Gear Types Research Articles

Application of instantaneous phase detection technology based on laser displacement sensor in fault diagnosis of spur gear of rotation vector reducer

Aiming at the problem of a spur gear fault of the rotation vector (RV) reducer in industrial robots, an instantaneous phase detection technology based on eccentric modulation and laser displacement sensor is proposed. Taking the RV-20E reducer as the object, through the analysis of the RV reducer gear fault mechanism, an RV reducer fault diagnosis test bed is developed to simulate the actual operating conditions of the RV reducer of industrial robot. The instantaneous phase information of the RV reducer is collected, and the adaptive permutation entropy is used to process the instantaneous phase data, which can judge the gear fault type quickly and effectively. The test results show that the fault diagnosis test bench based on this detection technology can effectively and quantitatively judge the fault type of the spur gear of the RV reducer.

Simulation and Experimental Research on Electrical Control Anti-backlash Based on a Novel Type of Variable Tooth Thickness Involute Gear Pair

This paper presents an electrical backlash control method based on a novel variable tooth thickness involute gear pair (VTTIGP) through acceleration judgment. First, the principle, characteristics and theoretical tooth surface equation of the novel type of variable tooth thickness involute gear (VTTIG) are proposed. Compared with the traditional variable tooth thickness gear (VTTG), each transverse of the novel type of VTTIG has the same tooth root circle and the addendum circle. Therefore, there will be no interference caused by the excessive axial relative movement distance between the gear pairs when eliminating the backlash. The theoretical calculation equation of no-load transmission error (TE) and time-varying backlash for a dual-eccentric novel type of VTTIGP are deduced. Second, using the theoretical backlash equation and the eccentricities and the initial phases obtained through the experimental TE curve obtained with angular displacement sensors and the developed TE equation, the continuous backlash curve of the gear pair is obtained. Based on the RecurDyn software and its Colink control module, the co-simulation model of the novel type of VTTIGP and its backlash control system is used to explore the electrical backlash control method through acceleration judgment in the case of time-varying backlash. Finally, using angular displacement sensors and linear actuators, the experimental study on the anti-backlash control with different reversed positions under different input speeds is carried out, demonstrating that this novel electrical anti-backlash control method is effective.

Comparison of Electrofishing and PIT Antennas for Detection of Hatchery-Reared Roundtail Chub (Gila robusta) Stocked into a Desert Stream

Stocking of rare native fishes for conservation purposes is a common practice in the southwestern United States. Monitoring typically occurs after hatchery-reared fish are released to assess post-stocking movement and survival. We conducted a two-year study, in which tow-barge electrofishing and portable, flat-bed passive integrated transponder (PIT) antennas were used to monitor PIT-tagged, hatchery-reared roundtail chub (Gila robusta) following release into the upper Verde River in Arizona. Specifically, our study aimed to compare the performance of PIT antennas and electrofishing in detecting PIT tagged fish released in a small desert river and to examine the behavioral response of hatchery-reared roundtail chub after stocking. In both years, more fish were detected by antenna arrays (84%) than by electrofishing (30%). roundtail chub were significantly more likely to be detected by antennas than electrofishing each year; however, when antenna data were evaluated only during the few days in which electrofishing took place, there was no significant difference (Year 1, p=0.1784; Year 2, p=0.6295) in detection between gear types for the same time interval, suggesting that electrofishing and antennas are equally likely to detect fish during 48-72 hour time frames. Within 72 hours of release, antennas detected 100% of fish that moved upstream and 93.8% of fish that moved downstream from the stocking location. Overall, less than half (45.6% in Year 1; 41.1% in Year 2) of the stocked roundtail chub were detected using both methods in both years. Utilization of both active capture gear (electrofishing) and passive gear (antennae) had advantages over monitoring with a single method. PIT antennae can be especially useful for managers who lack the personnel or time to implement more intensive methods of capture but want to monitor post-stocking movement and survival of stocked fish.

Face-gear drive: Meshing efficiency assessment

The estimation of the losses due to friction of meshing tooth flanks is an important point in the design of gear drives. In addition to other design factors, the efficiency of a gear stage is an important criterion for selecting the type of gear and the number of gear stages in order to achieve a desired gear ratio. This manuscript deals with various approaches with which the friction losses that result from the meshing flanks of a face-gear stage can be estimated. In addition, the influence of the directions of sliding and rolling speed is investigated, which is particularly important for gear stages with axle offset, since the two velocities are not collinear. The calculation method is validated for low speeds by means of experiments on a transmission test bench.

