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Artículo científico: postprint
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Billfish movements relative to the International Commission for the Conservation of Atlantic Tunas management areas, as well as U.S. domestic data collection areas within the western North Atlantic basin, were investigated with mark-recapture data from 769 blue marlin, Makaira nigricans, 961 white marlin, Tetrapturus albidus, and 1,801 sailfish, Istiophorus platypterus. Linear displacement between release and recapture locations ranged from zero (all species) to 15,744 km (mean 575, median 119, SE 44) for blue marlin, 6,523 km (mean 719, median 216, SE 33) for white marlin, and 3,845 km (mean 294, median 98, SE 13) for sailfish. In total, 2,824 (80.0%) billfish were recaptured in the same management area of release. Days at liberty ranged from zero (all species) to 4,591 (mean 619, median 409, SE 24) for blue marlin, 5,488 (mean 692, median 448, SE 22) for white marlin, and 6,568 (mean 404, median 320, SE 11) for sailfish. The proportions (per species) of visits were highest in the Caribbean area for blue marlin and white marlin, and the Florida East Coast area for sailfish. Blue marlin and sailfish were nearly identical when comparing the percent of individuals vs. the number of areas visited. Overall, white marlin visited more areas than either blue marlin or sailfish. Seasonality was evident for all species, with overall results generally reflecting the efforts of the catch and release recreational fishing sector, particularly in the western North Atlantic. This information may be practical in reducing the uncertainties in billfish stock assessments and may offer valuable insight into management consideration of time-area closure regulations to reduce bycatch mortality of Atlantic billfishes.
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The temporal variation of components of a moderately diverse (H=1.46) tropical estuarine fish assemblage (long. 146°30'E, lat. 8°45'S) was directed by salinities that had been determined by local oceanographic and probably topographic conditions. For this assemblage, two types of intrayear component profiles are predicted. Pooled data (1988-91) reveal a large component of regular/resident species (43%) in an assemblage which has been under a narrow temperature regime «5T). These results facilitate a discussion on the relevance and usefulness of three hypotheses often cited in studies concerning species diversity and component characteristics of the subtropical/tropical coastal nonreef fish assemblages. Manifestations of the assemblage are reflected in catch composition and weights of 39 trials conducted for a selective prawning gear whose performance in bycatch reduction, mainly for finfishes, is judged by an index, E, we have previously proposed. This gear is capable of harvesting the prawn while conserving the demersal fish. Behavioral responses to netting of the prawns and the finfishes, especially the nearshore surface schoolers such as leiognathids, are discussed from several points of view. An adaptation in terms of group selection for leiognathids of their locking mechanism of median fin spines has been interpreted. For the purpose of bycatch reduction or E enhancement, suggestions for improvements in net design and trawl configuration by considering the behavioral features of fish are made. Our original formula of E is modified for general use. Bycatch problems in the regional prawn fisheries and their possible impacts on fishery planning and development in Papua New Guinea as a developing country are discussed. The gear tested may offer enormous ecological and economic benefits. The gear is multipurpose, extremely simple, and can also be used as a biological sampler.
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星果草属至今仍包括两个种,它在毛茛科中的系统位置存在争议。本文针对该属的物种划分以及它在毛茛科中的系统位置所存在的问题,在云南东北和四川西南交界处,选择了5个居群(包括典型的近全缘型、裂叶型以及它们的中间类型),研究了16个形态性状的变异式样和规律;在扫描电镜下观察了它们的花粉形态,在光镜下统计了4个居群的花粉萌发孔类型;对这5个居群12个酶系统进行了等位酶分析,获得了19个位点的资料;对星果草属及相关的3个属进行了胚胎学研究,获得了星果草属较完整的胚胎学资料 和相关属的部分胚胎学特征。综合上述研究结果和前人的研究资料,对星果草属的形态变异、居群分化、种类划分和它的系统位置进行了分析和讨论,结果如下: l.形态上出现了中间类型是该属存在物种划分问题的主要原因。作者通过形态性状的分析发现,以前作为该属现存两个种的鉴别性状(叶形、叶片大小、植株高矮和叶柄被毛与否)为不稳定的性状,在居群内或居群间呈现连续变异,不能作为分种的鉴别性状;我们考察了根、花部器官的性状以后也未发现它们存在明显间断的性状。 2.居群水平的孢粉学研究表明,三种萌发孔类型(散孔型、散沟型以及它们的中间类型)出现在同一居群内,说明该性状在星果草属的种类划分中具有有限的系统学意义。值得提出的是萌发孔类型在不同居群中出现的频率不同,这种频率与叶形是相关的:叶片裂得越深,散孔类型的花粉所占的比例越大;反之,叶片裂得越浅,散沟类型的花粉所占的比例越大。 3.通过对这5个居群的细胞学研究,作者发现它们均为二倍体(2n=16),染色体从大到小逐渐过渡,不具有二型性,为R-型染色体;绥江与马边居群(均为典型的裂叶型)的核型资料表明它们的第一对染色体短臂上具有随体。该结果不同于杨亲二等对裂叶型的核型报道。为了探讨星果草属的进化机制还有必要对它的细胞学做进一步研究。 4.等位酶资料表明居群间的基因分化系数达到53.4%,说明居群间遗传分化程度较高。星果草属植物以营养繁殖为主,种子传播主要以重力所介导,又是高山或亚高山分布的植物,这些因素都不利于居群间的基因交流,致使居群间发生很强的遗传分化;居群间的遗传一致度值变化范围为0. 723--0. 912,其中峨眉居群(大多为典型的近全缘型)与绥江居群(典型的裂叶型)的遗传一致度值(0. 845),仅稍低于马边居群与绥江居群的遗传一致度值(0.912);聚类结果表明这5个居群分为两支,峨眉居群与天全居群聚为一支;其余三个居群聚为另一支,这与与形态分化相吻合。 5.该属胚胎学不少特征与毛莨科其它属相似:花药壁发育为双子叶型,腺质绒毡层,胞质分裂为同时型,成熟花粉为二细胞:双珠被,珠孔仅由内珠被形成,蓼型胚囊,胚胎发生属柳叶菜型。但是假厚珠心与双珠被的特殊组合,有别于毛莨科其它类群。我们还首次报道了鸡爪草属、黄连属和人字果属的部分胚胎学特征。 基于以上形态学、孢粉学、细胞学和等位酶的分析结果,作者认为将星果草属处理为单种属,种下分为两个亚种较为合适。并认为星果草属为金莲花亚科中的自然类群,并与金莲花亚科中金莲花族关系较近,给予族的等级较为合适。