Understanding the influence of early life growth on subsequent growth and body size in juvenile Lake Erie Yellow Perch

Abstract

Multiple hypotheses from marine ecosystems suggest that fast early life growth can enhance future growth and recruitment, yet their applicability to freshwater ecosystems is unclear. While some studies in freshwater systems have shown support for these hypotheses, others report mixed or non-significant effects, highlighting the need for more research in freshwater populations. Such knowledge could help us understand growth and recruitment variation in populations. Toward this end, we investigated the influence of early life (first four weeks of life) growth on growth performance during subsequent weeks of life and individual length-at-capture in age-0 (juvenile) Yellow Perch (Perca flavescens) collected in central Lake Erie, where strong recruitment events have been absent since 2012. We measured otolith growth rates in 30 individuals per year collected during fall 2010 and 2018 from management units 2 and 3 (MU2 and MU3) in central Lake Erie. We expected to find positive relationships between early life growth rate and subsequent weekly growth rates, as well as juvenile Yellow Perch length-at capture in the fall. As expected, we found that average daily growth rates during the first two weeks of life were strongly correlated; however, the influence of any given week’s growth on subsequent weeks declined through time, with significant effects disappearing after about 6 weeks. Unexpectedly, we also found no relationship between growth rate during the first four weeks of life and juvenile length-at-capture. Collectively, these findings indicate that the effects of early life (e.g., larval) growth rate can carry over (linger) but only for a limited period. Further, they highlight the need for comparative studies between growth rates in the central basin – where recruitment has been declining – and other Lake Erie basins where it has remained stable. Such studies could help place our central basin growth rates in perspective (e.g., perhaps they are low compared to the west basin) and allow for relationships between the annual early life growth rate and annual recruitment success to be more fully explored.No embargoAcademic Major: Evolution and Ecolog