Distribution models of deep-sea elasmobranchs in the Azores, Mid-Atlantic Ridge, to inform spatial planning

Elasmobranchs inhabiting depths beyond 200 m are extremely susceptible to overexploitation but are extracted by fisheries around the world either as target species or as bycatch. There is little information available to formulate management strategies to reduce elasmobranch-fishery interactions in the deep sea. In European Union waters, prohibiting the catches of deep-sea elasmobranchs has provided the necessary impetus to study by-catch avoidance of these threatened species. We used over 20 years of fisheries-independent and fisheries-dependent data to model the spatial distribution of 15 species of deep-sea elasmobranchs (12 sharks and 3 rays) captured frequently in the Exclusive Economic Zone of the Azores Archipelago (Mid-Atlantic Ridge) to explore spatial management to reduce unwanted catches of these species. We applied Generalised Additive Models to predict the probability of presence of 15 species, as well as the abundance of 6 of those species, within the Azores EEZ and neighbouring seamounts (up to 2000 m depth), using environmental and operational variables as predictors. Our results identified that depth is most influential in determining the distribution of these sharks and rays, in addition to seafloor topography. Distinctive bathymetric features such as seamounts and ridges were highlighted as areas where the probability of presence of the greatest number of species overlapped. Although not related to habitat, gear type influenced the capture probability of certain species, with the artisanal handline, gorazeira, having lower captures than bottom longline. Our results support using depth-based, area-based, and gear-based tactics to design management measures to reduce elasmobranch bycatch, for more sustainable deep-sea fisheries.

Bayesian prediction of fishery biological impacts from limited data: A deep-set buoy gear case study

Predicting the biological impacts of new or expanding fisheries presents challenges due to limited data, high variability in catch rates, and the often low frequency of bycatch events. These issues arose in the case of the West Coast deep-set buoy gear (DSBG) fleet, which the Pacific Fisheries Management Council recommended in 2019 for authorization as a legal gear type. DSBG selectively targets swordfish (Xiphias gladius) with infrequent bycatch of other species. Limited effort and incomplete observer coverage result in a data-limited context for estimating the impacts of a fully authorized and expanded fishery. Recently, data analysts have explored Bayesian estimation for modeling rare-event bycatch in a manner that incorporates uncertainty and enables updating as more data become available. Here, we apply a Bayesian methodology to an integrated dataset of DSBG observer and logbook records to estimate bycatch rates under several plausible scenarios of DSBG authorization. We estimate posterior distributions of catch rates for three species caught in DSBG Exempted Fishing Permit (EFP) trials, and incorporate bootstrap samples of vessel-level effort to calculate posterior predictive distributions of catch counts under alternative management regimes. We discuss how our results can inform policy decisions about a new fishery with limited data, and how to extend this approach to other federal environmental actions. This approach allows policymakers to compare biological impacts of management alternatives while considering the uncertainty inherent in the predictions, and to determine whether the range of potential impacts is likely to significantly alter the affected environment.

Simulated trapping and trawling exert similar selection on fish morphology.

Commercial fishery harvest can influence the evolution of wild fish populations. Our knowledge of selection on morphology is however limited, with most previous studies focusing on body size, age, and maturation. Within species, variation in morphology can influence locomotor ability, possibly making some individuals more vulnerable to capture by fishing gears. Additionally, selection on morphology has the potential to influence other foraging, behavioral, and life‐history related traits. Here we carried out simulated fishing using two types of gears: a trawl (an active gear) and a trap (a passive gear), to assess morphological trait‐based selection in relation to capture vulnerability. Using geometric morphometrics, we assessed differences in shape between high and low vulnerability fish, showing that high vulnerability individuals display shallower body shapes regardless of gear type. For trawling, low vulnerability fish displayed morphological characteristics that may be associated with higher burst‐swimming, including a larger caudal region and narrower head, similar to evolutionary responses seen in fish populations responding to natural predation. Taken together, these results suggest that divergent selection can lead to phenotypic differences in harvested fish populations.

