遗传算法及其在渔饲料配方中的应用

首先阐述了参数编码、初始群体、适应度函数、遗传操作以及算法控制参数等遗传算法基本原理,然后着重介绍其在渔饲料配方中的应用,在该应用中采用了实数编码、基于线性排名的选择、算术杂交和非一致变异等遗传算法方法。结果表明,在渔饲料配方优化中应用遗传算法要优于目前饲料配方软件中大多采用的常规应用数学的优化方法。主要体现在单位产量饲料配方中的成本价格前者要低于后者。由于遗传算法能够解决因子较多,非线性程度高的问题,从而得出的饲料配方能更好的符合相关鱼种的营养含量标准。     

避风型渔港避风因素浅析

我国的东南沿海是最容易遭受热带气旋影响的脆弱地带,每年的5-11月,都会遭受热带气旋的影响,对渔港、渔船和渔民构成严重威胁.而渔港的避风能力是渔民最为关心的问题,通过近几年登陆我国的强台风等级以上的热带气旋对渔港、渔船及渔民造成损失的实例分析,从防波堤设计标准、避风锚地的底质、锚泊方式等3个方面对避风型渔港的避风因素展开讨论,得到了有价值的结论,为渔港、渔船和渔民减少灾害,为政府建设避风型渔港决策提供科学依据.     

渔船备件费用灰色马尔可夫预测模型与应用

在渔船备件费用灰色预测的基础上，结合马尔可夫链预测方法，建立渔船备件费用灰色马尔可夫预测模型，该模型兼有灰色预测和马尔可夫链预测的优点。实例计算证明，渔船备件费用灰色马尔可夫预测模型的预测精度高于灰色预测模型预测精度，模型可以用于渔船备件费用预测。     

三明各县（市）汛期特涝年气候特征分析

对福建省三明各县（市）1961—2008年汛期（5、6月份）的降水资料进行统计分析，揭示汛期雨量特多、特涝和异常偏涝年份的时间、地域分布特征和周期演变规律；用500hPa月平均高度场资料分析了2005年汛期异常偏涝的环流特征，并就2005年汛期异常偏涝与历史上特涝年的环流形势进行了对比分析。结果表明：5、6月份由于东亚大槽明显偏东，副高面积大、强度强，脊线明显偏南，印缅槽强度偏强，导致西风槽非常活跃，不断东移、南压，这是造成2005年三明各县（市）汛期异常偏涝的主要原因；5、6月份由于逐日副高脊线位置适中、稳定，导致三明各县（市）汛期开始早、结束迟、持续时间长，这是造成2005年汛期异常偏涝的原因之一。     

Management challenges of small-scale fishing communities in a protected reef system of Veracruz, Gulf of Mexico

Abstract  Socioeconomic characterisation of fishing activities in the Veracruz Reef System National Park was used to develop a management system which balances the community's livelihood, and the conservation needs of the protected area. A survey was applied to four sectors of the fishing community: the fishers, fishers' wives, retailers and local population. The survey determined their perceptions about: (1) fishing as a lifestyle; (2) economic alternatives; (3) perspectives about the future; (4) environment; and (5) knowledge of the National Park as a protected area. Fishers devoted an average of 27 years fishing, investing an average of 12 h per day giving a regular income of 15–20 US$. Most interviewed (60%) were full-time fishers, with fishing the only family income source. Fishers are predominately educated to primary school level (64%).The main problem faced by fishers and the communities were economic opportunities but 89% believed that mariculture could be an alternative income source. There was strong ecological awareness, with 75% aware of the decline in fisheries resource and 62% knowing about the role of protected areas. There was divided opinion about future perspectives. Inefficient organisation and communication between authorities and fishers were identified as obstacles to co-management. Discussion on alternative incomes and a proposal involve fishers in co-management initiatives are presented.     

