Effect of habitat selection on the dietary patterns of two triglid species

Abstract

The distribution patterns and feeding habits of 2 triglids, Trigloporus lastoviza and Lepidotrigla cavillone, were investigated for fish collected in experimental trawl surveys carned out along the Cretan continental shelf over 4 yr Despite their distribution overlap, depth and temperature selection differs considerably between species. T. lastoviza tended to select shallow depths and warm temperatures among those available, whereas L. cavillone was distributed throughout the exploited area and no significant temperature selection was found. Furthermore, no evidence of any size-depth relationship in either fish species was detected. Stomach content analysis revealed that both species were carnivores, feeding mainly on benthic invertebrates, and that each species consumed a narrow range of prey species with no significant dietary overlap. Classification and ordination of the gravin~etric and numerical contributions of prey species in their diets demonstrated that the dietary samples of the 2 species were distinct. Interspecific dietary overlap was less than intraspeclfic overlap between size classes and between months. Trophic diversity was higher for T. lastoviza and increased significantly with fish size, while no effect of size on the low dietary breadth of L. cavillone was found. Species differences in preference and utilization of prey are related to their distribution patterns. In particular, T lastoviza exhibited the most restricted distribution and appeared to have a broader trophic niche than L. cavillone, w h~c h occurs in a wider depth range. The results suggest that the abhty of these species to exploit particular habitats and/or specific prey characteristics is an important feature of predator foraging that allows them to segregate their feeding niche at the depth range at which they CO-occur.

Effect of an artificial reef in Posidonia meadows on fish assemblage and diet of Diplodus annularis

“…nMDS has been used before to detect changes in fish assemblages caused by fishing activities (Ehrich and Stransky, 1999), differences between seagrass and bare habitats (Connolly, 1994), and between coral and sandstone reefs (Ohman and Rajasuriya, 1998). Diet differences between two species and ontogenetic diet shifts among size classes have also been shown using nMDS (Labropoulou et al, 1997;Labropoulou and Machias, 1998). McCormick and Choat (1987) and Connell and Jones (1991) observed higher abundance of fish in reef habitat having higher complexity.…”

Relationships between macro‐epibenthic communities and fish on the shelf grounds of the western Mediterranean

“…Other species that showed different patterns of distribution depending on size were Chelidonichthys lastoviza and Trachinus draco, which presented the larger individuals clearly associated to Peyssonnelia beds, whereas smaller ones were more abundant on sandy-mud bottoms. The preference for sandy-mud and algae-covered areas by C. lastoviza, which mainly feeds on epibenthic and infaunal invertebrates, has been reported (Labropoulou and Machias, 1998). Trachinus draco has been associated with sandy-mud bottoms where they usually remain buried (Bagge, 2004).…”

A field experiment on trophic relations within the benthic boundary layer (BBL) over an oligotrophic continental shelf

“…Cartes et al, 2001Cartes et al, , 2009; Carrrass on and . Furthermore, most of the studies that have attempted to link prey selectivity by demersal fish with potential benthic food sources emphasize that there is a lack of data on the abundance of the prey organisms in the environment and therefore, it is not clear whether fish select their prey preferentially or exploit local food sources on a density-dependent pattern (Ben-Eliahu and Golani, 1990;Golani and Galil, 1991;Labropoulou and Eleftheriou, 1997;Labropoulou and Machias, 1998;Terrats et al, 2000).…”