基于分类回归树算法的东南太平洋智利竹筴鱼渔场预报

为了提高智利竹筴鱼渔场预报水平和满足渔业捕捞生产的需要,利用2002—2008年的东南太平洋公海海域捕捞的中国大型拖网渔船共计15艘的生产统计资料,以及海洋环境数据(包括海表温度、叶绿素a浓度、表温距平、叶绿素a浓度距平、海表温度梯度强度和海面高度异常等数据),基于CART的算法,构建了智利竹筴鱼渔场决策树预报模型。用含1 114条记录的数据集对模型进行训练,并采用ROC方法对该模型诊断中心渔场的准确性进行了分析。最后将该模型应用于2009年各月份的智利竹筴鱼中心渔场预报,并与实际渔场位置进行了对比,结果显示预报渔场与实际生产位置基本一致,表明利用CART决策树方法建立智利竹筴鱼渔场预报模型是可行的。     

基于主成分和BP神经网络的智利竹筴鱼渔场预报模型研究

东南太平洋智利竹筴鱼Trachurus murphyi是我国大型拖网渔船队的重要捕捞对象。准确预报中心渔场是提高渔业生产能力的重要工作。本文根据2003—2009年我国船队在东南太平洋海域捕捞智利竹筴鱼的渔捞日志数据,结合海洋遥感获得的海表温度(SST)和海面高度(SSH)等海洋环境因子,利用主成分和BP神经网络方法对智利竹筴鱼中心渔场预报模型进行了研究。研究利用主成分分析法(PCA)得到累计贡献率在90%以上样本的主成分,综合考虑模型测试的精度与速度,基于原始样本和经PCA处理后的主成分分别建立了BP模型,其最优BP模型结构分别为5∶10∶1和3∶7∶1。研究结果表明,经PCA处理后的主成分所建立的BP神经网络模型在训练结果和测试结果上均要优于用原始样本建立的BP神经网络模型,两者的预报准确率分别为67%和60%。     

东南太平洋智利竹筴鱼生物学特征与个体繁殖力研究

鱼类生物学特征研究包括叉长、体重分布,胃含物种类及出现频率,性腺发育状程度方面。根据2012年3-9月以及2014年4-8月在东南太平洋采集的1 055尾智利竹筴鱼样本,选取性腺成熟度Ⅲ期以上的智利竹筴鱼雌性样本,对个体繁殖力及其与生物学指标的关系进行了研究。结果显示,样本叉长范围为182~581 mm,体重范围为62.2~1 494 g,绝对繁殖力在42 211~305 305粒,平均繁殖力为145 482粒;个体叉长相对繁殖力在142~686粒/mm平均值为371粒/mm;个体体重相对繁殖力在133~349粒/g平均值为211粒/g。绝对繁殖力与叉长、体重、纯体重及性腺重等生物学指标显著性正相关,8月份的摄食强度较高,可能与性腺的发育和繁殖有关。     

智利外海竹筴鱼中心渔场时空变动的初步研究

根据2005年3～12月14艘中国渔船在智利外海的竹筴鱼生产统计数据和卫星遥感反演的海表温度、叶绿素浓度,分析智利外海竹筴鱼中心渔场的时空变动以及渔场与环境因子的关系.结果表明,随着南半球秋季转入冬季,竹筴鱼中心渔场相应地由南向北、由东向西推移,10月份渔场达到最北端,春末夏初开始南撤;智利外海竹筴鱼渔场的表层水温大致为12～16℃,中心渔场为14～15℃,月间略有差异;渔场的叶绿素质量浓度大致为0.06～0.12 mg/m~3,当渔场的叶绿素质量浓度处于0.08～0.10 mg/m~3时,渔船作业频次和竹筴鱼产量最高.     

基于环境因子的东南太平洋茎柔鱼资源补充量预报模型研究

东南太平洋茎柔鱼(Dosidicus gigas)是短生命周期种类,其资源量极易受到海洋环境变化的影响。根据2003—2012年我国鱿钓船在东南太平洋的生产统计数据,以及茎柔鱼栖息地的海表温度(SST)、海面高度(SSH)、叶绿素a浓度(chl a)数据,利用相关性分析法分析茎柔鱼资源丰度和补充量(以单位捕捞努力量渔获量为指标,t/d)与栖息海域20°S—20°N、110°W—70°W的SST、SSH、chl a浓度的相关性,获取相关系数大的关键海区位置,同时加入茎柔鱼产卵场、索饵场最适表层水温范围占总面积的比例(分别用PS、PF表示)两个参数,建立三种基于主要环境因子的误差反向传播(EBP)神经网络资源补充量预报模型,进行了比较。结果表明:茎柔鱼资源丰度与SST、SSH、chl a浓度的相关系数最大值海域为7月份的Point1(13°N,102°W)海区、9月份的Point3(11°N,102°W)海区和3月份的Point5(8°S,107°W)海区;资源补充量与SST、SSH、chl a浓度的相关系数最大值海域为6月份的Point2(8°N,103.5°W)海区、2月份的Point4(12°N,97.5°W)海区和10月份的Point6(10°S,93.5°W)海区。EBP神经网络预报模型结果认为:基于产卵环境关键影响因子的方案2(以Point2的SST、Point4的SSH、Point6的chl a浓度、PS作为模型输入因子)和基于全部环境关键影响因子的方案3(以Point1与Point2的SST、Point3与Point4的SSH、Point5与Point6的chl a浓度、PS、PF作为模型输入因子)的两种神经网络预报模型均方误差较小,其准确率可达90%左右。     

