An ecosystem-based assessment of the Korean blue crab trammel net fishery in the Yellow Sea and management implications

Landings in the blue crab, Portunus trituberculatus, fishery in Korean waters of the Yellow Sea have declined substantially from 11,000 t in the 1980s to 2,300 t in 2004. Blue crab habitat quality in the Yellow Sea has been degraded by anthropogenic activities including sand mining, land reclamation, and coastal pollution. Various traditional management measures have been implemented, including closed seasons during spawning and size limits, but these measures alone have been unsuccessful to conserve blue crab stocks. Consequently, a total allowable catch and a stock-rebuilding program using an ecosystem-based management approach were implemented in 2003 and 2006, respectively to rebuild blue crab stocks and restore habitats. This program involved assessment of both blue crab stock status and trammel-net fishery impacts at an ecosystem-level using an ecosystem-based fisheries assessment method ( [Zhang et al., 2009] and [Zhang et al., 2010]), which considered fishery data from catch and effort time-series, crab population biology, and ecosystem characteristics, including habitats and environmental conditions. Recent (2008) management status indices have shown significant positive change compared to conditions in 2000 with respect to sustainability of the stock and fishery and with regards to biodiversity and ecosystem habitat quality.     

捕虾桁拖网网囊网目的选择性研究

当网囊网目分别为４０ｍｍ,４５ｍｍ和５０ｍｍ时,哈氏仿对虾的５０％选择体长分别为８５．８８,９０．２６,９５．３２ｍｍ;中华管鞭虾的３０％选择体长为８７．５８,８８．０９,９２．５６ｍｍ;鹰爪虾的５０％选择丛长为８５．０４,８５．９６％,８８．３２ｍｍ。三种虾类的５０％选择体长和网囊网目内径的线性回归方程为,哈氏仿对虾Ｌ０．５－４８．０３＋０．９４Ｍｅ中华管鞭虾;Ｌ０．５＝６７．０＋０．４９８Ｍｅ     

一品红不同品种叶片叶绿素荧光特性比较

 利用叶绿素荧光技术测定了一品红4个品种‘金多利’、‘圣诞天使’、‘索诺拉飞雪’、‘旗帜’叶片光强依赖的叶绿素荧光特性。结果表明: ‘金多利’初始荧光( F_o ) 、最大荧光( F_m ) 和可变荧光( F_v ) 值极显著高于其它3个品种。在各个光强( PAR, 0～2 171μmol·m^{- 2} ·s^{- 1} ) 下, 表观电子传递速率( rETR) 、实际光化学效率(Yield) 和光化学淬灭( q_P ) 的变化趋势一致, 均为‘金多利’ > ‘圣诞天使’ > ‘索诺拉飞雪’ > ‘旗帜’, 在高PAR下这种差异更明显。拟合参数最大潜在相对电子传递速率( rETR_max ) 、半饱和光强( Ik) 和光抑制参数(β) 也同rETR等具有一致变化。说明‘金多利’有较高的PSⅡ活性, 耐强光; 而‘旗帜’则光化学效率较弱, 高光强下易受光抑制。     

柴油机功率强化前后气缸盖的温度场模拟与试

对功率强化前后的柴油机分别进行了性能仿真计算,进而确定了缸盖温度场计算的边界条件;利用有限元软件对气缸盖进行三维稳态热分析,并考虑了冷却水沸腾换热的影响;在该柴油机的单缸试验机上进行了稳态温度场测量试验,分析了试验和计算结果;得到了火力面边界条件的设置规律、稳态温度场随工况的变化关系和单缸机与多缸机的稳态温度场差别.     

辽西北矿区矸石废弃地造林关键技术研究

矸石是在煤炭生产过程中产生的固体废弃物。我国是煤炭生产和消费的大国,全国每年矸石排放量约1．7亿t,已形成矸石山1500余座,压占大量土地,污染环境。文章在分析辽西北矿区矸石废弃地立地生态特征及研究该地区造林适用原则基础上,对造林关键技术进行研究分析,提出相应栽植技术要点,对该地区矸石废弃地植被恢复、改善生态环境具有实际指导意义。     

孕穗期冷水胁迫对寒地水稻干物质生产的影响

以黑龙江省30份主栽水稻品种或品系为试材,在孕穗期设置17℃冷水灌溉处理(20d),以常规栽培管理为对照,分析冷水胁迫对水稻干物质生产的影响。结果表明,冷水胁迫导致所有试材每穴实粒数、结实率、千粒重和产量下降,并根据相对结实率将试材耐冷性分为1、3、5、7和9级,以7和9级最多,1级最少,分别占总材料的30%和10%。在冷水处理下,全部材料抽穗期至成熟期干物质积累量及比例、群体生长率、净同化率、粒叶比、收获指数、叶面积指数、剑叶叶基角、剑叶和倒2叶与倒3叶披垂度均下降,但高效叶面积率增加。相关分析表明,冷水处理的相对结实率与收获指数(r=0.96**)、产量(r=0.91**)、粒叶比(r=0.84**)和干物质积累量(r=0.48**)的冷水反应指数(CRI)呈极显著正相关,与群体生长率(r=0.44*)、净同化率(r=0.44*)和干物质积累比例(r=0.43*)的CRI显著正相关。综上,孕穗期冷水胁迫对水稻干物质生产的影响在品种间存在很大差异,在冷水胁迫下耐冷性极强品种(系)干物质积累量及比例、群体生长率、净同化率、粒叶比和收获指数对冷水反应迟钝,这是耐冷性极强品种(系)保持较高产量的重要形态特征和生理原因。     

中加燕麦种质的遗传多样性和群体结构分析

为揭示燕麦种质资源的遗传基础,采用内含子切接点引物和长随机引物的PCR分子标记技术,对加拿大和中国的64份燕麦种质的遗传多样性和群体结构进行了分析.结果表明,所用15条引物共扩增出171条带,平均每条引物扩增出11.4条带,其中多态性带共134务,多态性百分比为78.36%.燕麦各种质阃的Dice遗传相似系数分析表明,所有燕麦材料间的遗传相似系数变幅为0.699～0.934,平均值为0.81,表明参试燕麦种质间存在着一定的遗传差异,但遗传差异相对较小.群体结构分析结果表明,所研究的燕麦种质中81.25%的种质血缘相对比较单一,仅18.75%的种质拥有混合来源.     

文蛤染色体核型及三倍体诱导的初步研究

文蛤染色体核型及三倍体诱导的初步研究ＡＰＲＥＬＩＭＩＮＡＲＹＳＴＵＤＹＯＮＴＨＥＫＡＲＹＯＴＹＰＥＡＮＤＴＲＩＰＬＯＩＤＩＮＤＵＣＴＩＯＮＩＮＭＥＲＥＴＲＩＸＭＥＲＥＴＲＩＸ常建波魏利平杨建敏宫向红孙逢贤（山东省海洋水产研究所，烟台２６４０００）Ｃｈ...     

Toxicity of chlorine to different sizes of black tiger shrimp (Penaeus monodon) in low-salinity shrimp pond water

An experiment was conducted, in a dark room with controlled temperature (27.3–28.4 °C), to determine the acute toxicity of chlorine concentration to black tiger shrimp (Penaeus monodon fabicus) of sizes 0.02 g, 2.75 g, 8.47 g and 23.65 g. Toxicity tests on each of these shrimp sizes were run in triplicate in glass jars under static conditions without media renewal. The concentration of active chlorine that killed 50% of the shrimp of each size after 24‐h exposure (LC₅₀‐24 h) was used as an indicator of acute toxicity. Chlorine concentrations applied in the shrimp toxicity test ranged from 2.0 to 14.5 mg L^?1 in shrimp pond water. As the test water contained total suspended solids of 22.0–85.0 mg L^?1 and total ammonia nitrogen of 0.18–0.40 mg L^?1, the resultant concentrations of combined residual chlorine ranged from 0.6 to 3.5 mg L^?1, which were the effective doses causing shrimp mortality. The test results showed that 24‐h LC₅₀ for average shrimp size at 0.02, 2.75, 8.47 and 23.65 g occurred in water containing combined residual chlorine at a concentration of 0.91, 1.39, 1.74 and 1.98 mg L^?1, for which the original application doses were 6.96, 2.05 11.50 and 13.34 mg L^?1 respectively.