Berg, D. J., D. W. Garton, 1988.    Seasonal Abundance of the Exotic Predatory Cladoceran, Bythotrephes Cederstroemi, in Western Lake Erie, Ohio State University, Ohio Sea Grant College Program

Reprinted from J. Great Lakes Res. 14(4):479-488 Internat Assoc Great Lakes Res., 1988

Seasonal Abundance of the Exotic Predatory Cladocerans, Bythotrephes Cederstroemi, in Western Lake Erie

Abstract
The predaceous cladoceran, Bythotrephes cederstroemi , has recently invaded the Great Lakes and basic information on its seasonal abundance and population demographics is lacking. Accordingly, we examined seasonal variation in abundance, length - weight relationships, fecundity, ontogeny of lateral spine production, sex ratio, and incidence of resting vs. subitaneous eggs. Seasonal variation in these parameters was compared with water temperature variation and the presence of a potential competitor, Leptodora kindti. Specimens for these analyses were collected with nocturnal surface tows in the western basin of Lake Erie during summer and fall, 1987. Bythotrephes did not appear until 23 July, had its maximum abundance (111 individuals/m³) at the surface on the night of 9 October, and persisted at lower numbers in samples through the last sampling date, 14 December. The correlation of body weight with tail spine length varies seasonally, with individuals weighing less in the summer than in the fall. Neonates possess one pair of lateral spines on the tail spine and add a pair during each of the first two molts, enabling determination of instar distribution. Females produce one to 12 subitaneous eggs per brood, with males and resting eggs occurring rarely. Bythotrephes abundance was negatively correlated with water temperature and Leptodora abundance, suggesting that Leptodora abundance or temperature, or both, affect the success of Bythotrephes in the western basin of Lake Erie.

Entire Paper
Contact: D. W. Garton, Indiana University-Kokomo, 2300 S. Washington Street, P.O. Box 9003, Kokomo, IN 46904-9003 or dgarton@iukfsl.iuk.indiana.edu
Keywords: Basic_biology, Bythotrephes, Colonization
Product Type: Predicting_the_spread, Research
User Type: General