Lack of Vitamin B1 Killing Great Lakes Fish

Lack of Vitamin B1 Killing Great Lakes Fish

Source: usgs

7/7/2014

Great Lakes fish in the salmon family that rely on the fish “alewife” as part of their diet face a major obstacle in restoring naturally reproducing populations, according to new U.S. Geological Survey research published in the journal Fish and Shellfish Immunology.
Great Lakes fish in the salmon family that rely on the fish “alewife” as part of their diet face a major obstacle in restoring naturally reproducing populations, according to new U.S. Geological Survey research published in the journal Fish and Shellfish Immunology.

For more than a decade researchers have been trying to unravel the mystery of why Lake Trout and other salmonids that consume alewife produce spawn that die young. Although researchers have recognized the connection between thiamine and the death of the young fish for a decade, the new study provides an additional clue; fish that survive the initial impact of thiamine deficiency are experiencing changes in immune function that resemble those occurring in humans with inflammatory diseases.

Early Mortality Syndrome, or EMS, results in embryonic mortality in salmon, steelhead trout, brown trout, lake trout, and Chinook salmon. The symptoms of EMS include loss of equilibrium, swimming in a spiral pattern, lethargy, hyper-excitability, hemorrhage and death, which occurs between hatching and first feeding.

“Vitamin B1, or Thiamine, is an essential nutrient that animals must obtain through their diet,” said Chris Ottinger, a USGS immunologist and lead author of the study. “We found that alewives, one of the main diets of many Great Lakes fish, contains an enzyme called “thiaminase” that destroys the thiamine in fish that consume them. The lack of B1 leads to Early Mortality Syndrome as well as the newly reported immune dysfunctions that may be perpetuating infectious diseases in this fish community.”

Alewives came into the Great Lakes when the Welland Canal was built as invasive species. They dominated the prey base until Pacific salmon were introduced in part to control their population levels.