Assessing the size selectivity of capture gears for reef fishes using paired stereo-baited remote underwater video

All methods used to sample fish populations exhibit some degree of size selectivity, whether due to the physical properties of the gear, behavioral responses to the gear, or the spatial distribution of the targeted population. In most stock assessments, selectivity functions are assumed and their parameters estimated due to a paucity of empirical data necessary to estimate selectivity. However, incorrect assumptions about selectivity functions can impart significant bias, ultimately affecting assessment outcomes. In 2016, a study was conducted to assess the size selectivity of three fishery-independent survey methods for reef fish in the U.S. South Atlantic: (1) a chevron trap survey, (2) a standardized repetitive timed drop hooked-gear survey, and (3) an unstandardized hooked-gear survey designed to mimic industry fishing practices. Each survey method was paired with a stereo-baited remote underwater video (S-BRUV) camera, which was treated as a comparative reference, considering that it is the least selective of the four gears used. A total of 93 stations were sampled with all gear types, and size data were analyzed for three managed reef fishes: red snapper, Lutjanus campechanus (all gears), black sea bass, Centropristis striata (all gears), and vermilion snapper, Rhomboplites aurorubens (all gears except chevron traps). For red snapper, all three capture gears showed dome-shaped selectivity, the degree of doming being more pronounced for chevron traps as evidenced by a decreasing capture probability for individuals over ~500 mm FL. Despite the largest red snapper (> 800 mm FL) being observed more often on S-BRUV, mean size of red snapper was generally smaller on S-BRUV than for either hooked-gear survey, indicating that hooked-gears capture proportionally fewer smaller red snapper. For black sea bass, there was evidence of flat-topped selectivity for all gear types, but chevron traps captured smaller individuals on average than did hooked gears. For vermilion snapper, both hooked gears exhibited dome-shaped selectivity. Given these results it’s clear that improper assessment of selectivity can lead to poor assumptions about the sampled population. Therefore, when the selectivity function of a particular gear type is not explicitly known, studies that directly estimate selectivity should be conducted to reduce assumptions applied to assessments. This study demonstrates the utility of non-destructive video surveys to complement and evaluate the selectivity functions of standard fisheries assessment methods. Furthermore, efforts to broaden the spatial scale of this study’s survey methods, expand the species to be examined, validate collected life history data, and determine the potential influence of interannual recruitment variability on observed selectivity patterns are necessary to better understand selectivity processes for all reef fishes assessed in the region.

Using abrasive flow finishing process to reduce noise and vibrations of cylindrical and conical gears

This paper reports on reduction of noise and vibrations of cylindrical and conical gears through simultaneous reduction in their microgeometry errors, functional parameters, and surface roughness by finishing them with abrasive flow finishing (AFF) process. Previously identified optimum values of AFF medium viscosity and finishing time were used during AFF of the chosen gears. Noise and vibrations characteristics of the unfinished gears and the AFF finished gears were studied by varying motor speed and applied load at four levels each. An indigenously developed test rig was used for spur and straight bevel gears whereas drivetrain diagnostic simulator was used for helical gears. Indigenously developed dual flank roll tester was used to evaluate functional parameters of the unfinished and the best finished gears by AFF process. It was found that AFF process simultaneously reduced microgeometry errors, functional parameters, maximum and average values of surface roughness of spur, helical, and straight bevel gears. It reduced noise and vibration by 5.2 dBA and 5.3 m/s2 for spur gears, by 3.4 dBA and 7.5 m/s2 for helical gears, and by 4.6 dBA and 4 m/s2 for straight bevel gears. This study proves that AFF is an easy-to-operate and effective process for reducing noise and vibrations of cylindrical and conical gears through simultaneous reduction in their microgeometry errors, functional parameters, and surface roughness values. Outcome of this work will be helpful for various manufactures and users of different types of gears.

COVID-19 lockdowns reveal the resilience of Adriatic Sea fisheries to forced fishing effort reduction

The COVID-19 pandemic provides a major opportunity to study fishing effort dynamics and to assess the response of the industry to standard and remedial actions. Knowing a fishing fleet’s capacity to compensate for effort reduction (i.e., its resilience) allows differentiating governmental regulations by fleet, i.e., imposing stronger restrictions on the more resilient and weaker restrictions on the less resilient. In the present research, the response of the main fishing fleets of the Adriatic Sea to fishing hour reduction from 2015 to 2020 was measured. Fleet activity per gear type was inferred from monthly Automatic Identification System data. Pattern recognition techniques were applied to study the fishing effort trends and barycentres by gear. The beneficial effects of the lockdowns on Adriatic endangered, threatened and protected (ETP) species were also estimated. Finally, fleet effort series were examined through a stock assessment model to demonstrate that every Adriatic fishing fleet generally behaves like a stock subject to significant stress, which was particularly highlighted by the pandemic. Our findings lend support to the notion that the Adriatic fleets can be compared to predators with medium-high resilience and a generally strong impact on ETP species.

