The haek — the traditional Thai cast net — has been the primary food-gathering tool for riverine and coastal communities throughout Thailand for as long as records exist. It appears in ancient Thai murals, in the daily routine of fishing villages from the Mekong delta tributaries to the Gulf coast, and in the morning ritual of Bangkok's canal-side communities who still throw a net before heading to the market. For visiting anglers and sport fishermen it occupies a dual role: practical bait collection tool and the most satisfying physical fishing skill to master, requiring technique and reading of the water that no lure or rod can replicate.
The Haek: Construction and Terminology
A traditional haek is a circular net with specific components that every user should understand:
Brail lines (sai yam): The gathering cords attached from the perimeter at regular intervals to the central retrieval ring. When the retrieval line is pulled, the brail lines close the net's bottom, trapping fish inside. The number and length of brail lines determines how cleanly the net closes and how quickly the closure prevents fish escape.
The skirt (hem and lead line): The perimeter of the net is reinforced with heavier mesh or braid and carries the lead weights (tat lom). The lead weights — cast lead ovals or cylinders spaced evenly around the perimeter — provide the centrifugal force that opens the net during the throw and the downward momentum that closes it rapidly beneath the fish.
The horn or yoke: The central fitting at the top of the net where the retrieval line attaches. The quality of this fitting determines how evenly the tension distributes across the brail lines during retrieval.
Net diameter: In Thailand, haeks are described by their radius (the measurement from the horn to the perimeter edge), not diameter. A "3-metre haek" is 6 metres across. Market sizes range from 1.2 metres (appropriate for children and beginners) to 4 metres (requiring significant strength and technique to throw correctly).
Mesh Sizes and Their Applications
Thai haeks are sold with mesh sizes described in terms of the gap between knots (not the stretched measurement used in Western net specifications). Convert by multiplying the Thai mesh gap by approximately 1.4 to get the stretched equivalent.
Fine Mesh (8–12 mm stretched)
Purpose-built for small baitfish — herrings, sardines, small anchovies, and juvenile mullet. These nets are used by professional bait gatherers around Thai coastal piers and near the mouths of estuaries where small fish school densely. The fine mesh creates significant water resistance during the throw, making correct technique even more important than with coarser nets. Fine-mesh haeks are heavier per unit area and require a heavier lead skirt to ensure rapid sinking.
Best locations: Pier lights at night (Chalong pier, Rawai pier, Pattaya pier structures), shallow estuaries at dusk, beach surf zone at dawn when small herrings are schooling near shore.
General Purpose Mesh (14–20 mm stretched)
The most useful range for Thai freshwater and coastal bait collection. A 16 mm net retains tilapia of 8 cm and above (the minimum useful bait size for most applications), mullet above 12 cm, and small catfish — while allowing juveniles below 8 cm to pass through. This range is also appropriate for food-fish collection when tilapia and mullet of medium size are the target.
Best locations: Canal margins near Bangkok pay lakes, tidal estuaries on the Gulf and Andaman coasts, irrigation channel systems in central Thailand, reservoir margins at Cheow Lan and Lam Takong.
Coarse Mesh (22–28 mm stretched)
Designed for larger food fish — tilapia above 300g, mullet above 400g, and freshwater fish of carp family that are consumed rather than used as bait. These nets allow the smaller fish that a fine or general-purpose mesh would retain to escape, producing a cleaner catch of the specifically targeted food-size fish.
Best locations: River mouths where large mullet school, reservoir systems where large tilapia are present, estuaries at night during mullet runs.
Monofilament versus Braided Nylon
Monofilament Haeks
Monofilament netting filament (typically 0.25 to 0.35 mm nylon) is lighter, springier, and less visible in clear water than braided nylon. When wet, monofilament nets have a slightly higher elasticity that can actually improve fish retention — the mesh briefly stretches as the fish pushes against it, then contracts to hold the fish more securely.
The handling experience with a monofilament haek is superior for most users. The net dries faster, coils more naturally, and throws with less resistance than an equivalent braided net. For collection in clear water where fish visibility triggers escape behaviour, the monofilament net's lower visual profile is a genuine advantage.
Limitations: Monofilament abrades and weakens progressively on contact with coral rubble, submerged timber, and rough concrete. A monofilament haek used repeatedly in mangrove environments with submerged root systems and debris will develop small mesh breaks that worsen with each use. Repair is possible with matched filament thread but becomes laborious after several seasons of heavy use.
Braided Nylon Haeks
Traditional Thai haeks, particularly the older hand-knotted designs from rural fishing communities in the Northeast and South, are predominantly braided nylon. Braided filament is significantly more abrasion-resistant than monofilament — a braided haek dragged repeatedly over coral rubble and mangrove roots sustains far less damage per session than a monofilament equivalent.
The trade-offs are weight (braided haeks are heavier), slower drying time, and slightly higher visibility in clear water. In murky canal and river environments where visibility is irrelevant, these trade-offs disappear and the braided net's durability advantage is purely positive.
