热带印度洋黄鳍金枪鱼渔场时空分布与温跃层的关系

根据Argo浮标剖面温度数据重构热带印度洋各月月平均温跃层特征参数,并结合印度洋金枪鱼委员会(IOTC)黄鳍金枪鱼延绳钓数据,绘制了月平均温跃层特征参数和月平均CPUE的空间叠加图,用于分析热带印度洋黄鳍金枪鱼渔场时空分布和温跃层特征参数的关系。结果表明:热带印度洋温跃层上界深度、温度和下界深度,以及黄鳍金枪鱼中心渔场分布都具有明显的季节性变化特征,黄鳍金枪鱼中心渔场分布和温跃层季节性变化有关。在东北季风期间,高值CPUE渔区的温跃层上界深度的范围为30-40m,超过70m的渔区CPUE值普遍偏低;在西南季风期间温跃层上界最深达到120m。在东北季风期间,高值CPUE渔区温跃层下界深度不超过200m,在西南季风期间,深度会超过300m。在东北季风期间,高值CPUE渔区对应的温跃层上界温度都超过25℃,温度小于24℃的渔区CPUE值普遍较低;在西南季风期间,高值CUPE区域对应的温跃层上界温度范围变大,温跃层上界温度延伸到22℃,在22℃以下渔区CPUE值都很低。采用频次分析和经验累积分布函数计算其最适温跃层特征参数分布,得出黄鳍金枪鱼最适的温跃层上、下界温度范围分别是25-29℃和13-16℃;其上、下界深度范围分别为30-70m和140-200m。K-S检验结果表明,上述结论可靠。     

热带大西洋黄鳍金枪鱼垂直分布空间分析

为了解热带大西洋黄鳍金枪鱼(Thunnus albacares)延绳钓适宜渔获水温的等温线时空分布,分析黄鳍适宜的垂直和水平空间分布范围,采用Argo浮标剖面温度数据重构热带大西洋13℃和距海洋表层水温8℃(Δ8℃)的月平均等温线场,网格化计算了13℃和Δ8℃等温线深度值和温跃层下界深度差,并结合大西洋金枪鱼会委员(International Commission for the Conservation of Atlantic Tunas ICCAT)的黄鳍金枪鱼延绳钓渔业数据,绘制了13℃和Δ8℃等温线深度与月平均CPUE的空间叠加图,用于分析热带大西洋黄鳍金枪鱼中心渔场单位捕捞努力渔获量(Catch per unit effort CPUE)时空分布和次表层环境季节性变化关系。结果表明,13℃等温线,在高值CPUE出现的海域深度值大多小于250 m,主要在170—249 m,深度值超过250 m的海域CPUE普遍较小。5°S—9°N区域,Δ8℃等温线高值CPUE出现的海域深度值大多小于150 m,主要在50—139 m;7—10月份在南半球的非洲西海岸,在Δ8℃等温线深度值为150—350 m的海域也会出现中心渔场。全年在低纬度区域,高渔获率的垂直分布深度更加集中。13℃等温线影响热带大西洋黄鳍金枪鱼的空间分布,温跃层下界温度影响黄鳍金枪鱼的垂直分布。采用频次分析和经验累积分布函数计算其适宜次表层环境因子分布,13℃等温线180—240 m;Δ8℃等温线50—139 m;与下界深度差:13℃等温线-70—29 m;海表以下8℃等温线30—149 m。文章初步得出热带大西洋黄鳍金枪鱼适宜的水平、垂直深度分布区间。结果可以辅助渔情预报,为热带大西洋黄鳍金枪鱼实际生产作业和资源管理提供参考依据。     

