Mitigating unaccounted fishing mortality from gillnets and traps

Gillnets and traps often are considered to have fewer holistic environmental impacts than active fishing gears. However, in addition to the targeted catches, gillnets and traps still cause unwanted mortalities due to (i) discarding, (ii) ghost fishing of derelict gear, (iii) depredation, (iv) escaping or dropping out of gear, (v) habitat damage, and potentially (vi) avoiding gear and predation and (vii) infection of injuries sustained from most of the above. Population‐level concerns associated with such ‘unaccounted fishing mortalities’ from gillnets and traps have been sufficient to warrant numerous attempts at mitigation. In this article, we reviewed relevant research efforts, locating 130 studies in the primary literature that concomitantly quantified mortalities and their resolution through technical modifications, with the division of effort indicating ongoing concerns. Most studies (85) have focused on discard mortality, followed by ghost‐fishing (24), depredation (10) and escape (8) mortalities. The remaining components have been poorly studied (3). All problematic mortality components are affected by key biological (e.g. species), technical (e.g. fishing mechanisms) and/or environmental (e.g. temperature) factors. We propose that these key factors should be considered as part of a strategy to reduce impacts of these gears by first assessing modifications within and then beyond conventional configurations, followed by changes to operational and handling practices. Justification for this three‐tiered approach is based not only on the potential for cumulative reduction benefits, but also on the likely ease of adoption, legislation and compliance.     

捕捞网具逃逸死亡研究进展

幼鱼及非目标种类兼捕已成为许多网具作业共同存在的问题,提高网具选择性能是降低这种兼捕的重要途径。但是选择性能研究主要是基于从网具中逃逸后的鱼类较轻遭受到网具损害并最终存活。如果逃逸死亡率较高,即使选择性提高也是无宜的,因此应当将鱼类逃逸后生存能力作为网具改进效果的评价指标。本文主要由以下三个部分组成:(1)逃逸后死亡的主要影响因素概述,主要包括网具特征、作业时间、作业深度、渔获种类及体长、渔获量及环境因子等;(2)逃逸死亡对资源量和渔业管理决策的影响;(3)总结了近年来通过网具革新措施提高存活率的最新研究概况,如逃逸网片、分离栅及新型材料的应用等。综合分析,认为采取保护幼鱼和非目标种类的一系列措施尽管能够提高鱼类从网具的逃逸几率,但是并不能降低遭遇网具的概率,实施禁渔区、禁渔期制度管理,避免在幼鱼资源高密度区和产卵季节作业是降低这种未报告死亡的最重要的途径。     

Changes in a coral reef fishery along a gradient of fishing pressure in an Indonesian marine protected area

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A framework for adaptive gear and ecosystem‐based management in the artisanal coral reef fishery of Papua New Guinea

• 1. Artisanal fishing on coral reefs in Papua New Guinea is an important livelihood activity that is managed primarily at the level of local communities. Pockets of overexploitation exist and are expected to increase with plans for increased commercialization.
• 2. This paper provides a current assessment of the artisanal multi‐species coral reef fishery by examining selectivity of the dominant gear, namely line fishing, spearguns, and gill nets. Each gear has its own strengths and weaknesses in terms of use and conservation of resources, with no clear problem gear.
• 3. The three gears utilize different resources but there was moderate overlap in the species caught, particularly between gill nets and line fishing and marginally between lines and spearguns. Gill nets have the disadvantage of being destructive to coral and the advantage of catching commercial species. Line fishing catches an intermediate number of species but mostly large‐bodied and predatory species that could potentially reduce predation and the mean trophic level of the fishery. Spearguns catch the highest numbers of species, including many non‐commercial and herbivorous fish and could reduce the diversity of fish and encourage algal growth.
• 4. This information could be used in combination with scientific monitoring and traditional ecological knowledge to develop an adaptive management framework that uses local restrictions on the various gears to restore or balance the fishery and ecosystem. Restrictions could be selectively imposed: on gill nets when coral cover is low, line fishing when large‐bodied predators are depleted, and spearguns when biodiversity is reduced and algal abundance high.

Copyright © 2008 John Wiley & Sons, Ltd.     

