Midwest Fish & Wildlife Conference 2018

AUTHORS. Robert D. Hunter, Kim T. Scribner - Michigan State University; Edward F. Roseman, Robin DeBruyne - US Geological Survey, Great Lakes Science Center

ABSTRACT. Lake Sturgeon (Acipencer fulvescens) is an economically and culturally important species endemic to the Great Lakes region.  Once historically abundant, lake sturgeon populations have been extirpated or are estimated at less than one percent of their historic abundance.  As a result of documenting habitat modification, spawning habitat availability has been identified as a limiting factor in lake sturgeon recruitment in the St. Clair-Detroit River system.  Since 2004, largescale efforts have been under way to mitigate the loss of spawning habitat for lithophilic spawners such as lake sturgeon through construction of artificial spawning reefs.  To assess the effectiveness of artificial reefs in meeting lake sturgeon restoration goals, eggs and larvae were collected on and above two reefs in 2015 using benthic d-frame nets, egg mats, and vertically stratified conical nets.  Samples (N = 700) were genotyped using microsatellite loci and genetic pedigree analysis was used to estimate juvenile full- and half-sibling groups and estimate the number of breeding adults.  Comparisons of juvenile relatedness allow for estimation of the number of adult spawners contributing offspring at one or more reefs, in one or more spawning events, individual spawning success and larval dispersal.  Sampling in large river systems is difficult and resource intensive.  Data also identify the most effective sampling regime for assessment of spawning area use by adult lake sturgeon in large riverine systems.  These data are critical to assess and inform future aquatic habitat restoration efforts for lake sturgeon throughout the Great Lakes.