Growth dynamics of juvenile yellowfin sole (Pleuronectes asper) and northern rock sole (Lepidopsetta polyxystra) in the eastern Bering Sea

Abstract

The first five growth zones of 744 yellowfin sole and 512 northern rock sole otoliths were measured from year-classes 1974-1989, to identify patterns of annual growth and sources of temporal variation. Growth patterns were observed graphically and temporal variation was examined by partitioning growth into year and age effects via linear models. Growth and recruitment relationships with biological and environmental variables were explored through correlation analysis and stepwise regression. Results indicate that growth of yellowfin sole and rock sole declined from the late 1970s to the mid 1980s. Yellowfin sole length at age rebounded after 1985, while rock sole length at age continued to decline until at least the early 1990s. Density-dependent factors such as competition during early growth years overshadow the impacts of environmental variables on growth for both yellowfin sole and rock sole, possibly due to the complex oceanographic and atmospheric relationships that exist in the Bering Sea. Recruitment strengths of yellowfin sole and rock sole have significant environmental components suggesting that survival rates may be influenced by environmental conditions. Also, interspecific competition with yellowfin sole may be influencing rock sole recruitment in the eastern Bering Sea.