Short-term stress and mortality of juvenile school prawns, Metapenaeus macleayi, discarded from seines and trawls

Abstract  Two experiments were carried out to assess the short-term impacts to juvenile school prawns, Metapenaeus macleayi (Haswell) discarded from commercial seining and trawling in New South Wales, Australia, and the potential utility of modifications to operational and/or onboard handling practices designed to improve survival. For both gears, discards were handled according to two general categories of treatment (termed mild and extreme) chosen to represent the plausible limits of severity during existing commercial operations. A total of 600 trawled and 480 seined school prawns (from both treatments), along with appropriate numbers of controls (previously collected and housed in acclimation tanks), were placed into cages (in groups of 10). Subsets of each of these groups were then destructively sampled over periods of up to 5 days and examined for their mortality and physiological response (measured as levels of l -lactate in the haemolymph). In both experiments, the temporal mortalities in the treatment groups ranged between 0% and 15% and, for the most part, were not significantly different to controls. Prawns in the treatment groups had similar, significantly elevated levels of l -lactate approximately 40 min after being caught, but these returned to levels approaching baseline estimates within 48 h. Under the conditions examined, juvenile school prawns appear capable of withstanding a range of stressors associated with being discarded from active gears, and their fate is not greatly influenced by the duration of gear deployment and subsequent air exposure. However, further work is required to quantify other sources of unaccounted fishing mortality and, ultimately, the impacts that discarding has on stocks.     

The understudied and underappreciated role of predation in the mortality of fish released from fishing gears

The assumption that animals released from fishing gears survive has frequently been scrutinized by researchers in recent years. Mortality estimates from these research efforts can be incorporated into management models to ensure the sustainability of fisheries and the conservation of threatened species. Post‐release mortality estimates are typically made by holding the catch in a tank, pen or cage for short‐term monitoring (e.g. 48 h). These estimates may be inaccurate in some cases because they fail to integrate the challenges of the wild environment. Most obvious among these challenges is predator evasion. Stress and injury from a capture experience can temporarily impair physiological capacity and alter behaviour in released animals, a period during which predation risk is likely elevated. In large‐scale commercial fisheries, predators have adapted their behaviour to capitalize on impaired fishes being discarded, while in recreational catch‐and‐release fisheries, exercise and air exposure can similarly impede the capacity for released fish to evade opportunistic predators. Owing to the indirect and often cryptic nature of this source of mortality, very few studies have attempted to document it. A survey of the literature demonstrated that <2% of the papers in the combined realms of bycatch and catch‐and‐release have directly addressed or considered post‐release predation. Future research should combine field telemetry and laboratory studies using both natural and simulated predation encounters and incorporate physiological and behavioural endpoints. Quite simply, predation is an understudied and underappreciated contributor to the mortality of animals released from fishing gears.     

Fishing profiles of Danish seiners and bottom trawlers in relation to current EU management regulations

Danish seines and bottom trawls operate differently and have different catching processes. Both gears belong to the same legislative category in European fisheries, but different management strategies in other countries and criticism by fishers on grouping Danish seines and trawls together indicate disagreement on current gear classification. This study compared both gears in terms of their fishing characteristics and catches of commercial species based on 16 years of observer data. Danish seining is a specialised fishing method that targeted few species but with higher total catch rates than bottom trawlers. Bottom trawling is a more all‐purpose fishing method that targets a larger number of species, and bottom trawlers use larger engines than Danish seiners. A generalised additive mixed model indicated that catch rates of flatfish are generally higher for Danish seines, and catch rates of roundfish species are higher for trawlers. The results do not directly suggest a separation of the gears in terms of legislation as the quantities of fish below current minimum size were similar, but for example future survival studies may reach different conclusions. Additional factors were found to be important in determining catches of both gears.     

Changes in life history and ecological characteristics of coral reef fish catch composition with increasing fishery management

Abstract Length, life history and ecological characteristics of landed fish communities were studied over a 10‐year period to test theories of fishing disturbance during a time of increased gear and closure management in heavily utilised fisheries. It was predicted that with greater management restrictions: (1) the earliest and fastest responses in the fishery will be seen in those species with faster turnovers, or relatively lower vulnerabilities to fishing; (2) the fishery would transition to a landed catch with higher mean trophic levels, and greater mean body lengths. In addition, the removal of a non‐selective, small‐mesh seine nets should benefit the catch of gears that previously had the greatest species selectivity overlap with the seine net. Many predictions were supported, although maximum lengths and lengths at maturity responded more rapidly than anticipated. The response to eliminating the non‐selective seine net was a more rapid increase in sizes caught by gears with a larger overlap in size (hook and lines) than species selectivity (gill nets). The simultaneous comparison of management systems over time indicates that open‐access fishing grounds can benefit from restrictions imposed in adjacent fishing grounds. The study indicated that multi‐species coral reef fisheries management objectives of maximising yields, as well as maintaining the fish community’s life‐history diversity, require management trade‐offs that balance local socio‐economic and biodiversity needs.     

