Ten years of monitoring lake sturgeon spawning on artificial beds in the St. Lawrence River

Session: Seeing Below the Surface: Quantifying the Underwater Environment with Image Analysis

Michael Morgan, NYSDEC, [email protected]
Andrew Preston, NYSDEC, [email protected]

Abstract

The 2003 renewal of the FERC license for the US portion of the St. Lawrence Power Project required the implementation of a variety of aquatic and terrestrial habitat improvement projects, which included the creation of spawning beds for lake sturgeon.  The first two beds were constructed in the upper St. Lawrence River in 2007, and were used the following spring by spawning lake sturgeon (122 were observed at the peak of spawning activity).  Sturgeon use and condition of the beds is evaluated annually, and is primarily observed through the use of underwater cameras towed behind a boat.  Monitoring visits to the bed typically occur every other day during the spawning period.  The beds continue to be used each year by spawning sturgeon (and other fish), but observed numbers at peak spawning have fluctuated from a low of 34 to a high of 395 sturgeon.  Possible reasons for the fluctuations include shortcomings of the monitoring strategy, irregular spawning intervals for sturgeon, or changes in environmental conditions such as water temperatures or velocity.  Two additional beds were constructed in a different reach of the St. Lawrence River in 2012, but no spawning sturgeon have been observed at the newer locations.