渔用可降解材料的研究进展与展望

可降解渔具材料的研发与应用是减轻"幽灵捕捞"、保护海洋渔业资源和生态环境、实现可持续发展的有效途径之一。淀粉基材料、聚己内酯(PCL)、聚乳酸(PLA)、聚丁二酸丁二醇酯(PBS)等材料具有可完全生物降解、可加工、可再生等特点,作为不可降解渔用合成纤维材料的替代品,可为生物降解高分子材料在渔业领域的应用开辟新的途径。主要综述了近年来国内外有关淀粉基材料、 PCL、PLA、PBS 4种渔用可降解高分子材料的性能、生物降解机理及其与天然高分子共混、合成高分子共混改性的研究进展,介绍了加工工艺、表面处理、添加剂等对复合体系性能的影响,并分析了可降解材料在渔业上的应用及发展前景,以期为研发价格低廉、综合性能优越的可降解渔用材料提供参考。     

对辽宁省淡水渔具渔法今后发展的看法

近十余年来，辽宁省的淡水捕捞事业有了很大的发展，各地渔业工作者不仅完善与发展了原有的渔具渔法，而且还不断吸取国内外先进经验，引进和试验了不少新的渔具渔法，从而使我省淡水捕捞的渔具渔法进入了一个新阶段。纵观全省所使用的各种淡水渔具渔法，几乎包括了淡水渔具渔法的全部分。     

浅谈海洋捕捞技术的科学研究问题

<正> 海洋捕捞是一门综合性的应用技术科学。其范畴包括捕捞对象、渔场、渔具和渔法以及技术管理。广义而言,尚包括渔船、渔业机械和探鱼仪器,以及捕捞作业中进行渔具性能测试的有关仪器。然而,其核心应是研究渔具和渔法对捕捞对象习性行动和渔场环境条件变动的适应性问题。亦即以渔法     

沿近海捕捞业应当转型，实施栽培渔业势在必行

当今我们所经营的捕捞渔业，仍然是一种狩猎型的渔业，只是单纯地通过渔法、渔具对天然生长的水产生物进行采捕。因而，所谓捕捞渔业的发展与进步，主要地是渔法、渔具的改善和进步。但是到了今天这种狩猎型的传统捕捞业已陷于进退维谷的境地。主要表现有如下三个状况：     

新颖的拖网渔具渔法（续）

在科学技术突飞猛进的当今时代，海洋渔业同其他行业一样，生机勃勃、日新月异，作为世界海洋渔业中最有效的捕捞技术——拖网渔具渔法，也在不断革新，新颖独特的拖网设计和捕捞方法层出不穷。本文继续把国外一些新颖的拖网渔具渔法介绍给读者。     

光诱鱿鱼钓生产调查报告

<正> 随着近海渔业资源的逐渐衰退,大力开拓远洋渔业、改进渔具渔法和捕捞作业方式是我们这一代捕捞工作者的职责。鱿鱼钓是目前主要的渔具渔法之一。本文就舟山海洋渔业公司几年来光诱鱿鱼钓生产作业调查作一总结,并对渔况、渔期、渔场,渔捞设备装置与作业方法,影响渔获率的诸因素,今后的设想与建议等作较为详细的阐述,供参考。     

渔具渔法对底栖群落(Benthic Community)及其栖息地(Habitat)的影响

渔具渔法对底栖群落及其栖息地的影响，国外研究比较多。作者从互联网上收集了大量资料，给予编译整理。本文着重概述捕捞干扰与自然干扰、底拖网捕捞、桁拖网捕捞、耙网、底层旋曳网、底刺网捕捞、底层延绳钓以及笼壶渔业等6种渔具渔法对底栖群落的影响。     

当代海洋捕捞的发展现状和展望

海洋捕捞事关国际粮食安全和海洋生态系统健康。得益于科学技术的进步, 当代海洋捕捞发展迅速, 但依然面临着渔业资源衰退、海洋底栖环境破坏、兼捕与抛弃、废弃渔具引起的幽灵捕捞和塑料污染、气候变化、区域发展不平横等系列问题。本文综述了国内外为缓解上述问题在海洋捕捞管理、技术创新、最佳实践探索等方面的工作进展, 并提出了如下发展建议: (1) 应进一步加强生态友好型渔具渔法、高效节能技术、废弃渔具回收利用技术、生物可降解材料等方面的基础和应用研究; (2) 开展减少兼捕、降低底拖网对底栖环境的影响、海洋捕捞高效节能、减少废弃渔具流向海洋等方面最佳实践的探索; (3) 加强激励机制的研究和应用, 加强对废弃渔具回收产业的政策扶持, 完善海洋捕捞管理体系和废弃渔具管理体系建设, 增强治理能力; (4) 加强国家或地区间渔业合作, 分享管理知识, 促进区域间平衡发展。(5) 加强气候变化应对策略的探索研究。立足长远、多措并举, 促进海洋捕捞可持续发展。     

