Fact-checked by Grok 2 weeks ago

Fish trap

A fish trap is a passive fishing device that captures fish and other aquatic organisms by allowing them to enter an enclosure while making escape difficult or impossible, often through funnel-shaped entrances or one-way valves.^[1]^[2] These traps vary widely in construction, including submerged wire or wooden pots, woven basket designs, and fixed weirs built from stones, reeds, or wood that leverage currents, tides, or migrations to guide fish inward.^[3]^[4] Originating in prehistoric times, fish traps represent one of humanity's earliest and most sustainable harvesting methods, with archaeological evidence of stone weirs and related structures dating back thousands of years across continents, from Europe to the Americas and Pacific islands.^[5]^[6]^[7]

Definition and Principles

Mechanisms of Operation

Fish traps primarily operate through passive entrapment, wherein fish enter the structure voluntarily—drawn by environmental currents, shelter-seeking, or attractants—and are subsequently confined by design features that hinder escape. The core mechanism relies on funnel-shaped entrances that taper inward, guiding fish along a narrowing passage into an internal chamber; this configuration exploits the forward-swimming momentum of entering fish, making reversal through the constricted outlet physically arduous due to reduced space and altered orientation.^[2]^[8] Once inside, retention occurs via the chamber's mesh apertures, sized to retain target species while allowing juveniles or non-targets to exit, combined with the absence of clear egress paths that align with typical escape behaviors.^[2] Mechanisms differ in luring approaches: passive variants leverage hydrodynamic forces, such as tidal or riverine flows, to propel fish toward and into the funnel, capitalizing on natural water velocity gradients that concentrate prey in the trap's path without requiring fisher intervention.^[9] In contrast, active luring employs bait within the chamber to stimulate chemosensory or visual attraction, prompting fish to investigate and penetrate the funnel independently of external currents.^[10] Both methods underscore the trap's immobility relative to fish, contrasting active gears that pursue targets, with capture efficiency tied to the alignment of trap geometry and prevailing flow physics—wherein Bernoulli principles amplify entry currents while damping backflow.^[9] Fish behavioral responses further enable operation; upon entry, disorientation in the enclosed space often leads to futile circling or wall-following rather than relocating the narrow funnel, compounded by thigmotactic tendencies in confined flows that prioritize substrate contact over directed exit-seeking.^[11] This interplay of fluid dynamics and innate swimming patterns—such as rheotaxis, where fish orient upstream—ensures unidirectional progression into the trap during inflow phases, with minimal egress during slack or ebb tides.^[12] Empirical observations confirm that funnel angles and chamber volumes must match species-specific burst speeds and turning radii to optimize retention rates, typically exceeding 70% for targeted sizes in controlled deployments.^[13]

Advantages and Limitations Compared to Other Fishing Methods

Fish traps offer superior selectivity compared to active methods like trawling and certain netting techniques, minimizing bycatch of non-target species. Empirical data from Mediterranean fisheries indicate discard rates for fish traps as low as 0.11%, far below the 18.5% observed for drift gillnets and typically higher rates in trawling operations where non-selective encirclement or dragging captures juveniles, sharks, and other unintended organisms.^[14] ^[15] This advantage stems from traps' passive design, which permits escape of undersized or incompatible species through mesh or funnels, unlike the mechanical retention in mobile gears.^[16] Relative to hook-and-line methods, traps provide broader size selectivity via adjustable mesh, though hooks excel in targeting specific sizes with lower overall capture volume but higher post-capture mortality from gut-hooking.^[17] Operationally, fish traps demand substantially less fuel and labor than active gears, facilitating sustainable use in resource-limited small-scale fisheries. As passive devices, traps incur minimal propulsion costs during deployment and soaking, with studies classifying pot and trap systems as low-energy alternatives to trawling's high fuel intensity, often exceeding several liters per kilogram of catch in demersal operations.^[18] ^[19] Labor efficiency arises from intermittent hauling rather than continuous vessel maneuvering, reducing crew exposure and enabling one-person management in some designs, though hooks require ongoing baiting and monitoring.^[20] Despite these benefits, fish traps exhibit limitations tied to environmental dependencies and site specificity. Catches rely heavily on predictable fish migrations and schooling behaviors, yielding variable efficiency in areas lacking consistent passage, unlike the proactive pursuit possible with hooks or mobile nets.^[21] Fixed or semi-fixed traps prove vulnerable to storms and tidal shifts, which can displace structures or prevent access, exacerbating risks for small-scale operators amid intensifying weather variability.^[22] Deployment and retrieval also disturb benthic habitats through dragging, though less severely than trawling, and lost traps contribute to ongoing ghost fishing.^[16] Compared to versatile hooks, traps demand precise locational knowledge, limiting adaptability in dynamic conditions.^[23]

Historical Development

Prehistoric and Ancient Origins

The earliest confirmed physical evidence of a fish trap is a submerged stone weir discovered in Shakan Bay, Southeast Alaska, radiocarbon dated to approximately 11,100 years before present.^[24] This structure, composed of low arc-shaped walls of boulders placed across tidal gullies, facilitated the capture of fish by exploiting receding tides, demonstrating early human adaptation to coastal environments for reliable protein procurement.^[25] Prior to this find, the oldest dated weirs in North America were wooden structures around 6,000–8,000 years old, underscoring the Alaskan example's significance in extending the timeline of such technologies.^[26] Artistic depictions provide even earlier indications of trap concepts, with engravings on schist slabs from the Gönnersdorf site in Germany, dated to about 15,800 years ago, portraying net- or trap-based fishing arrangements during the Late Upper Paleolithic.^[27] These Magdalenian-era illustrations, among the oldest evidence of fishing gear in European prehistory, suggest cognitive planning for passive capture methods predating preserved physical remains. In intertidal settings worldwide, prehistoric traps typically employed natural materials such as stacked stones or woven reeds to form V- or heart-shaped enclosures that directed fish into holding areas as tides fell, optimizing energy expenditure over active pursuit.^[28]^[29] Such devices played a critical role in hunter-gatherer subsistence by enabling scalable harvests from migratory fish populations, with site longevity—evident in repeated use over centuries at locations like British coastal weirs dated to 7,000 years ago—implying effective resource management that sustained yields without evident depletion.^[30] This passive approach, rooted in observation of tidal and fluvial dynamics, contrasts with contemporaneous spear or hook methods by reducing risk and labor, thereby supporting population stability in resource-variable ecosystems.^[5]

Indigenous and Traditional Applications

Indigenous peoples of the Pacific Northwest constructed wooden stake weirs to harvest salmon, leveraging tidal and riverine flows to guide fish into traps while allowing escapement of juveniles and non-target species. These structures, often comprising stakes driven into substrates with lattice fencing or portable baskets, date back at least 3,000 years based on archaeological evidence from sites in British Columbia and Alaska.^[31]^[32] Groups such as the Coquille Indian Tribe and Lake Babine Nation employed these weirs seasonally during salmon runs, positioning them to exploit specific hydrological conditions for efficient capture without permanent barriers.^[33]^[34] In northeastern California, the Ahjumawi (Pit River Indians) built stone fish traps along lake shores, such as those preserved at Ahjumawi Lava Springs State Park, to selectively harvest sucker fish like the Sacramento sucker (Catostomus occidentalis). These V- or heart-shaped enclosures of stacked lava rocks impounded fish in shallow bays during low water levels, enabling hand capture while minimizing bycatch and habitat alteration.^[35]^[36] Constructed over generations, the traps demonstrate empirical understanding of fish behavior and seasonal hydrology, with over a dozen documented structures facilitating communal harvests that supported tribal populations for centuries.^[37]^[38] Such applications reflect sophisticated engineering attuned to local ecologies, sustaining fish stocks through practices like timed deployments, size-selective openings, and rotational use that avoided overexploitation. Archaeological records indicate continuous use without evidence of population collapse, contrasting narratives of inherent primitiveness by highlighting adaptive designs that integrated causal factors like migration patterns and water dynamics.^[39]^[34] Indigenous governance enforced rules on harvest timing and sharing, fostering resilience observed in stable salmon returns predating industrial fishing.^[40]^[34]

Modern and Industrial Evolution

In the 20th century, commercial fish traps increasingly incorporated metal wire frames and synthetic netting to enhance durability against biofouling and mechanical wear, replacing traditional wooden and natural fiber constructions that degraded rapidly in marine environments.^[41] This shift, evident in pot fisheries for species like lobster and crab, allowed for scalable deployment in industrial operations, with galvanized steel meshes and vinyl-coated wire extending trap lifespan from months to years.^[42] Such adaptations supported commercialization by reducing replacement costs and enabling larger fleets to target depleted stocks more efficiently than less selective methods like trawling.^[3] Regulatory measures, however, occasionally impeded these scalable designs; for instance, Washington State banned fixed gear traps including pound nets on the Columbia River in 1935 amid overharvest concerns, attributing declines to inadequate quotas rather than inherent flaws in trap selectivity.^[43] Despite this, empirical evidence from trap-based fisheries demonstrates their role in stabilizing depleted populations through low bycatch and targeted removal, as traps capture primarily desired sizes and species while allowing undersized or non-target fish to escape.^[3] In overexploited systems, this selectivity has helped avert total collapse by preserving breeding stocks, contrasting with high-discard practices in dragnet fisheries that exacerbate depletion.^[44] Into the 21st century, experimental and revived trap applications underscore their utility in managing hatchery-wild interactions; a 2019 study on a commercial-scale trap in the lower Columbia River reported 98% survival for released wild Chinook salmon, enabling selective harvest of hatchery-origin fish to mitigate genetic dilution of native runs.^[45] By 2025, this approach expanded into the first permitted commercial fish trap fishery there in nearly a century, prioritizing hatchery removals to bolster wild stock recovery amid ongoing regulatory scrutiny.^[43] These efforts highlight traps' potential to counter fishery declines when integrated with precise management, though historical bans illustrate how overly restrictive policies can delay adoption of proven, low-impact tools.^[46]