Modification of marine habitats by trawling activities: prognosis and solutions

Fishing affects the seabed habitat worldwide on the continental shelf. These impacts are patchily distributed according to the spatial and temporal variation in fishing effort that results from fishers' behaviour. As a consequence, the frequency and intensity of fishing disturbance varies among different habitat types. Different fishing methodologies vary in the degree to which they affect the seabed. Structurally complex habitats (e.g. seagrass meadows, biogenic reefs) and those that are relatively undisturbed by natural perturbations (e.g. deep‐water mud substrata) are more adversely affected by fishing than unconsolidated sediment habitats that occur in shallow coastal waters. These habitats also have the longest recovery trajectories in terms of the recolonization of the habitat by the associated fauna. Comparative studies of areas of the seabed that have experienced different levels of fishing activity demonstrate that chronic fishing disturbance leads to the removal of high‐biomass species that are composed mostly of emergent seabed organisms. Contrary to the belief of fishers that fishing enhances seabed production and generates food for target fish species, productivity is actually lowered as fishing intensity increases and high‐biomass species are removed from the benthic habitat. These organisms also increase the topographic complexity of the seabed which has been shown to provide shelter for juvenile fishes, reducing their vulnerability to predation. Conversely, scavengers and small‐bodied organisms, such as polychaete worms, dominate heavily fished areas. Major changes in habitat can lead to changes in the composition of the resident fish fauna. Fishing has indirect effects on habitat through the removal of predators that control bio‐engineering organisms such as algal‐grazing urchins. Fishing gear resuspend the upper layers of sedimentary seabed habitats and hence remobilize contaminants and fine particulate matter into the water column. The ecological significance of these fishing effects has not yet been determined but could have implications for eutrophication and biogeochemical cycling. Simulation results suggest that the effects of low levels of trawling disturbance will be similar to those of natural bioturbators. In contrast, high levels of trawling disturbance cause sediment systems to become unstable due to large carbon fluxes between oxic and anoxic carbon compartments. In low energy habitats, intensive trawling disturbance may destabilize benthic system chemical fluxes, which has the potential to propagate more widely through the marine ecosystem. Management regimes that aim to incorporate both fisheries and habitat conservation objectives can be achieved through the appropriate use of a number of approaches, including total and partial exclusion of towed bottom fishing gears, and seasonal and rotational closure techniques. However, the inappropriate use of closed areas may displace fishing activities into habitats that are more vulnerable to disturbance than those currently trawled by fishers. In many cases, the behaviour of fishers constrains the extent of the impact of their fishing activities. Management actions that force them to redistribute their effort may be more damaging in the longer term.     

涉海建设项目中深水海域渔业资源调查问题的研究

为解决涉海工程深水渔业资源评估的问题,于2014~2015年在南海北部局部海域开展底拖网与灯光罩网联合调查渔业资源活动。结果表明:在深水区底拖网渔获组成与灯光罩网有明显的不同,并受到季节与海域的影响(P0.05)。拖网渔获物中鱼类平均占渔获总尾数的93.36%,头足类占3.53%,甲壳类占3.11%;灯光罩网渔获物中鱼类平均占渔获总尾数的63.33%,头足类占36.65%,甲壳类占0.02%。两种调查的相同渔获物1~6种,主要为鱼类和头足类,在拖网中所占比值较低,平均占渔获总尾数的2.07%,而在灯光罩网中比值极高,平均占渔获总尾数的67.03%。灯光罩网与底拖网调查的渔业资源密度直接比值平均为0.06,灯光罩网与底拖网扣除相同渔获种类后的资源密度比值平均为0.06,相应的质量密度直接比值平均为0.62,扣除相同渔获种类后的比值平均为0.67。研究认为,深水海域的渔业资源量应该是两种渔具调查结果之和,对两种渔具调查中出现的相同渔获物,宜取其评估数据的平均值。由于各站点调查结果差异较大,采用所有站点的平均值来计算评估海域的损害赔偿较为合适。建议对SC/T9110-2007技术规程修订,规范中上层渔业资源调查方法。     

