Spatial and temporal trends of muscle lipid content in Great Lakes fishes: 1970s–2008

An evaluation of spatial and temporal trends in fish lipid content may provide insight into trends of lipophilic contaminant levels, fish population health, and nutritional benefits to fish consumers. Currently, little is known about lipid content in fishes of the Great Lakes, where commercial and recreational fisheries are important. We examined 35+ years of muscle lipid content data for ten Great Lakes fishes from Canadian waters and found lipid content to have significantly (p < 0.05) declined in 2/6 species in Lake Superior, 3/8 species in Lake Huron, 1/8 species in Lake Erie, and 5/10 species in Lake Ontario. Lake Erie showed the least number of declining trends and most increasing trends (2/8 populations, p < 0.1). For most species, recent (2000–2008) muscle lipid values for Lakes Erie and Ontario are significantly higher compared with Lakes Superior and Huron. These observed trends may be linked to a number of environmental changes within the Great Lakes, and the mechanism(s) of decline are likely to be complex.