Types and Designs

Portable Traps

Portable traps encompass mobile designs such as basket traps and fyke nets, optimized for deployment in rivers and lakes where transportability is essential. Basket traps typically feature a funnel-shaped entrance leading into a confined chamber, allowing fish to enter via attraction to bait but hindering escape through inverted cones or narrow openings. These are suited for targeting smaller freshwater species in flowing waters, where they can be anchored temporarily in eddies or shallows to exploit natural currents for ingress.^[2] Fyke nets, another prevalent portable variant, consist of a cylindrical netting bag supported by hoops, often with collapsible wings or leaders that funnel fish toward one or more internal cones. Designed for freshwater environments, they are deployed by stretching wings across currents to guide migratory or schooling fish into the trap, with models featuring multiple rings for sequential entrapment. Field studies in northern Wisconsin lakes demonstrated fyke net catch rates positively correlated with walleye density, yielding higher captures in littoral zones compared to electrofishing.^[47]^[48] In Polish lakes, type II fyke nets averaged 1.75 kg daily catch across extensive sampling efforts.^[49] Such traps excel in remote or inaccessible areas, where their lightweight construction and disassembly facilitate manual transport to sites unsuitable for fixed installations, minimizing logistical demands.^[3] Their passive operation reduces fisher effort post-deployment, enabling sustained monitoring with lower bycatch mortality than active gears, though catch variability remains high due to environmental factors like flow and bait efficacy.^[50] Selectivity is enhanced by funnel sizing, permitting targeted species retention while allowing undersized fish to exit.^[2]

Fixed and Tidal Structures

Fixed and tidal fish traps consist of stationary structures, often constructed from stone or wood, positioned in intertidal zones to exploit tidal fluctuations for passive fish capture. These traps typically feature V-shaped or curved weirs that funnel fish toward impoundment areas as water levels drop during ebb tides, preventing escape until harvest. In Australia, Indigenous stone-walled intertidal fishtraps, numbering over 179 documented sites in Queensland alone, demonstrate this design with alignments that direct migratory species into holding ponds exposed at low tide.^[51] Similarly, in Western Australia's Albany region, ancient tidal weirs formed by stacked stones create barriers that trap fish retreating with the ebbing tide, a method observed by early European explorers in the 19th century.^[52] In Europe, comparable fixed structures include stone tidal weirs along the foreshore of the Mol`ene Archipelago in Brittany, France, where low walls harness daily tidal ranges exceeding 5 meters to enclose fish as seawater recedes. These weirs, built perpendicular or at angles to the shore, rely on natural currents to guide fish inward, with historical evidence indicating use since prehistoric times in regions with pronounced tides. Semi-permanent variants incorporate wooden posts driven into the substrate, interwoven with wattle or reeds to form barriers extending from high to low water marks, as identified in Scottish coastal sites like the Moray and Forth estuaries.^[53]^[54] Such structures offer advantages in coastal and estuarine settings by passively aggregating fish over large areas during tidal cycles, particularly effective for capturing schools during seasonal migrations when compared to portable traps limited by manual handling and smaller scale. Empirical observations from intertidal sites show these fixed weirs can yield concentrated harvests from ebbing tides, minimizing labor while maximizing exploitation of predictable fish behaviors tied to tidal flows.^[28]^[3]

Specialized Variants

Lobster pots represent a specialized variant tailored to the behavior of clawed lobsters, featuring multiple funnel entrances leading to a central chamber and incorporating escape vents to enhance size selectivity. These vents, often rectangular openings measuring 38-57 mm in height depending on regional regulations, allow sublegal lobsters—typically those below a carapace length of 83 mm—to exit while retaining harvestable sizes, thereby reducing mortality of juveniles and immature individuals. Field trials have shown that such vents significantly lower the retention of undersized Homarus americanus, with selectivity curves indicating near-optimal performance for legal minimums when vent dimensions align with species morphology.^[55]^[56]^[57] Eel bucks, employed historically in tidal rivers for capturing European eels (Anguilla anguilla), utilize conical willow-woven baskets with upstream-oriented funnel mouths to exploit the species' migratory and positive rheotactic tendencies during autumn spawning runs. Strung along weirs or stages, these traps passively intercept eels navigating currents without active pursuit, minimizing entanglement risks compared to netting methods. Their design, refined over centuries in regions like the River Thames until early 20th-century restrictions, demonstrates causal adaptation to eel elver and adult upstream migration patterns, achieving targeted catches with low bycatch due to narrow funnel apertures suited to elongated body shapes.^[58]^[59] Hybrid trap variants, integrating funnel entrances with extended net wings or bags, address challenges in capturing migratory or schooling species in deeper freshwater or coastal environments, such as salmonids or pelagic fish. These fyke-net hybrids expand effective capture volume beyond rigid pots, funneling fish through sequential cones into a cod-end while permitting escape of non-target sizes via integrated vents, thus adapting to variable water depths and flows. Comparative studies reveal that vented trap systems, including hybrids, yield bycatch reductions of up to 70% for non-target species like undersized salmon in mixed fisheries, underscoring their empirical superiority in selectivity over unvented or drag-based gears by aligning retention with behavioral and morphological criteria.^[60]^[61]

Construction and Materials

Traditional Construction Techniques

Traditional portable fish traps, such as basket types, were constructed by weaving flexible natural materials like reeds, vines, or split wood splints into funnel-shaped enclosures featuring a one-way entrance to retain captured fish. In the Appalachian region, indigenous groups formed these baskets using white oak splints woven around stakes to create a tapered structure that directed fish inward while impeding escape.^[62] Ethnographic accounts from regions like Meghalaya document similar bamboo-woven traps arranged to allow entry through narrow openings but restrict exit via constricted funnels.^[63] Fixed stone weirs relied on dry-stacking locally sourced rocks, boulders, or coral heads without mortar to form low walls or V- and U-shaped barriers that channeled fish during tidal or current flows. Chamorro gigao traps in Guam involved piling irregularly shaped limestone blocks and coral directly onto coral outcrops, resulting in porous walls up to 1 meter high and 3 meters wide that withstood tidal forces through interlocking and gravitational stability.^[64] Archaeological evidence from Southeast Alaska reveals semi-circular arcs of stacked boulders, dating to approximately 11,100 years ago, built across gullies to exploit tidal movements without adhesive bindings.^[24] Construction sites were selected in shallow tidal zones, estuaries, or stream confluences where bathymetry and currents naturally funneled fish, as confirmed by remnants of these structures in sedimentary contexts. Stone weirs exhibited greater permanence in dynamic tidal environments due to their mass and low porosity allowing water passage while maintaining form, whereas woven organic traps biodegraded rapidly, necessitating annual reconstruction to counter rot and mechanical wear from water flow and marine organisms.^[64]^[62]^[24]

Contemporary Materials and Engineering

Modern fish traps have transitioned to synthetic polymers such as polyethylene and polypropylene, alongside galvanized or PVC-coated wire meshes, to achieve superior corrosion resistance in saline environments and reduced overall weight for easier handling and deployment. These materials withstand biofouling and mechanical stress better than untreated metals or organics, with PVC coatings providing a barrier against electrolytic degradation and plastics offering inherent flexibility to prevent cracking under tidal forces.^[65]^[66]^[67] Engineering innovations emphasize modularity through interlocking panels or collapsible frames, facilitating rapid assembly, stacking for storage, and customization of chamber volumes to target specific species depths. Integrated escape mechanisms, such as rectangular vents or circular gaps typically 5-7 cm in diameter, enable sub-legal fish to egress while retaining adults, with empirical tests showing up to 99% escapement efficiency for undersized sablefish via square panels.^[68]^[69]^[70] Performance data from comparative trials reveal no significant catch efficiency disparity between plastic traps and traditional rush variants, yet plastics exhibit extended operational lifespans—often exceeding 5-10 years in controlled use—due to resistance to rot and abrasion, thereby reducing replacement cycles. Life-cycle cost analyses for galvanized wire traps confirm lower total ownership expenses versus uncoated steel, as zinc barriers extend usability by mitigating pitting corrosion, even at discount rates up to 10%.^[71]^[72]^[73]

