Нерестовые группировки минтая в восточной части Берингова моря и их функционирование

• Main Author: Степаненко, М.
• Format: Text
• Language: unknown
• Published: Федеральное государственное унитарное предприятие «Тихоокеанский научно-исследовательский рыбохозяйственный центр» 2003
• Subjects: Bering Sea; Берингов*; Aleutian Islands
• Online Access: http://cyberleninka.ru/article/n/nerestovye-gruppirovki-mintaya-v-vostochnoy-chasti-beringova-morya-i-ih-funktsionirovanie; http://cyberleninka.ru/article_covers/12521016.png

Районы воспроизводства восточноберинговоморского минтая, как на шельфе, так и в глубоководной зоне, характеризуются большим разнообразием экологических условий. Значительная экологическая дифференциация нерестилищ потенциально имеет положительный эффект для воспроизводства минтая. Функционирование нерестилищ происходит на дискретном уровне и находится в постоянном динамическом равновесии. Дискретность нерестилищ, так же как и географическая изменчивость локализации нереста разновозрастных группировок, является видовым, устойчивым приспособительным признаком. Выявлен ряд свидетельств тому, что "шельфовый" и "котловинный" минтай являются самостоятельными нерестовыми группировками. Reproduction of Eastern Bering Sea pollock takes place at diverse habitats of shelf and deep water. Ecological differentiation of pollock habitats in spawning period has potentially beneficial impact for reproduction and recruitment. The Eastern Bering Sea pollock has two main spatially and ecologically separated reproductive areas: at shelf and in deepwater, off Aleutian Islands. The main shelf spawning centers at shelf place off Pribilof Isles and Unimak Island, the deep water centers in Bogoslof Island area and in Kanaga Sound. There are not only spatial but temporal differentiations of pollock spawning stocks: most pollock spawns in deep water basically by the end of winter early spring, and at shelf mostly in middle spring. The real functioning of each pollock reproductive stock is going at more discrete level. Each large spawning aggregation is formed by smaller groups, which differs by the pollock age, time of spawning peak, behavior and distribution of fish in feeding and prespawning time. There are four ecological parts in Bogoslof Island spawning stock, which differ by age and postspawning and prespawning habits: 1) 712 years old fish postspawning off eastern Aleutians; 2) 712 years old fish postspawning in the Aleutian Basin; 3) 79 years old fish postspawning over the eastern and northwestern Bering Sea continental slope; 4) 58 years old fish postspawning and prespawning at the eastern Bering Sea shelf. There are some different functional parts of pollock among shelf spawning fish. The oldest pollock (912 years old) spawns annually in the coastal water of Pribilof Isles in the second half of March. The 712 years old pollock spawns in the coastal waters of Amak Island in late January-February. The shelf pollock spawning grounds off Unimak Island and off eastern side of Рribilof Isles (4050 miles off) are the main ones for the first spawning and middle age fish. The 67 years old pollock basically spawns off Unimak Island in the second half of March and the 37 years old fish spawns off the eastern side of Pribilof Isles in the second half of March and in early April. The recruits of the Aleutian Basin spawning stock at age 57 years migrate from shelf to deep water adjacent to continental slope, basically in areas of the Bering, Zhemchug and Pribilof canyons, by the end of winter and early spring, and then migrate to Bogoslof Island spawning ground along continental slope at depth 420550 meters. Functioning of various ecological spawning pollock stocks depends on their abundance and age structure. There are some evidences that the "basin" and "shelf" pollock stocks differ not only by spatial and temporal gap of reproduction and certain age composition, but they are completely different reproductive stocks, possibly genetically determined.