Exotic Species and the Benthic Community of Seneca Lake – Hobart and William Smith Colleges \
The HWS Update

Exotic Species and the Benthic Community of Seneca Lake

How are the exotic zebra and quagga mussels affecting the ecosystem of Seneca Lake, particularly plants at the bottom? Two students at Hobart and William Smith are finding out this summer.

July 15, 2002 GENEVA, N.Y. – William Smith student Jess Werder and Hobart student Dave Costello, working with Professor Brian Shelley, are examining the distribution of zebra and quagga mussels in Seneca Lake. This work is being conducted from the Colleges’ research ship, the HWS Explorer, with the help of Captain John Nichols and First Mate John Abbott. Werder and Costello are looking at the spatial distribution of zebra and quagga mussels and any interactions these species may have with other exotic and/or native species in the lake. Special emphasis is being placed on how various species of submerged plants might be affecting the distribution of mussels.

This research is being accomplished by sampling at 24 transects covering the entire shallow water margins of the lake, reaching depths up to 80 meters. In addition to generating maps illustrating the distribution of mussels and plants in the lake, the project aims to provide valuable insight into various ways in which exotic mussels influence other benthic (at the bottom) organisms. This information is necessary to evaluate fully the long-term impacts of exotic species such as zebra and quagga mussels on the Seneca Lake ecosystem.

The introduction of exotic species (species not native to the new habitat) continues to pose serious risk to native species in a variety of different ecosystems, especially freshwater ecosystems such as lakes and streams. Most often without natural predators, these species are able to increase the size of their populations to the point where they can significantly influence the structure and function of the ecosystems in which they are now found. In the early 1990s, zebra mussels, originally native to the Black and Caspian Seas and Ural River in Asia, were introduced into Seneca Lake. This was followed by the introduction of a close relative, the quagga mussel.

Both species have become well established in the lake and have resulted in a number of significant changes in the lake (e.g., increased water clarity). But, still much is not known about how these exotic species might be affecting other organisms in the lake, especially those that also inhabit the benthic habitat of the lake. There are also questions about what affects the spatial distribution of these mussels throughout the lake, and thus the overall impact these species may be having within the lake. One interesting observation is that mussels readily attach to plants living submerged in the lake and questions thus arise about how some plant species, especially another exotic species, Eurasian water milfoil, might be influencing the distribution of mussels in the lake.

David Costello is the son of Matthew and Frances Costello of Gasport, N.Y. He is a junior at Hobart College, majoring in biology with a minor in environmental studies. Costello is a Dean’s Scholar and has also participated in Day of Service and Orientation. His future plans include a career in chiropractic medicine.

Jess Werder is the daughter of John and Judy Werder of Springwater, N.Y. A junior at William Smith, she is a biology major with a minor in public policy. She is a member of Laurel Society, the honor society for juniors, and has served on Judicial Board and participated in Day of Service. After graduating, Werder plans to attend graduate or professional school.

Both students will participate in the Colleges’ Queensland Study Abroad Program in the fall.


Download a large photo of David Costello.

Download a large photo of Jess Werder.