Diel-feeding activity in early summer of racer goby Neogobius gymnotrachelus (Gobiidae): a new invader in the Baltic basin

Abstract

The first recording of the Ponto-Caspian racer goby in Poland was during 1995 in the River Bug (River Vistula system). Within 5 years, the species had spread to the downstream section of the Vistula. One of the potential impacts of invasive species on native fauna is competition for food. Therefore, the diel patterns in diet composition and gut fullness coefficient (FC) of racer goby were examined at one study site in the Włocławski Reservoir (lower River Vistula), during May 2003. An average of 20 individuals were examined each 4 h over one 24-h period (125 fish in total). The proportion of main food items and diet width did not differ among three size-groups (43-59, 60-79 and 80-97 mm total length), and the relative biomass ratio of main food categories did not differ over the diel cycle. Amphipods constituted 11-70% of total gut content biomass and were found on average in 84% of analysed alimentary tracts. The second prey types were chironomid larvae (16-63% of total food biomass; frequency occurrence: 61-91%), and to a lesser extent chironomid pupa, ceratopogonid larvae, oligochaets, dipteran imagines and copepods, with fish larvae found in the gut of eight gobies. Gut fullness coefficient (FC) differed significantly over the 24-h period, with the highest value at night and in early morning. In conclusion, racer goby forages mainly on benthos and has a nocturnalfeeding activity. No significant diet overlap was found between racer goby and native percids, i.e. Eurasian perch Perca fluviatilis and ruffe Gymnocephalus cernuus.

Competitive interactions for food resources between invasive racer goby Babka gymnotrachelus and native European bullhead Cottus gobio

“…In our study, both fishes spent more time in the feeders in darkness, showing that they are both nocturnal species. Indeed, the bullhead has been reported as a dark-active species (Andreasson 1969;Prenda et al 2000), and recent research involving goby gut fullness coefficients indicates that the racer goby also feeds primarily at night (Grabowska and Grabowski 2005). The racer goby may possess enhanced sensory systems that facilitate better detection and capture of prey at night compared to the bullhead.…”

“…Both species are bottom dwellers of similar size, habitat use (crevices), and reproductive strategy (Tomlinson and Perrow 2003;Pinchuk et al 2003a) as well as similar dietary preferences, i.e. soft-bodied (non-mollusc) benthic invertebrates, especially chironomid larvae and amphipods (Welton et al 1991;Grabowska and Grabowski 2005;Kakareko et al 2005). The bullhead is effectively the European equivalent of the North American cottid, the mottled sculpin Cottus bairdi, which in the Great Lakes has been demonstrated to be adversely affected by invading round goby populations (Corkum et al 2004).…”

A New Species of the Gobiidae Family in Transylvania Waters: Racer Goby (Babka gymnotrachelus, Kessler 1857)

“…The following head measurements were determined: inter-orbital distance (I-oD) [1], nostrils intervals (N1-I, N2-I) [2,3], commissure interval (CI) [4], head length (HL) [5], head height (HH) [6], eye diameter (ED) [7], pre-orbital distance (Pre-o-D) [8], post-orbital distance (Post-o-D) [12], upper jaw length (UjL) [9], lower jaw length (LjL) [10] and snout length (SnL) [11].…”

Feeding habits ofPadogobius bonelli(Bonaparte, 1846) (Osteichthyes, Gobiidae): The importance of fish dimensions and hydrological conditions

“…and two Ephemeroptera species nymphs (Ephoron virgo, Potamanthus luteus) always represented the most important food items. Amphipoda constituted the most important food item in another Gobiidae, Neogobius gymnotrachelus, that also showed a marked preference for Chironomidae and, to a lesser extent, for Diptera Ceratopogonidae, Anellida Oligochaeta, adult Diptera and Copepoda (Grabowska & Grabowski 2005).…”