中西太平洋大眼金枪鱼中心渔场时空分布与温跃层的关系

采用Argo数据和中西太平洋渔业委员会的大眼金枪鱼延绳钓数据,绘制了温跃层和月平均单位捕捞努力量渔获量(CPUE)的空间叠加图,分析中西太平洋大眼金枪鱼渔场时空分布对温跃层的响应关系.结果表明: 全年中心渔场纬向主要分布在南北纬10°之间的低纬度区域.在赤道以南有季节性中心渔场的出现和消失,与温跃层上界温度、深度和温跃层厚度的积极性变化有关.中心渔场主要分布在温跃层上界较深(70～100 m)和厚度较大(>60 m)的海域,厚度小于40 m的区域难以形成中心渔场;适宜分布的上界温度区间在26～29 ℃,在此区间外CPUE多小于中心渔场阈值(Q3).中心渔场的空间分布随上界深度和跃层厚度的季节性变动而变动,当赤道以南海域的上界深度变浅以及厚度变薄时,中心渔场消失.温跃层下界温度、深度和温跃层强度季节性变化不显著,但与中心渔场出现有显著关系.中心渔场主要分布在温跃层下界深度两条高值带之间的区域,温度低于13 ℃以及强度大的区域;在温跃层下界深度超过300 m和小于150 m区域,下界温度超过17 ℃的区域,或者强度小的区域难以形成中心渔场.利用频次分析和经验累积分布函数计算其适宜温跃层特征参数分布,结果表明研究区域大眼金枪鱼适宜分布的上界温度、深度和下界温度、深度分别是26～29 ℃、70～110 m、11～13 ℃和200～280 m;适宜分布的温跃层厚度和强度分别是50～90 m和0.1～0.16 ℃·m^-1.本研究初步得出研究区域大眼金枪鱼CPUE空间分布和温跃层的关系,为我国远洋金枪鱼捕捞作业和资源管理提供理论参考.     

基于Argo数据的热带大西洋大眼金枪鱼时空分布

为了解热带大西洋延绳钓大眼金枪鱼适宜渔获水温的等温线时空分布,分析大眼金枪鱼适宜的垂直和水平空间分布范围,采用Argo浮标剖面温度数据,运用Kriging方法重构热带大西洋9、12、13和15℃月平均等温线场,网格化计算了12、13℃等温线深度值和温跃层下界深度差,并结合大西洋金枪鱼国际养护委员会(ICCAT)大眼金枪鱼延绳钓渔业数据,绘制了12、13℃等温线深度与月平均单位捕捞努力渔获量(CPUE)的空间叠加图,用于分析大眼金枪鱼中心渔场CPUE时空分布和高渔获率的水温等值线时空分布的关系.结果表明:热带大西洋大眼金枪鱼中心渔场延绳钓高渔获率的水层垂直分布在温跃层下界以下区域,在表层以下150~450 m深度.在水平空间上,12℃等温线高值CPUE出现的深度值大多小于300m,集中分布在190~260 m,深度值超过400 m几乎没有CPUE值.大眼金枪鱼水平空间分布受12℃等温线影响.13℃等温线高值CPUE出现的深度值大多小于250 m,集中分布在150~230 m,深度值超过300 m几乎没有渔获.采用频次分析和经验累积分布函数计算其适宜次表层环境因子分布:12℃等温线190~260 m;13℃等温线160~240 m;12℃深度差-10~100m;13℃深度差-40~60 m.文章初步得出热带大西洋大眼金枪鱼中心渔场适宜的水平、垂直深度值分布区间,结果可以辅助寻找中心渔场位置,同时指导投钩深度,为大西洋大眼金枪鱼实际生产作业和资源管理提供理论支持.     

基于栖息地指数的东太平洋黄鳍金枪鱼渔场预报

黄鳍金枪鱼是东太平洋海域重要的金枪鱼种类之一,也是我国金枪鱼延绳钓的主要捕捞对象之一。根据2011年东太平洋海域(20°N—35°S、85°W—155°W)延绳钓生产统计数据,结合表温(SST)和海面高度(SSH)的遥感数据,采用频次分析法获得黄鳍金枪鱼分布的SST和SSH适宜范围;运用一元非线性回归方法,以渔获量为适应性指数,按季度分别建立了基于SST和SSH的长鳍金枪鱼栖息地适应性指数,采用算术平均法获得基于SST和SSH环境因子的栖息地指数综合模型,并用2012年各月实际作业渔场进行验证。结果显示,黄鳍金枪鱼渔场多分布在SST为24—29℃、SSH为0.3—0.7 m的海域。采用一元非线性回归建立的各因子适应性指数模型在统计上均为显著(P0.05)。经与2012年实际生产情况比较,作业渔场预报准确性达66%以上。研究获得栖息地指数模型可为金枪鱼延绳钓渔船寻找中心渔场提供参考。     

