Individual‐based analyses reveal effects of behavioral and demographic variables associated with multi‐annual reproductive success of male and female lake sturgeon

Quantifying effects of individual attributes and population demographic characteristics that affect inter‐ and intrasexual interactions and adult reproductive success, and the spatial and temporal contexts in which they are expressed is important to effective species management. Multi‐year individual‐based analyses using genetically determined parentage allowed the examination of variables associated with the reproductive success of male and female lake sturgeon (Acipenser fulvescens) in the well‐studied population in Black Lake, Michigan, USA. Spawning lake sturgeon (a total of 599 individuals where many were captured more than once based on 1024 total captures) and larvae (N = 3436) were genotyped during each of seven consecutive years (2001–2007). Factors associated with individual reproductive success differed between sexes and varied among spawning groups within a year and among years depending on spawning date (higher reproductive success earlier in the season for females) and spawning locations (higher reproductive success in upstream spawning zones for females). Female reproductive success increased nonlinearly with increasing body size. Male reproductive success increased with increasing residence time in spawning areas and, to a modest degree, with increasing body size in a nonlinear fashion. Fixed effects of repeatability in spawn timing and location across years led to consistently higher or lower reproductive success for females. Results identified factors, including time spent at spawning areas by males and intersexual encounters and mate number, that contributed to higher interindividual variance in reproductive success and affected population levels of recruitment, the degree of subpopulation genetic structure (lack of isolation by time), and effective population size.