FOR IMMEDIATE RELEASE: Monday, Aug. 22, 2005

CONTACT: Mike Barnes, 642-6920

Tasmanian Interest in South Dakota Salmon Eggs

PIERRE, S.D. -- Chinook salmon rearing in South Dakota state fish hatcheries may be getting more efficient, thanks to a developing "down-under" relationship.

Researchers in Tasmania, Australia, along with biologists from the South Dakota Department of Game, Fish and Parks and Black Hills State University are all working to solve the origins of a mysterious condition that periodically affects Chinook salmon eggs.

South Dakota’s lone Chinook salmon population in Lake Oahe is maintained entirely by hatchery stocking because the fish cannot naturally reproduce. Each fall, the salmon are artificially spawned, and the eggs are typically shipped to McNenny State Fish Hatchery outside of Spearfish.

According Game, Fish and Parks Fish Health Specialist and McNenny Hatchery Manager Rick Cordes, every few years or so, some of the eggs are abnormally soft and squishy. "These soft eggs prematurely hatch and die during hatchery incubation," Cordes said.

The last case of this soft-egg disease was observed in 2001. Game, Fish and Parks Biologist Mike Barnes, in collaboration with Cordes, current Cleghorn Springs State Hatchery Manager Will Sayler, and Lake Oahe Biologist Robert Hanten, described the outbreak and some experimental treatments in the North American Journal of Aquaculture. This internationally published article caught the attention of a researcher from Tasmania who was having similar problems during Atlantic salmon egg incubation. He emailed Barnes, and a transcontinental collaboration began.

"I am really excited about this unique relationship," said Barnes. "With Tasmania’s salmon spawn occurring in the spring and ours occurring in the fall, ideas can be tested twice as often and more quickly than if we were each working alone. I am hopeful we can determine the causes of this still mysterious disease and work on preventative or therapeutic treatments which will improve hatchery rearing efficiencies, saving both money and labor in the long term." Barnes noted that plans are underway to examine the eggs from Lake Oahe salmon this fall using the same techniques employed in Tasmania.

Black Hills State University will also play a key part in this collaboration. Professor Emeritus Mark Gabel will be overseeing the microscopic techniques used to examine the eggs, including electron microscopy. Barnes and Gabel also expect to involve students in these investigations.

"There is a long history of successful collaboration between McNenny hatchery and the biology department at Black Hills State University," Barnes said. "Mark Gabel and his (former) student Hans Stephenson have already provided a wealth of information regarding South Dakota’s Chinook salmon eggs. Professors David Bergmann and Dan Durben have also made important contributions concerning this soft-egg disease. I cannot speak highly enough of my collaborators at Black Hills State."

Barnes added that hatchery researchers from foreign countries have sought advice from McNenny hatchery staff, but that this is the first time that such practical cooperation has developed.

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