人工鱼礁对防城港海域小型岩礁性鱼类诱集效果研究

为探究人工鱼礁聚鱼效果,于 2017 年 2 月、4 月、9 月和 11 月主要通过声学探测技术,对防城港海域渔业资源密度、空间分布与大小组成进行了调查研究。结果显示,防城港人工鱼礁区及其临近海域 4 次调查共捕获各类游泳生物和底栖无脊椎动物 201 种,包括鱼类 126 种、蟹类 32 种、虾类 20 种、虾蛄类 11 种和头足类 12 种。双因素方差分析结果表明,调查海域渔业资源密度在时空层面上均存在显著性差异(P<0.001),且交互作用显著(P<0.001)。2 月调查海域人工鱼礁区渔业资源密度(547745 ind/n mile2)约为其周边海域(203990 ind/n mile2)的 2.68倍,表现出明显的聚鱼效果。其中,二长棘鲷(Parargyrops edita)、多齿蛇鲻(Saurida tumbil)、花斑蛇鲻(Sauridaundosquamis)等岩礁性底层鱼类为该季度主要优势种类。各航次人工鱼礁区小型个体所占比重较高,其平均目标强度(TS)分别为 55.6 dB(2 月)、 54.5 dB(4 月)、 53.6 dB(9 月)和 52.2 dB(11 月),随个体生长其平均 TS 呈稳步增大的变化趋势。在垂直方向上, 2 月和 4 月航次人工鱼礁区 90%以上回波单体主要分布在 9~16 m 中下水层。上述研究结果表明,人工鱼礁建设对防城港海域小型岩礁性鱼类表现出明显的向底层诱集的效果,该结果能为海洋牧场生态效应系统评价提供重要支撑。     

广东人工鱼礁区增殖放流种类初探

以1964-1965年广东沿海没有捕捞过度的渔业资源状况作为处于良好状态的资源结构,根据2002-2004年广东16个人工鱼礁区的渔业资源本底调查结果研究了广东沿海渔业资源结构的历史变动,结合有关资料,提出了广东人工鱼礁区可供选择的增殖放流种类为:鱼38种、虾13种、龙虾4种、蟹5种、贝18种、海参8种和海藻27 种。指出增殖放流种类的确定要因地制宜多方面考虑。     

现场海域人工鱼礁分布状态聚类分析

人工鱼礁的流场营造、鱼类诱集等建设目标,一般是通过单位鱼礁、鱼礁群等不同规模的形式实现的;实际投放的成千上百个人工鱼礁处于何种分布状态、它们是否满足单位鱼礁等规模要求,是非常值得关注的课题。本文利用空间聚类分析,借助基于划分的算法、基于层次的算法和基于约束的算法对投放后的鱼礁进行划分、归类或剔除,并选择单位鱼礁的重心、影响面积、鱼礁单体数量以及礁体间距4个指标进行比较分析,探讨人工鱼礁实际的组合聚类模式。结果显示3种空间聚类算法误差的排列顺序为：约束算法<划分算法<层次算法。通过对比分析,在基于约束的聚类算法下,最能反映人工鱼礁的实际集聚情况。     

青岛市崂山湾公益性人工鱼礁建设的探索与实践

人工鱼礁建设是指在自然海区营造适宜于水产经济生物生长繁殖的环境,从而吸引野生或人工放养的海洋生物定居,促进水生生态系统健康发展与海洋渔业资源的增殖与养护。青岛崂山湾公益性人工鱼礁区位于崂山湾南部海域,建设周期三年（2012年~2015年）,工程建设采用了混凝土和废旧渔船两类鱼礁体,共建设三处人工鱼礁群,每处人工鱼礁群使用海域200 hm2。项目建设期间需要采取多项安全防治和环保治理措施,后期管理工作也要同步展开。该项目建成后具有显著的生态效益、经济效益和社会效益,并将为修复海洋生态环境和渔业资源、发展生态休闲渔业、实现渔业可持续发展发挥重要的促进作用。     

Petrarch's Principle: how protected human-made reefs can help the reconstruction of fisheries and marine ecosystems

