Relationship between albacore (Thunnus alalunga) fishing grounds in the Indian Ocean and the thermal environment revealed by cloud-free microwave sea surface temperature

Using cloud-free Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) sea surface temperature (SST) and daily set longline fishery data, we studied the relationship between albacore (ALB) fishing grounds and thermal conditions in the southern Indian Ocean. SST and Jensen-Shannon divergence (JSD) maps with a daily spatiotemporal resolution were related to sites with high catches per unit effort (CPUE) (>11 fish/10³ hooks). A high JSD is considered to be an index of a SST front. In winter, high CPUE occurred in the vicinity of the North Subtropical Front (Belkin and Gordon, 1996), where SST was 15-19 °C and JSD was 0.3-0.9. Histograms of the high CPUE plotted against SST and JSD indicated that 95% of the high CPUEs were in the 16-18.5 °C SST range and 97% were in the 0.4-0.9 JSD range. These ranges of SST and JSD are optimum ranges. These cloud-free SST/JSD analyses clearly demonstrate the seasonal north-south movement of the optimum SST and JSD band, which corresponds to the North Subtropical Front in the southern Indian Ocean. Monthly maps of joint probability density (JPD) with the optimum ranges of SST and JSD revealed that high CPUEs are located in the narrow bands with high JPD (>50%).     

利用耳石微结构研究西南大西洋阿根廷滑柔鱼的日龄、生长与种群结构

根据我国鱿钓船2007、2008和2010年在西南大西洋作业期间采集的3 462尾阿根廷滑柔鱼样本(其中2007年308尾、2008年262尾、2010年2 892尾),利用耳石微结构研究了西南大西洋阿根廷滑柔鱼的日龄、生长和种群结构。结果表明,阿根廷滑柔鱼生命周期大约为1年,渔获物主要由冬生群(6—7月)和秋生群(3—5月)组成,不同年份捕捞群体有差异。不同产卵群体、不同性别的阿根廷滑柔鱼胴长和体质量生长均存在显著性差异。冬生群,雌、雄个体胴长的生长方程分别用指数和线性函数来拟合为最适,体质量生长方程则分别用幂函数和指数函数来拟合最适;秋生群,雌、雄个体的胴长生长方程分别用指数和对数函数拟合为最适,体质量生长方程分别用指数和对数函数拟合为最适。随着日龄增加,阿根廷滑柔鱼胴长和体质量相对生长呈现下降趋势,绝对生长率则呈增加趋势,同一日龄段内,雌性个体的胴长与体质量生长率都稍大于雄性个体生长率。     

Controls on early post-fire woody plant colonization in riparian areas

Fire in riparian areas has the potential to influence the functions riparian vegetation provides to streams and aquatic biota. However, there is little information on the effects of fire on riparian areas. The objectives of the present study were to: (i) determine how fire severity interacts with riparian topographic setting, micro-environmental conditions, and pre-fire community composition to control post-fire regeneration; (ii) determine how riparian regeneration patterns and controls change during early succession; and (iii) determine how critical riparian functions are influenced by and recover after fire. Study locations included the Biscuit Fire in southwestern Oregon and the B&B Complex Fire in the Cascade Mountain Range of west-central Oregon, USA. We measured post-fire woody species regeneration, and measured factors such as fire severity, pre-fire species composition, and stream size as potential factors associated with post-fire regeneration patterns. At a relatively coarse spatial scale, patterns in post-fire colonization were influenced by elevation. At finer spatial scales, both conifer- and hardwood-dominated riparian plant communities were self-replacing, suggesting that each community type tends to occur in specific ecological settings. Abundant post-fire regeneration in riparian areas and the self-replacement of hardwood- and conifer-dominated communities indicate high resilience of these disturbance-adapted plant communities.     

印度洋大眼金枪鱼、黄鳍金枪鱼延绳钓渔场重心变化分析

大眼金枪鱼和黄鳍金枪鱼是印度洋金枪鱼延绳钓的主要渔获种类.通过计算以渔获量为权重的经度和纬度的加权平均值即渔场重心和利用空间距离分析方法,分别对1967-1987年、1988-2004年两个时间段的印度洋大眼金枪鱼、黄鳍金枪鱼延绳钓渔场重心的年内、年际变化规律和各月渔场重心空间聚类情况进行研究.研究表明,渔场重心在年内呈现出规律性变化,大眼金枪鱼月重心变化1-4月向西北移动,5-8月向东南方向移动,9-12月向东北方向移动;黄鳍金枪鱼月渔场重心变化1月向西北移动,2-4月向西移动,5-8月份向东南移动,9-12月份向东北移动,这在一定程度上反映了印度洋大眼金枪鱼、黄鳍金枪鱼的洄游规律.渔场重心的年间变化受到了海洋环境条件变化所引起的南方涛动现象(ENSO)的影响,大部分发生El Nio的当年或次年,年渔获量分布重心会向南、向西移;发生La Nia的年份前后渔获量分布重心会向北、向东移.同时捕捞行为也对渔场重心的年间变化产生影响.     

