菱塘养鱼技术研究

报导了“菱塘养殖”的某些关键技术。它们包括：（１）通过品种结构调整，解决鱼菱相克的矛盾；（２）通过在菱群落“开天窗”，避免鱼窒息致死；（３）实行混合养殖，拓宽生态位；（４）通过鱼种投放量与鱼产量关系的研究，为鱼种合理搭配提供了科学依据。由于上述问题的解决，这种农业模式发挥了明显的经济效益。     

Developing the Ethical Delphi

A number of EU institutions and government committees across Europe have expressed interest in developing methods and decision-support tools to facilitate consideration of the ethical dimensions of biotechnology assessment. As part of the work conducted in the EC supported project on ethical tools (Ethical Bio-TA Tools), a number of ethical frameworks with the potential to support the work of public policy decision-makers has been characterized and evaluated. One of these potential tools is the Delphi method. The Delphi method was originally developed to assess variables that are intangible and/or shrouded in uncertainty by drawing on the knowledge and abilities of a diverse group of experts through a form of anonymous and iterative consultation. The method has hitherto been used by a diversity of practitioners to explore issues such as technology assessment, environmental planning, and public health measures. From the original (classical) Delphi, a family of Delphi-related processes has emerged. As a result of the evaluation of the various Delphi processes, it is proposed that the classical method can be further developed and applied as a form of ethical framework to assist policy-makers. Through a series of exercises and trials, an Ethical Delphi has been developed as a potential approach for characterizing ethical issues raised by the use of novel biotechnologies. Advantages and disadvantages of the method are discussed. Further work is needed to develop the procedural aspects of the Ethical Delphi method and to test its use in different cultural contexts. However, utilizing an ethical framework of this type combines the advantages of a methodical approach to capture ethical aspects with the democratic virtues of transparency and openness to criticism. Ethical frameworks such as the Ethical Delphi should contribute to better understanding of and decision-making on issues that involve decisive ethical dimensions.     

Trace metal pollution in aquatic sediments and some fish species from the Kwilu-Ngongo River,Democratic Republic of Congo (Bas-Congo)

In this study, the concentrations of some metals in sediments and consumable fish from the Kwilu Ngongo River, province of Bas-Congo, Democratic Republic of Congo, are investigated. The digested muscle tissue, whole fish, and river sediment samples were subjected to trace element analysis by inductively coupled plasma mass spectroscopy and by using an automatic mercury analyzer. The highest values of trace metals in fish muscle tissue were found for Cr, Cu, Pb and Hg, with maximum values of 8.6 (Cr), 15.7 (Cu), 6.0 (Pb) and 3.3 (Hg) mg kg^?1. These values are higher than maximum tolerable limits recommended by the European Commission Regulation for Food. The highest metal concentrations in sediments were 81 (Cr), 86 (Cu), 21 (Sb), 41 (Pb), and 0.8 (Hg) mg kg^?1. Sediment toxicity tests using benthic crustaceans (ostracods) revealed mortality rates of up to 30% after six days of exposure to the sediments near the sugarcane industry outlet pipe discharge. The contamination of the sediments and fishes by the elements and the bio-accumulation of mercury in fish most likely arise from the adjacent agricultural fields where intensive sugarcane cultivation since 1925 has probably contaminated the soils through the long-term use of fertilizers and pesticides.     

渭河流域鱼类群落结构特征及其受环境因子的影响分析

本文以渭河流域为研究区,调查了全流域45个点位的鱼类群落和水环境理化特征,采用聚类分析确定渭河流域主要的鱼类群落分布类型,并运用典范对应分析方法(Canonical correspondence analysis,CCA)识别影响渭河流域鱼类群落结构的主要环境因子.本次鱼类调查共鉴定出鱼类36种,其中,鲤科和鳅科是构成渭河流域鱼类群落的主要类群.鱼类聚类结果显示,群落结构可分为3组,第1组主要分布在渭河源头及上游支流,鱼类以陕西高原鳅(Triplophysa shaanxiensis)、岷县高原鳅(Triplophysa minxianensis)为优势物种,包括拉式鱥(Phoxinus lagowskii)、北方花鳅(Cobitis granoei)等敏感物种,耐受物种分布极少;第2组主要分布在渭河上游和泾洛河上游,鱼类以达里湖高原鳅(Triplophysa dalaica)、背斑高原鳅(Triplophysa stoliczkae dorsonotata)、棒花鱼(Abbottina rivularis)为优势物种,包括少数拉式鱥等敏感种;第3组主要分布在渭河中下游,鱼类以泥鳅(Misgurnus anguillicaudatus)、马口鱼(Opsariichthys bidens)、麦穗鱼(Pseudorasbora parva)、棒花鱼和鲫(Carassius auratus)等江河平原鱼类为主,耐受物种较多.CCA分析结果显示,影响渭河流域的主要环境因子有海拔高度、溶解氧含量、流速、高锰酸盐指数、砂/淤泥/粘土所占比例和草地所占比例.而对于不同的指示物种,影响其分布的主要环境因子也各有不同.本研究是继20世纪80年代以来首次对渭河全流域进行水生态调查,并分析渭河流域鱼类的群落结构特征,可为流域水生态系统恢复提供重要的科学依据.     