南太平洋长鳍金枪鱼渔场CPUE时空分布及其与关键海洋环境因子的关系

根据2009—2012年南太平洋长鳍金枪鱼(Thunnus alalunga)延绳钓生产统计数据及遥感获取的海表温度(sea surface temperature,SST)、叶绿素a浓度(chlorophyll a concentration,Chl-a)和海面高度距平(sea surface height anomaly,SSHA)等环境数据,分析了长鳍金枪鱼单位捕捞努力量渔获量(catch per unit of fishing effort,CPUE)的时空分布及其与环境因子的相关性。结果表明:长鳍金枪鱼作业渔场主要集中在4°S—28°S、158°E—176°E附近海域;长鳍金枪鱼渔场CPUE呈明显的季节性变化,1—3月CPUE值较低(12.5尾·千钩-1),随后逐渐增加,至7月达到最大值为18.1尾·千钩-1,而8—12月基本呈逐渐降低趋势;1月渔场重心位于16°S、168°E附近海域,2—3月向西北偏移,而在3—7月逐渐向东南方向转移,8月以后开始逐渐回撤至西北方向,在9—12月渔场重心变化幅度相对较小,主要位于15°S—16°S、168°E—169°E海域;总体来说,长鳍金枪鱼中心渔场最适SST为27.0~30.5℃,次适SST为20~24℃;最适叶绿素a浓度为0.02~0.08mg·m-3,最适海面高度距平为3~23 cm。     

东南太平洋金枪鱼延绳钓主要渔获种类垂直分布

研究延绳钓渔获物的垂直分布特征,可以帮助人们制定有效措施减少兼捕鱼种的渔获率,更好地了解大洋生态系统结构,并为基于生态系统的渔业管理提供参考.本研究根据2013年9月-2014年1月我国金枪鱼科学观察员在东南太平洋采集的延绳钓钩位深度数据和主要渔获种类的钓获钩位数据,分析了各钩位的上浮率和钓获鱼种的垂直分布,比较了不同鱼种垂直分布的差异.结果表明: 钓钩相对上浮率变化范围为8.9%～17.1%,平均相对上浮率为13.5%;14种渔获物钓获深度范围差异较大,斑点月鱼的平均钓获深度最深,鲣鱼最浅;除黄鳍金枪鱼和条纹四鳍旗鱼外,其他兼捕鱼种钓获深度均与长鳍金枪鱼(目标鱼种)具有显著性差异.
     

中东太平洋金枪鱼延绳钓中心渔场的时空变化

根据2009年6月—2012年1月上海金优远洋渔业有限公司在中东太平洋作业的5艘金枪鱼延绳钓渔船的渔捞日志资料,结合卫星遥感反演的海表温度数据,分析了中东太平洋金枪鱼延绳钓渔场的年际和季节变化规律以及渔获量与海表温度的关系。结果表明:在厄尔尼诺年(2009年),金枪鱼延绳钓渔场作业重心会向偏东方向移动,且金枪鱼钓获率较高;而拉尼娜年(2010、2011年)则向偏西方向移动,且钓获率下降;研究海域作业渔场的最适宜海表温度范围为25~30℃;2009年最适海表温度略高于2010年和2011年;平均月渔获量与月平均海表温度呈显著正相关(P0.05)。     

中东大西洋中部海域中上层鱼类中心渔场的时空变化

根据2012年1—8月和2014年12月—2015年7月中国大型拖网渔船在中东大西洋中部海域佛得角海岸(FAO34渔区3.11小区)的渔捞日志资料以及遥感获取的海洋环境数据,利用产量重心法、地统计插值、数理统计、广义加性模型(generalized additive models,GAM)等方法 ,对该海域中上层鱼类平均单位捕捞努力渔获量(CPUE)的月变化、中心渔场的时空变动及其与海表温度(SST)、叶绿素a浓度、经度、纬度的关系进行了分析。结果表明:该海域各月平均CPUE基本呈先减少、后增加的趋势;中心渔场的分布具有明显的月变化,基本呈先由北往南推移,且在3—4月份到达最南端,后由南往北推移趋势;不同月份渔场中心叶绿素a浓度为0~10 mg·m-3,且渔场中心叶绿素a浓度以7~9 mg·m~(-3)居多;不同月份渔场中心的SST为17.3~27.6℃,且渔场中心的SST以19~21℃居多。GAM模型分析表明,渔场的最适SST为20~22℃,最适叶绿素a浓度为4.480~7.388 mg·m~(-3),经度集中在16°40'W附近,纬度集中在19°N附近。海洋环境与CPUE的回归方程显著性检验表明,除了SST呈不显著外,叶绿素a浓度和空间因子与CPUE的回归关系均极显著(P0.01),影响渔场的因子按重要性从大到小依次为经度、纬度、叶绿素a浓度和SST。分析认为,洋流产生并导致的涌升流的位置变化对佛得角海岸FAO34渔区3.11小区中心渔场的时空变化具有重要影响。     

