Dietary habits of the deep‐sea flatfish Lepidorhombus boscii in north‐eastern Mediterranean waters

Abstract

Stomach content analysis of four-spotted megrim Lepidorhombus boscii in the oligotrophic Aegean Sea revealed that specimens with fully filled stomachs were rarely encountered. The overall dietary breadth of the species appeared to increase in winter and spring, when stomachs fullness was reduced. The species exhibited a relatively high trophic diversity and could be considered a euryphagous carnivore preying mainly upon crustaceans. Decapod natants, namely Processa canaliculata and Alpheus glaber, dominated in terms of per cent mass, while mysids, represented mainly by Lophogaster typicus, were the most important dietary component in terms of per cent number. Isopods, amphipods and decapod brachyurans were also frequently encountered among stomach contents. Fishes were only ingested by larger specimens (>180 mm total length, L T ); mouth gape dimensions increasing in larger specimens, enabled them to consume larger organisms. Discriminant function analysis showed that size and then sex of predators had the highest weight in discriminating the dietary groups produced by cluster analysis. Resource partitioning along the trophic dimension seemed to exist among smaller males and females (<110 mm L T ), which also presented significant differences in their mouth gape dimensions. The study of the diel feeding pattern of the species demonstrated that foraging activity took place day and night, while observed qualitative differences might partly reflect variations in prey availability on a 24 h basis.

Diet, growth and reproduction of four flatfishes on the Portuguese coast

“…The present study showed that feeding activity was higher in summer, the females showed lower vacuity values than males and the largest individuals had lower feeding activity than the smallest ones. This feeding behaviour is consistent with the findings of several authors (Belghyti et al, 1993;Vassilopoulou, 2006;de Juan et al, 2007). However, some authors (Redon et al, 1994;Morte et al, 1999;de Juan et al, 2007) have reported that the vacuity index was highest in spring-summer.…”

“…azevia showed a broader diet spectrum than the other three flatfish species, according to season, sex and size class. The diet breadth of M. azevia was higher in seasons when the feeding activity was lowest, which could correspond to a balance to compensate the decrease in prey availability during these seasons (Vassilopoulou, 2006).…”

“…Redon et al, 1994;Andersen et al, 2005;Vassilopoulou, 2006). These variations could be related to changes in space and time of benthic prey (e.g.…”

“…Studies on four-spotted megrim diet, age and growth and reproduction have been conducted in the western Europe and Mediterranean (e.g. Santos, 1994;Vassilopoulou and Ondrias, 1999;Landa et al, 2002;Vassilopoulou, 2006). Several authors have studied the diet, age and growth and reproduction of Platichthys flesus in northwestern Europe and in the Black Sea (e.g.…”

Feeding ecology of three tonguefishes, genus Cynoglossus (Cynoglossidae) in the Seto Inland Sea, Japan

“…The wide range of prey items and high dietary diversities may be indications of their generalized and opportunistic feeding habits. Many flatfishes, including Cynoglossus species, can be classified as generalist feeders, with their diets composed of a wide variety of preys (Dou 1995;Gibb 1997;Cabral et al 2002;Vassilopoulou 2006). These generalized feeding habits appear to be common phenomena in flatfish.…”