Poor food quality is bad omen for Lake Ontario salmon and trout
Ann Arbor, MI — Lake Ontario top predator (salmon, trout and eel) food choices are limited to mostly new immigrants. The native prey fish historically eaten by top predators have been pushed out by new fish of questionable or unknown nutritional quality. There is evidence that essential nutrient deficiency of vitamin B1 (thiamine) is resulting in population collapse of lake trout and other native top predators.
An essential nutrient is a component that must be in the diet and cannot be produced by the organism. Essential nutrients such as vitamin B1 play a vital role in the health and well-being of an organism. Over the past 15 to 20 years, research has shown that vitamin B1 deficiency affects numerous life sustaining functions. According to Dale Honeyfield, Senior Scientist with U. S. Geological Survey, the resulting nutritional disease is killing lake trout, Atlantic salmon, and other species.
Previously, no studies had been conducted to determine amount of essential dietary nutrients other than vitamin B1 in prey fish. When the essential nutrients making up the families of vitamin A, E, B1 and fatty acids were measured in five important Lake Ontario prey fish, surprising results were found. Vitamin A family was lower than the dietary requirements of trout and salmon for all prey fish measured. Vitamin E also was extremely low in alewife and below trout and salmon dietary requirements. Vitamin A, E and B1 are considered antioxidant vitamins. Deficiencies of these vitamins reduce the body’s defenses against normal oxidative stress from using oxygen and oxidative stress from detoxifying contaminants. Continuing vitamin B1 deficiency remains a significant fish management problem. Furthermore, gobies exhibit elevated fatty acid ratios which means the products of omega-6 fatty acids that cause pain, heart attacks and immune dysfunction in humans may also act within fish that feed on gobies. In summary, the essential nutrient content of five important prey fish consumed by Lake Ontario top predators appears to be lacking.
This is the first study to document the potential for multiple essential nutrient deficiencies in Great Lakes trout and salmon food supply which is now made up of a high percentage of non native prey fish species. The effect of insufficient vitamins A and E in the top predator food needs further investigation.
Original Publication Information
Results of this study, "Survey of four essential nutrients and thiaminase activity in five Lake Ontario prey fish species," are reported by Dale Honeyfield, Marion Daniels, Lisa Brown, Michael Arts, Maureen Walsh and Scott Brown in Volume 38, No. 1, of the Journal of Great Lakes Research, published by Elsevier, 2012.
Contacts
For more information about the study, contact Dale Honeyfield, U.S. Geological Survey, Northern Appalachian Research Laboratory, Wellsboro, PA 16901, honeyfie@usgs.gov, (570) 724-3322.
For information about the Journal of Great Lakes Research, contact Marlene Evans, Editor, National Water Research Institute, Environment Canada, 11 Innovation Boulevard, Saskatoon, SK, S7N 3H5, Canada; jglr@ec.gc.ca; (306) 975-5310.
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