Operation and Deployment

Siting and Baiting Strategies

Fish traps are strategically sited in natural chokepoints to capitalize on predictable fish behaviors, such as concentrations at river confluences or tidal gullies where currents funnel prey and migrants.^[74] In stream environments, traps are often positioned in excavated channels across gravel bars to intercept upstream or downstream movements, enhancing capture efficiency by mimicking barriers that concentrate fish.^[74] Observational data from coastal fisheries indicate optimal placement in areas of moderate current adjacent to structure like grass beds, where traps can be anchored to sandy substrates to avoid displacement while allowing fish ingress.^[75] Baiting employs targeted attractants placed centrally within the trap to draw species via olfactory cues without excessive dispersion, thereby reducing waste and maintaining potency. Common baits include fish offal or scraps for carnivorous targets, dead crabs for bottom-dwellers like spot fish, and carbohydrate-rich options such as bread or crushed crackers for schooling baitfish, selected based on regional prey preferences.^[76] ^[77] Placement techniques minimize escape by securing bait in perforated compartments, ensuring scent release while preventing rapid depletion, as evidenced by higher retention rates in soaked traps.^[78] Seasonal adjustments derive from empirical catch logs tracking migration timings, with traps redeployed during peak influxes—for instance, spring downstream movements of juveniles or autumn spawning runs—to align with species-specific patterns.^[79] Analysis of monthly catch-per-unit-effort data reveals variations, such as elevated yields for arrowhead traps during high-migration months, informing shifts in trap density or relocation to upstream confluences.^[80] Such data-driven tactics, corroborated across fisheries, optimize efficacy by synchronizing operations with observed annual cycles rather than fixed calendars.^[81]

Harvesting and Maintenance Practices

Harvesting from fish traps typically involves timed retrieval to coincide with environmental conditions that facilitate access and minimize disturbance to the catch. For intertidal and fixed tidal traps, extraction occurs during low tides when receding waters expose the enclosures, allowing fish to be collected from shallow pools or dry basins without prolonged submersion.^[82] In portable pot or basket traps, retrieval is scheduled during calm weather or slack tides to avoid gear loss or entanglement, often every 1-3 days depending on target species and bait efficacy, ensuring fish remain viable upon removal.^[83] This timing reduces risks of storm damage and optimizes efficiency by leveraging natural currents that concentrate prey.^[35] Upon access, traps are opened via removable funnels, lids, or barriers, with catch extracted using dip nets, spears, or scoops to preserve liveliness and prevent injury from overcrowding-induced stress or oxygen depletion.^[35] In specialized cases like Ahjumawi lava rock traps, evening harvests during spawning runs (late January to early June) involve closing weirs with boards or stones, then illuminating and spearing fish, yielding over 100 individuals per session with minimal handling trauma.^[35] Passive trap designs, such as pound nets, enable sorting in live wells, achieving post-release survival rates of 94-99.6% for salmonids due to voluntary entry and limited air exposure, contrasting with active fishing methods where pursuit and haul stress elevate mortality by 20-50% or more through exhaustion and barotrauma.^[84] ^[85] ^[86] Maintenance protocols emphasize prompt cleaning post-harvest to avert biofouling by algae, barnacles, or debris, which clogs entrances and diminishes trap volume by up to 30-50% over weeks of deployment. Nets and frames are scrubbed or pressure-washed to remove organic buildup, with traditional traps cleared of silt via manual raking to expose substrates and sustain flow.^[35] Repairs address wear from currents or marine growth, using on-site materials like reweaving reeds, restacking stones, or patching meshes to restore structural integrity without specialized tools, ensuring reusability across seasons.^[35] Pound nets exemplify low-upkeep variants, requiring minimal intervention beyond periodic piling checks, which supports their efficiency in reducing operational downtime compared to high-maintenance active gears.^[84]

Cultural and Geographical Contexts

Indigenous Knowledge Systems

Indigenous knowledge systems for fish traps reflect empirical engineering honed through direct observation of fish migration patterns, tidal influences, and hydrological variability, prioritizing functional causality over symbolic narratives. Among the Ngemba people at Brewarrina, Australia, stone-walled structures spanning 400 meters along the Barwon River were iteratively refined over generations to accommodate flood-prone dynamics, with low walls and channels directing upstream-swimming fish into retention ponds during seasonal flows.^[87]^[88] This adaptation leveraged local ecology, allowing selective harvesting without disrupting breeding populations, as stone configurations minimized escape while permitting smaller fish to pass.^[28] Archaeological surveys and oral histories document sustained yields supporting multi-clan populations, with evidence of cooperative protocols—such as assigned pond custodianship—preventing overexploitation and maintaining ecosystem balance over millennia, in contrast to unsubstantiated claims of inherent pre-colonial depletion.^[89]^[90] On the Darling River system, similar wooden, earthen, and stone weirs, corroborated by 19th-century ethnographic accounts and indigenous testimonies, enabled regulated access to golden perch and other species, yielding protein surpluses for trade and storage without recorded collapses attributable to trapping.^[89]^[91] Pre-colonial transmission of these techniques relied on intergenerational oral instruction, embedding causal principles like bait placement aligned with lunar-tidal fish aggregations and material durability against erosion, unaltered by ideological impositions and validated by enduring archaeological integrity.^[34]^[32] Comparable systems among Kaiadilt communities featured intertidal traps up to 900 meters long, engineered for tidal retention and cooling to preserve catch viability, demonstrating scalable application of behavioral insights across coastal gradients.^[92] Such knowledge underscores adaptive realism, where trap efficacy stemmed from testable environmental interactions rather than abstracted ideals.^[6]

Regional Adaptations and Distributions

In Southeast Asia, bamboo-based conical traps, such as the bubo in the Philippines and similar variants in the Mekong Basin of Laos, predominate in coral reef and coastal fisheries due to the abundance of fast-growing bamboo and the need for lightweight, portable structures suited to tropical marine and estuarine environments. These traps, often 1-2 meters in length with funnel entrances, exploit tidal movements and reef topography to capture reef fish like moray eels and groupers, with prevalence documented in artisanal fisheries across the Visayas region and Andaman Sea islands.^[93]^[94]^[95] In Europe, fixed tidal weirs constructed from wooden stakes and brushwood hurdles are adapted to intertidal zones along river estuaries and coastal flats, as evidenced by medieval structures in the Netherlands and Severn Estuary, where they channel fish during ebb tides in shallow, sediment-rich waters. These adaptations, spanning from Mesolithic sites to post-medieval periods, reflect geographic constraints like strong tidal ranges and temperate river systems, with hurdles often deployed in linear formations up to 100 meters long to intercept migratory salmonids.^[96]^[5] Across the Pacific Islands, stone-built tidal weirs, such as those in Yap State, Micronesia, utilize coral rubble and basalt walls forming V- or arrow-shaped enclosures on reef flats, capitalizing on predictable tidal ebbs in atoll lagoons to trap schools of reef fish; over 800 such structures have been mapped, clustered near reef passes for optimal current flow.^[97] In contrast, freshwater adaptations in African rift lakes, like woven basket traps in Lake Kainji, Nigeria, and Volta Basin, Ghana, employ portable rattan or reed cylinders for lentic environments, targeting tilapiine cichlids in shallow, vegetated bays where fixed weirs would be impractical due to seasonal water level fluctuations.^[98]^[99] In Alaskan estuaries, historical wooden pile-driven traps adapted to glacial fjords and salmon runs have largely been supplanted by regulatory prohibitions since 1959, yet intertidal stone weirs persist in limited subsistence contexts in Southeast Alaska, illustrating geographic persistence in high-flow, anadromous fisheries despite broader bans in commercial salmon management.^[100]^[101]^[102] Large-scale stone weirs in the Persian Gulf, visible via satellite and spanning kilometers, further highlight arid coastal adaptations to shallow, hypersaline bays, where fixed barriers exploit extreme tides for mullet and shrimp harvests.^[103]

Environmental and Ecological Impacts

Sustainability and Selectivity Benefits

Fish traps, as passive fishing gears, demonstrate high selectivity by allowing targeted species to enter while enabling the release of non-target or undersized individuals with minimal harm, as evidenced by empirical studies on salmon fisheries. In the lower Columbia River, modified commercial fish traps achieved 100% post-release survival for bycatch Chinook and coho salmon, confirmed through peer-reviewed analysis of capture and release data from 2019-2021 operations.^[104]^[85] This selectivity stems from the traps' design, which permits live release without handling stress typical of active gears, reducing mortality rates to near zero for adult salmonids compared to gillnets, where bycatch survival often falls below 50%.^[105] Such outcomes challenge assumptions of inherent high bycatch in trap fisheries, as data indicate traps can eliminate detectable bycatch mortality when paired with visual identification protocols.^[106] Indigenous management systems incorporating fish traps have sustained fish populations over millennia, providing evidence of long-term ecological stability absent in regions reliant on unregulated active fishing methods. For instance, traditional salmon weirs and traps used by Pacific Northwest tribes maintained harvestable stocks through seasonal, low-pressure extraction, avoiding the boom-bust dynamics observed in overexploited active-gear fisheries where rapid depletion occurs due to constant pursuit and habitat disruption.^[34] Analysis of First Nations practices, including stone and wood traps, reveals consistent yields without evidence of collapse, attributable to the gears' passive nature that aligns harvest with natural fish behaviors and migration patterns rather than forcing encounters.^[40] This stability contrasts with active gears like trawls, which in unregulated contexts have led to serial depletions, as passive traps impose no selective pressure on escapees and allow population recovery between sets.^[107] The energy efficiency of fish traps further enhances their sustainability by minimizing fuel consumption and associated carbon emissions relative to motorized active gears. Trap deployment relies on tidal or river currents for operation, requiring negligible ongoing propulsion—often limited to initial placement and periodic checks—yielding fuel use intensities far below those of bottom trawling, which demands 2-3 liters of fuel per kilogram of catch due to dragging heavy nets across seabeds.^[108] Contemporary trap systems, such as pound nets, are described as low-carbon strategies, with emissions primarily from transport rather than continuous engine operation, potentially reducing fleet-wide fishery carbon footprints by substituting for high-fuel gears.^[109] This efficiency holds particularly for subsistence and small-scale applications, where human-powered or current-driven traps eliminate fossil fuel inputs entirely, supporting sustained yields without contributing to the elevated greenhouse gas outputs of industrial trawling.^[110]