A simulation method for free-form milling of cylindrical gears with disc cutters

Free-form milling is a flexible gear machining method that allows the use of general disc cutters to machine various gear types on a 5-axis machine tool. This paper proposes a two-dimensional simulation method for free-form milling of cylindrical gears with disc cutters. A mathematical model for free-form milling of cylindrical gears with disc cutters is constructed. By analyzing the spatial positional relationships between the cutter and the workpiece, the instantaneous contact line is derived and projected onto the gear end face; then, the intersection of the projected curves is used to obtain the final profile. This calculation method enables rapid simulation of the actual cutting conditions on the gear end face, which helps determine the machining interference and analyze the tooth profile accuracy during the gear machining process. The method proposed in this paper can also be used to analyze the sensitivity of geometric position errors of the machine tool axes.

Schemes of momentum/reaction wheels unloading by mechanical restructuring and gearbox for spacecraft

A new principle and linked schemes of reaction/momentum wheels unloading are proposed and constructed. This principle is based on the instantaneous restructuring and changing the mechanical system itself, when additional internal degrees of freedom become available. These releasing additional degrees of freedom correspond to additional rotors, which take “after unfreezing” their own opportunity to rotate. At the connection of additional “unfrozen” rotors to the main wheels by gear type, these rotors become involved in the rotation with opposite direction relatively to the main wheels rotation, and it instantaneously provides nulling the relative angular momentum. Then electric motors of additional rotors and wheels can start the process of the rotational energy recovery, which decelerates and unloads angular velocities of all rotors and wheels. The proposed principle of releasing additional degrees of freedom and reconfiguring internal mechanical multi-rotor subsystem allow to immediately change values and directions of the relative angular momentum. This changeable multi-rotor subsystem represents the multifunctional attitude control system, which can be figuratively called as a “gearbox”. As a part of the gearbox a special mechanical device is proposed, which represents a “gravitational damper” to unloading the total absolute angular momentum of spacecraft with the help of external gravitational torques.

Estimating the total allowable catch and management of Threadfin porgy (Evynnis cardinalis) fisheries in the northern South China Sea based on sampling surveys conducted at fishing ports

In order to develop a method that apply sampling survey data randomly obtained at fishing ports to fish stock assessments, based on fish landing surveys conducted at fishing ports in the northern South China Sea (SCS), 19 Threadfin porgy (Evynnis cardinalis) catch per unit effort (CPUE) datasets were collected for fishing vessels with different gear types and engine powers and incorporated into surplus production models. Considering only the fitting performance, the Schaefer model had the best overall goodness of fit, followed by the Fox, CYP, W–H, and Schnute models. Among fishing vessels with different gears and engine powers, the data were best fitted for single-trawl vessels powered by 301–400-kW engines and for gillnet vessels powered by > 200-kW engines. Eight model expressions were superior and selected for subsequent analyses based on their goodness of fit and relative residuals. The Kobe plot analysis results showed an optimistic fish stock status when using the four model expressions, required more caution when using three model expressions and output pessimistic estimations using one model expression. Considering the incomplete information acquired, a compromising decision-making method was used to derive a 2017 northern SCS E. cardinalis total allowed catch (TAC) of 44,691.21 t. The different conclusions drawn from estimations using CPUEs reflect variable exploitation and utilization fish stock statuses among fishing vessels with different gears and engine powers. Hence, the fishing operations were grouped according to their CPUE relationship, and recommendations regarding optimum fishing efforts were assigned to the groups following a fundamental principle: to improve fishery TAC management, fishing efforts should be reduced if the fish stock assessment is pessimistic and maintained if the assessment is optimistic. This study providing a feasible technical method for the TAC management of China's offshore fisheries.

Comparative analysis of surface characteristics of Nylon based polymer gears manufactured by different techniques

The comparative analysis of surface characteristics of Nylon based polymer gears manufactured by different techniques has been carried out in the present paper. Nylon based gears have been manufactured using three different techniques viz. machining, injection molding and additive (3D printing) manufacturing process. To investigate the surface characteristics of these gears, gear tooth samples were prepared for each type of gear in which surface roughness and surface hardness were measured. Roughness average (Ra) of 1.068 µm of injection molded gear tooth sample was found minimum whereas the roughness average of machined and printed sample was found 3 folds and 12 folds more, respectively. The hardness value has been measured on gear tooth profile and was found similar for machined and printed gear. However, hardness value for injection samples was found comparatively less.