基于GAM模型的阿拉伯海鲐鱼渔场分布与环境关系

基于2016-2017年中国印度洋围拖网生产数据以及同期的海表温度、叶绿素、表层海流和海面高度数据,采用广义加性模型(Generalized Additive Model,GAM)建立了围网单位捕捞努力量渔获量(catch per unit effort,CPUE)对海洋环境的非线性响应模型,分析了阿拉伯海鲐鱼(Scomber australasicus)渔场分布与海洋环境关系.结果表明:空间因子和环境因子对阿拉伯海鲐鱼渔场有显著影响,GAM模型的方差解释率为30.1%;印度洋季风对鲐鱼CPUE影响大,鲐鱼CPUE在印度洋东北季风高,在夏季季风低;全年阿拉伯海鲐鱼围网渔场主要分布在60°E、13°N-15°N斜向椭圆区域;模型表明,鲐鱼渔场适宜海表温度为26~28℃,叶绿素浓度0.2~0.5 mg·m^-3,海面高度0.2~ 0.4 m;影响鲐鱼渔场的因子按重要性依次为海面高度、经纬度、海表温度和叶绿素浓度.     

Multilocus phylogenetic analysis of the genus Aeromonas

A broad multilocus phylogenetic analysis (MLPA) of the representative diversity of a genus offers the opportunity to incorporate concatenated inter-species phylogenies into bacterial systematics. Recent analyses based on single housekeeping genes have provided coherent phylogenies of Aeromonas. However, to date, a multi-gene phylogenetic analysis has never been tackled. In the present study, the intra- and inter-species phylogenetic relationships of 115 strains representing all Aeromonas species described to date were investigated by MLPA. The study included the independent analysis of seven single gene fragments (gyrB, rpoD, recA, dnaJ, gyrA, dnaX, and atpD), and the tree resulting from the concatenated 4705 bp sequence. The phylogenies obtained were consistent with each other, and clustering agreed with the Aeromonas taxonomy recognized to date. The highest clustering robustness was found for the concatenated tree (i.e. all Aeromonas species split into 100% bootstrap clusters). Both possible chronometric distortions and poor resolution encountered when using single-gene analysis were buffered in the concatenated MLPA tree. However, reliable phylogenetic species delineation required an MLPA including several “bona fide” strains representing all described species.     

pha-2 encodes the C. elegans ortholog of the homeodomain protein HEX and is required for the formation of the pharyngeal isthmus

The pha-2 mutant was isolated in 1993 by Leon Avery in a screen for worms with visible defects in pharyngeal feeding behavior. In pha-2 mutant worms, the pharyngeal isthmus is abnormally thick and short and, in contrast to wild-type worms, harbors several cell nuclei. We show here that pha-2 encodes a homeodomain protein and is homologous to the vertebrate homeobox gene, Hex (also known as Prh). Consistent with a function in pharyngeal development, the pha-2 gene is expressed in the pharyngeal primordium of Caenorhabditis elegans embryos, particularly in pm5 cells that form the bulk of the isthmus. We show that in the pha-2 mutant there is a failure of the pm5 cells to elongate anteriorly while keeping their nuclei within the nascent posterior bulb to form the isthmus during the 3-fold embryonic stage. We also present evidence that pha-2 regulates itself positively in pm5 cells, that it is a downstream target of the forkhead gene pha-4, and that it may also act in the isthmus as an inhibitor of the ceh-22 gene, an Nkx2.5 homolog. Finally, we have begun characterizing the regulation of the pha-2 gene and find that intronic sequences are essential for the complete pha-2 expression profile. The present report is the first to examine the expression and function of an invertebrate Hex homolog, that is, the C. elegans pha-2 gene.     

Fate map of the distal portion of Drosophila proboscis as inferred from the expression and mutations of basic patterning genes

The late-third-instar labial disc is comprised of two disc-proper cell layers, one representing mainly the ventral half of the anterior compartment (L-layer) and the other, the dorsal half of the anterior compartment and most, if not all, of the posterior compartment (M-layer). In the L-layer, Distal-less represses homothorax whereas no Distal-less-dependent homothorax repression occurs in the M-layer where Distal-less is coexpressed with homothorax. In wild-type labial discs, clawless, one of the two homeobox genes expressed in distal cells receiving maximum (Decapentaplegic+Wingless) signaling activity in leg and antennal discs, is specifically repressed by proboscipedia. A fate map, inferred from data on basic patterning gene expression in larval and pupal stages and mutant phenotypes, indicates the inner surface of the labial palpus, which includes the pseudotracheal region, to be a derivative of the distal portion of the M-layer expressing wingless, patched, Distal-less and homothorax. The outer surface of the labial palpus with more than 30 taste bristles derives from an L-layer area consisting of dorsal portions of the anterior and posterior compartments, each expressing Distal-less. Our analysis also indicates that, in adults and pupae, the anterior-posterior boundary, dividing roughly equally the outer surface of the distiproboscis, runs along the outer circumference of the inner surface of distiproboscis.     