Habitat and Bycatch Concerns

Deployment and retrieval of fish traps, particularly those placed on soft sediments, can cause localized benthic disturbance through dragging, leading to temporary sediment resuspension. Experimental deployments in shallow waters (<7 m) have shown traps displacing up to 150 m due to currents and wave action, potentially disrupting infaunal communities and releasing nutrients from pore waters.^[16] Such movements are more pronounced in high-energy environments, where multi-trap lines may scuff the seabed over distances proportional to line length and bottom type.^[111] Bycatch in fish traps primarily consists of non-target fish, crustaceans, and occasionally mobile invertebrates that enter via funnels or remain due to inadequate escape vents. Rates vary by design and location, but studies indicate capture of undersized or protected species in up to 20-30% of trap contents in some reef fisheries, with higher incidences in unvented or oversized traps.^[112] Entanglement risks are elevated during faulty deployments, such as tangled lines snagging on epifaunal structures like corals or sponges, potentially damaging habitat features while incidentally harming non-target organisms.^[113] Compared to bottom trawls, which generate widespread sediment plumes and chronic habitat alteration, fish trap disturbances are confined to deployment footprints, typically recovering within days to weeks in cohesive sediments. Nonetheless, repeated use in sensitive areas like seagrass beds or biogenic reefs amplifies cumulative effects on epibenthic assemblages.^[114]^[115]

Debates and Empirical Evidence

Advocates for fish traps argue that they facilitate targeted removal of hatchery-origin or invasive fish, thereby supporting wild stock recovery without broadly depleting native populations. In the Columbia River Basin, experimental deployments since 2017 have demonstrated the ability to visually distinguish and release wild salmon and steelhead with near-zero mortality, while harvesting hatchery-marked individuals that compete with wild fish for resources. A 2022 study on spring- and summer-run Chinook salmon confirmed 100% post-release survival for wild fish captured in passive traps, attributing this to minimal physical injury compared to active gears like gillnets. Such selectivity addresses hatchery strays, which genetic analyses show reduce wild fitness through competition and introgression, with traps enabling precise management absent in mixed-stock fisheries.^[116]^[45]^[117] Critics contend that even brief capture and handling in traps induces physiological stress, potentially elevating delayed mortality in wild stocks, particularly for sensitive species like steelhead. Commercial fishing interests, such as Alaska trollers, have challenged trap proponents like the Wild Fish Conservancy, asserting that sorting processes—despite rapid release—disrupt migration and spawning success, based on observed handling effects in analogous catch-and-release scenarios. These concerns echo broader fisheries literature on capture stress, where elevated cortisol levels correlate with reduced post-release feeding and survival in some perches and salmonids, though trap-specific data often show lower impacts than nets. Lawsuits by conservation groups, including Wild Fish Conservancy actions against hatchery operations, indirectly fuel debates by highlighting cumulative stressors, but direct empirical challenges to trap selectivity remain limited to anecdotal reports rather than controlled trials.^[118]^[119]^[120] Empirical evidence counters precautionary restrictions by revealing millennia of stable trap use in indigenous systems without ecosystem collapse, contrasting with 20th-century commercial bans driven by overharvest rather than inherent flaws. Australian Aboriginal traps at Brewarrina, dated to over 7,500 years, sustained communities through regulated weirs that exploited tidal and riverine flows without depleting stocks, as evidenced by continuous archaeological occupation. In the Columbia, the 1934 ban followed intensive fixed-gear exploitation exceeding sustainable yields, yet recent trials indicate traps' high selectivity—releasing 90-100% of wild fish alive—undermines blanket prohibitions that overlook gear-specific data. Peer-reviewed assessments affirm traps' lower bycatch mortality versus trawls or seines, with historical precedents suggesting regulatory inertia favors active gears despite evidence of traps' causal role in maintaining balance through passive, size- and behavior-selective capture.^[121]^[43]^[34]

Regulatory and Economic Dimensions

Legal Frameworks and Restrictions

In the United States, the Magnuson-Stevens Fishery Conservation and Management Act (MSA) of 1976, as amended, establishes national standards for fishery management that prioritize reducing bycatch and promoting selective fishing gears to prevent overfishing.^[122] Traps and pots, including fish traps, are recognized under MSA-implemented plans as potentially low-bycatch methods when designed with escape vents and biodegradable panels to release undersized or non-target species, though regional councils may impose restrictions based on stock assessments showing incidental mortality risks.^[1] Despite empirical evidence from NOAA studies indicating traps' selectivity advantages over active gears like trawls, some state-level implementations under MSA have led to outright bans, such as Florida's prohibition on fish traps citing bycatch concerns, even as federal allowances persist for experimental or conservation-oriented use.^[123] Historical bans in U.S. rivers exemplify regulatory caution overriding sustainability data; for instance, Washington State outlawed commercial fish traps in 1935 following overharvest of salmon stocks under lax management, a policy that endured until 2025 when experimental authorizations revived them on the Columbia River to selectively harvest hatchery fish and support wild salmon recovery, demonstrating traps' utility when monitored.^[43] ^[124] Such restrictions often stem from precautionary bycatch fears, yet post-ban evaluations, including passive trap designs minimizing salmonid mortality, suggest inefficiencies where bans preclude evidence-based alternatives to gillnets or hooks.^[85] Indigenous treaty rights introduce conflicts with modern enforcement; Pacific Northwest tribes, under 1850s treaties reserving "usual and accustomed" fishing places, maintain priority access to anadromous fish resources, including trap methods, superseding state bans unless conservation necessity is proven.^[125] ^[126] Federal courts, as in the Boldt Decision of 1974, affirmed these rights against state regulations, yet enforcement tensions persist, with tribes advocating trap use for selective harvest amid disputes over habitat degradation impacts on reserved stocks.^[127] Internationally, frameworks like FAO guidelines endorse traps as sustainable for small-scale fisheries when equipped with size-selective features, but regional bodies such as ICCAT regulate trap fisheries for species like bluefin tuna with quotas and seasonal closures to curb overexploitation.^[128] The Marine Stewardship Council notes traps' low impact potential but highlights risks from lost gear, prompting standards for marking and retrieval, though enforcement varies, revealing gaps where empirical selectivity data challenges blanket restrictions in high-bycatch jurisdictions.^[44]

Subsistence, Commercial, and Conservation Uses

Fish traps fulfill a primary role in subsistence fishing across developing regions in the Pacific, Southeast Asia, and Africa, where they support food security by capturing reef-associated species with minimal equipment investment. Coastal communities in Thailand's Andaman Sea employ traditional coral reef fish traps to harvest locally consumed fish, sustaining household nutrition amid limited alternatives.^[129] In African coral lagoons, basket traps target reef fish, providing a reliable protein source for small-scale fishers dependent on nearshore resources.^[130] Pacific Island communities derive approximately 47% of their subsistence fishing income from reef species often caught via traps, underscoring their centrality to daily caloric needs in food-vulnerable areas.^[131] In commercial fisheries, traps scale effectively for high-value crustaceans like lobsters and crabs, driving export-oriented production reflective of market demand rather than subsidies. The American lobster industry, reliant on bottom-set traps, underpins Canada's 40% global export share in 2020, with landings processed into products sustaining steady international trade.^[132] United States lobster exports form a key component of the $5.5 billion annual seafood export value from 2.5 billion pounds, demonstrating traps' efficiency in delivering premium catches to global markets.^[133] Crab pot fisheries similarly yield economic returns, as evidenced by Alaska's commercial operations contributing to broader seafood industry outputs exceeding billions in value.^[134] Conservation efforts leverage fish traps for selective harvesting that minimizes bycatch and counters overfishing pressures on non-target stocks. Incorporation of escape gaps in traps reduces bycatch by up to 80% while maintaining target species yields, enabling sustainable reef fisheries.^[135] Experimental modifications to commercial traps achieve 100% post-release survival for salmonids, facilitating live release of wild fish and targeted harvest of hatchery-origin individuals to preserve genetic integrity.^[136] These applications promote ecosystem resilience by allowing precise removals that alleviate overexploitation without broad-area closures.^[106]

