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GLIN==> Invasive mysid shrimp found in Lake Ontario

Submitted by Jason Wyda <jwyda@normandeau.com>
Invasive mysid shrimp found in Lake Ontario
The Ponto-Caspian native mysid shrimp, Hemimysis anomala, which has recently been observed in the Muskegon, Michigan area of Lake Michigan ( http://www.jsonline.com/story/index.aspx?id=544851) has also been observed in southeastern Lake Ontario approximately 7 miles northeast of Oswego, New York.  Normandeau Associates Inc. of Bedford, New Hampshire and West Haverstraw, New York is conducting an ichthyoplankton survey of the nearshore waters adjacent to Nine Mile Point in 2006 and 2007.  Night samples in May, 2006 revealed large concentrations of mysid shrimp in 10-25 feet of water.  Although the objective of the sampling program was to quantify fish eggs and larvae, Normandeau scientists were surprised by the large densities of mysid shrimp because the native species, Mysis relicta, is reported to primarily occur in deep waters below the thermocline.  Examination in the laboratory revealed taxonomic characters inconsistent with Mysis relicta, and the species was identified as Hemismysis anomala.  Voucher specimens were sent to an international authority on Ponto-Caspian mysid systematics at the Finnish Museum of Natural History (Dr. Mikhail Daneliya, Dr. Risto Vainola) who confirmed the identification of the mysid in our Lake Ontario samples as Hemimysis anomala.  Although samples are still being processed in the laboratory, both immature and mature specimens were observed suggesting the species is reproducing in Lake Ontario.  The rocky, ledge bottom in the nearshore areas of Nine Mile Point is likely ideal habitat for this species based on observations in the Azov and Black Seas.  Ichthyoplankton sampling will resume in the Nine Mile Point area of Lake Ontario in April 2007 and should provide additional information on the abundance and life history of this invasive species.  We intend to submit our findings to a peer-reviewed fisheries journal for publication.

For more information please contact: Jason Wyda, Normandeau Associates Inc. (603) 472-5191, jwyda@normandeau.com