Environmental abundances of the non‐native round gobyNeogobius melanostomusinfluence feeding of native fish predators

Abstract

AbstractThe authors assessed the importance of the round gobyNeogobius melanostomusas prey for three native predatory fish species, Atlantic codGadus morhua, European perchPerca fluviatilisand northern pikeEsox lucius, in a northern and southern area of the Baltic Proper, using a combination of visual analysis and DNA metabarcoding of predator stomach contents. To explore the influence of environmental abundances ofN. melanostomuson predation, they related the occurrence ofN. melanostomusin predator diets to its abundance in survey fishing.Gadus morhuaandE. luciusin the southern area showed the highest tendency to feed onN. melanostomuswhen it was abundant, asN. melanostomusoccurred in up to 100% of stomachs and constituted up to 88% of the total diet volume proportion. The diet contribution ofN. melanostomuswas associated withN. melanostomusabundances forG. morhuaandE. lucius, and whenN. melanostomuswas abundant, these predators exhibited lower prey richness and a higher degree of piscivory.G. morhuaandP. fluviatilisalso fed less on crustacean prey whenN. melanostomuswas abundant. The high importance ofN. melanostomusin diets of native fish predators may modify indirect interactions betweenN. melanostomusand native prey species in invaded coastal communities.