西北太平洋公海秋刀鱼渔场浮游动物数量分布的初步研究

根据2005年7—10月在北太平洋E 150°~158°56′、N 42°34′~46°25′进行秋刀鱼资源探捕所获得的15个站点浮游动物样本资料,测得甲壳纲的桡足类、端足类、糠虾类、磷虾类,毛颚类、腔肠动物以及被囊动物等的代表种。其中桡足类占绝对优势,隶属于1目4科5属8种。浮游动物生物量4~699 mg/m3,均值168.6 mg/m3。根据浮游动物的种类、分布状况及优势种类的强弱,判断和分析黑潮暖流的强弱趋势,对确定秋刀鱼渔场的南北位置具有重要参考价值。     

Changes in trimethylamine oxide and trimethylamine in muscle of wild and farmed cod (Gadus morhua) during iced storage

Trimethylamine oxide (TMAO) is found at high levels in wild Atlantic cod. Trimethylamine oxide is reduced to trimethylamine (TMA) during iced storage. In this study, the levels of TMAO and TMA in wild and farmed cod and the impact of storage, gender and season on these levels were investigated. Wild cod had higher levels of TMAO than farmed cod. Wild cod also had higher levels of TMA after 15 days of iced storage. Farmed cod were found to have levels of TMA‐N <5 mg/100 g after 15 days of iced storage, which is below the maximum permitted level for fresh fish. Therefore, TMA appears to be an unsuitable measure of freshness in farmed cod. Female farmed cod had higher levels of TMAO than male farmed cod; no such difference between genders was found in wild cod. Female and male farmed cod had similar levels of TMA after post‐mortem iced storage. The hepatosomatic index (HSI) of female farmed cod was higher than that seen in male cod and this may be the underlying reason for the differences in muscle TMAO. Levels of TMAO in male farmed cod were higher during the autumn and were correlated with a larger HSI during the same period.     

渔用高强度聚乙烯和普通聚乙烯编织线的拉伸力学性能比较试验

渔用高强度聚乙烯编织线（以下简称HSPE编织线）和普通聚乙烯编织线（以下简称PE编织线）的拉伸力学性能比较试验结果表明，在同等编线工艺（编织线捻距为27mm、线股结构为3×16、线芯用丝数量为7和线芯为不加捻的平行丝束）条件下，规格为“HSPE-37tex×3×16＋7”HSPE编织线断裂强力、单线结强力分别比规格为“PE-37tex×3×16＋7”PE编织线增加了10.0%和9.1%，而前者的断裂伸长率比后者减少了11.3%；在同等编线工艺（编织线捻距为30mm、线股结构为4×16、线芯用丝数量为18和线芯为不加捻的平行丝束）条件下，规格为“HSPE-37tex×4×16＋18”HSPE编织线断裂强力、单线结强力分别比规格为“PE-37tex×4×16＋18”PE编织线增加了8.1%、6.1%，而前者的断裂伸长率比后者减少了13.3%；HSPE编织线较PE编织线具有强力优势，HSPE编织线在渔具或网箱上推广应用具有可行性。     

Nitrate leaching in a silage maize field under different irrigation and nitrogen fertilizer rates

Quantification of the interactive effects of nitrogen (N) and water on nitrate (NO₃) loss provides an important insight for more effective N and water management. The goal of this study was to evaluate the effect of different irrigation and nitrogen fertilizer levels on nitrate-nitrogen (NO₃-N) leaching in a silage maize field. The experiment included four irrigation levels (0.7, 0.85, 1.0, and 1.13 of soil moisture depletion, SMD) and three N fertilization levels (0, 142, and 189 kg N ha⁻¹), with three replications. Ceramic suction cups were used to extract soil solution at 30 and 60 cm soil depths for all 36 experimental plots. Soil NO₃-N content of 0-30 and 30-60-cm layers were evaluated at planting and harvest maturity. Total N uptake (NU) by the crop was also determined. Maximum NO₃-N leaching out of the 60-cm soil layer was 8.43 kg N ha⁻¹, for the 142 kg N ha⁻¹ and over irrigation (1.13 SMD) treatment. The minimum and maximum seasonal average NO₃ concentration at the 60 cm depth was 46 and 138 mg l⁻¹, respectively. Based on our findings, it is possible to control NO₃ leaching out of the root zone during the growing season with a proper combination of irrigation and fertilizer management.