AN OVERVIEW OF FISH BIODIVERSITY AND SOCIOECONOMIC SITUATION OF THE PADMA RIVER’S FISHER COMMUNITY IN BANGLADESH

The current study focused on the status of fishing and livelihood status of fishers through employing household interviews, Focus Group Discussions and key informant interviews at Sujanagar Upazila under the Pabna district. The catch was quite substantial during the period of the study, and fishing operation was especially intense from early hours to midday. There were three main types of gears recorded in this study namely nets, traps, and wounding gears and the most used gear was Thela jal (push net). The result of this research indicates that a total of 33 fish species were identified where 18% of catfish, 31% of carp, 9% of snakehead, 6% of eel, 12% of barbs, clupeids and minnows, 18% of perch and 6% of crustaceans were identified. Fishing is the primary source of income for 68% of the fishermen, which has a serious influence on their livelihood. According to the study’s findings, the majority of fishers (62%) had tin-shaded dwellings and 82% of the fishermen had tube well as the source of drinking water. The fishers’ healthcare facilities were poor. About 66% of fishers got electricity and 54% of them belonged to the medium income (TK. 41,000-70,000/year) group. The overall livelihood condition of the fishers was unsatisfying related to socioeconomic obstacles such as an increase in the number of fishers, limited income, a lack of credible revenue-producing activities, credit issues, infringement, price inflation, and resource disputes among stakeholders. So the comprehensive strategies and their efficient execution are essential for improving fishermen’s livelihood.

A Study on Traditional Fishing Gears and Fish Capturing Methods Used by The Mising Community of Gohpur Subdivision, Biswanath District, Assam

The implementation of various fishing hing gears is the product of experiences gathered over the course of a significant amount of time. Every water body has its own particular arrangement of gears. The use of fishing equipment also provides insight on the community of fishermen's financial situation. In order to produce substances of technological delight while keeping costs to a minimum, fishermen employ materialmaterials that are readily available in their local area. A research was carried out on the fishermen in the Mising subdivision of the Gohpur district in order to collect data on the various traditional fishing gears and methods of catching fish. It has been discovered vered that Mising fisherman employ a variety of fishing gear, the majority of which they designed on their own. Different fishing gear is utilized during different times of the year and in distinct bodies of water for catching fish of varying sizes. In addition to their participation in community fishing, Mising women also participate in fishing on their own. They fish for enjoyment in addition to commercial reasons. Total 28 types of gears and different methods of fish capturing have have been reported during the survey period. All gears ar are eco-friendly. To raise awareness among fishermen of the long-term effects of their fishing techniques, workshops or training programmes should be organised.

An efficient dynamics model of spur gear drive with curved path of contact in mixed elastohydrodynamic lubrication

Design of new tooth shapes have been the focus of gear researchers aimed at overcoming the defects of involute gears. For the spur gear drive with curved path of contact, normal contact loads between engaged teeth vary in direction and magnitude, which makes it difficult to build the dynamics model of the gear drive. The current models treat the curved path of contact as an equivalent straight line without considering directional variation of normal tooth loads. This paper presents an efficient tribo-dynamics integrated model for this type of gear drive including effects of alternate meshing of single-double tooth pairs. Directional variation of normal tooth loads is considered by invoking geometric parameters of meshing points instantly. And the transient lubrication properties in mixed elastohydrodynamic lubrication are also taken into account without extensive numerical simulations. The dynamics model of a gear drive with constant relative curvature (CRC gear drive) is given as an example. The model is verified with the results of the finite element model. The results indicate that the CRC gear drive has advantages over the involute gear drive in terms of lubrication performance and mechanical efficiency. The proposed model can be used to analyze dynamics features of gear drives with curved path of contact comprehensively.

Fishing Gear Pattern Recognition by Including Supervised Autoencoder Dimensional Reduction

Fishing is a crucial worldwide activity as it provides a source of food and economic income. A challenge in ecology and conservation is decreasing overfishing and illegal, unreported, and unregulated fishing (IUUF). One strategy to decrease those issues is to track vessels for detecting fishing behaviors through monitory systems. In this letter, we present an approach to classify fishing behaviors, specifically, for four fishing gear types (trawl, purse seine, fixed gear, and longline) using automatic identification systems (AISs) data from the Global Fishing Watch platform. Thus, our main contribution is how we propose data processing by including a supervised autoencoder dimensional reduction (SA-DR) processing data step. This step allows removing redundant features and noise, avoiding overfitting, decreasing data complexity, and preserving the differences between classes. Specifically, we propose to use IVIS and centroid encoder (CE) methods. The experimental results show how our approach applying SA-DR over the vessel trajectory feature representation reduces the variation results among different classifiers and achieves a high classification accuracy of up to 95%. This result could help prevent IUUF, overfishing, and improve fishery management strategies.

