scholarly journals Diet overlap and feeding preference of Oreochromis niloticus (Linnaeus, 1758) versus two native cichlids of the upper Kabompo River, northwest of Zambia.

2021 ◽  
Author(s):  
Arthertone Jere
Keyword(s):  
Oreochromis Niloticus ◽  
Native Species ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Size Class ◽  
Diet Shift ◽  
Food Web Structure ◽  
Size Classes ◽  
Dietary Niche

Evaluating the food and feeding habits of fish is fundamental in fisheries and conservation biology research. In this study, the diet of exotic Oreochromis niloticus was compared with the 2 most abundant and aquaculture preferred native cichlids of native species (Orochromis macrochir and Coptodon rendalli) in the upper Kabompo River, Zambia. We hypothesized that exotic and native cichlids would show no dietary niche overlap. We analyzed the stomach contents of 114 specimens of the fishes sampled. Fishes were grouped into 3 major feeding groups: microphages, macrophages and carnivores, and omnivores. They were also grouped into size classes of <50, 51−100, 101−150, and 151−302 mm total length (TL). O. niloticus had a larger dietary niche than two native species (71% and 22%, respectively). The dietary niche overlap between O. niloticus and native C. rendalli species in size classes <50 was significant (F (2, 45) = 0.084, p < 0.05). Dietary niche overlap between the native O. macrochir species in size class <50 mm was low (F (2, 33) = 2.13, p > 0.05), while as in size classes 51−100 mm and 101−150 mm was high (F (2, 35) = 0.27, p < 0.05) for C. rendalli. There was no clear evidence of ontogenetic diet shift of native cichlids, with the exception of O. macrochir, which showed ontogenetic diet shifts within the 51−100 mm size class. The dietary overlap results indicate interspecific competition between exotic O. niloticus and native O. macrochir, which may have major impacts on food web structure in the upper Kabompo River and may explain population decreases of some native species.

Diet of the endangered spirlin (Alburnoides bipunctatus) at the centre of its distribution in Europe

2018 ◽  
Vol 69 (11) ◽  
pp. 1712
Author(s):  
L. Marszał ◽  
M. Grzybkowska ◽  
D. Błońska ◽  
J. Leszczyńska ◽  
M. Przybylski
Keyword(s):  
Resource Use ◽  
Diet Composition ◽  
Feeding Habits ◽  
Open Water ◽  
Size Class ◽  
Habitat Segregation ◽  
Chironomid Larvae ◽  
Size Classes ◽  
Taxonomic Groups ◽  
Distribution In Europe

The feeding habits of spirlin Alburnoides bipunctatus were investigated in a tributary of the River Vistula (Poland). To evaluate size-related patterns of resource use, fish were assigned to three size classes, defined according to size at first maturation: small (29–70-mm total length, TL), medium (71–90mm TL) and large (91–104mm TL). There was a significant ontogenetic shift in the feeding pattern among size classes, marked by differences in the proportion of the main taxonomic groups of prey consumed: small spirlin primarily consumed chironomid larvae, whereas medium and large spirlin showed a preference for Coleoptera, Ephemeroptera and imagines of unidentified insects. The proportion of prey taken from the water column was significantly lower for small- than medium- and large-sized spirlin. This difference was attributed to the benthic habits of small spirlin compared with medium and large spirlin. The shift to open water feeding in spirlin corresponded with sexual maturation, with habitat segregation between the smallest size class (comprising juveniles) and larger size classes (mature individuals). Size-specific changes in the diet composition of this species have not previously been documented.

Diet, feeding behaviour and habitat utilisation of the blue stingray Dasyatis chrysonota (Smith, 1828) in South African waters

2003 ◽  
Vol 54 (8) ◽  
pp. 957 ◽  
Author(s):  
David A. Ebert ◽  
Paul D. Cowley
Keyword(s):  
Surf Zone ◽  
Stomach Contents ◽  
Size Class ◽  
Behaviour Pattern ◽  
Medium Size ◽  
Secondary Importance ◽  
Size Classes ◽  
Important Prey ◽  
Large Size ◽  
Large Size Class

Analysis of stomach contents for Dasyatis chrysonota revealed that diet varied with size and habitat. The diet of all size classes in the surf zone was comprised primarily of Callianassa spp., Donax spp. and unidentified polychaete species. The medium and large size classes fed primarily on Donax spp., whereas the very large size class fed mainly on Callianassa spp. Polychaetes were of secondary importance as prey for the medium size class. The diet of D. chrysonota in the nearshore zone consisted mainly of Balanoglossus capensis and Callianassa spp. Balanoglossus capensis decreased from an index of relative importance (IRI) of 75.3% for the medium size class to 59.9% for the very large size class, whereas Callianassa spp. increased from 22.8% to 39.4% between the medium and the very large size classes. The offshore zone was the only area in which small size class D. chrysonota were caught. The diet of these small D. chrysonota was primarily polychaetes and amphipods. Polychaetes increased in importance in the medium size class, but declined in each successively larger size class. Conversely, Pterygosquilla armata capensis became the single most important prey item for the very large size class, comprising an IRI of 50.9%. The behaviour pattern used by D. chrysonota to locate and extract prey is described.

