Spatial distribution, size composition, feeding habits, and dynamics of abundance of Alaska skate Bathyraja parmifera in the North Pacific

Autor: I. V. Grigorov, A. A. Baitalyuk, A. M. Orlov
Rok vydání: 2015
Předmět:
Zdroj: Journal of Ichthyology. 55:644-663
ISSN: 1555-6425
0032-9452
DOI: 10.1134/s0032945215050069
Popis: The results of long-term studies on the spatial and vertical distribution, dynamics of abundance, size composition, and feeding habits of the Alaska skate Bathyraja parmifera in the northern Pacific Ocean are presented. The species is most abundant at depths of 200 to 700 m; in a cold season of the year, the species migrates to larger depths for overwintering, and its feeding occur at smaller depths in the warm season. Specimens of the length 17 to 131 cm with prevalence of skates of 40 to 100 cm long were recorded in catches. The difference between males and females in body weight and length was not considerable. The condition (plumpness) of skates increased from April to October and decreased from November. Females dominate among skates of the length to 30 cm, in the size group from 30 to 90 cm the ratio of males to females is almost 1: 1, and males dominate among larger individuals. The dynamics of the abundance of Alaska skate is different in different regions: catches of skates constantly increased in the Bering Sea during the surveyed period; in the Kuril and Kamchatka waters of the Pacific Ocean and in the Sea of Japan and the Sea of Okhotsk, the decrease in catches in the 1990s was succeeded by the increase in the abundance of skates; in waters of Aleutian Islands and the Gulf of Alaska, the increase in catches until the beginning of the 2000s was succeeded by their stabilization and a slight decrease in the abundance in recent years.
Databáze: OpenAIRE
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