基于BP神经网络模型的福建海域赤潮预报方法研究

赤潮往往给渔业生产和人类的生命安全造成极大的危害,但由于赤潮的成因十分复杂,对其进行预报非常困难。本研究收集了福建海区2000年至2016年发生的219个赤潮案例有效数据,应用BP神经网络人工智能模型建立了其与气温、降水、风速、气压和日照5个气象因子的非线性关系,并将这些赤潮案例数据与相应的气象指标按闽东、闽中和闽南3个海区,分别输入模型进行学习、训练与预测。结果显示:1)闽东海区53个训练样本45个预测正确,正确率达84.91%,3个模拟预测样本全部正确;2)闽中海区69个训练样本58个预测正确,正确率达84.06%,4个模拟预测样本全部正确;3)闽南海区85个训练样本的运算预测结果63个正确,正确率74.12%,5个模拟预测样本全部正确,达到预期的结果。研究表明,以气象因子为自变量采用BP神经网络模型对赤潮的发生进行预测是可行的,该方法可为赤潮的预测提供新的途径。     

中国的稻米消费及其对亚洲国家经济的影响——基于投入产出分析法

在分析我国稻米消费特性及消费变动的基础上,采用投入产出分析模型,利用亚洲国际投入产出表的数据,定量分析了中国稻米消费需求对国内及亚洲其他国家产生的经济影响.消费特征分析结果表明,我国的稻米消费具有地域差异性及品种多样性,并且近年来稻米的消费需求出现较快下降趋势.投入产出分析结果表明,中国稻米消费需求的变动,对中国农业、中国非农产业附加价值的影响较大,对亚洲水稻、亚洲农业、亚洲非农产业附加价值的影响较小.在对亚洲其他国家(或地区)产业附加价值的影响中,以对亚洲非农产业的影响为最大.此外,对于中国水稻产业的附加价值,中国农业对其影响最大,亚洲水稻产业对其影响最小.     

大连海域刺参原产地大型底栖动物群落结构调查及修复策略

2014年6月,按照海洋资源调查规范,调查北黄海大连沿岸的刺参Apostichopus japonicas原产区中的旅顺口区塔河湾附近海域和大连金州新区城山头海滨地貌保护区海域内大型底栖动物的种类、密度、生物量,计算优势种、生物多样性和群落物种相似性,探讨其修复策略。结果表明,两处海域刺参生境大型底栖动物群落结构基本相同,优势种组成相似,优势类群均为软体动物;物种组成因饵料条件及周边海域底质不同呈现差异性分化;两处海域内海星类与刺参的密度比分别约为1∶3和1∶1,海星类与刺参的生物量比值与密度比相同;海星类与海胆类密度比均约为1∶1和3∶1,海星类与刺参及海胆类密度和的比分别为1∶4和1∶1,海胆类与刺参密度比均约为1∶2。根据调查结果认为刺参生境和增养殖区的养护、修复策略为:(1)多种共养,以参为主;(2)控制海星,适度增殖海胆;(3)提高初级生产力,降低污染。     

Are circle hooks effective in reducing incidental captures of loggerhead sea turtles in a Mediterranean longline fishery?

• 1. A known fishing hot spot for loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea is in the waters of the Strait of Sicily where interactions with fish hooks and branchlines are believed to be a major cause of mortality for sea turtles.
• 2. Hooks with different shapes but a similar gape width (circle hook size 16/0 vs J hook size 2) were tested in order to determine the potential effectiveness of the hook design to both reduce sea turtle capture as well as to maintain acceptable levels of target species capture rates in a shallow‐set longline swordfish fishery in the Mediterranean.
• 3. Seven experimental fishing trips, 30 000 hooks total, were conducted on a single commercial fishing vessel (18 m in length) in the Strait of Sicily during the months of July through October over a period of three years from 2005 to 2007. Circle and J hooks were alternated along the mainline.
• 4. A total of 26 sea turtles were hooked, all immature‐size Caretta caretta. Turtles were caught at a statistically greater frequency on J hooks than on circle hooks. The capture rate, weight, and upper jaw fork length of the target species were not significantly different between the two types of hooks employed.
• 5. Five sea turtles swallowed the hook and in all such cases these were J type. Circle hooks tended to be located externally and were more easily detected by fishermen, and could be removed with the correct dehooking action before returning the turtle to the sea.
• 6. These findings suggest that 16/0 circle hooks can effectively reduce the incidental capture of immature loggerhead sea turtles in a Mediterranean swordfish longline fishery without affecting the catch size of the target species.

Copyright © 2009 John Wiley & Sons, Ltd.     

Grow-out of juvenile seahorse Hippocampus kuda (Bleeker; Teleostei: Syngnathidae) in illuminated sea cages

This paper examines the feasibility of rearing 10–15-day- and 0.7–1.5-month-old seahorse Hippocampus kuda in illuminated sea cages to continue existing hatchery protocols to mass produce H. kuda for trade and enhance depleted wild stocks in their natural habitats. Thawed Acetes (a planktonic crustacean abundant in inshore seas) was fed to juvenile seahorses in lighted and unlighted sea cages while one group in lighted cages was not fed Acetes . After 10–12 weeks of rearing, both mean body weight and stretch height increased in all treatment groups, with lighted cage-reared seahorses fed Acetes being heavier (2 g) and longer (8 cm) than the other two treatment groups. Although instantaneous growth rates declined during the rearing period, these were generally higher among Acetes -fed seahorses in lighted cages (0.02–0.07) compared with those in the unlighted cages with Acetes and lighted cages without Acetes feeding. Mean survivorship in all groups ranged from 9% to 74% after the trials, but mean survivorship of juveniles in lighted cages with Acetes feeding (9–74%) was consistently lower than the two treatment groups as a likely result of crustacean and piscine predators being attracted by light and the odour of leftover Acetes in the lighted cages. These results demonstrate that light-attracted zooplankton prey supplemented by Acetes feeding may provide essential nutrients for the growth of H. kuda juveniles in illuminated sea cages. With further improvement in the grow-out protocol, it may provide a possible alternative livelihood to seahorse fishers and sufficient seed to re-populate depleted wild stocks of H. kuda .     

