The length and weight relationships and feeding ecology of knout goby, Mesogobius batrachocephalus (Pallas, 1814) from Southern Black Sea

Among ecologically diverse gobies species, knout goby, Mesogobius batrachocephalus (Pallas, 1814), or previously known as Gobius batrachocephalus, is a Black Sea endemic species. There are studies on this species biological features along the Black Sea but there are only studies on its length and weight relationship along the Turkish coasts of the Black Sea. This study aims to contribute to the lack of knowledge on knout goby length and weight relationship and feeding ecology inhabiting Southern Black Sea. Total of 470 individual of knout goby was collected and it was previously reported that knout goby shows negative (-) allometry though within this study it was found that it only shows negative (-) allometry in spring and positive (+) allometry in other seasons. The diet was composed of crustaceans, teleost fishes and gastropods. According to the relative importance analysis, teleost fishes are the main food item for all and male individuals but for female crustaceans are the main food item. Trophic level results show that for all individuals trophic levels is 4.34, and when sexes are compared females have higher trophic level than males. While both sexes only consume teleost during summer, in other seasons females prefer more crustacean in their diet compared to males. Niche breadth index results indicated that when all individuals diet was compared among seasons in winter the niche breadth was the broader and summer was the narrower, in case of females the broader was fall and for males it was winter. In conclusion, feeding ecology of knout goby changes between seasons and sexes but general prey groups remain the same

Snakes of the Pernambuco Endemism Center, Brazil: diversity, natural history and conservation

The Atlantic Forest is one of the largest and richest tropical rainforests on the planet, being one of the 25 world priorities for conservation. The Atlantic Forest portion located north of the São Francisco River corresponds to the Pernambuco Endemism Center (PEC). We describe the snake composition of the PEC, providing information about the diversity, natural history and geographical distribution of the species, based on records from five scientific collections and additional information from the literature. A total of 78 species of snakes distributed in eight families was registered in the Pernambuco Endemism Center. The Caatinga is the Brazilian biome that most shares species with the PEC, followed by Cerrado. On the other hand, seven species are considered endemic of this region. Most of the snake species in the PEC have been registered in forest (94.8%), followed by “Brejos Nordestinos” (46.1%), Tabuleiros (43.5%), Restingas (14.1%) and Mangroves (5.1%). The PEC snake fauna includes mainly terrestrial species (60.2%) and cryptozoic and/or fossorial species (21.7%), but also presents a high richness of semi-arboreal and arboreal species (29.5%). Vertebrates are the main food item consumed by the species (78% of species), among the main prey are mammals, lizards, and amphibians. Most species show a strictly nocturnal activity period (50%), followed by strictly diurnal (38%). The PEC is the most degraded and least known region of the Atlantic Forest, yet it has revealed a high richness of snake species, including seven endemic species. It is emphasized that regional conservation efforts need to be intensified, because few forests in the region are formally protected, and the majority consist of small and poorly protected fragments, which means that many species in the region may be in risk of extinction.

Variation in diet composition of the mudskipper, Periophthalmodon septemradiatus, from Hau River, Vietnam

Periophthalmodon septemradiatus (Hamilton, 1822) is a mudskipper of the Mekong Delta that can be found along estuaries and lower reaches of rivers. In the present study, we determined diet and feeding ecology of this species by analyzing the contents within the stomachs of 1360 fish samples collected from August 2017 to July 2018. Data analysis suggested that P. septemradiatus is a carnivorous fish. We found six main food item categories: small fishes, prawns (Acetes spp.), crabs (Uca spp.), molluscs, ants (Dolichoderus sp.), and detritus. Both males and females at different sizes, seasons, and habitats ingest primarily Dolichoderus sp., secondarily detritus, and rarely other prey. Diet composition was similar between sexes but varied according to fish size, season, and habitat. Dolichoderus sp. and detritus regulate the spatial variation of food composition. Our findings contribute to future artificial cultivation for conservation.

Contrasting variations in the diet of the Andean fox Lycalopex culpaeus Molina, 1782 on geographical and environmental scales in the Atacama Desert

We determined the seasonal diet of the Andean fox Lycalopex culpaeus in three habitats in the Atacama Desert, northern Chile, by analyzing their scat contents. We estimated the biomass and the number of individuals of each prey species consumed and compared our results with those of other studies on Lycalopex foxes in Chile and South America. In general, the L. culpaeus diet was characterized by a generalist behavior and higher dietary breadth than those in other ecosystems. In contrast with the other biomes of southern Chile and South America, insects represented the most frequent prey species in the present study and the main food item, comprising more than 50% of all prey at the three study sites; however, in terms of biomass, rodent and reptile prey showed the highest percentage from summer to winter. Significant differences were found between the biomass consumed among sites. Likewise, we found a relationship between the niche breadth of the diet and the primary productivity of the sites. Statistically significant differences in prey items consumed were noted across seasons and sites located at different altitudes, which reflected an opportunistic response to the availability of prey. Our report contributes to current data about the natural history of L. culpaeus in hyper-arid habitats.

