Spatio-temporal trends in the food habits of age-0 lake whitefish

Assessing the health of lake whitefish populations in the Laurentian Great Lakes: Lessons learned and research recommendations

“…For the recruitment study, comparisons were made primarily among six to ten stocks distributed throughout Lake Michigan, with additional, but less extensive, comparisons with stocks in lakes Erie and Superior. Despite the relatively large areas over which stocks were evaluated, both the natural mortality and recruitment projects found relatively little contrast in measured variables (Blukacz et al, 2010;Claramunt et al, 2010;Ebener et al, 2010-a;Faisal et al, 2010-a,-b;Wagner et al, 2010). We suggest that there were two major reasons for this lack of contrast.…”

“…Although both projects yielded valuable information on lake whitefish stocks in the Great Lakes, particularly in lakes Huron and Michigan, both also encountered difficulties relating measures of individual and population health to stock demographic rates. These difficulties stemmed from several factors, most notably the limited degree of contrast in measurements among stocks (Blukacz et al, 2010;Claramunt et al, 2010;Ebener et al, 2010-a;Faisal et al, 2010-a,-b;Wagner et al, 2010). Our goal for this concluding paper of the special issue is to take what was learned during the natural mortality and recruitment studies to provide recommendations for future studies attempting to improve understanding of linkages between ecological factors affecting individual lake whitefish health and important population demographic attributes.…”

Assessing the health of lake whitefish populations in the Laurentian Great Lakes: Foreword

“…Claramunt et al (2010a) attempted to help fill in this knowledge gap by characterizing diets of age-0 lake whitefish collected from throughout Lake Michigan and from Whitefish Point, Lake Superior. They found that copepods were generally the most prevalent diet item of lake whitefish in early summer; however, the proportion of benthic macroinvertebrates (e.g., chironomids, odonates and ostracods) increased substantially later in the summer.…”

“…They found that copepods were generally the most prevalent diet item of lake whitefish in early summer; however, the proportion of benthic macroinvertebrates (e.g., chironomids, odonates and ostracods) increased substantially later in the summer. Claramunt et al (2010a) hypothesized that at approximately 40 mm, lake whitefish undergo a morphological change in mouth opening position, which allows fish to shift from pelagic to benthic feeding. The timing of this shift to benthic feeding is hypothesized to be regulated by prey availability and to coincide with the emergence of important benthic macroinvertebrates (Claramunt et al, 2010a).…”

“…Claramunt et al (2010a) hypothesized that at approximately 40 mm, lake whitefish undergo a morphological change in mouth opening position, which allows fish to shift from pelagic to benthic feeding. The timing of this shift to benthic feeding is hypothesized to be regulated by prey availability and to coincide with the emergence of important benthic macroinvertebrates (Claramunt et al, 2010a).…”