Altered yellow perch stock-recruit relationships in Saginaw Bay, Lake Huron - Data

<p>In Saginaw Bay, a large productive embayment of Lake Huron, yellow perch (<em>Perca flavescens</em>) experienced a multi-decadal decline in adult abundance despite increasing reproductive success (age-0 relative abundance in fall), suggesting a shift in recruitment dynamics. To assess the relative influence of ecosystem changes in altering yellow perch stock-recruit relationships, we compared candidate models to evaluate potential shifts in the age at which year-class strength (YCS) is set and the importance of environmental and biotic factors in explaining yellow perch reproduction and recruitment success (1970-2022), assuming either stationary or nonstationary dynamics. Results indicate that the age when YCS is set shifted from age-0 to age-1 in the early-2000s. Incorporating nonstationary breaks in models best explained annual variation in yellow perch reproductive (~79% variation explained) and recruitment success (~48%). Increased reproductive success was attributed to reduced competition and predation following the 2003-2004 collapse of alewife (<em>Alosa pseudoharengus</em>). However, increases in walleye (<em>Sander vitreus</em>) abundance (since late-1980s), coinciding with alewife declines, may have intensified predation pressure on age-1 yellow perch, leading to declines in annual recruitment success. </p>