Publication: The Consequences of Changing Hatch Times of Fish Larvae in Lake Michigan

Figure showing locations of larval emergence from daily nearshore hatch locations throughout Lake Michigan, where different colors indicate the five distinct regions.
Figure 1 from the report. See full caption in body text. 

A new study published by researchers on a MW CASC-funded project explores the potential consequences of changing hatch times of fish larvae in large lakes. Using Lake Michigan as a case study, the research team used several different models to simulate hatch and transport of fish larvae, evaluate patterns, and consider consequences for overlap with suitable temperatures and prey.

Spencer Gardner, a MW CASC-affiliated PhD student at Purdue University, is the lead author on the publication. 

In large lakes, for example, Lake Michigan, larval fish dynamics are directly influenced by climate-driven physical transport processes that advect mostly passive larvae through heterogeneous habitats. Under changing climatic conditions, hatch times may not coincide with phenologies of favorable transport and prey availability... Historic and future simulations of larval transport indicate strong intra- and inter-annual variability, with advection to generally less suitable offshore habitats increasing seasonally... and occurring earlier in warm years. While earlier offshore transport in future years might be offset by changes in hatch timing, mismatches in emergence of larval fish and their zooplanktonic prey may limit future recruitment potential.

Read more in Limnology and Oceanography Letters. 

Figure 1. (a) Locations of larval emergence from daily nearshore hatch locations throughout Lake Michigan, where different colors indicate the five distinct regions. Black isobath indicates the extent of the nearshore boundary used in this study (25 m), with subsequent light gray isobaths indicating 50-, 75-, and 100-m depths. Seasonal effects of physical transport processes are demonstrated by visual comparison of location (50-d post-release) of larvae released on (b) 01 May 2010 (DOY 122) and (c) 28 June 2010 (DOY 180). Interannual effect of thermal conditions (warm vs. cool) on larval transport highlighted by location (50-d post-release) of larvae released 01 June (DOY 153) in (d) 2015 (cool year), and (e) 2047 (warm year). Final locations represent climate-driven physical transport processes experienced by individuals throughout the 50-d simulation.