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Stream studies back in action

By Aaron DeLonay, Dr. Robert Jacobson, Kim Chojnacki, and Casey Hickcox

April 21, 2015

USGS Biologist prepares to artificially spawn a female lake sturgeon
USGS Biologist prepares to artificially spawn a female lake sturgeon in the laboratory at the Columbia Environmental Research Center.(Public domain.)

Final preparations are underway to initiate lake sturgeon laboratory and artificial stream studies at the Columbia Environmental Research Center (CERC).  One 46.5 lb. female and three males have been selected for the study.  The female and males were induced for artificial spawning by the injection of hormone. Milt from the males was collected throughout the second week of April and has been cryo-preserved for future studies. Eggs were collected from the female early on the morning of Wednesday, April 15.  Following egg collection, CERC scientists conducted a specific gravity study using a small number of eggs to improve understanding of the fate of eggs on spawning grounds. The fertilized eggs are being incubated in a recently completed laboratory incubation system located at CERC.  Embryos will be used to seed an artificial stream, and released into two substrates within the stream: one substrate composed of gravel and one composed of cobble.  The objective of the stream studies is to compare behavior of lake sturgeon free embryos, which are known to hide in interstices, with pallid and shovelnose sturgeon.  The artificial streams will be monitored for 96 hours (4-days).  The stream will then be cleared and re-seeded with day-8 embryos, followed by a 96-hour monitoring period. These studies will be repeated later in the spring with pallid sturgeon and shovelnose sturgeon.