Spiny Waterflea - Bythotrephes longimanus
State Rank Reason (see State Rank above)
A conservation status rank is not applicable because this species is not a suitable target for conservation activities as a result of being exotic or introduced.
Bythotrephes longimanus is a large cladoceran (zooplankton) with a long straight tail spine that is twice as long as its body and has one to three pairs of barbs. Parthenogenically produced animals have kink in middle of their spine and sexually produced animals lack the kink. This species has not been found in any Montana waterbodies yet.
This species is most abundant in late summer and autumn.
Bythotrephes longimanus is a large cladoceran distinguished by a long straight tail spine that is twice as long as its body and has one to three pairs of barbs. Parthenogenically produced animals have kink in middle of their spine and sexually produced animals lack the kink. Bythotrephes' appearance is similar to Cercopagis pengoi, another Great Lakes invader, except Bythotrephes is larger with a more robust spine that lacks a hook at the end.
Native To: Northern Europe and Asia.
Nonindigenous Range: First discovered in Lake Huron in 1984; established in all of the Great Lakes by 1987 (Cullis and Johnson 1988). Have since been introduced into some lakes of northern Minnesota and the Alleghany Basin of New York (Liebig et al. 2017).
This species can make diel migrations within the water column of the lakes (Straile and Halbich 2000).
This species lives in large and small temperate lakes, can tolerate brackish water (Liebig et al. 2017).
Bythotrephes occurs in oligotrophic and mesotrophic lakes and has a lower tolerance to low dissolved oxygen concentrations than native cladocerans.
This species feeds on other smaller zooplankton and phytoplankton.
Bythotrephes is found among the zooplankton in the upper water column of large and small temperate lakes, can tolerate brackish water, and is most abundant in late summer and autumn. Occurrence and density of Bythotrephes populations are apparently determined mainly by water temperature and salinity. Bythotrephes is limited to regions where water temperature ranges between 4 and 30°C and salinity values between 0.04 and 8.0‰, but it prefers temperature between 10 and 24°C and salinity between 0.04 and 0.4‰ (Grigorovich et al. 1998). Has caused a decline in the population of zooplankton as a result of predation (Vanderploeg et al. 2002); may also compete with some native species, such as perch and small crustaceans (Branstrator and Lehman 1996)
Bythotrephes can reproduce asexually as well as sexually; unfertilized eggs are carried in a brood pouch, and fertilized eggs are cast off in the fall, hatching the following spring (Evans 1988).
The first noticeable impact of Bythotrephes was on fisherman. The tail spines of Bythotrephes hook on fishing lines, fouling fishing gear. Has caused a decline in the population of zooplankton as a result of predation (Vanderploeg et al. 2002); may also compete with some native species, such as perch and small crustaceans (Branstrator and Lehman 1996)Contact information for Aquatic Invasive Species personnel:Montana Fish, Wildlife, and Parks Aquatic Invasive Species staff.Montana Department of Natural Resources and Conservation's Aquatic Invasive Species Grant Program.Montana Invasive Species Council (MISC).Upper Columbia Conservation Commission (UC3).
Threats or Limiting Factors
Temperature appears to play a major role in determining the abundance and location of Bythotrephes in the Great Lakes, as it prefers cooler water and cannot tolerate very warm lake temperatures (Berg and Garton 1988, Garton et al. 1990, Brown and Branstrator 2004). Bythotrephes occurs in oligotrophic and mesotrophic lakes and has a lower tolerance to low dissolved oxygen concentrations than native cladocerans.
- Literature Cited AboveLegend: View Online Publication
- Berg, D.J., and D.W. Garton. 1988. Seasonal abundance of the exotic predatory cladoceran, Bythotrephes cederstroemi, in western Lake Erie. Journal of Great Lakes Research 14(4):479-488
- Branstrator DK and JT Lehman. 1996. Evidence for predation by young-of-the-year alewife and bloater chub on Bythotrephes cederstroemi in Lake Michigan. J Great Lakes Res 22:917–924
- Brown, M.E., and D.K. Branstrator. 2004. A 2001 survey of crustacean zooplankton in the western arm of Lake Superior. Journal of Great Lakes Research 30:1-8
- Cullis, K.I., and G.E. Johnson. 1988. First evidence of the cladoceran Bythotrephes cederstroemi Schoedler in Lake Superior. Journal of Great Lakes Research 14:524-525.
- Evans, M.S. 1988. Bythotrephes cederstroemi: its new appearance in Lake Michigan. Journal of Great Lakes Research 14(2):234-240.
- Garton, D.W., D.J. Berg, and R.J. Fletcher. 1990. Thermal tolerances of the predatory cladocerans Bythotrephes cederstroemi and Leptodora kindtii: relationship to seasonal abundance in western Lake Erie. Canadian Journal of Fisheries Aquatic Sciences 47:731-738.
- Grigorovich, I.A., O.V. Pashkova, Y.F. Gromova, and C.D.A. Van Overdijk. 1998. Bythotrephes longimanus in the Commonwealth of Independent States: variability, distribution and ecology. Hydrobiologia 379:183-198.
- Liebig, J., A. Benson, J. Larson, T.H. Makled, and A. Fusaro, 2017. Bythotrephes longimanus: Nonindigenous Aquatic Species Database, Gainesville, FL, U.S. Geological Survey.
- Straile, D., and A. Halbich. 2000. Life history and multiple antipredator defenses of an invertebrate pelagic predator, Bythotrephes longimanus. Ecology 81:150-163.
- Vanderploeg, H.A., J.R. Liebig, and M. Omair. 1993. Bythotrephes predation on Great Lakes zooplankton measured by an in situ method: implications for zooplankton community structure. Archiv für Hydrobiologie 127:1-8.
- Additional ReferencesLegend: View Online Publication
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- Branstrator, D.K. 1995. Ecological interactions between Bythotrephes cederstroemi and Leptodora kindtii and the implications for species replacement in Lake Michigan. Journal of Great Lakes Research 21:670-679
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