Frontiers in Marine Science (Nov 2015)
Feeding activity and diet composition of round goby (Neogobius melanostomus) in the coastal waters of SE Baltic Sea
Abstract
The round goby (Neogobius melanostomus) is a very successful invasive fish species, which was unintentionally introduced to the central Baltic Sea (Gulf of Gdansk) in 1990. Several years later after initial introduction round goby established a viable population, highly increased in abundance and expanded to the south-eastern and northern Baltic Sea coastal waters, becoming a key component of benthic ichthyofauna in invaded areas. To evaluate a potential threat of round goby to the coastal zoobenthic communities, feeding patterns, including feeding activity and diet composition of this invasive fish was examined using gut content analysis. Sampling was performed in the SE Baltic Sea, Lithuanian coastal waters during May-October 2012. Round gobies >100 mm were caught with multimesh gill nets, while <100 mm individuals were collected using baited minnow trap. Dietary analysis was performed in 318 differently sized round gobies. Feeding activity of round goby varied depending on body size, sex and stage of the reproduction period. Diet composition of individuals with the body length <100 mm and ≥200 mm was relatively constant in the course of the study, while individuals of the intermediate 100-200 mm length had more variable diet, which used to change depending on season. The gut contents of <50 mm gobies were dominated by small zooplanktonic and meiobenthic organisms, shifting to amphipods and mollusks in larger individuals (50-99 mm). In spring 100-200 mm round gobies mainly consumed infaunal bivalves Macoma balthica, in summer - polychaetes Hediste diversicilor, while in autumn the share of epibenthic bivalves Mytilus trossulus and fish prey increased considerably in their diet. Diet of ≥200 mm individuals was predominated by mollusks during whole study period.
Keywords
