Winter mortality of young-of-the-year Hudson River striped bass (Morone saxatilis): size-dependent patterns and effects on recruitment

Abstract

Winter mortality plays a significant role in the dynamics of some temperate fish populations and has been shown to be size-dependent for some species, but not for others. Our objective was to determine how winter mortality affects the recruitment dynamics of Hudson River striped bass (Morone saxatilis). We used catch-per-unit-effort data from three separate surveys targeting young-of-the-year (YOY), overwintering, and age 1 striped bass. Age 1 abundance was negatively correlated with the severity of winter. In contrast, the abundance of age 0 fish was not correlated with age 1 abundance, suggesting that winter mortality greatly modifies year-class strength. A progressive increase in the mean length of YOY fish, coupled with a decrease in the coefficient of variation in length, occurred during some winters. Laboratory experiments showed that growth in length requires temperatures in excess of 10°C; hence, these changes likely result from selective mortality of smaller fish. Direct evidence of size-dependent mortality was obtained from a laboratory experiment that exposed fish to ambient conditions throughout the winter. Accounting for interannual differences in the severity and size dependency of winter mortality may improve our ability to evaluate striped bass year-class strength in the Hudson River.

Shifts in the estuarine demersal fish community after a fishery closure in Puget Sound, Washington

“…Although loss of eelgrass beds has been identifi ed as a threat in Puget Sound, their importance to the groundfi sh species examined here is unknown. In well-studied estuarine ecosystems, extensive time series of fi sh abundance indices have permitted exploration of the roles of density dependence, overwinter survival, predation, and growthdependent mortality on year-class strength of fi shes (Hurst and Conover, 1998;Buckel et al, 1999;Kim-merer et al, 2000;Taylor et al, 2009). The processes that regulate juvenile survivorship and fi sh population dynamics in Puget Sound are not easily discerned because of a paucity of long-term monitoring data.…”

Mortalité hivernale de l'éperlan arc-en-ciel d'eau douce /

“…Hudson river (Hurst and Conover 1998). Chaput and Robichaud (1995) observed sizerelated overwinter mortality for YOY striped bass; Post and Evans (1989) and Toneys and Coble (1980) have the same results for smaller yellow perch {Perca flavescens), and Oliver et al (1979) for smallmouth bass (Micropterus dolomieui).…”

Overwinter Mortality of Sympatric Juvenile Bluegill and Yellow Perch in Mid-Temperate Sandhill lakes, Nebraska, U.S.A

“…To this end, we qualitatively truncated our lengthfrequency histograms by excluding bluegill greater than 60 mm and yellow perch greater than 90 mm TL, (i.e., the upper tail of the length-frequency distributions), because these fish could occlude the interpretation of the histograms [39].…”