Petrarch's Principle, named here, is to know things unseen, yet to ignore things seen. We apply the principle to the debate over the appropriate role and utility of human-made reefs (HMRs) in fishery and ecosystem management by reviewing four linked issues that were discussed at the recent 7th International Conference on Artificial Reefs and Related Aquatic Habitats. First, deploying protected HMRs can help to mitigate the depletion of fishery stocks through overharvest and habitat degradation. Secondly, to achieve this objective effectively, it is essential that HMRs are protected as no-take areas, and that, thirdly, HMRs are large, well-planned, evaluated and monitored. Finally, ecosystem modelling and adaptive management responses are necessary to forecast and manage the benefits of HMRs. Moreover, uncertainty about the resolution of the well-rehearsed attraction/production debate may be resolved by ensuring that HMRs are managed as protected no-take areas. And to ensure an unbiased attitude that will aid the clarification of consequences, costs and benefits, we propose a change in terminology, from artificial reefs to human-made reefs.     

人工鱼礁流场效应的模型实验

摘要：本文针对正方体、金字塔及三棱柱人工鱼礁模型,选取三个不同工况6m/s、9m/s和12m/s,通过风洞实验研究不同类型人工鱼礁单体和不同组合正方体模型的流场效应。结果表明,模型迎流面和背流面分别产生上升流和背涡流,其规模随来流速度的增大而增大;相同来流速度下,同种模型空心模型的上升流和背涡流规模较实心模型小,空心模型背涡流回流速度随模型空隙率增大而减小;不同模型z方向的湍流强度均大于x方向。对于组合模型,随着来流速度的增大,中心点流速均逐渐增大;一定来流速度下,当模型间距在1~1.5倍模型尺度时,流场变化最大;且模型平行组合比垂直组合产生的流场效应更大。     

The epidemiology of Argulus spp. (Crustacea: Branchiura) infections in stillwater trout fisheries

Problem infections caused by species of the crustacean ectoparasite, Argulus, in UK stillwater trout fisheries appear to have increased in recent years. A cross-sectional study of 77 such fisheries was conducted to establish the perceived problem and the extent and severity of this problem, and to identify associated risk factors. An interview-based study was conducted in 2001 using a standardized questionnaire based on the management and infection status of each fishery in the previous year. Logistic regression was used to identify potential risk factors. Argulus spp. were perceived to cause economic losses in infected fisheries through a reduction in the number of anglers due to reduced aesthetic appeal and catchability of fish. Of the sites studied, 29% experienced such a problem infection in 2000. Argulus foliaceus was identified in all but one case and was found to be widely distributed throughout the UK. The remaining case was identified as Argulus coregoni. Three risk factors were associated with problem infections: the presence of an algal bloom, slow rates of stock turnover and whether water level dropped by <1 m during the summer months.     

中国常用人工鱼礁流场效应的比较分析

人工鱼礁是建设现代化海洋牧场的基础设施,为了研究在不同海域流速下,迎流角度对人工鱼礁的影响,实验基于Ansys-Fluent平台,采用RNG $ k - \\varepsilon $的湍流模型,进行数值水槽模拟,对结构边长为3 m的立方对角面开孔鱼礁在3种来流速度 (0.5、1.0和1.5 m/s)、4种迎流角度 (0°、15°、30°和45°)下的上升流体积、背涡流体积、阻力、倾覆力矩等水动力特性进行比较分析。结果显示,人工鱼礁内部和周围存在具有显著特征的上升流区域和背涡流区域;流场规模的大小基本不受来流速度的影响;流速是影响立方对角面开孔人工稳定性的主要因素,流速越大,作用在礁体上的阻力和倾覆力矩相应变大,礁体的稳定性越差;迎流角度是影响人工鱼礁流场效应的主要因素,鱼礁的流场效应规模在迎流角度为30°~45°时达到最优,礁体为45°迎流时上升流体积和背涡流体积都达到最大值。利用权重赋值法,引入人工鱼礁建设效果综合评价模型,通过综合评价分析,在不考虑海底底质淤积、风浪等条件下,投放人工鱼礁时宜选取最大流速不超过1 m/s的海域,且迎流角在30°至45°范围内,鱼礁的建设效果最佳。

