Gut length for several marine fish: relationships with body length and trophic implications

Tissue pH and gut ecomorphology in six freshwater teleostsoccupying different trophic levels

“…However, it is not always possible to place species in accordance with feeding category and relative gut length (Pogoreutz and Ahnelt, 2014). The differences are determined not only by the diet available, but also ontogeny and phylogeny of species (Elliott and Bellwood, 2003;Karachle and Stergiou, 2010). These observations were confirmed by relatively large differences in relative gut length between the omnivorous C. carpio and C. auratus in the present study.…”

“…In previous studies it has been demonstrated that relative gut length indicated that morphological features are correlated to feeding habits (Kapoor et al, 1976;De Silva et al, 1980;Karachle and Stergiou, 2010), and also that in a species it could vary depending on the habitat and the type of food ingested (De Silva et al, 1984). Noncarnivores in general need more time to digest food types like plants, detrital material, fragments, or small crustaceans in the extended intestine for abundant nutrient breakdown and absorption.…”

Morphometrics and Allometry in Fishes

“…The effect of diet could be anticipated, since, with food, organisms attain the necessary energy and nutrients for somatic growth and reproduction. Carnivorous feeding is considered as more profitable in terms of energy, whereas herbivorous diets or inclusion of plants in the daily "menu" (such as in the case of omnivores) requires larger 0373TL 1.7908 , N i =425, N s =8, R 2 =0.47, SE (b) =0.094, p<0.05 TA=0.0461TL 1.6871 , N i =863, N s =19, R 2 =0.74, SE (b) =0.034, p<0 quantities of food (e.g., Gerking 1994, Wootton 1998 or morphologic adaptations (e.g., longer intestines: Wootton 1998, Pennisi 2005, Karachle & Stergiou 2010b) to meet with energetic demands. When habitat type was examined, there was also a significant difference in the weight-length relationships.…”

“…it allows the detection of morphologic changes in shape, which is the basic hypothesis in the study of morphometrics (Lleonart et al 2002) 2. in contrast with the other types of models, the allometric one is the only one for which when X=0, then Y=0, a fact that is meaningful in morphometrics (Lleonart et al 2002), and 3. especially in the case of feeding related characteristics, it is the only one that can explain changes in the morphology such as required for a growing fish to meet its increasing energetic demands, while the energy spent for the acquisition of food is minimized (Karachle & Stergiou 2010b, 2011a.…”

“…The relationships of fish gut length (GL) with body length (BL), presented in Karachle & Stergiou (2010a) and Karachle & Stergiou (2010b), were used in order to check for GL changes in relation to feeding habits and habitat. Overall, relationships of GL-BL were used for 99 species, and the individual data for these species were grouped according to the FTGs of the species and habitat (see section 2.1).…”