Response of benthic fauna to experimental bottom fishing: A global meta‐analysis

Bottom‐contact fishing gears are globally the most widespread anthropogenic sources of direct disturbance to the seabed and associated biota. Managing these fishing disturbances requires quantification of gear impacts on biota and the rate of recovery following disturbance. We undertook a systematic review and meta‐analysis of 122 experiments on the effects‐of‐bottom fishing to quantify the removal of benthos in the path of the fishing gear and to estimate rates of recovery following disturbance. A gear pass reduced benthic invertebrate abundance by 26% and species richness by 19%. The effect was strongly gear‐specific, with gears that penetrate deeper into the sediment having a significantly larger impact than those that penetrate less. Sediment composition (% mud and presence of biogenic habitat) and the history of fishing disturbance prior to an experimental fishing event were also important predictors of depletion, with communities in areas that were not previously fished, predominantly muddy or biogenic habitats being more strongly affected by fishing. Sessile and low mobility biota with longer life‐spans such as sponges, soft corals and bivalves took much longer to recover after fishing (>3 year) than mobile biota with shorter life‐spans such as polychaetes and malacostracans (<1 year). This meta‐analysis provides insights into the dynamics of recovery. Our estimates of depletion along with estimates of recovery rates and large‐scale, high‐resolution maps of fishing frequency and habitat will support more rigorous assessment of the environmental impacts of bottom‐contact gears, thus supporting better informed choices in trade‐offs between environmental impacts and fish production.     

几何相似原理在过滤性渔具网目选择性研究中的应用

利用几何相似原理将传统的过滤性渔具选择性曲线转化为选择性曲面。运用选择性方程，并假设不同网目大小的渔具对相同尺寸渔获个体的渔获服从多项分布后，对过滤性渔具的网目选择性建立模型。使用极大似然估计法对模型进行拟合，同时，通过假设检验对模型进行简化。使用平行作业法试验条件下的张网渔具的黄鲫(Setipinrm taty)渔获数据进行模型拟合。结果显示，所建模型可以在没有对照网的情况下估算出各不同网目大小网囊的选择率，并同样适用于套网法试验条件下的选择性分析。模型的建立为今后进行过滤性渔具网目选择性试验方法改革提供了理论参考。通过与SELECT模型比较，认为模型使用选择性方程并区分渔获能力和捕捞努力量使得模型更具普遍性。     

An underwater laser stripe seabed profiler to measure the physical impact of towed gear components on the seabed

A laser stripe seabed profiler that can be positioned and operated by SCUBA divers is developed. The system is shown to be accurate to within 0.5 mm. A number of examples are presented which demonstrate how the physical impact of towed gear components on a range of sediment types can be measured. These examples also highlight the need to consider the impacts of fishing gears at the level of the gear component.     

The effect of a closed area and beach seine exclusion on coral reef fish catches

Fish landing data from the Mombasa Marine National Park (MNP) and a marine reserve exploited by various gears were studied over a 5‐yr period to determine the influence of the closed area and different gears in fisheries. The number fishing and boats per landing site was constant, but total and catch per unit effort progressively declined in all sites on an annual basis irrespective of the existence of a marine reserve, exclusion of the beach seines or use of gear. Differences between landing sites were most pronounced when analysed on a catch per area as opposed to the more standard catch per fisherman, suggesting compensation in human effort when catches decline. A marine reserve next to a closed area that excluded beach seines had the highest catch per area (5.5 kg ha^?1 month^?1) despite having the highest density of fishermen (0.07 ± 0.02 fishermen ha^?1 month^?1). The annual rate of decline in the catch was lower than the other sites at around 250 g day^?1 compared with 310–400 g day^?1 in the other sites. One landing site, which excluded beach seine landings for more than 20 yrs, had a high catch per area (～5.3 kg ha^?1 month^?1), but after experiencing a doubling in the effort of other gears (line, speargun and trap), the catch per fisherman and area were reduced. Environmental or habitat degradation and excessive effort remain the most likely explanation for the overall declines in catch from 1995 to 1999. Closed areas and beach seine exclusion have the potential to increase catch rates, but the first often reduces the total fishing area and possibly leads to a loss of total catch, at least on a time scale of less than 10 yrs. The exclusion of beach seines can lead to an increase in other gear types that can also cause reductions in catch.     