     

南麂列岛海域两种框型人工鱼礁水动力性能试验

为改良南麂列岛海域投放的人工鱼礁礁体存在的沉陷、位移现象,试验研究了人工鱼礁水动力性能,并进行对比验证.采用水槽试验方法,对两种框型人工鱼礁模型在5种水流速度(0.15、0.20、0.25、0.30、0.35 m/s)和4种迎流角(0°、15°、30°、45°)条件下的阻力进行测定,并计算阻力系数.以水槽试验所测得的阻...     

长江三峡库区铜锣峡江段人工鱼礁生态效果初步评估

为了研究长江三峡水库变动回水区人工鱼礁建设后的效果,分别于2019年8月和12月,采用渔业资源传统调查与水声学探测结合的方法,对铜锣峡江段开展了资源现状调查.结果显示:人工鱼礁区域鱼类组成共计70种,隶属于6目14科,其中长江上游特有鱼类10种;人工鱼礁区域鱼类分布以小个体为主,夏季和冬季体长超过6 cm的个体占比分别...     

Managing the development of artificial reef systems: The need for quantitative goals

Fisheries enhancement initiatives are a potentially useful tool for managers to supplement traditional approaches. Habitat‐based enhancements often deploy artificial reefs with the aim to increase the available structure to augment local production, yet current assessment approaches make it difficult to assess whether these reefs achieve pre‐deployment goals. This makes it hard for managers to determine whether artificial reefs could improve their fishery outputs, potentially leading to missed opportunities and reduced production. We reviewed 270 research articles to determine whether existing monitoring studies identify whether artificial reefs meet their pre‐deployment goals, thereby providing some evidence of their suitability for certain fisheries. We found only 62% of these studies clearly articulated the original goals of the reef. Goals were qualitative, and most studies were conducted over insufficient time frames to allow for ecological communities to stabilize and mature. It is therefore difficult to determine the success or failure of many artificial reefs in addressing the management issues for which they were deployed. In the light of these findings, we think the setting of explicit quantitative goals (which may be biological, social or economic), and monitoring the performance of reefs against these goals, could stimulate the broader application of artificial reefs in fisheries management strategies. Such an approach has been successfully adopted in aquaculture‐based fisheries enhancement, and we explain how current evaluation methods such as harvest strategies can be easily adapted to quantitatively monitor artificial reef performance.     

Fyke-netting and coarse fisheries in lowland Britain: practical advice for fishery owners and managers

Abstract  The by-catches of fish, mammals and birds from a fyke-net survey of eel, Anguilla angilla (L.), stocks (total effort 1593 end days) at 45 sites in rivers and lakes in the Thames catchment and tidal river were examined. Sizes and compositions of by-catches varied between sites, yielding a total of 21 fish species representative of the types of water body sampled. The largest catches were of shoaling juvenile perch (especially in lakes). Small roach, perch and ruffe were also fairly frequent in running waters (especially the tidal and non-tidal Thames). Carp, tench and pike were less frequently caught (mainly in still waters and upper tributaries). Juvenile flounders and smelt were fairly common in the tidal Thames. Salmonids were rarely caught and fish mortalities overall were very low. Few mammals, wildfowl or crustaceans were trapped, but it is important that nets are set below water level to avoid trapping birds swimming on the surface, and the use of otter guards is recommended. Fouling of fishing tackle was rare. Recommendations are made for practical steps that can be taken to minimize undesirable impacts of commercial fyke-netting, whilst realizing the potential financial and management benefits. The cost-effective uses of fyke-nets for sampling and culling fish for management purposes are discussed.     