栉孔扇贝成长因子研究

[目的]研究栉孔扇贝成长因子。[方法]对麻子港自然海域的栉孔扇贝养殖场进行水质、浮游植物及地形的研究。[结果]结果表明,在扇贝的1个生长周期内各种条件的变化对扇贝的生长都有影响。其中,浮游植物的密度对其影响作用最关键：密度小时扇贝食物来源少生长缓慢,在一定的密度范围内扇贝快速增长,当达到赤潮的密度时又会导致扇贝的大量死亡。其他条件通过影响浮游植物的密度对扇贝起间接的作用。温度也是影响扇贝成长的重要因素。调查表明,10月水温在18℃左右,此时浮游植物的密度相对较大,是扇贝的黄金生长期,扇贝的壳高和肥度有明显的变化,11月中旬扇贝壳高达8 cm,产量可达17 kg/笼,11月中旬后,温度下降,浮游植物含量也随之下降,扇贝大小基本无变化。此时海水只是暂时的存放地,以供鲜货上市。[结论]为找到一种改善栉孔扇贝养殖的方法提供科学依据。     

东南太平洋智利竹䇲鱼资源渔场时空分布

根据2003—2011年东南太平洋智利竹■鱼生产统计数据,利用灰色关联评价等数理方法对东南太平洋智利竹■鱼资源和渔场的时空分布特征进行分析。结果表明,2003—2011年间东南太平洋智利竹■鱼渔场重心主要分布在80°W～95°W、40°S～45°S范围内,随着月份的增加逐步向西北方向移动,并从8月份渔场开始分为两个区域,其渔场重心逐渐向西北和东北两个方向偏移,到10月份逐渐偏移到最北端。在产量比重上,东南太平洋智利竹■鱼渔场分布具有明显的季节变化:秋季渔场分布纬度处于最南端,变化范围相对集中,主要分布在80°W～95°W、40°S～45°S区域内;冬季渔场纬度逐渐北移,春季渔场处于最北端,且变化范围较大。这种变化与渔场重心的分布相一致。经度上集中分布于79°W～101°W区域,纬度上集中分布于30°S～45°S区域。79°W～101°W和30°S～45°S这一区域作业次数也相对较高。灰色关联度表明,9年间东南太平洋智利竹■鱼的资源状况较好,研究竹■鱼的资源时空分布为其今后的可持续开发与管理提供科学依据。     

Climate change impacts and forest adaptation in the Asia–Pacific region: from regional experts' perspectives

Expert opinions have been used in a variety of fields to identify relevant issues and courses of action. This study surveys experts in forestry and climate change from the Asia–Pacific region to gauge their perspectives on the impacts of climate change and on the challenges faced by forest adaptation in the region, and explores recommendations and initiatives for adapting forests to climate change. There was consensus regarding the impacts of climate change on forest ecosystems and on economic sectors such as agriculture and forestry. Respondents also indicated a lack of public awareness and policy and legislation as challenges to addressing climate change. However, the results indicate differences in opinion between regions on the negative impacts of climate change and in satisfaction with actions taken to address climate change,highlighting the need for locally specific policies and research. The study presents specific recommendations to address issues of most concern, based on subregion and professional affiliation throughout the Asia–Pacific region.The results can be used to improve policy and forest management throughout the region. This research will also provide valuable suggestions on how to apply research findings and management recommendations outside of the AP region. The conclusions should be communicated relative to the level of the research and the target audience,ensuring that scientific findings and management recommendations are effectively communicated to ensure successful implementation of forest adaptation strategies.     

近57年中国北方气候干湿变化及与太平洋年代际振荡的关系

利用中国北方424个气象站点1960—2016年逐日地面观测资料,应用联合国粮农组织(FAO)Penman-Monteith模型计算潜在蒸散(ET0),基于降水量和潜在蒸散计算的湿润指数研究了1960—2016年中国北方干湿气候时空变化特征,分析了太平洋年代际振荡(PDO)对气候干湿变化的影响。结果表明:北方总体干湿变化不显著,空间上表现为西北、青藏高原、内蒙古湿润化而华北干旱化的特征。极端干旱区面积显著缩小,干旱区、半干旱区则明显扩张,表明气候敏感区域在扩张。极端干旱区和干旱区显著变湿润,半干旱区有变湿润的趋势。1960—1990年至1991—2016年,北方经历了变湿润的过程。西北西部、青藏高原湿润化趋势明显,极端干旱—干旱区的界线呈西界东移、南北界线收缩的变化。干旱化趋势主要发生在华北和东北部分地区,华北黄河沿线一带半干旱—半湿润区界线向东南方向扩张。东北中部和西北西部由于降水增加而ET0减少,气候变湿润。华北中西部、内蒙古东部和东北部分地区降水减少、ET0增加,气候变干旱。在PDO暖位相,西北、东北北部及内蒙古东部地区地表气候偏湿润;在PDO冷位相,地表气候偏干旱。而华北则相反。     

西南大西洋拉氏南美南极鱼脂肪酸组成及其食性研究

拉氏南美南极鱼Patagonotothen ramsayi为南极鱼科中数量最多、生态地位非常重要的次南极鱼种,为了解拉氏南美南极鱼的营养动力学与生态功能,利用脂肪酸生物标记法探究了该鱼种的脂肪酸组成及其食性。结果表明:从西南大西洋拉氏南美南极鱼肌肉中共检测出16种脂肪酸,其中含量较高的脂肪酸包括C_(16∶0)、C_(18∶1n9)、C_(20∶5n3)(EPA)和C_(22∶6n3)(DHA),DHA平均含量显著高于EPA(P0.05);多种特征脂肪酸含量与体长存在着显著的相关性,饱和脂肪酸、多不饱和脂肪酸和7种脂肪酸含量与体长之间存在着显著的负相关关系(P0.05),而指示摄食对象营养级高低的DHA/EPA值与体长之间存在着显著的正相关关系(P0.05)。研究表明,拉氏南美南极鱼主要摄食浮游生物和底栖生物,其肉食性特性随体长的增大而增强。