Feeding ecology of little tunny Euthynnus alletteratus in the central Mediterranean Sea

2007 ◽  
Vol 87 (4) ◽  
pp. 999-1005 ◽  
Author(s):  
Manuela Falautano ◽  
Luca Castriota ◽  
Maria Grazia Finoia ◽  
Franco Andaloro
Keyword(s):  
Mediterranean Sea ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Prey Abundance ◽  
Central Mediterranean ◽  
Size Classes ◽  
Larval Stages ◽  
Important Prey ◽  
Predator Size ◽  
Central Mediterranean Sea

The feeding habits of Euthynnus alletteratus and its variations compared to predator size in the central Mediterranean Sea were investigated. The stomach contents of 187 specimens were analysed, ranging from 26.8 to 50.3 cm total length, caught by authorized experimental drift-nets. The difference in food items found in the stomachs was evaluated by occurrence of prey frequency, prey weight, and prey abundance; these criteria were used to calculate an index of relative importance. Fish were the dominant food detected according to all numerical indicators examined and were mainly represented by Maurolicus muelleri and larval stages of teleosts. Hyperiid amphipods, dominated by Anchylomera blossevillei and Phrosina semilunata, were well represented in terms of frequency of occurrence. Variations in the diet composition compared to fish size were observed. Comparative analysis performed on prey abundance highlighted a trend of increasing predator size-classes among prey items. The specimens of the smallest sizes ate mainly adult clupeiforms and larvae or other juvenile teleosts. As fish grew, there were increased amounts of adult teleosts, crustaceans (hyperiids and isopods) and cephalopods. Maurolicus muelleri was the most important prey for the largest specimens analysed. Significant differences among size-classes, both in prey abundance and in prey weight, were confirmed by non-parametric multivariate analysis of variance (NP-MANOVA).

Feeding habits of John Dory, Zeus faber, off the Portuguese continental coast

1999 ◽  
Vol 79 (2) ◽  
pp. 333-340 ◽  
Author(s):  
Alexandra Silva
Keyword(s):  
Prey Species ◽  
Feeding Habits ◽  
Parallel Evolution ◽  
Stomach Contents ◽  
Abundant Species ◽  
Temporal Variations ◽  
Food Composition ◽  
Diet Shift ◽  
Feeding Intensity ◽  
Zeus Faber

The feeding habits of John Dory (Zeus faber) were studied, based on the analysis of stomach contents from fish sampled in five groundfish surveys. These surveys were carried out off the Portuguese coast during different seasons between 1990 and 1992. The main aspects of feeding biology analysed in this paper are: ontogenetic diet changes, temporal variations in food composition and feeding intensity. Multivariate methods were used to investigate ontogenetic diet shifts. Two main length groups were identified: 8.0–24.9 cm fish, feeding mainly on dragonets and silvery pout, and 25.0–55.9 cm fish whose diet was mainly composed of blue whiting and snipefish. A transitional phase (24.0–30.9 cm fish) with a mixed food composition was observed. This ontogenetic diet shift does not seem to correspond to any important change in body morphology but it does coincide with the onset of sexual maturity in the species.John Dory switched from a diet of small prey species with more pronounced benthic behaviour to a diet of larger schooling pelagic species. This suggests parallel evolution to more pelagic foraging behaviour. However, John Dory feeding habits appear to be largely controlled by the availability and accessibility of prey species: (i) the diet of adult John Dory is dominated by very abundant species; (ii) shifts in the main prey items between different times of the year and between different areas seem to be related both with their absolute and relative abundance in the environment and with the overlap between the depth distribution of predator and prey.

scholarly journals New insight into the trophic position and ecological role of the European hake (Merluccius merluccius L., 1758) in Central and Southern Tyrrhenian Sea (Central Mediterranean Sea).

