Metazoan parasites and feeding behaviour of four small-sized fish species from the central North Sea.

The metazoan parasites and stomach contents of the small-sized demersal fishes Agonus cataphractus, Buglossidium luteum, Callionymus lyra and Rhinonemus cimbrius were studied and analysed. The fishes were captured using various sampling gears at 12 stations in the central North Sea. A total of 16 metazoan parasite species were isolated: six adult Digenea, three larval and adult Cestoda, four larval and adult Nematoda and three larval and adult Crustacea. With nine parasites species each, A. cataphractus and R. cimbrius harboured the highest parasite diversity, while B. luteum and C. lyra hosted only six and five parasite species, respectively. Eighteen new hosts and four new locality records were established. No Myxozoa, Monogenea or Acanthocephala were found. Most of the detected parasites showed a wide geographical range and a low host-specificity. The composition of the parasite fauna differed between the fish species, in accordance with their different feeding behaviours. The diet of bentho-pelagic feeders ( A. cataphractus, R. cimbrius) was more diverse in comparison with the more specialised benthic feeders ( C. lyra, B. luteum). This correlated with the lower diversity of heteroxenic parasites within both small-sized benthic fish species.