东海中北部海区头足类资源量的评估   总被引：12，自引：0，他引：12       下载免费PDF全文

丁天明 《水产学报》2001,25(3):215-221

根据1994年6月至1996年6月二年整6艘单拖调查船的调查资料，采用资源密度法，评估了26°00＇-31°00＇N、120°30＇-127°30＇E约40-200m水深范围87个渔区头足类及其主要种类的资源量，阐明了头足类及主要种类资源密度的季节变化和时空分布，提出可捕量，为今后利用和管理提供科学的理论依据。  相似文献   

黄海南部与东海的隆剑水蚤(桡足类：剑水蚤目)生态分布     

李丁成  徐兆礼  高露姣  陈亚瞿 《中国水产科学》2003,10(6):481-484

利用1981年2、5、8和11月4个航次的海洋调查资料,对黄海南部及东海(28°00′～34°00′N、121°00′～127°00′E)水域中、小型浮游桡足类隆剑水蚤科(Oncaeidea)的种类组成和分布特征进行了初步分析。研究结果表明,调查水域共出现隆剑水蚤9种,其中等刺隆剑水蚤(Oncaeamediterranea)、背突隆剑水蚤(Oncaeaclevei)和角突隆剑水蚤(On caeaconifera)为主要优势种。夏季丰度最高(60.38ind·m-3),秋季次之(15.16ind·m-3),冬季最低(2.34ind·m-3)。通过对同步温度和盐度资料分析后发现,隆剑水蚤主要分布在受台湾暖流和黑潮暖流影响的高温、高盐区域,其中等次隆剑水蚤可作为暖流的指示种。  相似文献   

东海北部与黄海南部黄鲫群体洄游分布的初步研究     

刘勇  程家骅  陈学刚 《海洋水产研究》2006,27(3):1-6

根据2000年春(4月)、夏(6月)、秋(9月)、冬(12月)四季东海底拖网鱼类资源调查资料,从中选出关于黄鲫的数据,分析了其资源密度的四季空间分布变化,发现在所调查的区域中黄鲫资源可以分成两个群体:一个分布在东海北部水域,另一个分布在东海南部水域。本文主要对分布在北部的这一群体进行了四季空间分布变化的研究,不同大小的黄鲫在各个季节的分布区域有较大的变化,表现出明显的产卵、索饵、越冬等洄游活动行为,并根据研究结果描绘出黄鲫的产卵育卵场、索饵场、越冬场的大致分布位置。  相似文献   

东海区主要经济鱼类开捕规格的初步研究   总被引：13，自引：1，他引：13       下载免费PDF全文

林龙山  程家骅  凌建忠  张寒野 《中国水产科学》2006,13(2):250-256

根据1997-2000年东海区底拖网渔、№资源调查资料，以Beverton—Holt模型的单位补充量渔获最方程估算东海区18种主要经济鱼类的最适开捕年龄。运用von Bertalanffy，丰长方程估算最适开捕体长。结合鱼类生长的拐点年龄、临界年龄和初届性成熟年龄的体长，以及各鱼种实测最小性成熟体长，确定开捕规格。结果表明，目前东海区产量较高的带鱼（Trichiurus japonicus）和小黄鱼（Larimichthys polyactis）的建议开捕规格分别应为体长230mm和170mm。调整后的开捕规格与旧开捕规格相比，带鱼、短尾大眼鲷（Priacanthus macracanthus）、灰鲳（Pampus cinereus）、自姑鱼（Argyrosomus argentatus）均有所增大，小黄鱼、银鲳（Pampus argenteus）的开捕规格有所减小，变化较小的有蓝点马鲛（Scomberomorus niphonius）、日本鲭（Somber japonicus）、慌圆鲹（Decapterus maruadsi）等。建议以这18种主要经济鱼类为指标种类，制定新的法定开捕体长和幼鱼比例检查措施，实现东海区渔业资源的可持续利用。  相似文献   