Distribution and habitat characteristics of fishes in the Pearl River Estuary北大核心CSCD

To explore the current situation and distribution of fish in the eight major estuaries of the Pearl River Estuary in China, acoustic detection and water quality monitoring were conducted in 2018. The results showed that almost living in eight major estuaries were juvenile, the proportion of strong echo was higher in winter, and Jiaomen and Modaomen Estuary were relatively rich in adult fish. In winter, the Humen, Jiaomen, and Yamen Estuary had a high density relatively, for 46.05 (± 50.30), 33.12 (± 93), and 32 (± 78) ind/103 m3, respectively. However, the fish densities of the Hengmen, Modaomen, and Hutiaomen estuaries were higher in summer at 55.72 (± 83.23), 37.52 (± 55) and 36 (± 99) ind/103 m3, respectively. Thus, fish are mainly concentrated in the flood tidal estuary in winter and in the ebb tidal estuary in summer. In addition, fish density was higher in flood tide than in ebb tide, and the strong echo proportion was lower. In winter, the key water quality factors affecting the biodiversity of estuary fish Shannon were chlorophyll a (P < 0.05), while what affected the fish density were turbidity and salinity (P < 0.05). This study showed that the Pearl River estuary was still the main habitat for juvenile fish. However, habitat variability is obvious; hence, it is important to flexibly carry out the delimitation of estuarine fish reserves and ecological restoration. © 2022 Authors. All rights reserved.     

The effects of subchronic exposure to NeemAzal T/S on zebrafish (Danio rerio)

The objective of the study was to investigate the subchronic effects of the insecticidal preparation NeemAzal T/S at concentrations of 3, 10 and 30?mg/L on the mortality, growth and histopathology of juvenile zebrafish (Danio rerio), as well as its related effects on selected indices of oxidative stress during a 28-day toxicity test. The juvenile growth toxicity test was performed according to OECD Guidelines 215 (Fish, Juvenile Growth Test). The results of this study indicate that these tested concentrations of NeemAzal T/S (containing 1% of the active ingredient azadirachtin A) affect fish growth and have a negative influence on the indices of oxidative stress in the juvenile stage of zebrafish, as well as cause mild histopathological changes in liver tissue.     

基于斑马鱼的水生生态毒理学实验教学体系的构建

在我国现有的生态毒理学教学体系中,相对于理论教学,其实验教学体系的构建和实践相对滞后,阻碍了相关领域的人才培养。斑马鱼是国际上广受瞩目的小型模式鱼,本文在目前已成功开发并应用于科研的一系列斑马鱼毒性测试策略和方法的基础上,初步构建较为完整的水生生态毒理学实验内容和案例。虽然仅基于斑马鱼这一实验物种,但包括了致死效应、致畸效应、神经毒性、内分泌干扰效应、免疫毒性、遗传毒性等,涵盖不同生物学层面的多个毒理学终点,有助于充分训练学生的实验技能,巩固所学的理论知识。此外,在学生初步掌握上述实验手段的基础上,设置综合性或者设计性实验,可进一步培养学生的创造性思维和科研能力。本文对于现有的生态毒理学实验教学有一定的参考和借鉴意义。     

Integrating Large Wood Jams into Hydraulic Models: Evaluating a Porous Plate Modeling Method

Large wood (LW) jams are key riverine habitat features that affect hydraulic processes and aquatic habitat. The hydraulic influence of LW jams is poorly understood due to the complexity of fluid dynamics around irregular, porous structures. Here we validated a method for two‐dimensional hydraulic modeling of porous LW jams using the open‐source modeling software Delft3D‐FLOW. We sampled 19 LW jams at three reaches across the Columbia River Basin in the United States. We used computer‐generated porous plates to represent LW jams in the modeling software and calibrated our modeling method by comparing model outputs to measured depths and velocities at validation points. We found that modeling outputs are error‐prone when LW jams are not represented. By representing LW jams as porous plates we reduced average velocity root mean square error (RMSE) values (i.e., improved model accuracy) by 42.8% and reduced average depth RMSE values by 5.2%. These differences impacted habitat suitability index modeling. We found a 15.1% increase in weighted useable area for juvenile steelhead at one test site when LW jams were simulated vs. when they were ignored. We investigated patterns in average RMSE improvements with varying jam size, bankfull obstruction, porosity, and structure type, and river complexity. We also identified research gaps related to field estimation of LW jam porosity and porous structure modeling methods.     

Reduction of the association preference for conspecifics in cave-dwelling Atlantic mollies, Poecilia mexicana

Cave animals are widely recognised as model organisms to study regressive evolutionary processes like the reduction of eyes. In this paper, we report on the regressive evolution of species discrimination in the cave molly, Poecilia mexicana, which, unlike other cave fishes, still has functional eyes. This allowed us to examine the response to both visual and non-visual cues involved in species discrimination. When surface-dwelling females were given a chance to associate with either a conspecific or a swordtail (Xiphophorus hellerii) female, they strongly preferred the conspecific female both when multiple cues and when solely visual cues were available to the female. No association preference was observed when only non-visual cues were provided. In contrast, cave-dwelling females showed no preference under all testing conditions, suggesting that species recognition mechanisms have been reduced. We discuss the role of species discrimination in relation to habitat differences.     

广州市场食用鱼和贝类重金属含量及评价

以高氯酸 -硝酸消化法和火焰原子吸收分光光度计测定了广州石牌市场食用鱼类和双壳贝类的Cd、Pb、Cr、Ni、Cu和Zn等重金属的含量。结果表明 ,双壳类对重金属积累的能力高于鱼类。鱼类不同组织器官对各种重金属积累能力明显不同 ,有毒重金属元素Cd、Pb、Cr和Ni主要分布于鳞片、鳃中 ,其食用部分中各重金属含量都远低于“PHNSO”和“人体卫生消费标准” ,具安全的食用价值。但贝类的Cd含量已超过“人体卫生消费标准” ,其中牡蛎的Cu和Zn含量则略超过“人体卫生消费标准” ,其食用价值受到严重威胁 ,应引起重视