Movement and Habitat Use of Yearling and Juvenile Lake Sturgeon in Black Lake, Michigan

Abstract

AbstractInformation about the distribution, movement, and home ranges of lake sturgeon Acipenser fulvescens was incomplete in the Great Lakes region; therefore, the objective for this study was to determine habitat selection and the extent of movement by two life stages of lake sturgeon in Black Lake, Michigan. Ultrasonic transmitters were surgically implanted into yearling (age‐1) and juvenile (age‐5–13) lake sturgeon. The yearling lake sturgeon implanted with transmitters averaged 36.04 cm total length (TL) and 207.2 g, while the juvenile lake sturgeon tracked during this survey averaged 97.23 cm TL. Previous studies of movements and habitat use by lake sturgeon have noted distinct areas of use by groups of adult lake sturgeon in riverine environments. In contrast to these findings, yearling and juvenile lake sturgeon in the present study used individual areas of activity. Comparisons between our study and studies conducted in lotic environments suggest that core areas of activity for groups of lake sturgeon may be more important for lake sturgeon inhabiting flowing environments. Two distinct mean depths (nearshore and deep offshore habitats) were used by yearlings, while juveniles utilized deep, flat‐bottomed offshore habitat. Yearling lake sturgeon were associated significantly with sand and organic substrate types rather than clay or sand–organic substrate, while juveniles were associated with organic substrate types. Median distances moved between locations were significantly different between yearlings that used nearshore habitat and those that used offshore habitat. Juvenile lake sturgeon larger than 90 cm displayed longer median daily linear movements and occupied larger home ranges than did juveniles smaller than 90 cm. The findings from this study illustrate the different habitats used at various lake sturgeon life history stages in a lake environment.