scholarly journals Intraspecific food resource partitioning in Brazilian silverside Atherinella brasiliensis (Atheriniformes: Atherinopsidae) in a tropical estuary, Brazil

2019 ◽  
Vol 17 (2) ◽  
Author(s):  
Gitá J. S. Brito ◽  
Lidiane G. de Lima ◽  
Ronnie E. M. C. C. Oliveira ◽  
André Pessanha
Keyword(s):  
Food Resource ◽  
Strong Relationship ◽  
Feeding Strategies ◽  
Tropical Estuary ◽  
Size Classes ◽  
Trade Offs ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
The Mean ◽  
Food Resource Partitioning

ABSTRACT We investigated the intraspecific partitioning of food resources of the Brazilian silverside Atherinella brasiliensis in a tropical estuary. A total of 1,099 stomachs were analyzed, and the diet consisted mainly of Gastropoda, Ceratopogonidae larvae, Decapoda larvae, Calanoida, Cyclopoida, Hymenoptera and Brachyura. Ordination of the mean volumetric percentage contribution of preys indicated differences in the dietary compositions between sites and size classes. By SIMPER analysis, we detected high dissimilarity between size classes, suggesting ontogenetic niche shifts: the diet of the early juveniles was based in zooplankton, whereas adults consumed mainly benthic macroinvertebrates. These shifts were related to changes in feeding structures and foraging abilities that show a strong relationship with body size, and showed functional trade-offs in swimming capacity, and feeding strategies used to capture prey. Differences in the diet between size classes and habitat selection by Brazilian silverside are likely strategies to avoid intraspecific competition, clearly related to the abundance and accessibility of resources along the estuarine habitats.

scholarly journals Application of Combined Analyses of Stable Isotopes and Stomach Contents for Understanding Ontogenetic Niche Shifts in Silver Croaker (Pennahia argentata)

2021 ◽  
Vol 18 (8) ◽  
pp. 4073
Author(s):  
Bohyung Choi ◽  
Won-Seok Kim ◽  
Chang Woo Ji ◽  
Min-Seob Kim ◽  
Ihn-Sil Kwak
Keyword(s):  
Isotope Analysis ◽  
Stomach Contents ◽  
Growth Stages ◽  
Essential Information ◽  
Δ13c And Δ15n ◽  
Size Classes ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Pennahia Argentata ◽  
Ontogenetic Niche

Stable isotope analysis (SIA) and stomach content analysis (SCA) were conducted to understand ontogenetic niche shifts in silver croaker Pennahia argentata inhabiting the southern coastal waters of the Korean peninsula. Sampled P. argentata were classified into three groups based on their total length (TL; 60–80 mm TL, 80–120 mm TL, and 120–210 mm TL). Carbon isotope (δ13C) ratios were distinguishable, whereas nitrogen isotope (δ15N) ratios were not significantly different among size classes, and Standard Ellipse Area (SEA), estimated by δ13C and δ15N, was expanded with increasing TL from 0.2 ‰2 (60–80 mm TL) to 2.0 ‰2 (120–210 mm TL). SCA results showed variable contribution of dietary items to each size class. In particular, higher dietary contribution of Polychaeta to P. argentata of 80–120 mm TL than 120–210 mm TL mirrored variation in δ13C values of P. argentata in those size classes. Based on the combined analyses involving SIA and SCA, we concluded that P. argentata underwent ontogenetic niche shifts, particularly dietary shifts, with growth stages. Ontogenetic niche shifting is a representative survival strategy in fish, and, therefore, represents essential information for managing fisheries. The present study demonstrated applicability of combined SIA and SCA analyses, not only for dietary resource tracing, but also for ecological niche studies.

Ontogenetic shifts in ambush-site selection of a sit-and-wait predator, the Chacoan Horned Frog (Ceratophrys cranwelli)

2015 ◽  
Vol 93 (6) ◽  
pp. 461-467 ◽  
Author(s):  
C.M. Schalk ◽  
L.A. Fitzgerald
Keyword(s):  
Site Selection ◽  
Foraging Strategy ◽  
Intraspecific Interactions ◽  
Ontogenetic Shifts ◽  
Gran Chaco ◽  
Trade Offs ◽  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Morphological Variables ◽  
Selection Of

