Major Goals and Objectives

Since the early 2000s, alewife populations have been on the decline and at an all-time low. This is a major concern to many recreational fishery specialists and salmonid managers. Although some species of salmonids are flexible in their diets, Coho and Chinook Salmon are not very flexible and rely heavily on alewife for the majority of their diet. In years prior, it was believed that the main basin of Lake Michigan was responsible for the majority of alewife recruitment. In recent years, evidence has begun to show that alewife may utilize other habitats like creek and river tributaries and drowned river mouth lakes (DRMLs). These environments may provide additional habitat with warmer temperatures, greater vegetation cover, and greater abundance in prey availability. The main objectives of the study include: 1) estimation of relative contribution of recruits from DRMLs, 2) comparison of growth and survival rates of larvae between the main basin and DRMLs, and 3) prey availability and diet analysis between the main basin of Lake Michigan and DRMLs. With the additional support requested with this proposal, an increased number of samples would be able to be processed with technician support. Additionally, genetic verification of larval alewife will be performed to ensure the larvae being analyzed are not the closely related species Gizzard Shad.

Accomplishments / Benefits

Video: Quantifying the importance of nursery habitats to alewife recruitment in Lake Michigan

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