Processes Contributing to Variability in Regional Patterns of Juvenile River Herring Abundance across Small Coastal Systems

摘要: Abstract Many populations of anadromous herring, (e.g., alewives Alosa pseudoharengus and blueback herring A. aestivalis, collectively referred to as river herring) are in decline. To help understand the various processes influencing their relative abundance, we studied juvenile 11 small, coastal Massachusetts systems. We examined diel seasonal movements, variation patterns relationships between numbers seven abiotic biotic factors (stream discharge, pond temperature, habitat availability, transparency, pH, food spawning stock size). Seasonally, downstream migration peaked early summer, most emigrated 1200 1600 hours. Little or no emigration occurred late summer when stream channels were often dewatered, although several streams experienced a smaller, more variable peak fall. In univariate regressions, vol...