Some issues related to catches of northern Atka mackerel <Emphasis Type="Italic">Pleurogrammus monopterygius</Emphasis> (Scorpaeniformes: Hexagrammidae) in the near-surface water layer of the northern Kuril Islands

Studies performed in Pacific waters of the northern Kuril Islands from May to August 2003–2007 demonstrated that not only juveniles of Pleurogrammus monopterygius but also its adult specimens are found in the near-surface layer. Some adult fish migrate to the near-surface layer for feeding, while occurrence in this layer for other specimens is related to the change of spawning grounds. Among specimens with a length of 36–48 cm, females comprise 86.2%; among specimens with a length of 22–28 cm, females comprise 56%. Migrations in the near-surface layer have no mass pattern.