Размерная структура нектона Охотского моря

• Main Authors: Суханов, В., Иванов, О.
• Format: Text
• Language: unknown
• Published: Федеральное государственное унитарное предприятие «Тихоокеанский научно-исследовательский рыбохозяйственный центр» 2007
• Subjects: Okhotsk; okhotsk sea
• Online Access: http://cyberleninka.ru/article/n/razmernaya-struktura-nektona-ohotskogo-morya; http://cyberleninka.ru/article_covers/740793.png

Работа посвящена изучению распределения особей охотоморского нектона по массе тела. Выявлена полимодальная структура этого распределения, устойчивая во времени и в пространстве. Дистанция между соседними пиками на этом распределении в среднем равна 1,25 в шкале натуральных логарифмов. Таким образом, нектеры разных видов сосредоточиваются в окрестностях неких "оптимальных" размеров тела. Эти размеры образуют геометрическую прогрессию такую, что соседние оптимумы отличаются друг от друга по массе тела в 3,5 раза. Body weight is used as a parameter of size. Weight distribution of nekton species from epipelagic and mesopelagic layers of the Okhotsk Sea is considered on the base of trawl surveys data. Mean body weight of any species in each catch was calculated as the ratio of total biomass of this species 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. Mean estimations of these parameters are: X1 = 7.80 ± 0.14, D = 1.25 ± 0.03, S = 0.434 ± 0.060. The distribution determined by these parameters describes any empirical distribution (for all available data or for different variants of the data composition: by regions, by seasons, by day or night time) with coefficient of determination R2 > 0.995 (mean value R2 = 0.997). The value D = 1.25 means than body weights of any neighbor groups differ one from another by e1.25 = 3.5 times. Besides, a weak but significant negative correlation was found between mean body weight of a species and its mean number in catches. The largest group (№ 10) is presented by the sharks Prionace glauca, Lamna ditropis and swordfish Xiphius gladius. Next two groups (№ 9 and № 8) are absent in the Okhotsk Sea, other 7 smaller groups are presented mainly by common species of the Sea. Spatial distribution of mean body weight in the Okhotsk Sea is not obeyed with Bergmann rule, where large-size specimens should inhabit cold-water northern areas, whereas small animals have to live in southern warm environments.