scholarly journals Diet and foraging behavior of Ageneiosus inermis (Teleostei, Auchenipteridae)

2020 ◽  
Vol 15 (3) ◽  
pp. 209-218
Author(s):  
Tiago Magalhães da Silva Freitas ◽  
William Oliveira dos Santos ◽  
Bruno da Silveira Prudente ◽  
Luciano Fogaça de Assis Montag
Keyword(s):  
Habitat Use ◽  
Foraging Behavior ◽  
Prey Species ◽  
Feeding Strategy ◽  
Stomach Contents ◽  
Pelagic Species ◽  
Bottom Substrate ◽  
Xingu River ◽  
The Family ◽  
In The Wild

Ageneiosus inermis is the largest species of the family Auchenipteridae (Siluriformes) and has a primarily piscivorous diet, although no comprehensive data are available on the habitat use of this species. Given this, the present study describes the diet of A. inermis, and provides inferences on its habitat use, based on the known behavior of its prey species. We analyzed the stomach contents of 14 specimens collected in the middle of Xingu River in the Brazilian state of Pará, which we complemented with data on 47 other specimens obtained from two published studies. Most of the ingested items were fish associated with the bottom substrate and riverbanks. Although A. inermis is considered a pelagic species, we conclude it forages by exploring the river’s bottom and margins. Furthermore, as A. inermis is presumed to be diurnal, we assume that it does not pursue its prey actively, given that most of the prey species are nocturnal, but rather searches actively during the daytime for prey hidden in the bottom substrate. This hypothesis on the feeding strategy of A. inermis can only be confirmed by underwater observations, either in the wild or under captive conditions.

scholarly journals Ecología trófica de dos peces de la familia Gempylidae en aguas oceánicas del Pacífico Sur Oriental

2018 ◽  
Vol 53 ◽  
pp. 57
Author(s):  
Carlos Canales-Cerro ◽  
Patricio Barria ◽  
Patricia Zárate ◽  
Jorge Azócar ◽  
Roberto Meléndez ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Habitat Use ◽  
Feeding Strategy ◽  
Stomach Contents ◽  
Trophic Relationships ◽  
Mixing Models ◽  
Southeastern Pacific ◽  
Pacific Waters ◽  
Low Probability ◽  
Δ15n And Δ13c

The feeding of the escolar fishes Ruvettus pretiosus and Lepidocybium flavobrunneum has not been reported yet for southeastern Pacific waters. The main goal of this work was to study the trophic relationships using stomach contents and stable isotopes, δ15N and δ13C, based on mixing models. Results showed that both fish had differences in the importance of the prey, feeding strategy and habitat use. Also, they presented similar values of δ15N (~20‰) and δ13C (~-16‰), but a low probability of niche overlapping.

Diet and sexual maturation of the neon flying squid Ommastrephes bartramii during autumn and spring in the Kuroshio–Oyashio transition region

2008 ◽  
Vol 88 (2) ◽  
pp. 381-389 ◽  
Author(s):  
Hikaru Watanabe ◽  
Tsunemi Kubodera ◽  
Taro Ichii ◽  
Mitsuo Sakai ◽  
Masatoshi Moku ◽  
...  
Keyword(s):  
Transition Region ◽  
Sexual Maturation ◽  
Prey Species ◽  
Feeding Strategy ◽  
Ommastrephes Bartramii ◽  
Neon Flying Squid ◽  
The Difference ◽  
Diaphus Theta ◽  
The Kuroshio ◽  
Prey Items

Diet and sexual maturation were examined in the winter–spring cohort of the neon flying squid, Ommastrephes bartramii, during its southward migration through the Kuroshio–Oyashio transition region of the western North Pacific. The main prey items are micronektonic animals and small pelagic fish, which were abundantly distributed throughout the study area. Among the prey species, O. bartramii was dependent on the Japanese anchovy Engraulis japonicus, which also migrate from the northern to southern transition region during the winter, and the micronektonic squid Watasenia scintillans throughout the study period. Other common prey items were Gonatopsis borealis, Diaphus theta, and Ceratoscopelus warmingii from October to November or December, and Tarletonbeania taylori after December. These dietary changes can be explained by the difference in the seasonal north–south migration patterns of the predator and prey species. Male sexual maturation progressed throughout the season, and most individuals were fully mature in January. In contrast, most of the females were immature throughout the study period. The feeding strategy of the squid in relation to their seasonal north to south migration and sexual maturation was discussed.