基于个体的东海鲐鱼补充量年际变动模拟研究

东海鲐鱼（Scomber japonicus）是我国近海重要经济鱼种,年际资源量波动较大,物理环境对其资源量的丰歉影响很大。本文运用基于个体的东海鲐鱼生长初期生态模型,模拟1978-2013年东海鲐鱼资源补充量。模拟发现,物理环境的变化确实能导致东海鲐鱼资源补充量的年际差异,并且在90年代后出现了较大的波动,资源补充量最多的2002年（1.8×109尾）与最少的1996年（6.5×108尾）相差1.15×109尾。产卵后的15~30 d,即4月份鱼卵仔鱼所处的海洋物理环境对东海鲐鱼最终的资源补充量起到重要作用,4月底鱼卵仔鱼的存活量基本上决定了东海鲐鱼最终的资源补充量的多寡。4月份的水温是影响鲐鱼资源补充量的物理因素之一,4月份水温高有利于提高鲐鱼的资源补充量,相反,水温偏低不利于鲐鱼的资源补充量。4月份的台湾暖流的流速也是影响鲐鱼资源补充量的另外一个物理因素,4月份台湾暖流的势力强对东海鲐鱼最终资源补充量是有利的,相反,流速小对补充量较不利。4月份台湾暖流的水温、流速决定最终东海鲐鱼资源补充量。     

海洋环境因子对澳洲鲐亲体补充量关系的影响——基于贝叶斯模型平均法的研究

澳洲鲐（Scomber australasicus）是西北太平洋重要的中上层经济鱼类,生命周期相对较短,资源量受补充量影响明显,了解澳洲鲐太平洋群系补充量状况对掌握其资源量及确保其可持续利用具有重要的意义。本文利用产卵场1（30°~32°N,130°~132°E）海表面温度（sea surface temperature,SST1）、产卵场2（34°~35°N,138°~141°E）海表面温度（SST2）、索饵场（35°~45°N,140°~160°E）海表面温度（SST3）、潮位差（tidal range,TR）、太平洋年代际涛动（Pacific decadal oscillation,PDO）和亲体量（spawning stock biomass,SSB）6个影响因子任意组合与补充量构建多个模型,运用贝叶斯模型平均法（Bayesian model averaging,BMA）分析各个环境因子对资源补充量的解释能力,并预测其补充量的变化。结果表明,SSB对补充量具有最长期且稳定的解释能力,其次是SST3,PDO、TR、SST2、SST1也对补充量模型具有一定的解释能力。SST3是环境因子中影响最大的因子,可能是由于补充群体在索饵场内生活时间较长,索饵场温度对仔鱼或鱼卵的生长存活有较大的影响。研究认为,基于BMA的组合预报综合考虑了各个模型的优势,优于单一模型,可用于澳洲鲐资源补充量的预测。     

东海鲐鱼(Scomber japonicus)仔幼鱼游泳行为对输运和补充量的影响

采用物理环境因子,确定鲐鱼仔幼鱼运动和物理环境之间的响应关系,建立起了基于个体具有游泳行为的鲐鱼早期生长史模型。结果表明,具有游泳行为仔幼鱼前期对输运分布的影响不大,后期随着游泳能力的增强,逐渐在温盐梯度较大锋面,靠近暖水的一侧进行集群和滞留,并使向东北输运速度降低,输运到太平洋和日本海的幼鱼数量下降,所处水深降低,适应生长发育,死亡率降低。产卵场位置的变动使偏西产卵的集群受台湾暖流影响较大,导致集群偏西,主要聚集在偏北的台湾暖流水和长江冲淡水交汇区高温、高盐一侧。偏东产卵受黑潮影响较大,集群偏东,不形成大量聚集和滞留;在生存率方面正常产卵位置是最佳产卵位置。研究认为,物理环境和生物因素同样会对具有游泳行为仔幼鱼的输运和补充产生影响。     