Net Storage in Thai Heat
Never store a wet haek rolled or compressed. The combination of tropical humidity and contact pressure accelerates nylon degradation at the knot points, where the filament is already under mechanical stress. Always hang the haek to dry fully in a shaded, ventilated position before coiling for storage. A net hung on a single nail through its horn will dry completely within 4 to 6 hours in Thai conditions.
The Weighted Skirt: Lead Design and Weight
The lead weight system on a haek's perimeter skirt is the primary determinant of how the net sinks after it is thrown. Correct lead weight balances two competing requirements: the net must sink quickly enough to close beneath the fish before they escape under the lower edge, but it must not be so heavy that the net cannot be thrown to its full diameter.
Lead Weight per Metre of Circumference
The standard specification for general-purpose Thai haeks is 80 to 120g of lead per metre of net circumference. A 2.4-metre radius haek (4.8 metres diameter, 15 metres circumference) at 100g/m carries approximately 1.5 kg of lead around its perimeter.
Increasing lead weight improves sinking speed but makes the net harder to throw and creates more water disturbance on landing (the heavier perimeter strikes the water with greater impact). Decreasing lead weight produces a gentler landing and easier throw but sacrifices the fast closure that prevents fish escape beneath the net edge.
For fast-sinking in current: Increase lead to 120 to 150g per metre. Essential in tidal estuaries where current would carry the net off-target during the sinking phase if the perimeter is too light.
For still water and bait collection: Standard 80 to 100g per metre is ideal. The gentler landing disturbs fish less, giving slightly better collection rates before fish panic and escape under the net edge.
Lead Spacing
Leads spaced at 20 to 25 cm intervals around the perimeter produce a uniform sinking rate and clean circular closure. Wider spacing allows the skirt to bunch locally between lead weights during the throw, creating "pockets" that don't sink at the same rate and producing an uneven closure that allows fish to escape through the gaps.
Throwing Technique: The Thai Method
The traditional Thai haek throw differs from the over-shoulder Western method taught in many general fishing guides. The Thai method is a horizontal body-rotation throw that produces a more consistent circular spread and is more efficient for repeated throws over a session.
Preparation
Lay the haek on a smooth flat surface and remove all tangles by starting from the horn and working outward to the perimeter. Coil the retrieval line loosely and hold in the non-dominant hand with the horn. With the dominant hand, gather approximately one-third to one-half of the perimeter, hold against the body.
The Throw
Stand facing the water at 45 degrees. Hold the horn and retrieval coil in the left hand (for a right-handed thrower). Drape the gathered perimeter section over the right forearm and hand. Load the body by rotating left. Release with a smooth horizontal sweep across the body, releasing the perimeter at the apex — typically when the throwing arm reaches its furthest forward extension. The momentum of the rotation carries the net into a circular spread.
The net should open in the air before landing flat on the water. A full circular spread (no bunching at the centre or edges) is the mark of correct technique.
The most common error: Releasing the perimeter too early, before full body rotation. This causes the net to bunch at the centre rather than opening fully. Practice with an empty net (no fish targeted) is the only way to develop correct release timing.
Water Reading
Throwing at the right location matters as much as technique. Observe the water surface for:
- Circular disturbance: A school of feeding fish near the surface creates a dimpling pattern. A haek thrown slightly ahead of the pattern's movement intersects the school.
- Silver flashes: Individual fish turning at the surface in sunlight. Multiple flashes in a small area indicate a dense school.
- Bird activity: Cormorants or terns circling and diving indicate a baitfish school. Throw at the leading edge of the bird activity rather than at the centre where birds have already disturbed the fish.
- Shadow and current edges: In estuaries, mullet school at the transition between shaded and sunlit water and at current edges where flow changes. These are reliable throw positions when no surface activity is visible.
The haek is not a net you throw at fish — it is a net you throw ahead of where fish will be in the two seconds it takes to open and sink. Every cast is a prediction.
Target Species and Seasonal Patterns
Mullet (Mugil cephalus and relatives): Available year-round in Thai estuaries and coastal areas. Peak density in river mouths and tidal flats in the cool season (November to February) when offshore migrating schools push into estuarine systems.
Tilapia (Oreochromis spp.): Year-round in canals, reservoirs, and irrigation channels throughout Thailand. Most abundant in the warm season (April to September) when water temperatures are highest and breeding activity concentrates fish in shallow areas.
Common carp and grass carp: Primarily in reservoirs and managed waterways in northern and central Thailand. Best collection in the cool season mornings when carp are feeding actively in the shallows.
Small catfish (Mystus spp., Pangasius juveniles): Canal and river systems in the central and northeastern regions. Most active during the rainy season flood pulse (June to October) when the fish enter flooded rice fields and return to channels on the ebb.
Herrings and sardines: Coastal and estuarine, with highest availability in the Gulf coast dry season (November to April). The Andaman coast herring availability depends on the monsoon cycle — best in April to May before the southwest monsoon restricts access.
Maintaining your haek catch alive for bait use after collection requires the aerator systems described in the companion guide to bait aerator systems in tropical conditions.
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