Размерная структура нектона Японского моря

• Main Authors: Суханов, В., Иванов, О.
• Format: Text
• Language: unknown
• Published: Федеральное государственное унитарное предприятие «Тихоокеанский научно-исследовательский рыбохозяйственный центр» 2006
• Subjects: Pacific; Theragra chalcogramma
• Online Access: http://cyberleninka.ru/article/n/razmernaya-struktura-nektona-yaponskogo-morya; http://cyberleninka.ru/article_covers/11774036.png

Рассмотрено распределение япономорского нектона по массе тела особей. Обнаружена устойчивая полимодальная структура этого распределения, мало изменчивая во времени и в пространстве. Расстояние между соседними пиками на этом распределении в среднем равно 1,4 в логарифмической шкале. Это означает, что размеры нектеров разных видов концентрируются в окрестности неких "оптимальных" величин. Размеры образуют геометрическую прогрессию такую, что соседние оптимумы отличаются друг от друга по массе тела в 4 раза. Body weight is used as a parameter of size. Weight distribution of nekton species from epipelagic and mesopelagic layers of the northwestern Japan Sea is considered on the base of trawl surveys data. Mean body weight of a species in a trawl catch is calculated as the ratio of total weight of its caught to total number of its specimens. Spatially and temporally stable polymodal structure of the weight distribution is found. Its modes are determined with the method of K-means. They distribute at equal distance on the log-scale body weight axis. Position of the peaks along this axis is well described by arithmetical progression Xi = X1 + D (i 1), where Xi is modal position of the group i, X1 is modal position of the group # 1 (the smallest, located at the left part of the body weight axis X), D is the distance between centers of neighbor groups; the values X1 and D are estimated parameters of the progression. Width of the groups could be described as the standard deviation S of their members weight from the centers of groups. Determination coefficient of this model never falls below 0.995 for any spatial or temporal sampling: for certain parts of the Sea, for certain season, for day/night time, for certain depths, for all species or for all data set. Mean estimations of its parameters are: X1 = 6.83 ± 0.07; D = 1.40 ± 0.05; S = 0.456 ± 0.008; R2 = 0.997. The D = 1.40 means that any neighbor modal weights differ in e1.40 = 4 times. The modes of weight distribution are formed mainly by the common nekton species of the Japan Sea: japanese sardine Sardinops melanostictus, walleye pollock Theragra chalcogramma, pacific herring Clupea pallasii, japanese flying squid Todarodes pacificus, japanese anchovy Engraulis japonicus, etc. The modes # 7 and 8 at the right side of the weight axis are absent in the Japan Sea, and the largest mode # 9 is presented by the sharks Prionace glauca, Lamna ditropis, Isurus oxyrinchus and the headfish Mola mola. Spatial distribution of mean body weight at the Japan Sea water area is not obeyed with Bergmann rule, where large-size specimens inhabit cold-water northern areas whereas small animals live in warm environments in the south. In the northwestern Japan Sea, the large-size fishes concentrate in shelf areas both in the northern and southern its parts.