Journal Article

Resource switching in fish following a major food web disruption

Johnson, Timothy B., Rennie, Michael D., Sprules, W. Gary

2009

Overview

Dreissenid mussels (Dreissena polymorpha and D. bugensis) have re-engineered Great Lakes ecosystems since their introduction in the late 1980s. Dreissenids can have major indirect impacts on profundal habitats by redirecting nutrients and energy away from pelagic production (which supplies profundal production) and depositing nutrients and energy in the nearshore zones that they occupy. However, strong empirical evidence for the effects of this redirection of resources on fish populations is currently lacking. Here, we report significant shifts in isotopic signatures, depth distribution and diets of a coldwater profundal fish population that are all consistent with a greater reliance on nearshore resources after the establishment of dreissenid mussels in South Bay, Lake Huron. Isotopic signatures of scales collected from 5-year-old lake whitefish (Coregonus clupeaformis) demonstrated remarkable stability over the 50-year period prior to the establishment of dreissenids (1947-1997) and a sudden and significant change in isotopic signatures (3[per thousand] enrichment in δ¹³C and 1[per thousand] depletion in δ¹⁵N) after their establishment (2001-2005). These dramatic shifts in isotopic signatures were accompanied by a coincident shift in the mean depth of capture of lake whitefish towards the nearshore. A comparison of previously unpublished pre-invasion diets of lake whitefish from South Bay with contemporary diets collected between 2002 and 2005 also indicate a greater reliance on nearshore prey after the invasion of dreissenid mussels. This study is the first to report changes in the carbon source available to lake whitefish associated with restructured benthic communities after the appearance of dreissenid mussels. Further, this study contributes to a growing body of work that demonstrates the ecological insights that can be gained through isotopic analysis of archived fish bony tissues in ecosystems that have experienced significant levels of disturbance.

• Publisher: Berlin/Heidelberg : Springer-Verlag,Springer,Springer-Verlag,Springer Nature B.V
• Subject: Agnatha. Pisces / analysis / Animal and plant ecology / Animal Nutritional Physiological Phenomena / Animal, plant and microbial ecology / Animals / Aquatic ecosystems / Benthic communities / Benthic invertebrates / Biological and medical sciences / Biomedical and Life Sciences / Bivalvia / Bone and Bones / Bone and Bones - chemistry / carbon / Carbon Isotopes / Carbon Isotopes - analysis / Carbon sources / chemistry / Coregonus clupeaformis / Diet / Dreissena polymorpha / Ecology / Ecosystem Ecology - Original Paper / ecosystems / energy / fish / Fish populations / Fish scales / Food Chain / food webs / Fresh Water / Freshwater / Freshwater fishes / Fundamental and applied biological sciences. Psychology / General aspects / habitats / Hydrology/Water Resources / Isotopes / Lake Huron / Lakes / Lentic systems / Life Sciences / metabolism / Mollusks / mussels / Nitrogen Isotopes / Nitrogen Isotopes - analysis / Nutrients / Ontario / physiology / Plant Sciences / Population Dynamics / Salmonidae / Salmonidae - metabolism / Salmonidae - physiology / Signatures / Thermoclines / Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution / Water depth / Whitefish