Habitat selection of freshwater‐dependent cetaceans and the potential effects of declining freshwater flows and sea‐level rise in waterways of the Sundarbans mangrove forest,Bangladesh

• 1. Generalized additive models of sighting data for cetaceans collected during two surveys of waterways in the Sundarbans mangrove forest of Bangladesh indicated that Ganges River dolphin Platanista gangetica gangetica distribution was conditionally dependent (P<0.05) on low salinity, high turbidity, and moderate depth during both low and high freshwater flow; and Irrawaddy dolphin Orcaella brevirostris distribution was conditionally dependent (P<0.05) on low salinity during high freshwater flow, high and moderate depths during low and high freshwater flow, respectively; low and high‐low extremes of turbidity during low and high freshwater flow, respectively; and high temperature and increasing numbers of large–small channel confluences during low freshwater flow.
• 2. According to sighting data collected over a 3‐year period by the captains of three nature tourism vessels, there were significant differences between the actual and expected frequencies of Ganges River dolphin sightings and individuals according to various channel types (chi‐square=64.22, P<0.0001 and chi‐square=134.14, P<0.0001, respectively, df=6) and of Irrawaddy dolphin sightings and individuals (chi‐square=15.28, P=0.0182, and chi‐square=29.42, P<0.0001, respectively, df=6), with shared preferences for wide sinuous channels with at least two small confluences or one large confluence.
• 3. The dependency exhibited by both species for environmental characteristics associated with abundant freshwater flow, including low salinity and the availability of confluences, make them particularly vulnerable to habitat loss due to upstream water abstraction and sea‐level rise.
• 4. Although the results of this study may not affect plans for construction in India of large‐scale, inter‐basin water transfer projects that will result in further declines in freshwater flows, or decisions within the international community about CO₂ emissions affecting global sea levels, they can be used to prioritize locations where protective measures could be employed to benefit the long‐term conservation of both species.

Copyright © 2008 John Wiley & Sons, Ltd.     

Comparative fatty acid composition of eggs from wild and captive black sea bass, Centropristis striata L.

Lipid content, lipid class and fatty acid compositions were determined in eggs from wild and captive black sea bass, Centropristis striata L., from northern (New England) and southern (South Carolina) regions to determine the effects of diet on egg composition and fertilization success. The formulated diets fed to the northern captive (NC) fish were higher in total lipids (22%) compared with the cut fish and squid diet fed to the southern fish (SC; 3.3% lipid) and had a higher relative amount of linoleic acid (LA) and lower relative amounts of docosahexaenoic acid (DHA) and arachidonic acid (AA). These dietary differences were broadly reflected in the egg lipid composition. The LA levels were higher in all lipid classes in eggs of NC fish while AA levels were lower. The DHA was higher in the major polar lipids (PL) (phosphatidylcholine and phosphatidylethanolamine) of SC eggs compared with NC. Compared with wild fish, both captive groups produced eggs with PLs richer in LA and lower in DHA and AA. Over all fish groups, fertilization success was directly correlated with levels of DHA and AA in the PLs and was inversely correlated with LA levels.     

The effects of temperature on sex differentiation and growth of black sea bass (Centropristis striata L.)

To examine the effects of temperature on sex differentiation in the black sea bass ( Centropristis striata L.), a protogynous hermaphrodite, juveniles (∼0.5 g) were cultured in recirculating systems at 17, 21 or 25 °C. Growth was assessed at 155, 182, 241 and 275 days post hatch and sex differentiation was determined histologically. No differences were found in the sex ratios of fish reared at different temperatures, but only 55–64% developed as females. Growth was significantly greater in males across all temperature treatments. These results suggest that black sea bass exhibit sexually dimorphic growth patterns and that female-specific sex determination can be disrupted in culture.     

国家间海洋资源共同开发博弈策略分析——以韩中两国为例

文章利用博弈模型分析了国家间海洋资源共同开发联盟的建立及维持问题。指出影响联盟建立的因素：两国合作开发的投资回报率、投入和利益分配比率及两国的利益相关系数;影响联盟稳定的因素：背叛动机方的惩罚金额、隐藏背叛行为的成本、反惩罚成本等。并用实证分析了韩中海洋生物资源、海洋能资源、海洋化学资源、海洋矿产资源、海洋新资源等共同开发现状及其具备的共同开发条件分析。提出了政府政策扶持、转变企业观念,发挥行业协会作用的应对策略。     

凝胶浓度对SSCP技术的影响

SSCP技术易受凝胶浓度、丙烯酰胺与甲叉双丙烯酰胺的比例和添加物等诸多因素的影响。本研究探讨了凝胶中丙烯酰胺与甲叉双丙烯酰胺的比例、凝胶浓度和添加物等对海胆SSCP技术的影响。结果显示:凝胶中丙烯酰胺与甲叉双丙烯酰胺的比例为29∶1、凝胶浓度为10%、凝胶中甘油为最佳的凝胶组成,单链DNA条带清晰,杂带少,容易观察。