Changes in Habitat Use and Feeding Chronology of Juvenile Rainbow Trout (Oncorhynchus mykiss) in Fall and the Onset of Winter in Silver Creek, Idaho

1993 ◽  
Vol 50 (10) ◽  
pp. 2119-2128 ◽  
Author(s):  
Michael D. Riehle ◽  
J. S. Griffith
Keyword(s):  
Rainbow Trout ◽  
Habitat Use ◽  
Oncorhynchus Mykiss ◽  
Density Distribution ◽  
Stomach Contents ◽  
Early Morning ◽  
Invertebrate Drift ◽  
Juvenile Rainbow Trout ◽  
Rainbow Trout Oncorhynchus Mykiss

We assessed changes in density, distribution, and microhabitat of age-0 rainbow trout (Oncorhynchus mykiss) in Silver Creek, a partially spring-fed stream, by periodic snorkeling in August 1987 through January 1988. We examined trout stomach contents and invertebrate drift samples in diel collections in August, September, October, and January to test if the period of feeding shifted from daytime to nighttime, concurrent with a transition to day concealment. In late September, fish aggregated briefly during the day and then began to conceal themselves in macrophyte beds, undercut banks, and submerged sedges and grasses along streambanks as temperature dropped below 8 °C in early October. Fish emerged from concealment at night, and numbers of trout visible were greatest 30–60 min after sunset and about 30 min before sunrise. Periods of peak feeding changed from afternoon and evening in August and September, when fish were day active, to mainly at night in October after the initiation of day concealment. Trout did not feed upon abundant chironomids in the daytime drift in October. In January, fish fed at 1–4 °C on mayflies, and stomachs were fullest in the early morning. Observations suggest that Silver Creek trout experienced a metabolic deficit that began in September.

scholarly journals Effect of Fermented Feed on the Microbial Population of the Gastrointestinal Tracts of Pigs

2001 ◽  
Vol 67 (7) ◽  
pp. 3071-3076 ◽  
Author(s):  
Ren� L. van Winsen ◽  
Bert A. P. Urlings ◽  
Len J. A. Lipman ◽  
Jos M. A. Snijders ◽  
David Keuzenkamp ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Significant Positive Correlation ◽  
Stomach Contents ◽  
Significant Negative Correlation ◽  
Inhibitory Effect ◽  
Positive Correlation ◽  
Fermented Feed ◽  
The Family ◽  
Colon And Rectum

ABSTRACT An in vivo experiment was performed with pigs to study the inhibitory effect of fermented feed on the bacterial population of the gastrointestinal tract. Results demonstrated a significant positive correlation between pH and lactobacilli in the stomach contents of pigs in dry feed as well as in the stomach contents of pigs fed fermented feed. Furthermore, a significant positive correlation between the pH and the numbers of bacteria in the familyEnterobacteriaceae in the contents of the stomach of pigs fed dry feed was found. In the stomach contents of pigs fed fermented feed, a significant negative correlation was found between the concentration of the undissociated form of lactic acid and the numbers of Enterobacteriaceae. The numbers ofEnterobacteriaceae in the contents of the stomach, ileum, cecum, colon, and rectum of pigs fed fermented feed were significantly lower compared with the contents of the stomach, ileum, caecum, colon, and rectum of pigs fed dry feed. The numbers of total lactobacilli were significantly higher in the stomach contents of pigs fed fermented feed and in the ileum contents of one pig group fed fermented feed compared with the contents of pigs fed dry feed. However, the influence of lactobacilli on numbers of Enterobacteriaceae could not be demonstrated. It was concluded that fermented feed influences the bacterial ecology of the gastrointestinal tract and reduces the levels of Enterobacteriaceae in the different parts of the gastrointestinal tract.

Assisted colonisation trial of the eastern barred bandicoot (Perameles gunnii) to a fox-free island

2017 ◽  
Vol 44 (7) ◽  
pp. 484 ◽  
Author(s):  
Rebecca Groenewegen ◽  
Dan Harley ◽  
Richard Hill ◽  
Graeme Coulson
Keyword(s):  
Habitat Use ◽  
Body Condition ◽  
Red Fox ◽  
Suitable Habitat ◽  
Viable Option ◽  
Predator Exclusion ◽  
In The Wild ◽  
Radio Transmitters ◽  
Release Group ◽  
Small Sites

