Towards the development of an ecosystem model for the Hamilton Harbour, Ontario, Canada

Introduction Hamilton Harbour, also known as Burlington Bay, is a large embayment located at the western tip of Lake Ontario (Fig. 1). For decades, waste discharges from industrial andmunicipal activities had converted this scenic port into one of the most polluted sites in the Laurentian Great Lakes (Barica, 1989; Mayer and Johnson, 1994; Wolfe et al., 2000). As early as the 1850s, the Harbour was considered an unsuitable source of drinkingwater due to concerns about raw sewage contamination from the surrounding urban area. Toxic wastes from the steel and iron industry contaminated the system with heavy metals and coal tar that contained polyaromatic hydrocarbons and polychlorinated biphenyls (Poulton, 1987). By the 1940s, local beaches were closed to swimming and soon thereafter the Harbour water quality deteriorated to its lowest level, resulting in limited public access to the shoreline. The water quality problems were primarily manifested as excessive algal blooms, low water transparency, predominance of toxic cyanobacteria, and low hypolimnetic oxygen concentrations during the late summer (Gudimov et al., 2010, 2011; Hiriart-Baer et al., 2009; Leslie and Timmins, 1992; Ramin et al., 2011). Further, the elimination of the vegetated littoral zone and the disappearance of essential wetlands and fish nursery habitats, due to infilling for industrial activities as well as for railway or highway construction along the south and east shores of the Harbour, posedmajor threats to the integrity of the native fish community (Burley, 2007; Holmes andWhillans, 1984;Minns et al., 1994). Recognition of the broader repercussions of pollution to ecosystem functioning led to the designation of the Hamilton Harbour as one of 17 Canadian Areas of Concern (AOC) by the International Joint Commission (IJC) (International Joint Commission, 1988). Notably, several of the Beneficial Use Impairments (BUIs) and delisting objectives referred directly to fish, such as restrictions on fish and wildlife consumption, tainting of fish and wildlife flavour, degradation of fish and wildlife populations, fish tumours or other deformities, and loss of fish andwildlife habitat. Hamilton Harbour and its watershed previously supported more than 106 fish species and the local fish community historically contained a mixture of coldwater, coolwater, and warmwater species (Holmes, 1988). The system was considered an important habitat for lake trout (Salvelinus namaycush), Atlantic salmon (Salmo salar), lake herring (Coregonus artedii), and lakewhitefish (Coregonus clupeaformis), Journal of Great Lakes Research 38 (2012) 628–642 ⁎ Corresponding author. Tel.: +1 416 208 4858. E-mail addresses: [email protected] (M. Hossain), [email protected] (G.B. Arhonditsis), [email protected] (M.A. Koops), [email protected] (C.K. Minns). 0380-1330/$ – see front matter © 2012 International Association for Great Lakes Research. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jglr.2012.09.015