12/16/13

In the news: Less food for fish in Lakes Huron and Michigan

A recently published study shows that food supplies for fish and other important organisms in the Great Lakes have been on the decline, and there are a few reasons why. 

"The study, based on years of data compiled by government agencies and university researchers, found evidence of drop-offs in phytoplankton — tiny plants essential to many food chains — since the late 1990s. A decline in tiny invertebrates and prey fish, such as alewives and round gobies, also was detected.

It's likely that invasive quagga and zebra mussels have played a significant role by gobbling plankton, according to the paper, which was published online this month in the journal BioScience. The mussels arrived in the Great Lakes in the 1980s after being scooped into cargo ships' ballast tanks in foreign ports and hauled across the Atlantic...
The study was designed to document trends in Great Lakes food webs and determine whether the webs were influenced more by the feeding habits of top predator fish or by developments at the lower end of the chains."
Read the complete article, which includes more information about causes of the decline found in the study, at the link above.

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