东海区头足类群聚空间分布特征的初步研究   总被引：4，自引：2，他引：4  

李圣法  严利平  李惠玉  李建生  程家骅 《中国水产科学》2006,13(6):936-944

根据2000年东海区(27°00′~34°00′N、127°00′E以西海域)150 m等深线以浅4个季节的底拖网监测调查资料,运用聚类分析和非度量多维标度(NMDS)的方法分析东海区头足类群聚的空间分布特征,并且探讨各个群聚类型的指示种类以及头足类群聚分布与环境的关系。头足类主要种类为剑尖枪乌贼(Loligo edulis)、太平洋褶柔鱼(Todarodes paci-ficus)、金乌贼(Sepia esculenta)等。多元分析结果显示,各季节头足类群聚类型不同。根据各群聚类型分布的海域大致可以将其划分为黄海南部-东海外海-东海中南部群聚、长江口外海域群聚和东海北部海域群聚3种群聚类型。它们的空间分布区域随着季节的不同而发生变化,群聚类型的分布区域也会相互交错。各季节不同群聚类型的种类组成不同,多数种类一般同时出现于不同的类群中,有的种类在所有群聚类型中都有分布。它们的空间分布也是交错的,只是相对集中的区域有所不同,在不同群聚类型中的渔获率和出现频率不同。头足类各群聚类型种类组成的季节差异较明显,各群聚类型中相对稳定的主要特征种类较少。调查海域中影响头足类种类空间分布特征的主要环境因子为水温,而水深等环境因素的影响并不明显  相似文献   

2004年夏季黄、东海表面水温状态分析   总被引：3，自引：4，他引：3  

沈建华  周甦芳  董玉来  崔雪森 《海洋渔业》2005,27(1):80-84

对 2 0 0 4年夏季黄、东海表面水温进行了分析。结果表明 :黄、东海 2 0 0 4年夏季表面温度表现为沿岸区域偏高、暖流势力一般的特点 ,并显示出前中期偏高较甚 ,后期趋缓的特征。在沿岸的大部分区域 7、8月的平均表面水温都超过了历史同期新高 ,意味着 2 0 0 4年夏季至少就沿岸海域而言是一个非同寻常的夏季。  相似文献   

Long-term changes in zooplankton and its relationship with squid, Todarodes pacificus, catch in Japan/East Sea     

Young S. Kang  Jin Y. Kim  Hak G. Kim  Jong H. Park 《Fisheries Oceanography》2002,11(6):337-346

Long‐term change in zooplankton biomass and composition of major zooplankton assemblages was studied with a focus on climate change and squid catch in the Japan/East Sea. This study deals with data sets of zooplankton biomass, abundance of major zooplankton assemblages, and sea surface temperature (SST) obtained during the period from 1965 to 1998, and the catch of squid, Todarodes pacificus, from 1978 to 1998. Based on its physical characteristics, the study area was divided into two subregions, a northern and southern region. The SST during the winter and spring (February and April) steadily increased after the late 1980s in the southern region. On the other hand, the northern region did not have a warm winter and had higher interannual fluctuations. Zooplankton biomass also showed an increasing trend and major zooplankton assemblages have shifted in their composition since the early 1990s. The northern region exhibited a greater increasing trend than the southern region in zooplankton biomass. Macrozooplankton such as chaethognaths, euphausiids and amphipods gradually increased after the early 1990s. In the Japan/East Sea, squid catches increased continuously after the early 1990s. The squid catch for the autumn of year n is significantly associated with the zooplankton biomass collected in October and December of year n ? 1 (r=0.864 in the northern region and r=0.818 in the southern region, P < 0.001) and macrozooplankton, especially euphausiids (r=0.578 in the northern region and r=0.840 in the southern region, P < 0.05) and amphipods (r=0.695 in the northern region and r=0.648 in the southern region, P < 0.05).  相似文献   

Enclosure culture ban and its effects on water quality and phytoplankton community in a subtropical shallow lake     

Jing Nan  Changtao Yang  Huaiyong Yu  Xinyi Shi  Qinghui Huang  Jin Huang  Jianhua Li 《Aquaculture Research》2022,53(1):221-231