Minimizing the impact of fishing

Minimizing the impact of fishing is an explicit goal in international agreements as well as in regional directives and national laws. To assist in practical implementation, three simple rules for fisheries management are proposed in this study: 1) take less than nature by ensuring that mortality caused by fishing is less than the natural rate of mortality; 2) maintain population sizes above half of natural abundance, at levels where populations are still likely to be able to fulfil their ecosystem functions as prey or predator; and 3) let fish grow and reproduce, by adjusting the size at first capture such that the mean length in the catch equals the length where the biomass of an unexploited cohort would be maximum (L_opt). For rule 3), the basic equations describing growth in age‐structured populations are re‐examined and a new optimum length for first capture (L_{c_opt}) is established. For a given rate of fishing mortality, L_{c_opt} keeps catch and profit near their theoretical optima while maintaining large population sizes. Application of the three rules would not only minimize the impact of fishing on commercial species, it may also achieve several goals of ecosystem‐based fisheries management, such as rebuilding the biomass of prey and predator species in the system and reducing collateral impact of fishing, because with more fish in the water, shorter duration of gear deployment is needed for a given catch. The study also addresses typical criticisms of these common sense rules for fisheries management.     

Reducing the impact of blue mussel (Mytilus edulis) dredging on the ecosystem in shallow water soft bottom areas

• Dredging blue mussels (Mytilus edulis) and thus removing structural elements, inducing resuspension of sediment as well as reducing filtration capacity, will inevitably affect the ecosystem. The study demonstrates that the impacts of fishing can be reduced through gear developments.
• A new light dredge was tested on commercial vessels using two different experimental setups. First, a twin haul experiment tested the standard gear (i.e., a Dutch dredge) against the light dredge by fishing the two gears side by side onboard the same vessel. Second, a single dredge experiment tested the absolute performance of the two gears by fishing in areas with a known blue mussel density.
• Results from the twin haul experiment demonstrate that the weight of sediment retained in the gear per square metre fished is 49% less in the light dredge compared with the Dutch dredge which will reduce resuspension of sediment at the surface. Also, the drag resistance of the light dredge was significantly less (177.1 vs. 202.7 kg m^‐1). In the twin haul experiment no significant difference was found in the catch per unit effort (CPUE) of the two gears. The single dredge experiment, on the other hand, demonstrated a significant increase in CPUE exceeding 200% when using the light dredge.
• Seafloor tracks made by the two dredges could not be distinguished by use of side‐scan sonar and the tracks were still detectable 2 months after fishing.
• It was concluded that replacement of the Dutch dredge with the light dredge would reduce the impact of the fishery on the ecosystem by (i) reducing resuspension of sediment, (ii) reducing fuel consumption, and (iii) potentially reducing energy transfer to the sediment through a reduced gear drag resistance. A potential increase in catch efficiency may reduce the area affected.
• Fishing with the light dredge is discussed in relation to management of Natura 2000 sites.

Copyright © 2014 John Wiley & Sons, Ltd.     

A synthesis to understand responses to capture stressors among fish discarded from commercial fisheries and options for mitigating their severity

Discarding non‐target fish from commercial fisheries is controversial and has been a persistent concern for fisheries managers globally. Discard management strategies typically begin by understanding mortality rates among discarded fish, a challenging task given the dynamic, highly context‐specific nature of fisheries. An alternative is to develop our knowledge of how stressors operate by first understanding the causes of mortality that drive this context dependence. Particularly relevant to mitigation efforts is an understanding of how fish respond to the physical factors of fishing, such as the gear itself and methods of fishing and handling the gear. We provide a synthesis of how commercial fishing methods may influence discard mortality and outline means by which capture‐induced stress and injury can be mitigated for common commercial gear types, emphasizing method variants or alternatives during capture, handling, and release that could improve survival. This synthesis identifies exhaustion and injury as the most detrimental and ubiquitous stressors experienced by discarded fish, with few options for mitigating their effects. Trawls and hanging net fisheries are identified as the most harmful gears for by‐catch, characterized by high stress regardless of method variants and limited options for mitigation. Irrespective of gear type and type of stressor, minimizing durations of capture and handling and encouragement of good handling behaviour (e.g., during landing and sorting) will reduce the magnitude of stress and injury in fish, and ultimately increase survival.     