2021 ◽  
Author(s):  
Claudio D'Iglio ◽  
Nunziatina Porcino ◽  
Adriana Profeta ◽  
Anna Perdichizzi ◽  
Enrico Armeli Milicante ◽  
...  
Keyword(s):  
Trophic Position ◽  
Feeding Habits ◽  
Diet Shift ◽  
Tyrrhenian Sea ◽  
Ecological Role ◽  
Size Classes ◽  
Geographical Variations ◽  
Prey Composition ◽  
European Hake

This paper aims to investigate the ecological role of Merlucicius merluccius, Linnaeus, 1758, in the southern and central Tyrrhenian Sea (GSA 10, Resolution GFCM/33/2009/2 General Fisheries Commission for the Mediterranean), analysing ontogenetic diet shift, geographical variations on prey composition and feeding habits. A sample of 734 hake specimens between 6 cm and 73 cm of total length (TL) were collected in 2018. To value the ontogenetic shifts in prey composition, five size-classes were created from the sample and for each class were calculated quantitative feeding indices. The cluster and MDS analysis, based on the % IRI, resulted in three trophic groups of hake size classes. The most abundant preys for small hake (size class I) were the Euphausiids, Stylocheiron longicorne and Mysidacea, while for hake with size over 10.5 cm of TL were crustaceans and fish. Engraulis encrasicolus was the most abundant prey fish for hake, followed by Boops boops and Myctophids. The mesopelagic fauna had a relevant role in the European hake diet in the southern zone. The high presence of Euphausiids, Mysids, Myctophidae and Sternoptychidae in the gut content of juvenile hakes (6-23 cm) showed the importance of organic matter and energy flowed from the mesopelagic environment to the epipelagic. Important is also the presence of decapod crustaceans in hake with size over 36 cm TL considering that our study area includes an important Gulf for the fishing of decapod crustacea.

Feeding habits of Urotrygon microphthalmum (Myliobatiformes: Urotrygonidae) caught off northeastern Brazil

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Jones Santander-Neto ◽  
Dante J. V. Freitas ◽  
Hugo Bornatowski ◽  
Rosângela Lessa
Keyword(s):  
Trophic Level ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Critically Endangered ◽  
Northeastern Brazil ◽  
Diet Shift ◽  
Ontogenetic Diet Shift ◽  
Food Items ◽  
Males And Females ◽  
Stomach Contents Analysis

Abstract The feeding habits of Urotrygon microphthalmum, a Critically Endangered (CR) species, were investigated through stomach contents analysis from specimens caught on bottom double rigged otter trawls in Pernambuco state, Brazil, between March of 2010 and March of 2012. A total of 338 stomachs were analyzed, and 31 food items were identified in the diet of U. microphthalmum. The species ingests mainly shrimps. The diets between males and females were not different, and an ontogenetic diet shift was not observed. The estimated species’ trophic level is 3.5, classifying it as a secondary order consumer.

scholarly journals Feeding ecology of invasive Perccottus glenii (Perciformes, Odontobutidae) in Slovakia

2008 ◽  
Vol 53 (No. 11) ◽  
pp. 479-486 ◽  
Author(s):  
J. Koščo ◽  
P. Manko ◽  
D. Miklisová ◽  
L. Košuthová
Keyword(s):  
Feeding Ecology ◽  
Diet Composition ◽  
Stomach Contents ◽  
Size Class ◽  
Perccottus Glenii ◽  
Class Groups ◽  
Size Classes ◽  
Lower Size

Stomach contents of 331 specimens of <I>Perccottus glenii (Perciformes: Odontobutidae</I>) were analysed. Chironomids and ephemeropterans dominated the diet of all size classes of fish; however, the frequency of crustaceans was also high. Micro-crustaceans (ostracods, copepods and cladocerans) dominated in lower size classes (20–39 mm); macro-crustaceans <I>(Isopoda, Amphipoda</I>) dominated in higher size classes (up to 79 mm). The proportion of crustaceans decreased from the size class 80–89 mm. With the increasing size of fish the frequency of molluscs (<I>Gastropoda</I>) increased, the maximum was in size class 70–79 mm. Cannibalism occurred from 60 mm, and it was significant from 80 mm. The highly mobile invertebrates (<I>Coleoptera, Heteroptera</I>) were found in the largest size classes. In middle size classes (40–59 mm), the widest spectrum of prey units was documented; the food variability of small (90 mm) individuals was poor. Differences in the diet composition of small individuals were negligible; the diet of the largest ones differed significantly. According to diet, two feeding size class groups were recognised: the first

Spatial and trophic niche overlap between Diplodus bellottii and Diplodus vulgaris in the Tagus estuary, Portugal

2004 ◽  
Vol 84 (4) ◽  
pp. 837-842 ◽  
Author(s):  
Manuel Horta ◽  
Maria José Costa ◽  
Henrique Cabral
Keyword(s):  
Feeding Habits ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Sea Bream ◽  
Tagus Estuary ◽  
Otter Trawl ◽  
Limiting Factor ◽  
Species Competition ◽  
Competition For Space

