Bioenergetics and Prey Consumption of Breeding Double-crested Cormorants in the Beaver Archipelago, Northern Lake Michigan

A review of estimates of daily energy expenditure and food intake in cormorants (Phalacrocorax spp.)

“…There is a diversity of approaches even within categories such as bioenergetic models as well as within regions such as the Laurentian Great Lakes (Johnson et al 2002, Diana et al 2006, Seefelt and Gillingham 2008 and European sites (Gremillet et al 2003, Stewart et al 2005. When scaled-up, this inconsistency in per capita consumption parameters can lead to real differences in population levels of consumption.…”

Double-crested Cormorant (Phalacrocorax auritus) chick bioenergetics following round goby (Neogobius melanostomus) invasion and implementation of cormorant population control

“…Findings are compared to earlier research in the archipelago completed in 2000 (Seefelt and Gillingham, 2008) prior to the invasion of the round goby and cormorant control efforts. This study documents how changes in fish community structure and the recent intensity of human disturbances are manifested in cormorant nesting success and prey consumption.…”

“…High densities of birds combined with their observed fish-eating behaviors have led to their implication in declines of both commercial and recreational fisheries throughout the Great Lakes region (Lantry et al, 1999;Ludwig et al, 1989;Neuman et al, 1997). Although they can sometimes have an impact on fish populations, a number of studies have indicated that cormorants tend to have a small impact on Great Lakes fish populations and that impacts tend to be site-specific (Diana et al, 2006;Rudstam et al, 2004;Seefelt and Gillingham, 2008). Regardless, the perceived conflicts have spurred an active cormorant population control program by the U.S. Department of Agriculture-Wildlife Services (USDA-WS) through permits issued by the U.S.…”

“…Findings indicate that cormorant chicks consumed less fish in year 2001 compared to 2000; adults were also able to produce more offspring in 2001 compared to 2000. One possible reason for this was that a higher proportion of alewives were found in the diets of cormorants in 2001, and alewife has a higher caloric value than other fish in the diet (Seefelt and Gillingham, 2008). Studies have indicated a link between energy density of an organism's diet and its growth and body composition.…”

“…Many studies discuss the possible impact cormorants have on fish populations and their bioenergetic role (Craven and Lev, 1987;Fielder, 2008;Glanville, 1992;Seefelt and Gillingham, 2008). In a study conducted in the Beaver Archipelago in 2000 and 2001, the biomass of prey consumed by breeding cormorants was estimated using bioenergetics models (Seefelt and Gillingham, 2008).…”