FEEDING INTERACTION OF THE NON-NATIVE AFRICAN CATFISH (Clarias gariepinus BURCHELL, 1822) IN ITANHÉM RIVER ESTUARY, BAHIA, BRAZIL

A total of 214 stomachs of Clarias gariepinus, Centropomus undecimalis and C. parallelus from the Itanhém and Caravelas Rivers, northeastern Brazil, were analyzed to investigate the impact of the non-native species Clarias gariepinus on the Itanhém River food web as compared to that of the adjacent Caravelas River, where this species has not been registered. In Itanhém River, shrimp was the most important food for C. gariepinus, and Teleostei for C. parallelus. In the Caravelas River, Brachyura was the main food item for C. parallelus, and Teleostei for C. undecimalis. There was no food overlap between the species within or between rivers. There is no evidence, in the results of this study, of changes in the diet of the Centropomus parallelus due to the presence of the non-native species.

Description of diet of pelagic fish in the southwestern Atlantic, Brazil

This study reveals the food composition of pelagic fishes living in the southwestern Atlantic Ocean. As such more common pelagic species are considered to be top predators, the study proposes to know what constitutes their main food. Fish are not commonly found within their stomach contents, but instead, cephalopods are their most common food. As can be observed, Teuthida cephalopods compose their principal diet. The stomach contents of specimens of Xiphias gladius, Thunnus albacares, T. obesus, T. alalunga, Isurus oxyrinchus and Alopias superciliosus caught during July 2007 to June 2009 by using tuna longliners were studied. Teuthida cephalopods constitute the main food item for the three tuna species, while X. gladius feeds mainly on Ommastrephidae cephalopods. Though the differences among the kinds of cephalopods exist, they constitute the principal resource these fish use to live at least in the southern Atlantic Ocean.

Feeding habits of the pelagic stingray Pteroplatytrygon violacea (Chondrichthyes: Dasyatidae) in the Adriatic Sea

The feeding habits of the pelagic stingray (Pteroplatytrygon violacea) were studied using 84 stomachs of specimens caught in the northern Adriatic Sea in the period from April 2004 to October 2005. Percentage of empty stomachs found was overall very low, being a bit bigger in smaller specimens. The diet consisted of two main taxonomic groups such as teleost fish and cephalopods, but few specimens of crustaceans were recorded as well. The main food item was represented by anchovy, while cuttlefish and red band fish represented the alternative preys. Prey size was positively correlated with the size of predator. The proportion of anchovies in the diet grew with size of predator, while the one for red band fish decreased. The stingray was confirmed to be a top predator of pelagic fish species, although the presence of benthic prey shows that it feeds also at the bottom.

Diet composition and foraging activity of Pipistrellus pygmaeus in a floodplain forest

In 2000–2002 bat droppings were collected under the emerging crevice of a nursery colony of Pipistrellus pygmaeus. The locality was situated in a floodplain forest at the confluence of the Dyje and Morava rivers (S Moravia, Czech Republic). In total, 27 samples (20 pellets in one sample) of droppings were used to analyze prey remains. In the diet, 40 taxonomic groups of invertebrates were found. As expected, small dipteran insects were the main food item in which Nematocera dominated. Besides Chironomidae and Ceratopogonidae also a high percentage of nematoceran eggs were recorded. Surprisingly, a relatively high percentage of Brachycera was recorded. Further frequent prey items belonged to the orders of Trichoptera, Hymenoptera, Coleoptera and Sternorrhyncha. A heterodyne bat detector was used to follow foraging activity of P. pygmaeus on line transects in forest and water habitats in the vicinity of the colony. A significant decrease in foraging activity over water habitats and in forest sites during the late pregnancy (mid-May — early June) and an increase during the lactation and post-lactation periods (mid-June — early August) were found. Changes in the frequency of occurrence of Chironomidae, Neuroptera, Trichoptera, Aphidinea and Simuliidae were correlated with the bats’ foraging activity.

siphon nipping of the bivalve amiantis purpurata by the electric ray discopyge tschudii in mar del plata, argentina

a total of 67 discopyge tschudii was captured. individuals were sexed, measured and their stomach content analysed. siphon tips of the bivalve amiantis purpurata from each stomach were individually counted, weighed and their length and width measured. the size–frequency distribution of the local population of a. purpurata was surveyed for two years. siphons of a. purpurata were the main food item in 90% of individuals having stomach contents. the clam population was markedly bimodal, with 24 mm and 46 mm mean shell length for the younger and older size-classes, respectively. grazing by d. tschudii on a. purpurata varied with size and sex of the fish. small rays mainly ingested small siphons and large rays large siphons. nipped siphon tips were longer in male than in female rays.

Cannibalism as the main feeding behaviour of tucunares introduced in Southeast Brazil

Individuals of its own genus were the main food item of two species of tucunares (Cichla cf. ocellaris and Cichla monoculus) introduced into the Volta Grande Reservoir. The abundance of adult tucunares may cause intra-specific competition, possibly leading to the high cannibalism rates found.