Enclosure culture, ubiquitous anthropogenic activity in shallow lakes, was prohibited in East Taihu Lake with all breeding infrastructure demolished at the end of 2018. However, the ecological responses of water quality change and phytoplankton community succession to the enclosure culture ban remain largely unknown. In this study, we conducted field investigations monthly in East Taihu Lake to present a comprehensive study of water quality and phytoplankton community variation before (2018) and after (2019) the enclosure culture ban. With the cessation of aquaculture activities, water quality significantly improved, TN and TP decreased by 54% and 34%, respectively, and eutrophic state shifted from light eutrophic (mean TSI = 59) to mesotrophic status (mean TSI = 48) in autumn. Chl-a decreased from 33.34 ± 16.87 to 24.84 ± 15.43 μg/L, and SDD increased from 0.76 ± 0.19 to 0.95 ± 0.36 m. Meanwhile, phytoplankton abundance significantly decreased from 3.6 × 10⁷ to 1.6 × 10⁷ cell/L, with the contribution of Cyanophyta markedly decreasing from 82% to 63%. In addition, the heterogeneity of phytoplankton community markedly increased. The changes in water quality and phytoplankton following the enclosure culture ban were largely due to the suspension of external nutrient input from breeding activity and improved water clarity. Redundancy analysis (RDA) analysis further elucidated that water temperature and nutrients were the main factors affecting phytoplankton dynamics. Our findings showed that the ban on enclosure culture had an extremely positive ecological impact.  相似文献   

Tree regeneration and future stand development after bark beetle infestation and harvesting in Colorado lodgepole pine stands   总被引：1，自引：0，他引：1  

Byron J. CollinsCharles C. Rhoades  Robert M. HubbardMichael A. Battaglia 《Forest Ecology and Management》2011,261(11):2168-2175

In the southern Rocky Mountains, current mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreaks and associated harvesting have set millions of hectares of lodgepole pine (Pinus contorta var. latifolia Engelm. ex Wats.) forest onto new stand development trajectories. Information about immediate, post-disturbance tree regeneration will provide insight on dynamics of future stand composition and structure. We compared tree regeneration in eight paired harvested and untreated lodgepole pine stands in the Fraser Experimental Forest that experienced more than 70% overstory mortality due to beetles. New seedlings colonized both harvested and untreated stands in the first years after the beetle outbreak. In harvested areas the density of new seedlings, predominantly lodgepole pine and aspen, was four times higher than in untreated stands. Annual height growth of pine and fir advance regeneration (e.g., trees established prior to the onset of the outbreak) has doubled following overstory mortality in untreated stands. Growth simulations based on our regeneration data suggest that stand basal area and stem density will return to pre-beetle levels in untreated and harvested stands within 80-105 years. Furthermore, lodgepole pine will remain the dominant species in harvested stands over the next century, but subalpine fir will become the most abundant species in untreated areas. Owing to terrain, economic and administrative limitations, active management will treat a small fraction (<15%) of the forests killed by pine beetle. Our findings suggest that the long-term consequences of the outbreak will be most dramatic in untreated forests where the shift in tree species composition will influence timber and water production, wildfire behavior, wildlife habitat and other forest attributes.  相似文献   

西藏色季拉山川滇高山栎种群结构与动态   总被引：2，自引：2，他引：0       下载免费PDF全文

王国严  罗建  徐阿生  庄颖梅 《林业科学研究》2011,24(3):292-299

采用种群大小级结构、生命表、生命曲线和秩相关分析对西藏色季拉山川滇高山栎种群的结构与数量动态以及种群高度—环境关系的研究得出:川滇高山栎种群总体呈增长型,不同地段种群的年龄分布差异较大(P<0.001),种群表现出林隙更新和阶段性更新的特征,迹地型种群以大量同龄或近同龄林出现,幼苗缺失,呈现出偏途顶极的特征,存在被其他树种替代的可能。川滇高山栎存活曲线介于DeevyⅡ与DeevyⅢ型之间,整个生命过程出现4次死亡高峰,以幼苗进入幼树时期最为强烈(死亡率77.3%),高死亡率会带来高的生命期望值,种内资源竞争是影响个体寿命和造成种群波动的主要原因。环境因子对川滇高山栎种群高度的影响程度排序为:土壤湿度>年降水量>坡位>坡向>坡度>海拔,土壤湿度和年降水量是影响川滇高山栎种群高度分化的显著因子,另外种群对海拔的适应幅度较宽,对坡度响应不强,水分格局是影响个体增长和种群发展的重要因素。  相似文献