Context Assisted colonisation has the potential to protect species from intractable threats within their historical ranges. The Australian mainland subspecies of the eastern barred bandicoot (Perameles gunnii) is extinct in the wild, with surviving populations restricted to small sites protected by predator–barrier fences. PVA modelling shows that a self-sustaining bandicoot population would require an area free of the introduced red fox (Vulpes vulpes) of at least 2500ha. French Island is outside the historic range of the species, but is fox-free and contains around 9000ha of potentially suitable habitat. Aims This study will assess the suitability of French Island as a potential site for a self-sustaining eastern barred bandicoot population by conducting a 1-year assisted colonisation trial to assess habitat use, body condition and survival. Methods Between July and September 2012, 18 adult bandicoots were released. We radio-tracked bandicoots using intraperitoneal radio-transmitters for up to 122 days and trapped fortnightly. Key results The release group met the three measures of success: (1) appropriate habitat use; (2) recovery of post-release bodyweight; and (3) founder survival exceeding 100 days. Habitat use and body condition throughout the trial reflected that of mainland populations, and seven bandicoots survived longer than 100 days. Mortality was greatest in the first month, with veterinary investigations confirming two deaths due to cat predation, two deaths from toxoplasmosis and one unknown cause of death. Bandicoots that survived longer than 100 days occupied higher, drier ground than those that did not. Toxoplasmosis cases were associated with lower topographic position on the site. Conclusions Our results suggest that French Island provides suitable habitat for the establishment of a population of eastern barred bandicoots. On French Island, toxoplasmosis was identified as an important source of mortality in addition to cat predation, and warrants further investigation. Implications Given the costs and challenges of predator control and the maintenance of predator exclusion fences, assisted colonisation to one or more fox-free islands remains the most viable option to establish self-sustaining bandicoot populations. Our results highlight the value in conducting trial releases ahead of major translocations.

scholarly journals Prey consumed by Guiana dolphin Sotalia guianensis (Cetacea, Delphinidae) and franciscana dolphin Pontoporia blainvillei (Cetacea, Pontoporiidae) in an estuarine environment in southern Brazil

2012 ◽  
Vol 102 (2) ◽  
pp. 131-137 ◽  
Author(s):  
Marta J. Cremer ◽  
Pedro C. Pinheiro ◽  
Paulo C. Simões-Lopes
Keyword(s):  
Prey Species ◽  
Stomach Contents ◽  
Frequency Of Occurrence ◽  
Teleost Fishes ◽  
Southern Brazil ◽  
Sympatric Populations ◽  
Sotalia Guianensis ◽  
Important Prey ◽  
Pontoporia Blainvillei ◽  
Lolliguncula Brevis

The present study provides information about the diet of sympatric populations of small cetaceans in the Babitonga Bay estuary. This is the first study on the diet of these species in direct sympatry. The stomach contents of seven Guiana dolphins Sotalia guianensis and eight franciscanas Pontoporia blainvillei were analyzed. The prey of both cetaceans was mostly teleost fishes, followed by cephalopods. We identified 13 teleost fishes as part of the diet of the franciscanas, and 20 as part of the diet of Guiana dolphins. Lolliguncula brevis was the only cephalopod recorded, and was the most important prey for both cetaceans. Stellifer rastrifer and Gobionellus oceanicus were also important for franciscana, so as Mugil curema and Micropogonias furnieri were important for Guiana dolphins. Stellifer rastrifer and Cetengraulis edentulus were the fishes with the highest frequency of occurrence for franciscana (50%), while Achirus lineatus, C. edentulus, S. brasiliensis, Cynoscion leiarchus, M. furnieri, M. curema, Diapterus rhombeus, Eugerres brasilianus and G. oceanicus showed 28.6% of frequency of occurrence for Guiana dolphins. Franciscanas captured greater cephalopods than the Guiana dolphins in both total length (z= -3.38; n= 40; p< 0.05) and biomass (z = -2.46; n = 40; p<0.05). All of the prey species identified occur inside the estuary, which represents a safe habitat against predators and food availability, reinforcing the importance of the Babitonga Bay for these cetacean populations.

Diet and feeding strategy of thornback ray, Raja clavata (Chondrichthyes: Rajidae) from the Gulf of Gabes (Tunisia—Central Mediterranean Sea)

2014 ◽  
Vol 94 (7) ◽  
pp. 1509-1516 ◽  
Author(s):  
Hasna Kadri ◽  
Sondes Marouani ◽  
Mohamed Nejmeddine Bradai ◽  
Abderrahmen Bouaïn
Keyword(s):  
Feeding Strategy ◽  
Stomach Contents ◽  
Ontogenetic Changes ◽  
Central Mediterranean ◽  
Gulf Of Gabes ◽  
Gulf Of Gabès ◽  
Thornback Ray ◽  
Raja Clavata ◽  
Food And Feeding ◽  
Quantitative Analyses

