Diet analysis of burbot (Lota lota) from eastern Lake Michigan: 1996–2012

Abstract

Burbot (Lota lota) stomach content was analyzed from eastern Lake Michigan using 835 stomach samples collected from 1996 to 2012. Our results show alteration in the prey community consumed between the early study period (1996–2006) and the more recent period (2007–2012). In the early years, alewives (Alosa pseudoharengus), slimy sculpin (Cottus cognatus), and mottled sculpin (C. bairdii) were the most important prey items, with regional variation suggesting greater use of Cottus spp. in the southern lake sites compared to northern sites where alewives were predominant. Non-native round gobies (Neogobius melanostomus) replaced Cottus spp. and alewives as the most frequently found prey item in the more recent years in the dataset, and other minor constituents of the prey assemblage nearly disappeared from the stomach samples. Round gobies first appeared in the diet in 1999 and became frequent by 2006, reaching 55.80% (±5.36) in 2012. The dominance of round goby as prey for burbot is important for the transfer of benthic nutrients into the upper food web in Lake Michigan. Our data highlight the striking food web shift linked to the non-native species invasion that has taken place in Lake Michigan since 2000 and emphasize its impact on native predator ecology.