Differential Delta expression underlies the diversity of sensory organ patterns among the legs of the Drosophila adult

Many studies have shown that morphological diversity among homologous animal structures is generated by the homeotic (Hox) genes. However, the mechanisms through which Hox genes specify particular morphological features are not fully understood. We have addressed this issue by investigating how diverse sensory organ patterns are formed among the legs of the Drosophila melanogaster adult. The Drosophila adult has one pair of legs on each of its three thoracic segments (the T1-T3 segments). Although homologous, legs from different segments have distinct morphological features. Our focus is on the formation of diverse patterns of small mechanosensory bristles or microchaetae (mCs) among the legs. On T2 legs, the mCs are organized into a series of longitudinal rows (L-rows) precisely positioned along the leg circumference. The L-rows are observed on all three pairs of legs, but additional and novel pattern elements are found on T1 and T3 legs. For example, at specific positions on T1 and T3 legs, some mCs are organized into transverse rows (T-rows). Our studies indicate that the T-rows on T1 and T3 legs are established as a result of Hox gene modulation of the pathway for patterning the L-row mC bristles. Our findings suggest that the Hox genes, Sex combs reduced (Scr) and Ultrabithorax (Ubx), establish differential expression of the proneural gene achaete (ac) by modifying expression of the ac prepattern regulator, Delta (Dl), in T1 and T3 legs, respectively. This study identifies Dl as a potential link between Hox genes and the sensory organ patterning hierarchy, providing insight into the connection between Hox gene function and the formation of specific morphological features.     

Spatial and temporal regulation of the homeotic selector gene Antennapedia is required for the establishment of leg identity in Drosophila

Antennapedia is one of the homeotic selector genes required for specification of segment identity in Drosophila. Dominant mutations that ectopically express Antennapedia cause transformation of antenna to leg. Loss-of-function mutations cause partial transformation of leg to antenna. Here we examine the role of Antennapedia in the establishment of leg identity in light of recent advances in our understanding of antennal development. In Antennapedia mutant clones in the leg disc, Homothorax and Distal-less are coexpressed and act via spineless to transform proximal femur to antenna. Antennapedia is negatively regulated during leg development by Distal-less, spineless, and dachshund and this reduced Antennapedia expression is needed for the proper development of distal leg elements. These findings suggest that the temporal and spatial regulation of the homeotic selector gene Antennapedia in the leg disc is necessary for normal leg development in Drosophila.     

Description of Idiomarina insulisalsae sp. nov., isolated from the soil of a sea salt evaporation pond,proposal to transfer the species of the genus Pseudidiomarina to the genus Idiomarina and emended description of the genus Idiomarina

A halophilic, aerobic Gram-negative bacterium, designated strain CVS-6^T, was isolated from a sea salt evaporation pond on the Island of Sal in the Cape Verde Archipelago. Phylogenetic analysis of the 16S rRNA gene sequence revealed a clear affiliation of the organism with members of the family Idiomarinaceae. Sequence similarities between CVS-6^T and the type strains of the species of the genera Pseudidiomarina and Idiomarina ranged from 93.7% to 96.9%. The major isoprenoid quinone was ubiquinone 8 (Q-8). The major cellular fatty acids were 15:0 iso (21.8%), 17:0 iso (12.5%), 17:1 iso ω9c (10.7%), and 16:1 ω7c (10.6%). The DNA G+C content was 51.6 mol%. The species represented by strain CVS-6^T could be distinguished from the species of the genera Pseudidiomarina and Idiomarina; however, it was not possible to distinguish both genera from each other using the phenotypic or chemotaxonomic characteristics examined. Consequently, we propose that the species classified in the genus Pseudidiomarina should be transferred to the genus Idiomarina. We also propose that, on the basis of physiological and biochemical characteristics, strain CVS-6^T (=LMG 23123=CIP 108836) represents a new species which we name Idiomarina insulisalsae.