Small-scale fisheries of the Tana Estuary in Kenya

The role of small-scale fisheries in maintaining socio-ecological systems (SES) in the Western Indian Ocean is well-documented, yet few studies have addressed estuarine fisheries in the region. Small-scale fisheries in the Tana Estuary in Kenya are described in this paper, accounting for location along a salinity gradient, seasonality, gear types used, species composition and relative abundance of landings. Monthly shore-based sampling was undertaken at four locations in 2017 – Ungwana Bay near the estuary mouth, lower and mid-estuary, and upper estuary at Ozi village, ⁓10 km upstream. Fishing gear comprised of seine nets, gillnets, hook-and-line and traditional gear such as self-made traps, sticks and spears operated from the shore (foot fishers), dugout canoes, dhows and fibreglass boats with outboard engines. A total of 12,840 fish and crustacean specimens belonging to 89 species in 45 families were sampled. Landings were dominated by catfishes Arius africanus (31 %) and Clarias gariepinus (21 %), small pelagic fishes Pellona ditchela (10 %) and several sardine species (⁓5 %), croaker Otolithes ruber (10 %), eel catfish Plotosus limbatus (6 %), mullet Mugil cephalus (4 %) and Nile tilapia Oreochromis niloticus (4 %). Multivariate analyses (nMDS and ANOSIM) found that fishing gear (p < 0.05) and location (p = 0.001) significantly influenced catch composition, but season (p = 0.146) was not significant. Traps were used in the upper and mid estuary only and were selective for three catfish species. Seine nets (54 species) and gillnets (40 species) were least selective and used at all four locations. Rarefaction curves indicated that species diversity was higher at the bay and lower estuary than the mid and upper estuary, and that diversity was highest for canoe-gillnet and canoe-encircling net combinations. Catch rates (avg. of 2.3 to 8.4kg.fisher-1.day-1) depended on gear type and was highest for monofilament gillnets. Catches comprised a broad size range of multiple species, but on average, seine nets selected smaller individuals than traps, gillnets and long lines. The high complexity and organization of the fishery at an estuary-scale makes it a good example of a relatively intact SES suitable for regional comparative analyses.

Participatory Risk Assessment of Humpback Whale (Megaptera novaeangliae) and Leatherback Turtle (Dermochelys coriacea) Bycatch in Northern Peru

Uncertainties about the magnitude of bycatch in poorly assessed fisheries impede effective conservation management. In northern Peru, small-scale fisheries (SSF) bycatch negatively impacts marine megafauna populations and the livelihoods of fishers which is further elevated by the under-reporting of incidents. Within the last decade, accounts of entangled humpback whales (HBW) (Megaptera novaeangliae) off the northern coast of Peru have increased, while Eastern Pacific leatherback turtles (LBT) (Dermochelys coriacea) have seen over a 90% decline in nesting populations related in large part to bycatch mortality. By leveraging the experience and knowledge of local fishers, our research objectives were to use a low-cost public participation mapping approach to provide a spatio-temporal assessment of bycatch risk for HBW and LBT off two Peruvian fishing ports. We used an open-source, geographic information systems (GIS) model, the Bycatch Risk Assessment (ByRA), as our platform. Broadly, ByRA identifies high bycatch risk areas by estimating the intersection of fishing areas (i.e., stressors) with species habitat and evaluating the exposure and consequence of possible interaction between the two. ByRA outputs provided risk maps and gear risk percentages categorized as high, medium, and low for the study area and seven subzones for HBW in the austral winter and LBT in the austral summer. Overall, the highest bycatch risk for both species was identified within gillnet fisheries near the coast. Bycatch risk for most gear types decreased with distance from the coast. When we separated the ByRA model by port, our map outputs indicate that bycatch management should be port specific, following seasonal and spatial variations for HBW, and specific fishing gear impacts for HBW and LBT. Combined with direct bycatch mitigation techniques, ByRA can be a supportive and informative tool for addressing specific bycatch threats and marine megafauna conservation goals. ByRA supports a participatory framework offering rapid visual information via risk maps and replicable methods for areas with limited resources and data on fisheries and species habitat.