西北太平洋环境变化对柔鱼冬春生群体资源丰度的影响

During 1995–2011, annual production of winter-spring cohort of Ommastrephes bartramii for Chinese squidjigging fishery has greatly fluctuated, which is closely related to the environmental conditions on the spawning and fishing grounds. To better understand how squid recruitment and abundance were influenced by ocean environmental conditions, biological and physical environmental variables including sea surface temperature(SST), SST anomaly(SSTA), chlorophyll a(Chl a) concentration and the Kuroshio Current were examined during years with the highest(1999), intermediate(2005), and lowest(2009) catches. Catch per unit effort(CPUE) of the squid-jigging vessels was used as an indicator of squid abundance. The results indicated that high SST and Chl a concentration on the spawning ground in 1999 resulted in favorable incubation and feeding conditions for squid recruitment. Whereas the suitable spawning zone(SSZ) in 2009 shifted southward and coincided with low SST and Chl a concentration, resulting in a reduction in the squid recruitment. The small difference of SSZ area in the three years suggested the SSZ provided limited influences on the variability in squid recruitment. Furthermore,high squid abundance in 1999 and 2005 was associated with warm SSTA on the fishing ground. While the cool SSTA on the fishing ground in 2009 contributed to adverse habitat for the squid, leading to extremely low abundance. It was inferred that strengthened intensity of the Kuroshio force generally yielded favorable environmental conditions for O. bartramii. Future research are suggested to focus on the fundamental research on the early life stage of O. bartramii and mechanism of how the ocean-climate variability affects the squid abundance and spatial distribution by coupling physical model with squid biological process to explore transport path and abundance distribution.     

不同环境模态下空间分辨率对北太平洋柔鱼CPUE标准化的影响

单位捕捞努力量渔获量(catch per unit effort,CPUE)常被假设与渔业资源量成正比而被应用于渔业资源评估与管理中,不同的环境模态下,所选取的空间分辨率对CPUE的标准化会产生影响,从而影响对该渔业资源丰度的评价.本研究运用广义加性模型(generalized additive model,GAM),...     

Impact of climate and hydrology on juvenile fish recruitment towards estuarine nursery grounds in the context of climate change

Larvae of various coastal fish undergo immigration from spawning grounds towards estuarine nurseries. Several environmental factors can have an important impact on survival at this stage making it crucial for recruitment. Generalized linear models were applied in order to investigate the relation between river drainage, sea surface temperature (SST), NAO index and the North-South wind component intensity, over the two months prior to the estuarine colonization peak, and the densities of Platichthys flesus, Dicentrarchus labrax, Diplodus vulgaris and Diplodus bellottii in the nursery grounds based on a discontinuous historical dataset (from 1978 to 2006), for the Tagus estuary. The relation between SST over the 12 months prior to the estuarine colonization peak and fish densities in the nurseries was also investigated, as it integrates the periods of spawning stock maturation, spawning and larval immigration. While SST over the prior 12 months was negatively correlated with the abundance of P. flesus, it was positively correlated with the abundance of D. bellottii. Abundance of D. vulgaris was positively correlated with SST in the two months prior to the estuarine colonization peak, while the abundance of D. labrax was positively correlated with river drainage. The relations between SST and the abundance of P. flesus, a cold-water species with declining densities, and the subtropical species D. bellottii and D. vulgaris, which are increasing in abundance, are indicative of species abundance alterations related to climate warming. Dicentrarchus labrax will probably also be affected by climate change because of lowered precipitation and consequently river drainage.     

Climatic regimes and the recruitment rate of anchoveta, Engraulis ringens, off Peru

The recruitment rate of Peruvian anchoveta, Engraulis ringens, was studied to test the hypothesis that long-term environmental variation (regime shifts) had a significant impact on density-dependent processes governing the anchovy recruitment during the period 1963–2004. On the basis of previous defined regimes and turning points for the Humboldt Current System, we identified two groups of years for increased recruitment of anchoveta (1963–1971 and 1986–2004), and one unfavorable period (1972–1985). A common intercept and significantly different slopes were found when the recruitment rate was plotted as a function of the spawning stock biomass during those groups of years, suggesting that density-dependent effects on recruitment were affected during different climate regimes. The favorable (unfavorable) regime was characterized by higher (lower) zooplankton volumes, and with a higher frequency of colder (warmer) waters. Dome-shaped relationships between recruitment rate, spawning stock biomass and SST, were detected with a Generalized Additive Model for the favorable regime. Thus, recruitment could be explained by non-linear effects of environmental variables. Ultimately, climatic regimes are affecting the density-dependent effects on recruitment of anchoveta and the mechanisms involved may be associated with changes in the carrying capacity of the spawning habitat of anchoveta off Peru, which in turn are related with the effects of cold and warm regimes.     

