Feeding of Barbus cyclolepis Heckel, 1837 (Teleostei: Cyprinidae) and its relationship with benthic macroinvertebrate fauna in the Istranca Stream (İstanbul, Turkey)

The aims of the study are to determine what the organisms Barbus cyclolepis consume as food in its feeding environments and to compare prey consumption with prey abundance in the environment. The study was conducted in the Istranca Stream located in Istanbul (Turkey) during the spring and summer of 2012. A total of 142 B. cyclolepis specimens were captured and it is determined that 94 of them had full digestive tracts. Diet analyses of B. cyclolepis showed that its food spectrum consisted of 11 different food types, and the species was found to feed on insects, mainly Diptera (IRI%= 92.26%). The most abundant macroinvertebrate organisms in the environment were Diptera and Gastropoda. The electivity index of B. cyclolepis was positive for Diptera in the spring (E= 0.49), but the value was below the expected value of 0.6 for high selectivity. The electivity values for other macroinvertebrate groups, consumed in low proportions, were negative. In summer, the fish fed on Diptera, Plecoptera, and Trichoptera, but a high electivity index value was found only for Trichoptera (E= 0.87). Results showed that B. cyclolepis mainly consumed Diptera as food and did not consume Gastropoda, although it is the second most abundant macroinvertebrate group in the environment. A relationship was determined between the proportion of food groups consumed in the digestive tracts of fish and the ratios of macroinvertebrates in the environment, and as a result, it was specified that the fish was selective on Diptera.

Food Spectrum, Trophic and Length-Weight Characteristics of Nonindigenous Suckermouth Armored Catfishes Pterygoplichthys spp. (Loricariidae) in Vietnam

The food spectrum and trophic and length–weight characteristics of an invasive species, South American suckermouth armored catfishes Pterygoplichthys spp. (Loricariidae), from lotic and lentic inland waters of Vietnam have been studied. It is found that the diet of suckermouth armored catfishes consists of plant and animal food, as well as organic detritus. According to the predominant type and pattern of feeding, suckermouth armored catfishes can be classified as detritivore gatherers (janitor). Some specimens of catfish with a high consumption of animal food have been identified. It is noted that invasive suckermouth armored catfishes can be a significant food competitor for aboriginal fish species; detritivores; and, possibly, benthophages in the lotic and lentic inland waters of Vietnam.

Feeding of young-of-the-year fishes of the Curonian lagoon of the Baltic sea in 2016

Results of studies on nutrition of juvenile fishes of the Curonian Lagoon of the Baltic Sea are presented. Material on young-of-the-years nutrition was collected in October 2016 during the expeditions of «AtlantNIRO» at 14 standard stations in the Curonian Lagoon. A total of 418 specimens of young-of-the-years were collected and processed. Juveniles of fishes of the Curonian Lagoon were represented by 10 species: pikeperch, bream, roach, perch, smelt, ruffe, three-spined stickleback, ninespine stickleback, bleak and sabrefish. Planktonic and benthic invertebrates formed a basis of the young-of-the-years diet. In most species of juvenile fishes, the nutritional spectra did not differ from the nutritional spectra in the range. An exception was juveniles of the ruff and ninespine stickleback, in which planktonic crustaceans predominated in the diet, while in other reservoirs they consumed bottom organisms. Only Cladocera and Copepoda were found in the diet of roach of juveniles; bottom organisms were absent. In the range of roach juveniles, bottom organisms and mollusks prevailed. The food similarity indices for juvenile fish in the Curonian Lagoon are quite high, which may indicate a tension in food relations between juveniles and (or) partial or complete overlap of their food niches. The weakening of food competition is ensured by the divergence of daily dietary peaks. Three-spined and nine-spined sticklebacks as well as a sabrefish and sticklebacks have the closest food spectrum. On the contrary, sabrefish and bream have a different food spectrum. The peculiarity of feeding of pikeperch juveniles in 2016 was the lack of transition to predatory nutrition.

A food spectrum analysis of three bufonid species (Anura: Bufonidae) from Uttarakhand region of the western Himalaya, India

The ecological diversity of insects and its predators like amphibians are important determinants in ecological balance. A total of 1,222 prey items in 84 specimens were examined to contribute the understanding of the diets of three Duttaphrynus species, viz., himalayanus, melanostictus, and stomaticus from Uttarakhand, the western Himalaya, India. Gut content analysis of three bufonids revealed acceptance of a wide range of terrestrial insects and other invertebrates as their food. The index of relative importance indicated that the most important preys were Formicidae, Coleoptera and Orthoptera. Duttaphrynus melanostictus had the broadest dietary niche breadth, followed by D. himalaynus and D. stomaticus. The wide prey spectrum well indicates that these species are the generalist and opportunist invertebrate feeder. Information pertaining to the food spectrum analysis contributes to understanding the ecological roles and used as a baseline data for future successful amphibian conservation and management programs in the Himalayan ecosystem.