|Feeding ecology of four pelagic fish species: a case of the Belgian part of the North Sea|
Matola, H.D. (2014). Feeding ecology of four pelagic fish species: a case of the Belgian part of the North Sea. MSc Thesis. Universiteit Gent/VUB/Universiteit Antwerpen: Gent, Brussel, Antwerpen. 43 pp.
Pelagic fishes, planktonic food, stomach contents, North Sea
A comprehensive study of the feeding ecology of pelagic fish was conducted in the Belgian part of the North Sea. The aim of this study was to assess and compare the link of pelagic fish and their planktonic food sources of the Belgian part of the North Sea. The stomach contents of herring, mackerel, sprat and horse mackerel collected from January 2009 to January 2011 using RV Zeeleeuw. A total of 364 stomachs of 100 Herring (Clupea harengus), 56 Mackerel (Scomber scombrus), 145 Sprat (Sprattus sprattus), and 63 Horse mackerel (Trachurus trachurus) were analysed during this study. This study observed 64 prey taxa in the stomachs of fish which were dominated by Temora longicornis, Centropages hamatus and Schistomysis kervillei. The fullness index of all pelagic fish was not significant difference in all seasons. Only herring fullness index were significance different between nearshore, midshore and offshore while mackerel, sprat and horse mackerel were not differ. The ANOSIM pairwise comparison test shows no significant difference in the diets of herring versus mackerel while sprat versus horse mackerel and mackerel versus horse mackerel were significant difference. This study revealed highest dissimilarity (SIMPER) of herring and horse mackerel diets than mackerel and sprat. The SIMPER indicates greater dissimilarity in summer and autumn than winter and spring. More results indicated greater dissimilarity between nearshore and midshore. The size feeding selectivity of the herring and mackerel help to reduce competition in feeding whereby small size herring and mackerel select copepodites stages while large herring and mackerel select larvae stage of crustacean and fish. This study indicated that sprat was exclusively zooplanktivorous compared to herring, mackerel and horse mackerel.