Polymethylene-interrupted fatty acids: Biomarkers for native and exotic mussels in the Laurentian Great Lakes Tadej Mezek a , Ed Sverko b , Martina D. Rudy b , Donna Zaruk b , Alfredo Capretta c , Craig E. Hebert d , Aaron T. Fisk e , Daryl J. McGoldrick b , Teresa J. Newton f , Trent M. Sutton g , Marten A. Koops h , Andrew M. Muir i , Timothy B. Johnson j , Mark P. Ebener k , Michael T. Arts b, ⁎ a National Institute of Biology, Department of Freshwater and Terrestrial Ecosystem Research, Večna pot 111, SI-1000 Ljubljana, Slovenia b Water Science and Technology Directorate, National Water Research Institute, 867 Lakeshore Road, P.O. Box 5050, Burlington, ON, Canada L7R 4A6 c Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON, Canada L8S 4M1 d Wildlife and Landscape Science Directorate, Environment Canada, 1125 Colonel by Drive (Raven Road), Ottawa, ON, Canada, K1S 5B6 e Great Lakes Institute for Environmental Research and Department of Earth Sciences, University of Windsor, Windsor, ON, Canada, N9B 3P4 f U.S. Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Road, La Crosse, WI 54603, USA g University of Alaska, School of Fisheries and Ocean Sciences, 905 Koyukuk Drive, Fairbanks, AK 99775, USA h Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 i Great Lakes Fishery Commission, 2100 Commonwealth Blvd., Suite 100, Ann Arbor, Michigan 48105, USA j Glenora Fisheries Station, R.R. #4, 41 Hatchery Lane, Picton, ON, Canada K0K 2T0 k Inter-Tribal Fisheries and Assessment Program, Chippewa/Ottawa Resource Authority, 179 W. Three Mile Road, Sault Ste. Marie, MI, 49783, USA abstract article info Article history: Received 23 July 2010 Accepted 6 March 2011 Available online 20 April 2011 Communicated by Lars Rudstam Index words: Biomarkers Fatty acids Great Lakes Mussels Invasive species Lake whitefish Freshwater organisms synthesize a wide variety of fatty acids (FAs); however, the ability to synthesize and/or subsequently modify a particular FA is not universal, making it possible to use certain FAs as biomarkers. Herein we document the occurrence of unusual FAs (polymethylene-interrupted fatty acids; PMI-FAs) in select freshwater organisms in the Laurentian Great Lakes. We did not detect PMI-FAs in: (a) natural seston from Lake Erie and Hamilton Harbor (Lake Ontario), (b) various species of laboratory-cultured algae including a green alga (Scenedesmus obliquus), two cyanobacteria (Aphanizomenon flos-aquae and Synechococystis sp.), two diatoms (Asterionella formosa, Diatoma elongatum) and a chrysophyte (Dinobryon cylindricum) or, (c) zooplankton (Daphnia spp., calanoid or cyclopoid copepods) from Lake Ontario, suggesting that PMI-FAs are not substantively incorporated into consumers at the phytoplankton–zooplankton interface. However, these unusual FAs comprised 4–6% of total fatty acids (on a dry tissue weight basis) of native fat mucket (Lampsilis siliquoidea) and plain pocketbook (L. cardium) mussels and in invasive zebra (Dreissena polymorpha) and quagga (D. bugensis) mussels. We were able to clearly partition Great Lakes' mussels into three separate groups (zebra, quagga, and native mussels) based solely on their PMI-FA profiles. We also provide evidence for the trophic transfer of PMI-FAs from mussels to various fishes in Lakes Ontario and Michigan, further underlining the potential usefulness of PMI-FAs for tracking the dietary contribution of mollusks in food web and contaminant-fate studies. Crown Copyright © 2011 Published by Elsevier B.V. on behalf of International Association for Great Lakes Research. All rights reserved. Introduction Zebra and quagga mussels (Dreissena spp.) are freshwater bivalves native to the Caspian, Black and Azov Seas of Eastern Europe. They were introduced into the Laurentian Great Lakes through ballast water discharge from ocean-going ships and were first discovered in Lake St. Clair in 1988. Their adaptability, rapid life cycle, and high reproductive potential has ensured their continued invasion success and has led to their dominance over native mussels in the Great Lakes and elsewhere (Schloesser et al., 2006; Zanatta et al., 2002). The ecosystem impacts that zebra and quagga mussels (hereafter Journal of Great Lakes Research 37 (2011) 289–297 ⁎ Corresponding author. Tel.: +1 905 336 6460. E-mail addresses: tadej.mezek@gmail.com (T. Mezek), ed.sverko@ec.gc.ca (E. Sverko), martina.rudy@ec.gc.ca (M.D. Rudy), donna.zaruk@ec.gc.ca (D. Zaruk), capretf@mcmaster.ca (A. Capretta), craig.hebert@ec.gc.ca (C.E. Hebert), afisk@uwindsor.ca (A.T. Fisk), tnewton@usgs.gov (T.J. Newton), tmsutton@alaska.edu (T.M. Sutton), marten.koops@dfo-mpo.gc.ca (M.A. Koops), amuir@glfc.org (A.M. Muir), tim.johnson@ontario.ca (T.B. Johnson), mebener@lighthouse.net (M.P. Ebener), michael.arts@ec.gc.ca (M.T. Arts). 0380-1330/$ – see front matter. Crown Copyright © 2011 Published by Elsevier B.V. on behalf of International Association for Great Lakes Research. All rights reserved. doi:10.1016/j.jglr.2011.03.008 Contents lists available at ScienceDirect Journal of Great Lakes Research journal homepage: www.elsevier.com/locate/jglr