Innovations and Future Prospects

Technological Advancements

Recent developments in fish trap technology emphasize passive selectivity mechanisms to target specific sizes and species while minimizing bycatch mortality, particularly in salmon fisheries. Trials conducted in the Lower Columbia River during 2019-2020 evaluated modified passive commercial fish traps, achieving nearly 100% survival rates for released adult steelhead and Chinook salmon bycatch through optimized escape vents and handling protocols that allow non-target fish to exit without stress.^[137] Similar 2022 studies on passively operated traps confirmed selectivity exceeding 90% for target stocks, with bycatch survival rates approaching 100% via size-selective apertures that permit undersized or protected salmonids to escape voluntarily, reducing overall handling time and injury.^[138] These empirical upgrades, tested under commercial conditions, enhance precision by leveraging fish behavior rather than active sorting, outperforming traditional active-haul methods in post-release viability.^[139] Material innovations post-2010 have introduced biodegradable alternatives for trap components, addressing lost gear persistence without compromising structural integrity or catch efficiency. Norwegian research since 2020 has prototyped bio-based polymers for static gears like pots and traps, which degrade within 1-2 years in marine environments, mitigating "ghost fishing" from derelict equipment while maintaining tensile strength comparable to synthetics during deployment.^[140] Initiatives such as B4Plastics have developed fully biodegradable trap nets and frames from plant-derived composites, field-tested to retain over 95% functionality for operational lifespans of 6-12 months before controlled breakdown, as verified in North Sea trials.^[141] These materials prioritize causal durability—resisting premature failure from biofouling or currents—while enabling enzymatic degradation, supported by lifecycle assessments showing reduced microplastic release versus conventional nylon.^[142] Emerging sensor integrations, though less widespread in traps than in mobile gears, enable real-time catch monitoring to further refine selectivity. Electronic monitoring systems deployed in trap fisheries since 2019 incorporate low-cost cameras and activity sensors (e.g., motion detectors at escape vents) to log entry/exit events and size distributions autonomously, facilitating data-driven adjustments like vent sizing based on observed fish lengths.^[143] Autonomous underwater cameras, such as the FishCam developed around 2020, have been adapted for trap interiors to provide video feeds of catch composition, achieving detection accuracies above 85% for species identification in low-light conditions without disturbing trap operation.^[144] These post-2010 tools, powered by solar-rechargeable batteries, transmit data via acoustic modems, allowing remote optimization of trap arrays for precision harvesting in dynamic environments like riverine salmon runs.^[145]

Integration with Aquaculture and Management

Fish traps facilitate integration with closed-loop aquaculture systems by enabling selective capture and sorting of juveniles and adults, minimizing stress and mortality compared to active netting methods. In trap-and-haul operations for Pacific salmonids, sorting mechanisms within traps allow separation of hatchery-origin fish from wild stocks, supporting broodstock collection while preserving genetic integrity.^[146] This approach aligns with recirculating aquaculture models where traps serve as passive holding devices for size-based grading, enhancing efficiency in species-specific farming without soil-based substrates.^[147] In adaptive management frameworks, fish traps play a key role in mitigating hatchery-wild interbreeding, as demonstrated by 2025 initiatives in the lower Columbia River. Commercial trap fisheries there target hatchery salmon for removal, directly reducing genetic dilution in wild populations by preventing straying adults from spawning.^[46] This marks a revival of trap use after nearly a century of prohibition, emphasizing real-time monitoring and adjustment to balance harvest with ecosystem recovery.^[43] Such applications prioritize empirical feedback loops over rigid stocking protocols, fostering resilience in mixed-stock environments. Prospects for fish trap integration favor property rights-based models over individual transferable quotas (ITQs), as economic analyses indicate superior incentives for stewardship and stock conservation. Assigning durable, exclusive rights to fixed trap locations encourages long-term investment in site maintenance and bycatch reduction, circumventing the race-to-fish dynamics inherent in quota systems.^[148] Unlike mobile quota fisheries, trap-centric regimes align harvester interests with sustained yields, as evidenced by historical and simulated outcomes where property rights enhance economic efficiency and reduce overcapitalization.^[149] This shift supports balanced ecosystems by decentralizing control, allowing localized adaptations to environmental variability.^[150]