To evaluate the consequences of the coexistence of the Senegal sea bream Diplodus bellottii with one other species of Diplodus, Diplodus vulgaris, in the Tagus estuary (Portugal), the distribution and feeding habits of juveniles and adults of both species were studied. Sampling took place between May 2001 and March 2002, in five zones, including the estuary and adjacent coastal area, using an otter trawl. Both species were abundant in the estuary and their distribution overlapped. The stomach contents analysis showed that the diet of both species was mainly composed of algae, bivalves and crustaceans. Diphodus bellottii and D. vulgaris showed a generalist feeding behaviour and were clearly omnivorous, being detected in a high trophic niche overlap between the two species. Competition for space and food may occur when densities are high and food became a limiting factor.

High Dietary Niche Overlap Between Non-native and Native Ant Species in Natural Ecosystems

2020 ◽  
Author(s):  
Anna F Probert ◽  
Darren F Ward ◽  
Jacqueline R Beggs ◽  
Sarah J Bury ◽  
Syrie M Hermans ◽  
...  
Keyword(s):  
Native Species ◽  
Sequence Data ◽  
Niche Overlap ◽  
Trophic Levels ◽  
Gut Contents ◽  
Isotopic Niche ◽  
Dietary Overlap ◽  
Natural Ecosystems ◽  
Pattern Sequence ◽  
Dietary Niche

Abstract Ants represent a highly diverse and ecologically important group of insects found in almost all terrestrial ecosystems. A subset of ant species have been widely transported around the globe and invade many natural ecosystems, often out-competing native counterparts and causing varying impacts on recipient ecosystems. Decisions to control non-native ant populations require an understanding of their interactions and related impacts on native communities. We employed stable isotope analysis and metabarcoding techniques to identify potential dietary niche overlap and identify gut contents of 10 ant species found in natural ecosystems in Aotearoa New Zealand. Additionally, we looked at co-occurrence to identify potential competitive interactions among native and non-native ant species. Ants fed mainly across two trophic levels, with high dietary overlap. Relative to other ant species sampled, two non-native ant species, Linepithema humile and Technomyrmex jocosus, were found to feed at the lowest trophic level. The largest isotopic niche overlap was observed between the native Monomorium antarcticum and the invasive Ochetellus glaber, with analyses revealing a negative co-occurrence pattern. Sequence data of ant gut content identified 51 molecular operational taxonomic units, representing 22 orders and 34 families, and primarily consisting of arthropod DNA. Although we generally found high dietary overlap among species, negative occurrence between a dominant, non-native species and a ubiquitous native species indicates that species-specific interactions could be negatively impacting native ecosystems. Our research progresses and informs the currently limited knowledge around establishing protocols for metabarcoding to investigate ant diet and interactions between native and non-native ant species.

scholarly journals DIETARY ANALYSIS OF THREE SPECIES OF THE GENUS Anolis (SAURIA: DACTYLOIDAE) IN “LOS TUXTLAS,” VERACRUZ, MEXICO

2019 ◽  
Vol 2 (1) ◽  
pp. 26
Author(s):  
Oscar Alberto Flores Villela
Keyword(s):  
Dietary Diversity ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Los Tuxtlas ◽  
Generic Competition ◽  
Dietary Analysis ◽  
Shannon’S Index ◽  
Dietary Niche ◽  
Niche Displacement ◽  
Generalist Diet

Anoles have been studied by researchers to a greater extent than any other group of lizards. Their high diversity has led them to colonize a variety of niches, making them an ideal model group for evaluating ecological hypotheses such as dietary niche overlap. This work analyzes the stomach contents of 73 individuals from three species of the genus Anolis: A. barkeri (34), A. sericeus (17), and A. tropidonotus (22) occurring in the vicinity of Los Tuxtlas, Veracruz. Analyses performed included Shannon’s index in its log form to calculate dietary diversity, the Jaccard index to estimate the dissimilarity of the species’ diets, and Schoener’s index to measure dietary overlap.  The results suggest that A. barkeri (10.08) hast the most generalist diet, followed by A. sericeus (8.75) and A. tropidonotus (5.78). Schoener’s index showed a considerable amount of diet overlap between A. barkeri and A. sericeus (0.76). We conclude that the three focal species show a generalist feeding behavior in times of abundant prey, such as the rainy season in which this study was conducted. This may lead to the elusion of intra-generic competition, explaining why we did not observe dietary niche displacement between these three species of Anolis.

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