Reproductive Success and Juvenile Growth Following an Experimental Alewife Translocation to a Massachusetts Pond

Targeted management action to counteract declines in eastern North American anadromous alewife populations is hindered by poor ecological knowledge for all life stages, except short periods when spring runs pass chokepoints that allow for enumeration.  A multi-institutional collaboration exploring links between adult run size, adult reproductive success, juvenile cohort dynamics and eventually the adult run counts used in management, will provide information necessary to understand the implications of temporal and spatial variation in ecological drivers that influence the juvenile freshwater life phase of alewives. Specifically, an experimental translocation of 428 adult fish in spring 2013 to an isolated (by dams) but historically occupied pond in eastern Massachusetts, USA, will serve as our study system. Five separate translocation events occurred over a 21-day period and 117 offspring were sampled throughout the summer growth period. Pedigrees were reconstructed using 15 microsatellite markers and growth rates and hatch dates of age-0 offspring based on otolith daily growth increments were obtained from a companion study. These data will be combined to elucidate the influence of run timing and adult body size on reproductive output (a proxy for adult fitness) and ensuing cohort dynamics.