of continental Europe treat trebles as the default on spoons and spinners.
- Tropical tuna longline fleets treat J versus circle as an operational and bycatch-compliance choice under ICCAT, IATTC and WCPFC rules.
- Bone, shell, wooden and composite hooks remain in ethnographic and subsistence use in parts of the Pacific and Arctic even where steel is otherwise standard.
- Which of these regional variation hold for the sense of fishing hook this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- gaff - A landing or killing spike, much larger, not presented as bait or fly and not the terminal knot of a fishing line in ordinary angling.
- snag hook / snagging treble - Built to foul-hook the body rather than take the mouth; often a separate, restricted legal class.
- jig head - A hook with a moulded weighted head sold as a lure component; the hook is the wire, the jig head is the weighted assembly.
- lure (plug, spoon, spinner, fly body) - The attractor; hooks are attached to it. Separable by whether the object is the point that penetrates the fish or the body that is merely presented.
- butcher's meat hook - Similar J-shape for hanging carcasses; not line-eyed, not sized or pointed for a fish mouth, not terminal tackle.
- fish spear / leister - A thrusting or thrown piercing weapon, not a hooked retainer left on a line.
- grappling hook / grapnel - Multiple large tines for holding structure or wreck, not for taking fish by the mouth.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of fishing hook this model covers, and on what evidence? provenance
Sources
- Fish hook - Wikipedia - Anatomy (point, barb, bend, shank, eye), trade-size numbering, and the main pattern families anglers distinguish.
- Harmonized System heading 9507.20, Fish-hooks, whether or not snelled - World Customs Organization - The internationally used customs identifier for the commodity, including snelled hooks.
- 50 CFR Part 635, Atlantic Highly Migratory Species - U.S. Office of the Federal Register / NOAA Fisheries - U.S. gear rules that treat circle hooks as a regulated class distinct from J-hooks in billfish and related bait fisheries.
- Definition and classification of fishing gear categories - Nédélec, C. and Prado, J., FAO Fisheries Technical Paper, Food and Agriculture Organization of the United Nations, Rome - Placement of baited hooks in longline, handline, pole-and-line and related capture methods as used in fisheries statistics.
What the second pass must settle
- Which measurement conventions should standardise gape, shank length and point offset across substantially different hook patterns?
- Which repeatable, non-destructive inspection methods and acceptance criteria adequately establish point sharpness and serviceability?
- What manufacturer evidence is available for load limits, materials and coatings, and how should suitability remain qualified when that evidence is absent?
- Under what documented conditions are sharpening, barb flattening or other modifications acceptable for particular hook constructions?
- How should unusual fish-catching forms without conventional point-and-bend geometry be distinguished from fishing hooks within the registry?