基于单位鱼礁规模的米字型人工鱼礁流场效应定量研究

流场效应是人工鱼礁发挥其生态效应的基础,流场效应强弱受单位鱼礁规模影响,同时是衡量人工鱼礁建设模式优劣与规划人工鱼礁建设模式的重要参考因素,流场体积是表征流场效应强弱的重要指标。本研究基于数值实验方法,分析米字型人工鱼礁在4种布设模式下28种单位鱼礁规模的流场体积变化规律,并建立上升流、背涡流流场体积与人工鱼礁建设规模指标的多元非线性模型。结果表明,单位鱼礁建设一级指标投放量(T_a)、布设间距(L_d)及目标速度比(R_u)与上升流体积分别呈线性、三次函数及幂函数关系,建立上升流体积回归模型为V_u=T_a×(0.002L_r~2-0.055L_r-2.429V_R×R_u+0.011R_u~(-1.833)+0.227L_d+0.437),回归拟合R~2为0.957,相对误差为18.61%。与背涡流体积分别呈幂函数、三次函数及指数函数关系;结合单位鱼礁建设二级指标相对边长(L_r)、容积率(V_R),背涡流体积回归模型为V_b=R_u×(-0.543L_r~2+2.388L_r)–51.779V_R~2+75.045V_R+1.449×10~(-4)T_a×e~(12.049 Ru)+1.620L_d×T_a,回归拟合R~2为0.938,相对误差为10.09%。该流场体积回归模型可用于规划指导均匀布设模式的人工鱼礁建设,为"减量增质提效"的人工鱼礁建设策略提供参考。     

以数值实验为基础的米字型鱼礁布设模式差异下的流场效率

人工鱼礁投放规模是鱼礁建设的核心问题之一,其中礁体数量与布设间距不仅表征了鱼礁规模的范围和密度,而且也决定着人工鱼礁流场效率。本研究采用数值实验方法,对典型结构边长为l的米字型人工鱼礁在4种投放量(2×2、3×3、4×4和5×5)、7种布设间距(0 l、0.5 l、1.0 l、1.5 l、2.0 l、3.0 l和4.0 l)下的流场相对体积、相对高度、相对长度等流场效率特性进行比较分析。结果显示,当上升流目标流速比分别为小于0.10、0.10～0.15和大于0.15倍时,上升流流场存在协同效应的最大布设间距分别为4.0 l、3.0 l、2.0 l,背涡流目标速度比下最大间距均为3.0 l;人工鱼礁投放量越多,上升流与背涡流相对体积越大,平均相对体积增长率越低,0.5 l布设间距的上升流相对体积与鱼礁单体相对流场体积最大,1.5 l布设间距的背涡流相对体积与鱼礁单体相对流场体积最大;上升流相对高度随投放量增加以1.01倍速率增加,随布设间距增加以0.90倍速率降低,背涡流相对长度随布设间距的增加先增后降,相对长度最大值位于1.0 l处。     

Dynamics of fish assemblages on coral reefs subjected to different management regimes in the Abrolhos Bank,eastern Brazil

• 1. Marine protected areas (MPAs) range from multiple‐use areas (MUA) to absolute no‐take reserves (NTR). Despite their importance for fisheries management, there are few long‐term studies comparing benefits from different types of MPAs within the same region.
• 2. Fish assemblages were monitored for five years (2001–2005) in the largest coral reefs in the South Atlantic (Abrolhos Bank, Brazil). Monitoring included one community‐based MUA, two NTRs (one established in 1983 and another in 2001), and one unprotected area. Benthic assemblages at these areas, as well as fish assemblages on unprotected deeper reefs (25–35 m), were monitored from 2003 onwards.
• 3. Habitat characteristics strongly influenced fish assemblages' structure. This, together with the lack of data from before establishment of the MPAs, did not allow an unequivocal analysis of the effects of the MPAs.
• 4. Biomass of commercially important fish, particularly small carnivores, was higher in the older NTR. Biomass of black grouper Mycteroperca bonaci increased by 30‐fold inside NTRs during the study period, while remaining consistently low elsewhere.
• 5. A single herbivore species, the parrotfish Scarus trispinosus, dominated fish assemblages (28.3% of total biomass). Biomass of this species increased in 2002 on the younger NTR and on the MUA, soon after establishment of the former and banning of the parrotfish fishery in the latter. This increase was followed by a decline from 2003 onwards, after increased poaching and reopening of the parrotfish fishery.
• 6. Fish biomass increased in 2002 across the entire region. This increase was stronger in sites closer to deeper reefs, where fish biomass was up to 30‐times higher than shallow reefs: movement of fish from deeper to shallower areas may have played a role.
• 7. The effective use of MPAs in the Abrolhos Bank is still dependent on adequate enforcement and the protection of critical habitats such as deep reefs and mangroves.

