Study

Implications of viability of invertebrate eggs exposed to saltwater for Great Lakes' ship ballast management; a laboratory experiment, Ontario, Canada

  • Published source details Gray D.K., Bailey S.A., Duggan I.C. & MacIsaac H.J. (2005) Viability of invertebrate diapausing eggs exposed to saltwater: implications for Great Lakes' ship ballast management. Biological Invasions, 7, 531-539

Summary

International shipping has been a major vector of non-native species introductions to the Great Lakes of North America. Apparent recent invasions stem from organisms within ship ballasts; as no-ballast-on-board (NOBOB) vessels currently dominate inbound traffic to the Great Lakes, it has been proposed that live or dormant organisms contained in residual ballast may be partly responsible for these invasions. In this study, an experiment was undertaken to assess if exposure to seawater reduced the viability of invertebrate eggs in ballast sediments. If exposure markedly reduced egg viability or the resulting species richness of hatched organisms, then ballasting a small amount of saltwater into NOBOB ships could reduce the future introduction risks.

Sediment samples: Sediment samples from ballast tanks were taken from three transoceanic ships entering the Great Lakes between November 2001 and June 2002. Due to the unknown origin of these sediments, and possible previous exposure to saltwater, samples were also collected between June and December 2002 from natural freshwater habitats.

Treatments: In the laboratory, two treatments were applied to subsamples of these sediments: exposure to seawater (salinity 32‰) collected from a loaded ballast tank, or exposure to freshwater. The treated sub-samples were stored in the dark at 4ºC for 10 days (the maximum length of a typical trans-Atlantic voyage).

Egg viability: Egg viability, assessed as the abundance of taxa hatched between sediments, was determined.

Exposing zooplankton diapausing eggs to seawater did not reduce total abundances or consistently affect the species richness of hatched invertebrates: egg viability was not affected by exposure; species richness of hatched eggs was reduced by saltwater exposure in only one of seven trials. Ballasting a small amount of saltwater into NOBOB ships therefore, does not appear to be an effective technique to reduce introductions of non-native organisms via ship ballast to the Great Lakes.


Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at:

http://www.springerlink.com/content/j823g60g61067647/fulltext.pdf

 

Output references

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read latest volume: Volume 17

Go to the CE Journal

Subscribe to our newsletter

Please add your details if you are interested in receiving updates from the Conservation Evidence team about new papers, synopses and opportunities.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust