\u3ci\u3eGomphus Spicatus\u3c/i\u3e (Odonata: Gomphidae) Rediscovered in Illinois and \u3ci\u3eLibellula Semifasciata\u3c/i\u3e (Odonata: Libellulidae) Recorded Near Wisconsin

(excerpt) Gomphus spicatus Hagen (Odonata: Gomphidae), commonly called dusky clubtail, is a common and widely distributed dragonfly in a variety of ponds, lakes, and slow streams throughout its range in the north-eastern and northcentral United States and adjacent areas of southern Canada (Donnelly 2004)

An analysis of the population dynamics of the yellow perch in Indiana waters of Lake Michigan

Age, growth, and abundance data were collected on yellow perch, Perca fla vescen, in Indiana waters of Lake Michigan in 1987 and 1988. The data collected were compared to data on yellow perch in Indiana waters of Lake Michigan dating back to 1975.Changes in growth, mortality, and abundance between 1975 and 1988 were clearly illustrated by the data. Growth has decreased; back-calculation indicates that "quality" (> 200 mm) perch in 1975 were about age II, however, "quality" perch in 1988 were over age V. Annual mortality values produced from following a cohort or comparing age classes indicate that mortality has decreased since 1981, most sharply in 1987 and 1988. Changes in growth and mortality are likely resultant of large changes in abundance. Indices of abundance (biomass and catch-per-uniteffort) reveal that the yellow perch population has become much more dense in the late 1980's than the 1970's and early 1980's. The percentage of quality perch has decreased, however, the abundance of quality perch has increased and peaked in 1988.Thesis (M.S.)Department of Biolog

\u3ci\u3eGomphus Spicatus\u3c/i\u3e (Odonata: Gomphidae) Rediscovered in Illinois and \u3ci\u3eLibellula Semifasciata\u3c/i\u3e (Odonata: Libellulidae) Recorded Near Wisconsin

(excerpt) Gomphus spicatus Hagen (Odonata: Gomphidae), commonly called dusky clubtail, is a common and widely distributed dragonfly in a variety of ponds, lakes, and slow streams throughout its range in the north-eastern and northcentral United States and adjacent areas of southern Canada (Donnelly 2004)