Gear restrictions create conservation and fisheries trade-offs for management

Gear-based management for coral reef fisheries is often overlooked in the scientific literature. Empirical studies have demonstrated the conservation benefits of gear-restricted areas (i.e. prohibiting fishing gears), which can support greater biomass than unrestricted areas and protect species that play key functional roles. However, population dynamics of functional feeding groups of reef fishes under specific gear-restriction regimes remains uncertain. Here, we constructed a multi-species, length-based fisheries model to observe relative biomass and catch of reef fishes under various gear-restriction management scenarios. We used fishery-dependent and fishery-independent data to determine the catchability of functional groups and selectivity of size classes for hook-and-line, net and spear fishing, which are widely used gear types on coral reefs globally. Our model revealed trade-offs involved with gear-restriction management such that no single management strategy was able to maximize biomass or catch of all functional groups simultaneously. Also, we found that spear fishing (i.e. prohibiting hook-and-line and net fishing) maintained the highest total biomass summed across functional groups, whilst hook-and-line fishing (i.e. prohibiting net and spear fishing) and a ban on spears maintained the lowest biomass. However, hook-and-line fishing generated the highest catch-per-unit-effort. Our model results were primarily driven by differential growth rates, maximum per capita production of recruits, and catchability of functional groups targeted by each fishing gear. We demonstrate that gear restrictions can be a critical management tool for maintaining biomass and catch of certain functional groups but will likely require additional management to protect all key functional feeding groups of coral reef fishes.     

Thunderstorms have species and gear-specific indirect effects on the catchability of Mongolian salmonids

Climate change is predicted to cause increasingly frequent and intense storms. Northern Mongolia is already warming at a rate twice the global average, and thunderstorms, defined as intense, short, patchy rains associated with thunder, lightning and high precipitation rates, are becoming more frequent. Because Mongolia's fish populations are lightly exploited, Mongolia provides a model system in which to study the effects of storms on fish behaviour and fishing vulnerability. The impacts of thunderstorm-related hydrological changes on fishes’ vulnerability to two fishing gears were evaluated. Two thunderstorm-related factors, turbidity and river stage, reduced catch rates of the salmonids lenok Brachymystax lenok (Pallas) and Baikal grayling Thymallus baicalensis Dybowski. Fly-fishing gear was more effective than spinning gear in this fishery and retained higher catch rates in extreme conditions. These gear-specific effects suggest that turbidity and rising river stage affect fishing vulnerability by influencing feeding behaviour.     

Gear-based management of a tropical artisanal fishery based on species selectivity and capture size

The population density, species composition and lengths of fish landed by artisanal fishermen using six types of gear: large and small traps, gill nets, hand lines, spears and beach seines were studied in the multi‐species fishery of southern Kenya. Selectivity and catch composition among gears were determined by studying the species richness, diversity, size and mean trophic level of the catches for each gear type, to develop gear‐based management recommendations for this artisanal reef lagoon fishery. One hundred and sixty‐three reef and reef‐associated species from 37 families were recorded in the catch. Beach seines and small traps accounted for the highest number of fish landed (34–35 individuals per fisherman per day). These gears also caught smaller fish than big traps, spears and gill nets. Beach seines caught the highest number of species (14 ± 7 species per day) while most other gears caught four to five species per day with no differences between gears. Predatory species with a mean trophic level of 3.6 dominated catches from hand lines, while the mean trophic level of the other gears was low and ranged from 2.6 to 2.9 with no differences between the gears. The high diversity and small size of fish caught in beach seines indicates that its selectivity overlapped most with large traps and gill nets. Spears and small traps also showed high similarity in species selectivity and small traps captured the smaller mean size of fish, indicating that they are likely to pre‐empt the resource of spears. Large traps, hand lines and spears catch the largest individuals and the species composition of the catch differed sufficiently such that their selectivity should overlap the least and may, therefore, be the preferred mix of gears. The elimination or reduction of beach seines and small traps should reduce the catch of small fish and overlap in selectivity among the existing gears.