Present address: San Diego State University, San Diego, CA 92215, U.S.A.
Fish as vectors in the dispersal of Bythotrephes cederstroemi: diapausing eggs survive passage through the gut
Article first published online: 19 NOV 2003
Volume 43, Issue 4, pages 579–589, March 2000
How to Cite
Taylor Jarnagin, S., Swan, B. K. and Charles Kerfoot, W. (2000), Fish as vectors in the dispersal of Bythotrephes cederstroemi: diapausing eggs survive passage through the gut. Freshwater Biology, 43: 579–589. doi: 10.1046/j.1365-2427.2000.00547.x
- Issue published online: 19 NOV 2003
- Article first published online: 19 NOV 2003
- Bythotrephes cederstroemi;
- diapausing eggs;
- exotic species;
- zooplankton dispersal
- 1Bythotrephes cederstroemi (Crustacea: Onychopoda: Cercopagidae) is an introduced invertebrate predator currently spreading through the Laurentian Great Lakes region of North America. We examined a previously unsuspected way in which B. cederstroemi may be dispersed by fish by their consumption of diapausing eggs.
- 2Ninety-four percentage of the mature B. cederstroemi diapausing eggs consumed by fish were egested apparently intact. This proportion is considerably above previous estimates for the ephippial eggs of Daphnia. The hatching success of diapausing eggs was compared among four categories: (a) eggs released naturally by B. cederstroemi (control, 73% hatched) (b) eggs released during ‘stressful confinement’ (46% hatched) (c) eggs dissected from dead females (13% hatched) and (d) eggs recovered from faecal pellets following consumption by fish (viable gut passage experiment, 41% hatched).
- 3Samples of small fish and B. cederstroemi were collected simultaneously. Examination of gut contents revealed that fish contained B. cederstroemi diapausing eggs and that B. cederstroemi bearing resting eggs were consumed selectively over those without eggs. Moreover, fish selected B. cederstroemi bearing mature rather than immature diapausing eggs.
- 4The fact that diapausing eggs survive gut passage is important for the dispersal of B. cederstroemi. Fish often move between the pelagic and littoral zones of lakes and may thus disperse diapausing eggs widely. Fish may also move between lakes connected by river systems and can be caught and passively dispersed by anglers or piscivorous birds. Our results demonstrate the potential for fish to act as vectors in the spread of B. cederstroemi.