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首页> 外文期刊>Progress in Oceanography >Geographic and bathymetric trends in abundance, biomass and body size of four grenadier fishes along the Iberian coast in the western Mediterranean
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Geographic and bathymetric trends in abundance, biomass and body size of four grenadier fishes along the Iberian coast in the western Mediterranean

机译：地中海西部伊比利亚沿海地区四只手榴弹鱼的丰度，生物量和体形的地理和测深趋势

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摘要

The present study is a mesoscale analysis of latitude and depth related trends in abundance, biomass and body size of the four grenadier species Caelorinchus caelorhincus, Hymenocephalus italicus, Nezumia aequalis and Trachyrinchus scabrus inhabiting the deep western Mediterranean. We have analysed data from seven annual bottom trawl surveys, carried out down to 800 m depth along the Iberian Mediterranean coast covering a distance of approximately 1200 km. The objectives were to establish general patterns in the mesoscale distribution of abundance, biomass and body size of deep-water grenadier fishes and also analyse the consistency of the bathymetric distribution of these parameters along a large latitudinal gradient. Five complementary series of analyses have been completed. The first focussed on describing the general patterns of abundance and size by correspondence canonical analysis, CCA, in the area. The second and third series focussed on the existence of temporal, geographical and bathymetric trends of abundance, weight and mean size by analysis of covariance, ANCOVA and multiple regression analysis. The fourth series compared the frequency distributions of body length. Finally, the last series focussed on the patterns of abundance versus size. The total number of individuals of all four grenadier species captured in 260 bottom trawls amounted to 27,435 and their weight was 1404 kg. No general trends for the four species have been observed between years. All four species showed a general pattern of increasing size with depth, which, except in the case of C. caelorhincus, was consistent along a large latitudinal gradient. Nezumia aequalis was unique in showing the same noticeable trend of increasing abundance with depth along the entire latitudinal range, but with clear differences in the intercepts. The abundance of N. aequalis and C. caelorhincus decreased significantly northwards. Hymenocephalus italicus was the least abundant species and had a homogeneous distribution without any specific trend along the entire latitudinal range analysed. The distribution of T. scabrus in the Mediterranean seemed to be more localised. Higher abundances were found to the north and south of the latitudinal gradient with lower values between. The grenadiers studied also showed a general trend of decreasing mean size northwards, except in the case of the smallest species, H. italicus. The relation between abundance and body size differed between sectors for the whole grenadier population and species-specific variations were also observed. The relationship between individual body mass and population density fit well to a second-order polynomial function rather than to a linear regression, showing a significant trend for density to increase with increasing size until some mid-point, then to decline with increasing size thereafter. The observed latitudinal gradient in the distribution patterns of grenadiers along the upper slope of the western Mediterranean can be discussed in relation to direct and indirect factors of biogeographic, environmental and anthropogenic origin.
机译：本研究是对居住在地中海西部深部的4个榴弹物种Caelorinchus caelorhincus，Hymenocephalus italicus，Nezumia aequalis和Trachyrinchus ab的纬度和深度相关趋势的丰度，生物量和体大小的中尺度分析。我们已经分析了七个年度底拖网调查的数据，这些调查沿着伊比利亚地中海沿岸深达800 m的深度，覆盖了大约1200 km。目的是建立深水掷弹鱼的中尺度分布，生物量和体型的一般模式，并分析这些参数沿大纬度梯度的测深分布的一致性。已经完成了五个互补的系列分析。第一个重点是通过该地区的对应规范分析CCA描述丰富度和大小的一般模式。第二和第三系列着重于通过协方差分析，ANCOVA分析和多元回归分析得出的时空，地理和测深趋势的丰度，体重和平均尺寸的趋势。第四个系列比较了人体长度的频率分布。最后，最后一个系列着重于丰度与大小的关系。在260条底拖网中捕获的所有四种榴弹兵物种的总数为27,435，其体重为1404千克。几年之间没有观察到这四个物种的总体趋势。这四个物种都显示出随深度增加大小的一般模式，除了在凯氏梭菌中，沿大纬度梯度一致。在整个经纬度范围内，水母Nezumia aequalis表现出相同的显着趋势，即随着深度的增加而增加，但截距却明显不同。马鞭草和caelorhincus的丰度向北显着下降。纤毛虫（Hymenocephalus italicus）是最不丰富的物种，在整个经纬度范围内分布均匀，没有任何特定趋势。地中海sc鳞甲的分布似乎更局限。在纬度梯度的北部和南部发现较高的丰度，而其之间的值较低。研究的手榴弹也显示出平均大小向北减小的总体趋势，除了最小的物种H. italicus以外。整个掷弹兵种群的各个部门之间，丰度与体型之间的关系有所不同，并且还观察到了特定物种的差异。个体体重与人口密度之间的关系很好地拟合了二阶多项式函数，而不是线性回归，显示出密度随大小的增加而增加直到某个中点，然后随大小的增加而下降的明显趋势。可以讨论与地中海地理上坡的手榴弹分布模式中的纬度梯度有关的生物地理学，环境和人为起源的直接和间接因素。

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