Food and feeding strategy of the thornback ray, Raja clavata, were studied from stomach contents analysis of specimens caught monthly in the Gulf of Gabes. The data were analysed according to sex, size and season. At total of 1280 stomachs was examined, from specimens ranging from 14 to 110 cm total length (TL), of which 1076 (83.98%) contained food. Thornback ray feed mainly on teleosts, crustaceans and cephalopods, whereas gastropods and polychaetes are occasionally consumed. Significant differences were found between the diets of males and females; however, ontogenetic changes were also detected, with crustaceans constituting the greatest proportion of the diet of smaller rays. Both teleosts and cephalopods increased in importance with growth of the skates. Prey diversity increased with size; large and mobile prey species were more commonly found in the diet of larger skates. Diet composition showed seasonal variations. Quantitative analyses and graphical methods indicate that the thornback ray is a generalist feeder.

Ontogenetic shifts in natural diet, chelae, and mandible of an omnivorous freshwater crab (Aegla uruguayana): linking morphology and function

2021 ◽  
Author(s):  
Maria Florencia Viozzi ◽  
Juan Manuel Cabrera ◽  
Federico Giri ◽  
Debora de Azevedo Carvalho ◽  
Verónica Williner
Keyword(s):  
Morphological Changes ◽  
Feeding Strategy ◽  
Stomach Contents ◽  
Trophic Niche ◽  
Composition Analysis ◽  
Diet Change ◽  
Geometric Morphometric ◽  
Natural Diet ◽  
Plant Remains ◽  
And Function

We analyze whether ontogenetic diet change in Aegla uruguayana (Schmitt, 1942) is related to the morphological changes in chelae and mandibles. We use a combination of scanning electron microscope observation (SEM), dietary composition analysis (stomach observation, trophic niche amplitude, trophic overlap, and feeding strategy), and geometric morphometric tools (discriminant analysis and two-block partial least squares analysis). The two structures analyzed by SEM show differences between juvenile and adult specimens, both in their cuticle and morphology specializations. In juveniles, the absence of the lobular tooth is the notable feature. However, in adult sizes it is marked development. Both groups have simple setae with infracuticular articulation and denticles with different arrangements between groups. In the incisive mandible process, the teeth and spines present sharper points in juveniles and considerable wear in adults. Aegla uruguayana presented two trophic strategies: a profile of more predatory traits when younger and mostly detritivorous when adults. The analysis of geometric morphometry substantiates the patterns observed in SEM and stomach contents analysis. The morphology of smaller specimens is associated with the consumption of animal items (ephemeropterans larvae and cladocerans), while in those of larger sizes; it is related to the consumption of plant remains.

scholarly journals Resource use by two electric fishes (Gymnotiformes) of the National Forest Saracá-Taquera, Oriximiná, Pará

2017 ◽  
Vol 15 (2) ◽  
Author(s):  
Bruno E. Soares ◽  
Daniela C. O. Rosa ◽  
Nathália C. S. Silva ◽  
Miriam P. Albrecht ◽  
Érica P. Caramaschi
Keyword(s):  
Resource Use ◽  
Niche Breadth ◽  
Feeding Strategy ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Feeding Strategies ◽  
National Forest ◽  
Microhabitat Use ◽  
Use Patterns ◽  
Head Morphology

ABSTRACT Fishes of the order Gymnotiformes have high diversity of oral and head morphology, which suggests trophic specializations within each clade. The aim of this study was to describe resource use patterns by two fish species (Gymnorhamphichthys rondoni and Gymnotus coropinae) in the National Forest Saracá-Taquera, Oriximiná - Pará, analyzing microhabitat use, diet composition, feeding strategies, niche breadth and niche overlap. Stomach contents of 101 individuals (41 G. rondoni and 60 G. coropinae), sampled in 23 headwater streams were analyzed and volume of food items was quantified to characterize their feeding ecology. Gymnorhamphichthys rondoni was captured mainly on sandy bottoms, whereas G. coropinae in crevices. Both species had a zoobenthivorous diet and consumed predominantly Sediment/Detritus and Diptera larvae, but also included allochthonous prey in their diet. These species had high niche overlap, with small variations related to the higher consumption of Ceratopogonidae larvae by G. rondoni and of Chironomidae larvae by G. coropinae. Both species had a generalist feeding strategy, but G. coropinae had a broader niche breadth. Our results demonstrate that G. rondoni and G. coropinae occupy different microhabitats but rely on similar food resources.

Sign in / Sign up

Export Citation Format

Share Document