西太平洋叶绿素a浓度对气候变化响应概念模型初探

西太平洋海区浮游植物的分布受气候变化影响,在不同时空尺度上呈现不同的变化。本研究旨在通过对历史文献及数据资料分析,建立气候变化响应概念模型来探讨Chl-a、海水表面温度(SST)及营养盐如何响应长期气候变化。分析了西太平洋不同区域Chl-a与气候变化相关因子SST及海水营养盐(硝酸盐)的相关性,对模型参数进行选择及验证,来探讨该海区Chl-a是如何响应长期气候变化。结果表明,K2站位Chl-a浓度与SST、硝酸盐浓度呈显著正相关关系,与该海区存在上升流有关;而S1、XT站位均呈现负相关关系,可能与海水水温升高导致层化加剧、营养输入减少有关。本研究为进一步完善和优化西太平洋海区的浮游植物的气候变化响应模型奠定基础。     

Influence of environmental data of different sources on marine species habitat modeling: A case study for Ommastrephes bartramii in the Northwest Pacific Ocean

The quality of environmental data and its possible impact on the marine species habitat modelling are often overlooked while the sources for these data are increasing. This study selected sea surface temperature(SST) from two commonly used sources, the NOAA Ocean Watch and IRI/LDEO Climate Data Library, and then constructed habitat suitability index model to evaluate the influences of SST from the two sources on the outcomes of Ommastrephes bartramii habitat models for the months of July–October...     

Projections of ocean climate for northwestern Pacific Ocean

The long-term adjustment processes of atmosphere and ocean in response to gradually increased atmospheric CO2 concentration have been analyzed in 70 and 140a integrations with NCAR fully-coupled climate system model (CSM). In these experiments the CO2 concentration has been increased to double and quadruples the initial concentration, respectively. After 70a, at the time of CO2 doubling, the model predicts surface air temperature rises by 1.2 and 1.5K for the globe and the northwestern Pacific Ocean, respectively. The behavior of the quadrupling run is similar: each global and regional mean surface air temperatures increase by 2.8 and 3.0K at the time of CO2 quadrupling. From the experiments, surface air temperature changes in the northwestern Pacific Ocean will be more distinctive compared with the global average, mainly due to exceptionally large warming and sea level change near the entrance of the Kuroshio extension.     

利用渔场环境因子标准化西北太平洋柔鱼CPUE的研究

本文利用1998-2016年西北太平洋柔鱼渔业数据及其渔场（35°~45°N,140°~165°E）的海洋遥感环境数据,包括海表温度、海面高度异常和叶绿素浓度,采用基于渔场环境的方法标准化西北太平洋柔鱼单位捕捞努力量渔获量（catch per unit effort,CPUE）。结果表明:柔鱼高频次作业的海表温度范围为10.2~22.2℃（96.05%）,海面高度异常范围为-15.9~28.2 cm（97.91%）,叶绿素浓度范围为0.0~1.0 mg/m3（96.69%）。名义CPUE和基于环境因子的标准化CPUE年际变化趋势基本一致。但由于柔鱼作业方式高度集中,有效捕捞努力量远低于名义捕捞努力量,以及考虑环境因子影响效应,名义CPUE均低于标准化CPUE。在深入理解鱿钓渔业和其生物学特性的基础上,基于渔场环境因子准化后的CPUE更具代表性,建议在以后的柔鱼资源评估与管理中使用基于渔场环境因子的标准化CPUE。     

Variability in scale growth rates of chum salmon (Oncorhynchus keta) in relation to climate changes in the late 1980s

Fish scales were used to investigate the interannual variability in chum salmon growth rates at specific ages in relation to climatic/environmental changes during the 1980s–1990s. Scales were obtained from adult salmon returning to the east coast of Korea between 1984 and 1998. Assuming proportionality between scale size increments and fish length, distances between scale annuli were regarded as the growth conditions in different habitat areas with respect to the life stages of chum salmon. In estuarine and coastal areas, growth rates of fingerling salmon were higher in the 1990s than in the 1980s. Zooplankton abundance off the east coast of Korea increased after the late 1980s, which may have provided favorable growth conditions for young salmon in the 1990s. Growth of juvenile chum salmon during the first summer (Okhotsk Sea) was relatively stable, and neither SST nor zooplankton biomass fluctuated significantly during the study period. However, in the Bering Sea, salmon growth rates between age-2 and age-4 (i.e. ocean-phase immature salmon) were higher in the 1980s than in the 1990s. Variability in salmon growth in the Bering Sea was correlated to zooplankton biomass. These results suggest that the climate regime shift of 1988/1989 in the subarctic North Pacific affected salmon growth mediated by changes of zooplankton biomass, revealing a bottom-up process.