长江流域渔具渔法概况

<正> 长江流域淡水捕捞在全国占有重要的地位,根据若干具有代表性年份的淡水捕捞量计算,占全国淡水捕捞量的57.08～65.38％。长江流域河川交错,湖泊、水库众多,并有着种类繁多的适合鱼类习性和各种不同水域环境的渔具渔法。一、主要渔具渔法及发展近况 1966年,长江水产研究所等编写的《长江流域渔具渔法渔船调查报告》(以下简称《报告》)介绍了具有代表性的渔具渔法     

农业部全面普查捕捞业渔具渔法

为了全面掌握当前我国捕捞业渔具渔法现状,加强和规范渔具渔法管理,推进捕捞渔具准入制度研究,建立渔具准用目录,日前,农业部办公厅向各省（区、市）渔业主管厅（局）、各海区渔政局以及流域渔业资源管理委员会发出通知,准备在全国范围内开展捕捞业渔具渔法调查工作。     

印度洋西北部海域鸢乌贼腕足断裂强度的试验

为降低鸢乌贼钓捕脱钩率,2004年12月~2005年1月对鸢乌贼的触腕和腕足断裂强度进行了现场测定。结果认为,触腕的平均断裂强度是其体重的1.06倍;第Ⅰ腕足的平均断裂强度是体重的2.55倍,第Ⅱ腕足的平均断裂强度是体重的2.87倍,第Ⅲ和Ⅳ腕足的平均断裂强度是体重的2.88倍。其断裂强度与体重的比值分别比太平洋褶柔鱼和柔鱼低。研究认为,触腕平均断裂强度低是造成高脱钩率的主要原因之一。断裂强度与体重之比值分别与体重和胴长呈直线相关。     

南海鸢乌贼水声学测量和评估相关技术研究

利用双频（38 kHz、120 kHz）Simrad EK60和频率分别为70 kHz和120 kHz的2部Simrad EY60科学探鱼仪于2013年获得的南海鸢乌贼（ Sthenoteuthis oualaniensis）声学调查资料,对鸢乌贼的目标强度（ TS）和空间分布、浮游动物的干扰、频差技术的应用等内容进行了分析。结果表明,以灯光罩网取样对鸢乌贼TS进行现场测量是可行途径;自然条件下鸢乌贼声学映像不明显,光诱条件下鸢乌贼开始聚集,22：00前主要分布于10~50 m和55~80 m水层,22：00后主要分布于10~35 m、50~75 m和115~155 m水层;浮游动物和深海鱼类是鸢乌贼声学探测的重要干扰,尤其是夜间,设置积分阈要考虑不同时间段的影响;频差技术是鸢乌贼声学映像鉴别的重要方法,应深入研究。     

Differences in swimbladder volume between Baltic and Norwegian spring-spawning herring: Consequences for mean target strength

Fish swimbladders, where present, contribute most to the scattering of sound by fish, as measured by the target strength (TS). The volumes of the swimbladders of two different European stocks of Atlantic herring were compared to consider the effect on estimates of TS. Swimbladder volumes of Baltic and Norwegian spring-spawning herring (Clupea harengus) were measured, together with individual herring fat content. Swimbladder volumes were found to differ significantly between the two herring stocks. Baltic herring have a larger swimbladder volume, which is suggested to be associated with the fish's low fat content, which in turn may be linked to its specific energy budget and the low salinity of the Baltic Sea. A buoyancy model that considered the different salinity conditions and fat proportions was used to evaluate the observed differences in swimbladder volume. The swimbladder volume data were subsequently used to model the mean target strength as a function of depth and growth pattern. Backscattering of the swimbladder was modelled using the modal-series-based deformed-cylinder model (MSB-DCM), describing the swimbladder as a gas-filled, elongated prolate spheroid. The fish body component was modelled as a fluid-filled ellipsoid using the distorted wave Born approximation (DWBA). Modelling results support a different TS-to-size relationship for Baltic herring, with a stronger echo, due to the larger swimbladder. Depth- and length-dependent TS relationships based on the model results are suggested.     