References

[1]
Fishing Gear: Traps and Pots - NOAA Fisheries
May 12, 2025 · Traps and pots are submerged three-dimensional wire or wood devices that permit organisms to enter the enclosure but make escape extremely difficult or ...Missing: credible | Show results with:credible
[2]
1. what is trapping?
Traps are simple, passive fishing gear that allow fish to enter and then make it hard for them to escape. This is often achieved by: putting chambers in the ...Missing: history credible
[3]
review and synthesis of the benefits, drawbacks, and considerations ...
The oldest traps were weirs made out of stones, reeds, or wood that captured fish moving with the current or tide or while they migrated up or down rivers ( ...Missing: credible | Show results with:credible
[4]
6. how to make various types of traps and pots
The four most common fish trap designs used in the Caribbean are the: Antillean "Z" trap (Figures 19a and 19b);; "S" trap (Figure 20);; arrowhead or chevron ...Missing: worldwide | Show results with:worldwide
[5]
Reconstructing a Prehistoric Fish Trap | The EXARC Journal
Feb 15, 2014 · This article will first review the fish traps found in the Netherlands since the excavation at Bergschenhoek, with emphasis on the materials and techniques ...Missing: device credible
[6]
The Ingenious Ancient Technology Concealed in the Shallows
Aug 3, 2021 · Fish traps have a long history around the world, and a vast network in a Vancouver Island estuary reveals generations of ecological wisdom.
[7]
Late Archaic large-scale fisheries in the wetlands of the pre ...
Nov 22, 2024 · This is the earliest large-scale Archaic fish-trapping facility recorded in ancient Mesoamerica. We suggest that such landscape-scale ...
[8]
Fyke Traps - FISHBIO | Fisheries Consultants
These traps have funnel-shaped openings that narrow toward the interior of the structure. Fish follow the funnel into the trap and, once inside, have ...Missing: mechanisms entrances way valves
[9]
REGULATION OF FISHING GEAR
With passive gears, the capture of fish is generally based on movement of the target species towards the gear (e.g. traps), while with active gears capture is ...<|control11|><|separator|>
[10]
[PDF] It's a Trap! An evaluation of different passive trap types to effectively ...
Dec 4, 2019 · Trap design, color, and placement, in addition to local habitat characteristics and bait type, are important variables to consider when planning ...
[11]
Experimental study of the behavioral response of fish to changes in ...
Fish swimming behavior is influenced by flow changes and diurnal variation (Davey et al., 2011), with most fish being more active during daytime and ecological ...
[12]
Full article: Advancements in Riverine Fish Movement Modeling
Jul 22, 2024 · Despite the lack of consistency, each model imposed some combination of the following behaviors: response to flow direction (i.e., rheotaxis), ...Missing: thigmotaxis | Show results with:thigmotaxis
[13]
[PDF] NOAA Fisheries West Coast Region Anadromous Salmonid Design ...
Often, smaller-sized fish find their way into and become caught in the adult trap holding pool. Provisions should be incorporated into the trap design to ...
[14]
Bycatch and habitat impacts of traps and gillnets - ScienceDirect
Fish traps had the lowest discard rates (0.11%) while lobster traps and drift gillnets had intermediate discard rates (15.1% and 18.5% respectively). In ...
[15]
What Is Bycatch? - World Wildlife Fund
Bycatch occurs because the nets also trap everything larger than the net's mesh, which includes juvenile fish, sharks, seabirds, marine turtles and ...
[16]
The ups and downs of traps: environmental impacts, entanglement ...
Aug 23, 2020 · One of the primary benefits is that trap catches are highly specific, with little bycatch of non-target organisms, compared to mobile gear such ...
[17]
Avoidance of fisheries-induced evolution: management implications ...
The other common type of curve is a dome-shaped selectivity curve (typically characteristic of gillnets, hook-and-line fisheries, and traps, i.e., fixed gear), ...
[18]
The low impact of fish traps on the seabed makes it an eco-friendly ...
Aug 21, 2020 · Trap fisheries have low fuel needs, the survival of unwanted bycatch species is high and, depending on soaking time and depredation, the traps ...2. Material And Methods · 2.2 Video Data Collection · 3.1. 2 Trap Slide And...
[19]
Reducing the Fuel Use Intensity of Fisheries - Frontiers
Danish seining and gillnets had a lower fuel use intensity and higher economic efficiency than demersal trawling; and purse seining than pelagic trawling. The ...
[20]
[PDF] noaa_56753_DS1.pdf - the NOAA Institutional Repository
Dec 28, 2023 · Generally, fishing with passive gears like traps has both fewer direct costs and fewer environmental costs than active gears like trawling ( ...
[21]
How well do fish traps work? How does the effectiveness of ... - Quora
Sep 10, 2013 · Fish traps are very effective, if there are fish in the water you are setting the trap in. The mesh type are good for ponds and small lakes.
[22]
The impacts of long-term changes in weather on small-scale fishers ...
Aug 24, 2022 · Increased adverse weather conditions, likely associated with climate change, could decrease fishers access to crucial resources needed for the ...
[23]
Harmful effects of derelict traps in selected U.S. coastal waters
Sep 15, 2014 · Traps that are abandoned or lost during fishing are pervasive and persistent. Derelict fishing traps (DFT) harm organisms and habitat, and cause economic ...Missing: migration | Show results with:migration
[24]
Scientists Discover Ancient Underwater Fish Weir in Southeast Alaska
Oct 21, 2022 · Stone weirs, or tidal fish traps, were typically low arced walls made of boulders and sited across gullies. The weirs were built so that during ...
[25]
Scientists Discover Ancient Fish Trap in Southeast Alaska
Sep 21, 2022 · Prior to the discovery, the oldest known weirs dated from 7,500 to 8,000 years ago. In Southeast Alaska, the oldest dated weir is 5,740 to 5,490 ...
[26]
Worldwide Weirs: An Ancient Fishing Technology Used By Modern ...
Jan 9, 2023 · Prior to the recent discovery of the Alaskan weir, the oldest known weir in North America, dated nearly 6,000 years old, was a wooden structure ...
[27]
15,800-year-old Ice Age engravings reveal earliest depictions of fish ...
Nov 7, 2024 · These discoveries are not only visually striking but also provide the earliest known evidence of net or trap fishing in European prehistory.
[28]
Aboriginal stone-walled intertidal fishtrap morphology, function and ...
Stone-walled intertidal fishtraps surround the Australian coastline and are among the largest structures built by Indigenous Australians.
[29]
Fish Weir - Ancient Fishing Tool of Hunter-Gatherers - ThoughtCo
May 12, 2025 · A fish weir or fish trap is a human-made structure built of stone, reeds, or wooden posts placed within the channel of a stream or at the edge of a tidal lagoonTypes of Fish Weirs · Invention and Innovation · Dating Fish Traps · Recent StudiesMissing: prehistoric intertidal
[30]
7000 year old fish traps and footprints reveal ancestors activities
Jan 4, 2024 · They were probably used to catch eels or other fish and date back 7,000 years, when hunter-gatherer-fisher communities lived before the arrival ...Missing: oldest evidence
[31]
Wood Stake Weirs and Salmon Fishing on the Northwest Coast
Weir fishing in the northern Northwest Coast has an antiquity of at least 3,000 years and continued into the historic period. To our knowledge, none of British ...
[32]
Fish Traps of the Northwest Coast — Sea Gardens Across the Pacific
Around the globe, and throughout time, coastal peoples have built and maintained fish traps and weirs as ways to harvest and tend fish en masse (Connaway 2007).<|control11|><|separator|>
[33]
wood stake fish weirs of the oregon coast
The Coquille Indian Tribe holds an annual salmon ceremony at the shoreline location of wood stake weirs that have provided fish for millennia (Ivy and Byram ...
[34]
Indigenous Systems of Management for Culturally and Ecologically ...
Dec 9, 2020 · Since time immemorial, LBN has managed and harvested Babine salmon using wood stake k'oonze (weirs) constructed at the outlet of Babine Lake ( ...
[35]
Ahjumawi Fish Traps - California State Parks
This paper argues that Ajumawi fish traps preserved at Ahjumawi Lava Springs State Park are also an example of active resource management.Missing: definition types credible sources
[36]
[PDF] Traditions of Sucker Exploitation in the Pit River System: An Ajumawi ...
This paper grew out of discussions with Pit. River Indians concerning the preservation of stone fish traps at Ahjumawi Lava Springs State Park. ... Salmon Fishery ...<|separator|>
[37]
ahjumawi fish traps: traditional harvest and management of sucker ...
Along the north shore of Big Lake in Shasta county of northeastern California are a series of stone fish traps constructed in ancient times by the Ahjumawi ...
[38]
Pit River Indians use of ancient stone traps fed tribes for centuries
Jul 30, 2018 · The Aparuge had a primary village along the banks of Pine Creek near Eagle Lake in Lassen County where they built an ingenious series of fish traps.Missing: salmon | Show results with:salmon
[39]
Indigenous marine resource management on the Northwest Coast of ...
May 24, 2013 · Approximately 200-year-old wooden riverine fish weir in South Bentick Arm, Central Coast, B.C. This was likely used to trap salmon by impeding ...
[40]
Indigenous Fishing Practices Hold Promise for Future
Dec 9, 2020 · A comprehensive analysis published in Bioscience finds that traditional salmon fishing practices and governance show promise for rebuilding resilient fisheries.Missing: evidence | Show results with:evidence
[41]
(PDF) The low impact of fish traps on the seabed makes it an eco ...
Aug 21, 2020 · Today, synthetic materials have largely replaced degradable material making fishing gear both more effective and with higher durability ...
[42]
[PDF] Trap Design and Ghost Fishing: Discussion - NOAA
On the other hand, a treated wood pot may last upwards of 2 years on the bottom in areas with low borer activity. Wood borers do not af- fect metal or plastic ...
[43]
After Nearly 100 Years, Commercial Fish Traps Make Historic ...
Aug 4, 2025 · Nearly a century ago, fish traps were banned in Washington State due to poor management that led to overharvest and the decline of wild ...
[44]
Pots and traps fishing gear - Marine Stewardship Council
Traps are typically considered to be a selective and low impact method of fishing. However, these gears can have a detrimental effect on the marine environment.<|separator|>
[45]
Survival of Salmonids from an Experimental Commercial Fish Trap
May 25, 2019 · Hatchery-origin Chinook Salmon and Coho Salmon are commercially lucrative target stocks within the lower Columbia River fall fishery. Wild ...
[46]
https://wildfishconservancy.org/working-against-the-current-a-new-experiment-brings-hope-for-sustainable-fishing/
[47]
Fyke Net - Seafish
A fyke net is a type of fish trap. It consists of long cylindrical netting bag usually with several netting cones fitted inside the netting cylinder.
[48]
(PDF) Catchability of Walleyes to Fyke Netting and Electrofishing in ...
Aug 7, 2025 · We found that the fyke-net catch rate was positively related to adult walleye density and percent littoral zone (percentage of lake surface area ...
[49]
effectiveness of catches from various types of trap net for the ...
The average daily catch of type II fyke nets amounts to 1.75 kg as estimated from 54 042 fyke-net/days from 44 lakes with a total surface area 15 042 ha. The ...
[50]
[PDF] DOCDM-997948 Freshwater fish: passive nets—fyke nets v1.1
