Recruitment research

Since Hjort's landmark work at the turn of the century it has been widely accepted that the mechanisms responsible for generating the wide variation in year class strength observed in fishes occur during the early life history phase. The majority of larvae born die; mortality rates are often in excess of 99%. Much of the work conducted since the 1920's has concentrated on either documenting whether starvation (critical period, match-mismatch hypotheses) or predation (bigger is better, stage duration hypotheses) regulated year class strength. However, to apply this approach one would have to be able to measure mortality rates in the field far more accurately than is possible. About a 15 years ago, rather than trying to measure mortality rates, scientists began asking whether there was anything unique about those few larvae that did survive. Knowledge of whether survivors were particularly fit or simply lucky, we help determine which and when mechanisms interact to determine year class strength. This approach has become known as the characteristics of survivors approach.

We have been applying this approach in consistently since then. Currently, this work has two focuses. In the first we are continuing to explore the role of biological-physical interactions in regulating survival. A particular interest in this area is in the role of small-scale turbulence in regulating feeding, growth and survival. The second area of research is into mechanisms that caused or are currently limiting yellow perch recruitment in Lake Michigan.

Recent Papers

Recruitment Projects

Striped bass recruitment

Biological-physical interactions during early life history

Yellow perch recruitment

Last revised: 12/16/2010