Eating the Invaders: The Prevalence of Round Goby (Apollonia melanostomus) in the Diet of Double-Crested Cormorants on the Niagara River

From yellow perch to round goby: A review of double-crested cormorant diet and fish consumption at Three St. Lawrence River Colonies, 1999–2013

“…Reduced consumption of yellow perch by cormorants at St. Lawrence River colonies may alleviate suspected localized impacts on perch (Klindt and Town, 2003) at some of the colonies. These observations are consistent with those of Coleman et al (2012) who suggested that round goby may reduce predation on native fish species that have more economic or recreational value. More recently, the introduction of alewife into Lake Champlain and their dominance in cormorant diet has led to speculation that it could act as a buffer on yellow perch predation at some colonies (DeBruyne et al, 2012).…”

“…Similar to previous studies, our results illustrate how quickly cormorants adapt to an abundant new prey species (Somers et al, 2003;Coleman et al, 2012;Van Guilder and Seefelt, 2013). Johnson et al (2010) suggested that both opportunistic and adaptive behaviors were involved when Lake Ontario cormorants switched their diet from predominantly pelagic (alewife) and demersal (yellow perch) prey to a benthic prey (round goby).…”

“…However, if round goby were smaller than the yellow perch they replaced in the diet, this would also tend to increase daily fish consumption. In a study examining consumption of round goby by cormorants in another Great Lakes connecting corridor, the Niagara River, Coleman et al (2012) found that gobies contributed up to 85% of the diet and that cormorants may have been selecting larger individuals. Whereas the low caloric value of round goby may have led to increased fish consumption by cormorants, the presence of gobies in the diet appears to have not influenced seasonal trends in daily fish consumption.…”

“…Only one other study has been conducted in a connecting corridor such as the St. Lawrence River (Coleman et al, 2012). Cormorants were first observed nesting in the upper St. Lawrence River at Strachan Island in 1991.…”

Seasonal plasticity in telencephalon mass of a benthic fish

“…When N . melanostomus migrate to shallow water, they encounter not only many species of piscivorous fishes (Dietrich et al ., ; Reyjol et al ., ; Taraborelli et al ., ), but also water snakes (King et al ., ) and aquatic birds that hunt fishes near the shore (Somers et al ., ; Jakubas, ; Coleman et al ., ), therefore, increasing demands on spatial cognition to locate and remember sheltered locations. Moreover, male N .…”