Catch rates are generally lower than those for gill nets (Hubert 1996). • Catch rate variability is often high, which means that relatively large numbers of ...
[51]
(PDF) Indigenous fish traps and weirs of Queensland - ResearchGate
Aug 9, 2025 · PDF | A Queensland state-wide review of coastal and inland fish traps and weirs is undertaken. More than 179 sites are described.
[52]
Albany Fish Traps, Western Australia - Odyssey Traveller
Mar 20, 2021 · Early European Observations of the Fish Traps. The earliest European descriptions of the stone structures in Albany refer to them as tidal weirs ...Missing: fixed V-
[53]
[PDF] The Stone Tidal Fish Weirs of the Mol`ene Archipelago, Iroise Sea ...
In regions with significant tidal range, people have used the daily fluctuations of sea level to trap fish from fixed structures installed on the foreshore ...
[54]
[PDF] Locating fish-traps on the Moray and the Forth - The SCAPE Trust
Type 2 Semi-permanent wattle and wood trap. These traps consisted of rows of wooden posts linked by wattle-work or nets. They extended from the high to low ...
[55]
[PDF] Lobster Trap Escape Vent Selectivity | Mass.gov
Adjustments to vent size can maintain fishing efficiency, maximize retention of legal lobsters, and mini- mize retention of sublegal lobsters and therefore ...
[56]
[PDF] The Effects of Different Escape Vents on the Selectivity of Lobster ...
Escape gaps, or vents, are commonly created on the sides of the pot by alter- ing the spacing between lower laths, and are intended to liberate sublegal.Missing: design | Show results with:design
[57]
Size-selectivity of lobster pots with escape-gaps - ScienceDirect.com
Size-selectivity curves confirm that the current escape-gap size of 60 mm is close to optimum for the legal minimum lengths used in the Victorian southern rock ...
[58]
The Fishing Museum Online - Eel Bucks
The biggest traps were called 'bucks', the name for any large basket - laundry baskets in particular - although big traps were also known as pots.
[59]
[PDF] Object in Focus 8: A Grig Weel - Marlow Museum
Unlike grigs, the mouths of bucks faced upstream, because they were used to catch migrating adult eels. Bucks mounted on stages were the largest sort of eel ...
[60]
Modified Commercial Fish Trap to Help Eliminate Salmonid Bycatch ...
Sep 30, 2020 · These results suggest that trap modifications can be made to significantly reduce bycatch mortality of ESA-listed salmonids and provide ...Missing: metrics | Show results with:metrics
[61]
https://www.sciencedirect.com/science/article/pii/S0165783624000663
[62]
Fish Weirs As Part Of The Cultural Landscape - National Park Service
Sep 30, 2008 · Fish weirs are efficient structures, made of wood or stone, that guide fish into capture situations, found in the Appalachian Mountains.Missing: intertidal | Show results with:intertidal
[63]
(PDF) Fishing Traps.Fishery Tech.2021 - ResearchGate
Aug 6, 2021 · This study attempts to document the traditional fish trapping devices from four districts of Meghalaya with respect to its structure and operation.
[64]
Ancient CHamoru/Chamorro Fish Weirs (Gigao) - Guampedia
The archeologists discovered 14 walled pools, together measuring a total of 6,612 square meters, with individual pools ranging from an average of 321 to 551 ...
[65]
Crab Trap Material - Galvanized Wire - Vinyl - Plastic
3–5 day delivery 15-day returnsThe vinyl-coated wire has been coated with a layer of PVC after the mesh has been welded. It provides protection against the element, rust, and corrosion.Trap Wire-Galvanized Wire... · Vinyl Wire · Galvanized Wire · Vinyl
[66]
The Art of Gargoor Construction: A Comprehensive Guide to ...
Aug 17, 2024 · Today, Gargoors made from galvanized wire have gained immense popularity among fishermen due to their high resistance to corrosion and long- ...
[67]
Hexagonal Mesh Crab Trap – Galvanized or PVC Coating for Durable
Hot dipped galvanized trap wires are coated with thick zinc coating. This zinc coating can protect crab, lobster and fish crabs from corrosion and rusts. They ...<|separator|>
[68]
[PDF] Unique improved selective fishing traps with adjustable escape ...
The unique improved selective fishing traps made with plastic material is highly recommended as they are more effective in boosting fish catch efficiency and ...
[69]
Effectiveness of Experimental Escape Mechanisms in Sablefish Traps
Jul 29, 2016 · The effectiveness of the escapement mechanisms in the traps was 56% with the 20-cm slash, 99% with the square panel, 90% with the triangular ...Missing: engineering | Show results with:engineering
[70]
Escape gaps in wire lobster traps reduce bycatch of coral reef fish ...
Escape gaps are a tool commonly used to reduce the catch of sublegal-size animals and bycatch in crustacean trap fisheries.Missing: modularity mechanisms
[71]
Performance of traditional rush and modern plastic traps on the ...
Our results showed that there was no significant difference in the catch efficiency of the two kinds of traps used suggesting that plastic traps could play an ...
[72]
Assessing the Technical and Economic Viability of Galvanizing ...
The life cycle cost for galvanized traps is lower than that of traditional, ungalvanized traps except during periods of high discount rates.
[73]
(PDF) Studies on materials for traps for spiny lobsters - ResearchGate
Aug 9, 2025 · The results show that bamboo traps are weak and fragile and wooden traps are unwieldy and so are not favoured. Metal traps made of mild steel ...
[74]
Fish trapping technique: funnel system. Best used in tidal waters ...
Dec 22, 2018 · How it works: The fish are funneled into an incline plane scoop trap. The trap is designed to direct the flow of fish up an incline belt to a ...Missing: valves | Show results with:valves<|separator|>
[75]
Pinfish Traps Tips & Tricks - Catch Live Bait
For pinfish, look for the thickest grass beds with slight to medium current movement and deploy the trap on a sandy spot surrounded by the grass.
[76]
Best Bait for Spot traps - Tidal Fish Forum
Jul 17, 2009 · Dead crab and yes , you need some bloodworms or fishbites for the spot . If you can find some fresh tuna scraps , they work well too.
[77]
https://www.tankmatez.com/blogs/news/best-bait-for-fish-traps
[78]
How to Use a Baitfish Trap for Saltwater Fishing
Jan 13, 2022 · The author uses an eel trap, minnow trap, and baitfish trap to capture live bait for inshore saltwater fishing, plus how to bait these.Missing: offal | Show results with:offal
[79]
[PDF] Annual and seasonal variation, relative abundance, and effects of ...
We evaluated annual and seasonal patterns of relative abundance and timing of migration from historic trapping data in non-anadromous Brown Trout (Salmo.
[80]
Economic and Seasonal Analysis on Catch Rate of Fish Traps ...
Jan 2, 2025 · The trap fishery at Therespuram fishing village showed promising economic benefits, with a benefit-cost ratio of 1.64. The study period revealed ...Missing: labor | Show results with:labor
[81]
Mismatch between fishway operation and timing of fish movements
Mar 10, 2016 · We hypothesized that restricted seasonal opening times of fishways can importantly reduce their effectiveness by interfering with the timing of fish migration.
[82]
Tidal Fish Traps Archives - Survival Harvesting
Jan 27, 2018 · In this post I have three examples of tidal fish traps. All three of these are fixed in place and depend on the receding tide to leave fish behind.
[83]
Efficiency of trap type, soak time and bait type and quantities for ...
The optimal period for setting the traps was 3–8 days. •. Fish bait attracted a much larger diversity and quantities of by-catch than the algae baits.
[84]
Fish Traps: The Pound Net Revival | MeatEater Conservation News
Pound nets emit zero carbon, require little maintenance, and are more gentle on the fish. Whereas most commercial fishing practices entangle fish in their ...
[85]
Maximizing salmonid bycatch survival with passively operated ...
Passively operated fish traps may allow for selective harvesting of targeted fish stocks with little to no mortality of adult salmonid bycatch.
[86]
[PDF] Mortality of fish escaping trawl gears - FAO Knowledge Repository
For some species, discard mortalities can be reduced through reduced exposure to air and improved on- deck handling procedures, but in many cases a significant ...
[87]
Brewarrina Aboriginal Fish Traps (Baiame's Ngunnhu) - DCCEEW
Oct 3, 2021 · The Ngemba people of Brewarrina used their advanced knowledge of river hydrology and fish ecology to trap and catch large numbers of fresh ...Missing: refinements | Show results with:refinements
[88]
Brewarrina fish traps - Deep Time Australia - ABC News
These groups cooperate and maintain a sustainable food and land management system, looking after their individual ponds along the river, under law. In this ...Missing: refinements | Show results with:refinements
[89]
Indigenous fish traps and fish weirs on the Darling (Baaka) River ...
Dec 1, 2022 · The celebrated Brewarrina stone fish traps (Ngunnhu) on the Barwon River are the largest and best documented stone fish traps in the Basin.
[90]
Archaeology demonstrates sustainable ancestral Coast Salish ...
Aug 25, 2023 · Many Indigenous communities from this Pacific Northwest region are finding success in bringing back traditional salmon fishery practices and ...
[91]
A palaeothermometer of ancient Indigenous fisheries reveals ...
May 19, 2022 · Indigenous oral histories, ethnographic accounts, and archaeological evidence document the sustained use of a wide range of coastal ...Materials And Methods · Deriving Biomass From Mni · Discussion And Conclusion
[92]
Ancient engineers - JCU Australia
James Cook University researchers have been investigating stone-walled fish traps up to 900 metres in length constructed by Kaiadilt Aboriginal people in the ...
[93]
[PDF] Persistence of Bubo, Fish Trap in the Philippine Artisanal Fishery ...
Dec 7, 2022 · Among the most pervasive fish traps in Asia and the Pacific, the bubo is the most common device in artisanal fisheries of Philippine ...
[94]
(PDF) Ecology and Technology of Bamboo Fish Traps in the Visayas ...
This paper focus on one of the shing tools and shing methods utilised in the Visayas inland sea area, the bamboo shing trap, which is used primarily to trap ...Missing: prevalence | Show results with:prevalence
[95]
[PDF] Eco-Material Culture Study of Fish Traps in the Mekong Basin of Lao ...
This study investigates fish traps in the Mekong Basin of Lao PDR, focusing on their types, made of bamboo and rattan, and their eco-material culture.
[96]
Full article: The social history of a medieval fish weir, c. 600–2020
Oct 27, 2021 · This article presents the longue durée social history of a medieval fish weir. It reveals the significant role of fishing and fish weirs in the construction ...
[97]
[PDF] Yapese Stone Fish Traps - ScholarSpace
Sep 21, 1981 · Arrow traps cluster around the northeastern tip of the island; two V-shaped lagoon traps are visible on either side of reef inlet channel in top.
[98]
fish trap and cordage - Improving African Futures Using Lessons ...
A basketry fish trap (exa in Ewe) made and used by Ewe fishermen in the Banda area, Ghana. Traps like these were used for fishing between the months of August ...Missing: freshwater | Show results with:freshwater
[99]
Preliminary evaluation of a new fishing pot trap in Lake Kainji, Nigeria
The result obtained have shown that spent female broodstock of M. vollenhovenii can become gravid again in plastic tanks in 35 days when fed fresh trash fish.
[100]
Alaska Statutes § 16.10.070 (2024) - Operation of fish traps