Copyright © 2008 John Wiley & Sons, Ltd.     

Method evaluation and risk assessment: A framework for evaluating management strategies for data-limited fisheries

Fisheries managers are in need of quantitative tools to inform decisions regarding selection of robust management practices, prioritising research gaps and stocks to focus on, particularly where there are limited resources or data. To support these decisions, the use of Management Strategy Evaluation (MSE), that is, closed loop simulation-testing of management procedures, is widely regarded as best practice. However, applying MSE is time- and computationally intensive, and requires highly skilled expertise and processes for stakeholder input and peer review. For data- and capacity-limited fisheries, MSE may be particularly challenging to implement. Yet, these are the contexts where it is most critical to test assumptions, evaluate the implications of all sources of uncertainty and identify the most informative data sources. To facilitate wider use of MSE, the Method Evaluation and Risk Assessment (MERA) framework was developed as an accessible online interface, with quick processing time, focused on generic data-limited management procedures, but allowing progression to tailored and more data-rich methods. The framework links a quantitative questionnaire and data input standard to a flexible operating model with optional customisation via command line access to the back-end open-source R libraries. Here, we illustrate a case study application of MERA for the bocinegro (Pagrus pagrus, Sparidae) fishery in the Gulf of Cadiz, where in conjunction with fishery stakeholders, a custom management procedure was developed and tested and key research gaps and data collection priorities were identified. We discuss implications for wider use of MSE in various contexts, including eco-certification and fishery improvement projects.     

Broadbill swordfish: status of established fisheries and lessons for developing fisheries

Guidelines for the assessment and management of developing swordfish fisheries are derived through an examination of five swordfish fisheries. As they develop, swordfish fisheries may be inclined to local depletion around underwater features, such as seamounts and banks. Few nations have applied the precautionary approach in managing their developing swordfish fisheries. Without controls, swordfish fisheries expand geographically and fishing effort increases, often overshooting optimum levels. However, it is difficult to distinguish clear evidence of fishery collapse; modern longliners harvest widely distributed tuna and swordfish and they are able to relocate to distant areas or switch between target species in response to fluctuations in species abundance and price. Furthermore, the wide distribution of swordfish combined with year‐round spawning and high growth rates amongst juveniles probably contribute to the apparent resilience of swordfish stocks to intensive harvesting. Over half the world’s swordfish catch is taken as an incidental catch of longliners fishing for tuna. In several areas, such as the North Atlantic, catch quotas have sometimes caused tuna longline fishers to discard swordfish. Minimum size limits have also resulted in discarding of swordfish in tuna fisheries and in dedicated swordfish fisheries. In addition to weakening the effectiveness of those management measures, bycatch and discarding add to the complexities of managing swordfish fisheries and to uncertainties in assessing the stocks. Longliners that target swordfish often fish at high latitudes where interactions with marine wildlife, such as seabird, are generally more frequent than at low latitudes. Concern over incidental catches of marine wildlife and other species is becoming a driving force in the management of several swordfish fisheries. Fishery management organisations will need to implement management measures to protect non‐target species and gather reliable data and information on the situation by placing observers on boats fishing for swordfish.     