深水网箱养殖中的声学监测问题探讨

针对深水网箱养殖过程出现的一些诸如网衣安全、鱼类逃逸等问题,介绍了几种类型的监测技术应用:(1)声学警戒带方式构成的被动式网衣安全监测技术,监视声纳可以是单波束,也可以是机械扫描的多波束或电子扫描的多波束,同时采用水下机器人进行巡视;(2)基于网箱中鱼的目标强度,实现对网箱中养殖品种大小、数量的统计监测,鱼的目标强度主要取决于鱼的体态特征,同时也与发射声波的波长有关;(3)数量识别技术以及饵料投饲过程中的声学监测技术,通过将声纳输出信号反馈到投饵机,实现饵料投放自动化。     

渔业声学数据后处理中积分阈的选择与优化Ⅰ:目标离散分布状态下积分阈的确定

积分阈是渔业声学数据后处理中对回声信号进行积分的临界值,是参与积分的最弱回声信号的体积反向散射强度.通过合理设置积分阈,能在保留目标信号的同时有效地消除噪音和非目标回声信号,从而提高渔业资源声学评估的准确性.为研究目标离散分布状态下选择和优化积分阈的方法,推导了单体目标体积反向散射强度与目标强度之间的函数关系,提出了利...     

Regular, cyclic oscillations in cohort strength in an allopatric population of brown trout. Salmo trutta L.

Abstract– Dominant year-classes of brown trout occurred at regular time-intervals in the alpine Lake Skavatn, Norway. In samples obtained by beach scining, electrofishing and gill-netting during 1989–1992, yearclasses 1979, 1982, 1985, 1988 and 1991 were much more abundant than their neighbouring year-classes. Correspondingly, in a sample of gillnetted fish from 1979, the year-classes 1973 and 1976 were dominant. Spawning areas in the outlet are virtually absent, and lotic rearing areas for juveniles very restricted. Young-of-the-year immigrated to the lake during the autumn, and juveniles inhabited the restricted littoral cobble areas until they reached a length of about 10–12 cm and an age of 3+. Competitive exclusion by dominant year-classes may cause the regular, cyclic oscillations in cohort strength. An abundant year-class of juveniles occupying the restricted suitable lacustrine rearing areas may exclude younger fish by inter-cohort interference. The smaller fish are forced to unsheltered marginal rearing areas where they presumably suffer increased mortality. A new strong year-class can arise every 3 years when the dominant fish leave the rearing areas.     

纤维绳索强度分析中线性回归与曲线拟合法的比较

介绍了对绳索的断裂强度与直径关系的直线回归、幂函数拟合及自然对数拟合的方法,图示比较了三种函数图形及其与标准指标值的偏差,分析了这三种方法所得结果的差别,其中自然对数函数的返回值与标准指标值最为接近。以自然对数函数对聚丙烯、聚乙烯和聚酰胺绳索产品国际标准建立了断裂强度与直径关系的数学模型。采用这种数据分析方法,在制定系列规格的产品标准中确定技术指标,比较具有规律性。     

Assessment of year class strength in freshwater recreational fish populations

A method for determining relative year class strength (YCS) in unexploited freshwater fish populations from individual surveys, based on reconstruction of the mortality schedule of the target population, is described. The method was tested against traditional approaches of assessment of YCS and the limitations and applicability discussed. The method is useful for analysing the factors regulating YCS in freshwater fisheries.     

Changes in purine content of tilapia surimi products during processing

ABSTRACT:   Changes in purine-related compounds of tilapia surimi product during processing were investigated. The washing step could result in about 60% decrease of total purine content in tilapia mince during processing. The main released purine substance was inosine monophosphate. The major reducing effect was conducted in the first 10 min during washing. No significant changes were observed after washing for 20 and 30 min. The lowest total purine content of tilapia surimi product was obtained with repeating the washing step twice. Thus, this procedure could reduce the purine content of tilapia mince from a high purine content level to a middle level. The gel strength of tilapia surimi product increased with increasing washing duration within 30 min. However, tilapia surimi product with a middle purine content and acceptable gel strength might be produced by washing twice in 10 min during processing.     

Does water temperature determine year class strength in New Zealand snapper (Pagrus auratus,Sparidae)?

The abundance of 1+ snapper (Pagrus auratus) was estimated by trawl surveys and was found to vary 17-fold over 7 years. There was a strong positive correlation between year class strength and autumn (April-June) sea surface temperature during the 0+ year, with the latter explaining 94% of the variability in year class strength. The underlying mechanism is unknown, but three hypotheses relating snapper growth and survival to temperature are discussed. The strengths of the 1991 and 1992 year classes are predicted to be below average and extremely weak, respectively.