|
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 |