Describing ecosystem contexts with single‐species models: a theoretical synthesis for fisheries

Fished populations exist within complex ecosystems but are typically assessed using single‐species models. It is often lamented that stock assessments rarely account for other ecosystem components explicitly, but in most fisheries there are clear difficulties in implementing data‐intensive ecosystem‐based assessment approaches. Addressing these competing challenges requires prioritizing investments in expanded assessment frameworks. To provide high‐level conceptual guidance to such prioritization, here we use general analytical theory to identify (i) characteristics of fish stocks that tend to facilitate or inhibit the precision and accuracy of reference points from single‐species assessments, (ii) characteristics of ecosystem components that introduce the greatest bias/imprecision into single‐species reference points and (iii) warning signs within single‐species frameworks that important ecosystem components may not be adequately accounted for. We synthesize and expand on theories from various branches of applied mathematics addressing analogous questions. Our theory suggests that (i) slow population dynamics (relative to the dynamics of other ecosystem components) and a wide range of abundance observations promote precision and accuracy of single‐species reference points; (ii) ecosystem components that strongly influence the focal stock's growth, and change on similar timescales as the focal stock's abundance, introduce the greatest bias/imprecision to single‐species reference points; and (iii) signs of potential challenges for single‐species assessment include fast population dynamics, ‘hydra effects’ (i.e. abundance and fishing pressure simultaneously increase), and recently detected extinctions, invasions or regime shifts in closely connected ecosystem components. Our results generalize to other levels of abstraction and provide strategic insights complementing tactical simulation approaches such as management strategy evaluation.     

Capture for culture: artificial shelters for grouper collection in SE Asia

This paper addresses a little‐discussed relationship between wild capture and mariculture, when the latter involves grow‐out of small wild‐caught fish or invertebrates in captivity. Seafood generated in this way is typically considered to be a form of aquaculture because it is assumed that, for animals removed from the wild when natural mortality is still very high, the protection conferred by culture operations will improve survivorship and enhance production. This assumption does not necessarily, however, apply when animals are removed well past the time of early high mortality. As one example of the implications of an early life‐history phase (ELP) fishery supplying culture operations, a preliminary study was conducted on an ELP fishery supplying live reef fish, especially groupers, in Southeast Asia. Grouper culture depends on both hatchery‐produced and wild‐caught fish which are then grown out to market size. Following interest to develop grow‐out operations in Indonesia, a pilot study was conducted to determine the sizes and capture rates of species of interest to the live fish trade, and to determine the likely environmental footprint of an artificial shelter (gango) type of capture method. From the results of the 15‐month study, we drew inferences regarding the sustainability of this fishing method and requirements of space, fish and materials for a viable grow‐out operation. The results showed that gangos were unselective for either species or size. Only 1.4% of the total fish catch (by number) were target species, mainly the grouper Epinephelus coioides, and most were large (mean total length was 13.6 cm) enough to have bypassed the early high mortality phase. Moreover, there were large non‐target catches that included many food fish species too small to be useful in catches. Given the large number and area of gangos needed for a viable operation, and that many groupers captured could probably have survived to reproduce, the ecological footprint of this approach could be substantial. These results, and literature on other ELP fisheries, suggest that these may often need management, have important links to other capture fishery sectors, and require careful evaluation of potential costs and benefits before introduction or development.     

Methods for identification and differentiation of different Shewanella spp. isolates for diagnostic use

Shewanella spp. are Gram‐negative, rod‐shaped, motile bacteria that are widely distributed in marine and freshwater environments. The bacteria are present in the physiological microflora of fish from temperate waters and are known as fish spoilage species. From clinically healthy fish and from fish with skin ulcerations, Shewanella spp. is regularly isolated, indicating a possible role as fish pathogen. In this study, 74 isolates of Shewanella spp. were analysed. For species identification, biochemical techniques, 16S rRNA sequencing, MALDI‐TOF MS and the Sherlock Microbial Identification System (MIS) based on the composition of fatty acid ethyl esters were compared. The phylogenetic relationship, cytotoxicity in vitro and resistance against antibiotics were tested. The most reliable method for species identification was 16S rRNA sequencing. From diseased fish, clinically healthy fish and the aquatic environment, different Shewanella species were isolated. This indicates that Shewanella spp. is widespread in the aquatic milieu and acts as a secondary pathogen. The virulence of Shewanella spp. is probably not depending on the species but on the isolate itself. Many isolates of Shewanella spp. were showing multiresistances against antibiotic substances, especially in samples derived from retailers and in routine diagnostics, all Shewanella spp. should therefore be tested for resistances against antibiotic agents.