Fish traps, including but not limited to floating, pile-driven, or hand-driven fish traps, may not be operated in the state on or over state land, tideland, ...Missing: estuaries | Show results with:estuaries
[101]
[PDF] GENERAL USE OF FISH TRAPS BARRED IN ALASKA SALMON ...
The regulations were approved by the Secretary of the Interior Fred A. Seaton on March 7. Despite the elimination of most fish,traps, little or no relaxation cf.Missing: estuaries current
[102]
[PDF] an update of intertidal fishing structures in southeast alaska Jane L ...
Aug 21, 2017 · This paper uses information from both gray and published literature to offer an overview of the resource and some current sta- tistics on fish ...<|control11|><|separator|>
[103]
Google Earth reveals secret, gigantic Persian Gulf fish traps - PBS
Nov 26, 2013 · The fishermen in the Persian Gulf region use traps that are so huge, they're visible from space. Called fishing weirs, the tidal traps catch marine life.
[104]
Peer-Reviewed Publication Confirms 100% Survival for Salmon ...
Oct 7, 2022 · Results of the publication provide the most irrefutable evidence to date that contemporary fish traps can allow for selective harvesting and ...
[105]
Modified Commercial Fish Trap to Help Eliminate Salmonid Bycatch ...
Analyzed through two separate survival estimation techniques, the modified trap demonstrated no detectable effect on salmon release survival and a significant ...
[106]
Fish Trap Research – Wild Fish Conservancy Northwest
The results of this effort have demonstrated the unprecedented ability of contemporary fish traps to reduce or eliminate bycatch mortality of wild salmon and ...Missing: metrics | Show results with:metrics
[107]
Indigenous Ecological Knowledge of marine and freshwater ...
Mar 20, 2025 · Fish traps are an ingenious example of sustainable fishing by First Nations communities (Welch 2024). Although there are differing types (mazes ...<|separator|>
[108]
Carbon Footprint - BLOOM Association
For fish caught using bottom trawls, up to 3 liters of fuel oil are needed per kilo of fish caught.
[109]
The Fish Trap Project – Wild Fish Conservancy Northwest
A fish trap (also called a pound net) is a low-carbon commercial fishing strategy with potential for efficient harvest of targeted stocks.
[110]
Bottom trawling and carbon footprint - Marine Stewardship Council
On average, bottom trawl fisheries use more fuel and produce higher carbon emissions than those using other other gear types, except for pots and traps.Missing: consumption | Show results with:consumption
[111]
Impacts of a multi-trap line on benthic habitat containing emergent ...
Sep 12, 2018 · ... fish traps) upon structure have been little studied. We ... Habitat-fisheries interactions: a missing link? ICES Journal of Marine Science.
[112]
Discards and bycatch: A review of wasted fishing - ScienceDirect.com
We provide an up-to-date overview of research on wasted fishing through bycatch and discards since 2012, including pots/traps, trawls, gillnets, and lines.
[113]
Impacts of a multi-trap line on benthic habitat containing emergent ...
Although the impacts of mobile gear are well known, effects of passive gear (e.g. fish traps) upon structure have been little studied. We modified commercial ...
[114]
(PDF) Pots as alternative and sustainable fishing gears in the ...
The literature review shows that pot fisheries have several considerable advantages over conventional gears, especially in terms of discards, bycatch, seabed ...
[115]
Fishing gear substitution to reduce bycatch and habitat impacts
Bycatch rates were highest in trawls and lowest in pots. Combining interview data with findings from a previous study, affirmed that habitat impacts were ...
[116]
New Study Supports Findings of 100% Wild Salmon Survival from ...
Apr 21, 2022 · A new bycatch survival study of passively operated fish traps was recently completed for spring-run and summer-run Chinook Salmon in the Columbia River.Missing: criticisms | Show results with:criticisms
[117]
What's Old May Be New Again
Dec 13, 2017 · An experimental fish trap on the Columbia River shows promise to separate wild from hatchery fish. Illegal since 1934, might fish traps make a comeback?
[118]
Problems with the WFC, their Fish Traps and their Lawsuit
Jan 25, 2021 · WFC claims that their fish traps aid wild Chinook in successful spawning, but they overlook the fact that handling and sorting both impact the ...
[119]
Measuring The Trauma Of Catch-And-Release - Faunalytics
Jan 22, 2019 · Researchers find that catch-and-release angling causes decreased feeding performance in marine perches.
[120]
Conservation Advocates Serve Notice of Intent to Sue Over Feds ...
Sep 12, 2025 · In 2024, WFC and TCA sued NOAA Fisheries and state hatchery operators for multiple violations of the 2017 Biological Opinion, which included ...
[121]
Learning from the land (4): Naiame's Nghunnhu—fishtraps at ...
Feb 8, 2019 · The traps (one of which is pictured above, from our visit in 2018) were constructed by the Menang peoples and are dated at over 7,500 years old.
[122]
Laws & Policies: Magnuson-Stevens Act | NOAA Fisheries
The Magnuson–Stevens Fishery Conservation and Management Act is the primary law that governs marine fisheries management in US federal waters.Missing: traps | Show results with:traps
[123]
[PDF] Caught in the Net: The Magnuson-Stevens Act, Extraterritorial ...
regulations are interpreted with regard to the Magnuson-Stevens Act. In that case, Florida enacted a statute banning the use of fish traps to catch.
[124]
Columbia River Fish Traps Return for the Recovery of Wild Fish and ...
May 5, 2025 · These policies encouraged transition away from gill netting, reduction of wild salmon bycatch mortality in fisheries, and selective removal ...
[125]
Hunting and Fishing Legal Rights of Native Americans - Justia
Jul 30, 2025 · The federal government generally guaranteed hunting and fishing rights when signing treaties with tribes in which the tribes gave up their lands.
[126]
The Tribes' Treaty Reserved Fishing Rights - SOTSP.
The four Columbia River treaty tribes are the only tribes in the basin that have reserved rights to anadromous fish in treaties with the United States.
[127]
The Right to Salmon: “Fish-Ins” and a Tradition of Activism in the ...
May 19, 2023 · Tribes across the state began staging “fish-ins” in 1963 to reclaim their treaty right to salmon. Fish-ins organized by the Nisqually and Puyallup tribes.Missing: traps | Show results with:traps
[128]
Fishing with traps and pots - FAO Knowledge Repository
This manual describes basic elements of fishing with pots and traps for small-scale fishermen. It presents the various types of pots and traps and their ...
[129]
Dr Paul Montgomery's investigation of the fish trap traditions of ...
May 27, 2024 · The tradition the fish traps fisheries on coral reefs are used by local coastal communities across the islands of Thailand's Andaman coast.Missing: prevalence | Show results with:prevalence
[130]
Escape gaps in African basket traps reduce bycatch while ...
Among the bycatch, numbers of butterflyfish and other low value species were reduced in the experimental traps. Overall, at the trap level, there were no ...Missing: empirical | Show results with:empirical
[131]
Decadal characteristics of small-scale fishing livelihoods in 13 ...
Jul 26, 2023 · Across the surveyed PICTs, the average subsistence fishing income generated from reef fish is 47%. Comparatively, the average percent of ...Results · Discussion · Fishing Participation
[132]
[PDF] 2021 Industry Report: Lobster - Tridge
Dec 21, 2021 · Canada is the world's largest lobster exporter, and had a market share of. 40% of both Homarus and rock lobster exports in 2020. • Lobster ...
[133]
[PDF] Fisheries of the United States, 2022
The United. States also exported 2.5 billion pounds of seafood valued at $5.5 billion. The top-valued exports included: whole lobster, surimi, whole sockeye.
[134]
[PDF] The Economic Value of Alaska's Seafood Industry
Commercial fishing in Alaska creates substantial benefits for Alaska's economy and provides consumers around the world with a wild, sustainable product. The ...
[135]
Solution: Escape Gaps for Fish Traps - Ayana Elizabeth Johnson
Putting vertical, rectangular holes, aka escape gaps, in opposing corners of fish traps can reduce bycatch by up to 80%, without reducing (and potentially even ...Missing: cleaning repairing prevention
[136]
New Research Shows Innovative Commercial Fishing Technique ...
Oct 6, 2022 · “The new publication provides the most clear-cut and irrefutable evidence to date that fish traps can nearly eliminate unintended mortality of ...
[137]
[PDF] Evaluation of an experimental salmon trap for stock-selective ...
Sep 11, 2020 · Reduce bycatch and hatchery impacts to wild salmonids. • Good for fishermen: • Increase fishing opportunity. • Improve the quantity and quality.
[138]
[PDF] Maximizing salmonid bycatch survival with passively operated ...
Passively operated fish traps can allow for selective harvesting with little to no mortality of adult salmonid bycatch, building on prior studies showing ...
[139]
Maximizing salmonid bycatch survival with passively operated ...
Commercial fish traps were recently implemented at a limited scale in the lower Columbia River in efforts to selectively harvest hatchery-origin fishes with ...
[140]
Scientists in Norway explore biodegradable fishing gear to tackle ...
Feb 24, 2025 · Scientists in Norway are developing biodegradable fishing gear to reduce plastic pollution in the ocean and prevent harmful microplastics.
[141]
B4Plastics - A whole new meaning to the notion of ghost gear
B4Plastics designs bio-based and biodegradable fishing equipment that address the massive problem of plastic pollution in our oceans.
[142]
Biodegradable fishing gears: A potential solution to ghost fishing ...
Biodegradable materials are suited as a potential solution to reduce ghost fishing. PA could resist in the environment much longer than the service time.Missing: advancements | Show results with:advancements
[143]
[PDF] Electronic monitoring in fisheries: Lessons from global experiences ...
Oct 4, 2019 · Electronic monitoring systems gen‐ erally consist of various activity sensors, GPS, computer hardware and cameras (Figure 1) which allow for ...
[144]
FishCam: A low-cost open source autonomous camera for aquatic ...
We describe the “FishCam”, a low-cost ( 500 USD) autonomous camera package to record videos and images underwater.
[145]
Sensors versus surveyors: Comparing passive acoustic monitoring ...
Oct 8, 2025 · Real-time acoustic monitoring facilitates the proactive management of biological invasions. Biological Invasions, 26, 3989–3996. https://doi ...
[146]
[PDF] Review of trap-and-haul for managing Pacific salmonids ...
Fish sorting is an important element in most adult trap- and-haul programs. Sorting can be used to remove non-target fish or species (e.g., hatchery-origin fish ...<|separator|>
[147]
Fish Trap (Nasse) for Fishing and Aquaculture
Advantages. Simple, cheap, durable. No energy consumption. Some selectivity (mesh size, funnel design).
[148]
(PDF) Advances in Property Rights Based Fisheries Management
Aug 9, 2025 · Property rights in fisheries have proven to be efficient and flexible tools for generating economic efficiency and conserving fish stocks ( ...
[149]
Property Rights to Fish | PERC
Nov 20, 2015 · Not all property rights systems are created equal. Thus, not all are equally effective at protecting fish stocks.Missing: traps | Show results with:traps
[150]
Structural behavioral models for rights-based fisheries - ScienceDirect
Simulation results reveal that such policies have the potential to distort price signals in the quota market and prevent quota prices from coordinating fishing ...