Comparative studies on goby (Teleostei) parasite communities from the North and Baltic Sea

The parasite communities of three goby species from the marine North and the brackish Baltic Sea were compared. The samples of summer 1992/93 from Helgoland, Lubeck and Kiel Bight comprised a parasite spectrum of 4-5 in Pomatoschistus microps, 2-3 in P. pictus or 3-8 parasite species in Gobiusculus flavescens. The highest numbers were found in Kiel Bight whereas those of Helgoland and Lubeck Bight differed between 3 and 7, respectively. In comparing the species identity of the studied localities the value was intermediate in P. microps, low in P. pictus and zero in G. flavescens. Values of prevalence and abundance were clearly lower in Helgoland than in Baltic localities. The prey of Helgoland goby populations comprised meio- and macrobenthos in P. microps, predominantly macrobenthos but also meiobenthos and some plankton in P. pictus, and predominantly plankton and some benthos in G. flavescens. Former studies (Zander in J Zool Syst Evol Res 32:220 1994) revealed a greater variability of prey choice in the Baltic. The greater parasite richness in the Baltic compared with that of Helgoland, may lie on better adaptations of genuine brackish components, lower defence mechanisms of hosts as a consequence of lower salinity, and greater variability in habitat choice. The effect of several filters on the colonisation of parasites in hosts is submitted here in a model.