Experimental whole-lake dissolved organic carbon increase alters fish diet and density but not growth or productivity

Canadian Journal of Fisheries and Aquatic Sciences
By: , and 

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Abstract

Negative relationships between dissolved organic carbon (DOC) concentration and fish productivity have been reported from correlative studies across lakes, but to date there have not been experimental tests of these relationships. We increased the DOC concentration in a lake by 3.4 mg L-1, using a before-after control-impact (BACI) design, to quantify the effects on the productivity and population structure of Largemouth Bass (Micropterus salmoides). Greater DOC reduced the volume of the epilimnion, the preferred habitat of Largemouth Bass, resulting in increased bass density. The likelihood that adult bass had empty diets decreased despite this increase in bass density; diet composition also changed. There was no apparent change in bass growth or condition. Overall, there was no net change in Largemouth Bass productivity. However, changes in YOY and juvenile recruitment and feeding success suggest the possibility that future effects could occur. Our results are the first to examine the effects of an increase in DOC on fish productivity through a five-year temporal lens, which demonstrates that the relationship between DOC and fish productivity is multi-dimensional and complex.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Experimental whole-lake dissolved organic carbon increase alters fish diet and density but not growth or productivity
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/cjfas-2017-0283
Volume 75
Issue 11
Year Published 2018
Language English
Publisher NRC Research Press
Contributing office(s) Great Lakes Science Center
Description 9 p.
First page 1859
Last page 1867