Ontogenetic shifts in habitat use are widespread among vertebrates. These niche shifts are often attributed to age-specific patterns of resource use, which are correlated with changes in morphology, diet, and habitat. We examined the ontogeny of ambush-site selection in a sit-and-wait predator, the Chacoan Horned Frog (Ceratophrys cranwelli Barrio, 1980), in the Gran Chaco ecoregion of Bolivia. We quantified covariation in microhabitat and morphological variables and tested for microhabitat selection against randomly selected points. We identified an ontogenetic shift in ambush-site selection between adult and metamorph frogs. When compared with random points, metamorphs selected a subset of available habitat, whereas adult frogs did not appear to select ambush sites. Metamorphs, compared with adults, selected ambush sites farther from a pond’s edge with a greater proportion of dry mud. The metamorph of C. cranwelli may have selected ambush sites based on spatial distribution of certain size classes of prey. Alternatively, metamorphs could have selected sites to minimize asymmetric agonistic intraspecific interactions with adults. These mechanisms are not mutually exclusive and probably occur in concert. Habitat selection and ontogenetic niche shifts by these organisms provide insights to the trade-offs between foraging strategy and mortality risk.

Feeding Strategies and Partition of Food Resources in Deep-Water Decapod Crustaceans (400–2300 m)

1998 ◽  
Vol 78 (2) ◽  
pp. 509-524 ◽  
Author(s):  
Joan E. Cartes
Keyword(s):  
Resource Partitioning ◽  
Feeding Strategy ◽  
Food Resource ◽  
Progressive Increase ◽  
Western Mediterranean ◽  
Food Resources ◽  
Feeding Strategies ◽  
Dietary Overlap ◽  
Decapod Crustaceans ◽  
Food Resource Partitioning

Food resource partitioning and trends in feeding strategies were examined in 3882 individual decapod crustaceans collected from 1989 to 1990, using bottom trawls at depths between 380 and 2261 m in the Catalan Sea (western Mediterranean). The vertical distribution of available food resources near the bottom was the most important factor responsible for food resource partitioning among bathyal decapod crustaceans by depth stratum and season. Decapods were assigned to five different trophic groups according to the food resource exploited and feeding strategy employed (macroplankton feeders, macroplankton-epibenthic feeders, epibenthic feeders, epibenthic-endobenthic feeders, and deposit feeders). There was little dietary overlap, indicating that species did partition the available resources. Overall, dietary overlap values among species increased with depth. Although a trend to increase H’ values for diets with depth was observed, this was not significant (P < 0.10), whereas differences in the percentage of empty stomachs and the frequency of foraminiferans and pteropods in the foreguts increased significantly (P < 0.05) with depth. This last result is indicative of a progressive increase in the importance of deposit feeding in decapod crustaceans as depth increases.

Dietary overlap and food resource partitioning among fish species of a tropical estuary in Northeastern Brazil

Gaia Scientia ◽  
2016 ◽  
Vol 10 (4) ◽  
pp. 86-95 ◽  
Author(s):  
Adna Ferreira da Silva Garcia ◽  
Ana Lúcia Vendel
Keyword(s):  
Resource Partitioning ◽  
Species Coexistence ◽  
Food Resource ◽  
River Estuary ◽  
Niche Overlap ◽  
Northeastern Brazil ◽  
Dietary Overlap ◽  
Feeding Niche ◽  
Tropical Environments ◽  
Food Resource Partitioning

The current work investigates dietary overlap and food partitioning among nine abundant carnivorous fishes caught in the shallow waters of the Paraíba do Norte river estuary, Paraíba State, Brazil. Fishes were sampled with a beach seine net between January and December 2008 and a total of 958 specimens had their stomach content analyzed. Crustacea was the dominant food resource for Lutjanus alexandrei, L. jocu and Bathygobius soporator, whereas Telostei were consumed mainly by Centropomus undecimalis and C. parallelus. In contrast, Polychaeta were preyed upon mainly by Diapterus rhombeus, Eucinostomus argenteus, Sciades herzbergii and S. parkeri. Although most species consumed similar food items, they did that in varying proportions and amounts. Overall, the niche overlap among species was low (< 0.60), but there were several cases where pair of species had their feeding niche highly overlapped (between 0.72 and 0.97). These findings corroborate the hypothesis that food resource partitioning determines species coexistence in estuarine tropical environments.

Computing trade-offs in robust design: Perspectives of the mean squared error

2011 ◽  
Vol 60 (2) ◽  
pp. 248-255 ◽  
Author(s):  
Sangmun Shin ◽  
Funda Samanlioglu ◽  
Byung Rae Cho ◽  
Margaret M. Wiecek
Keyword(s):  
Robust Design ◽  
Mean Squared Error ◽  
Squared Error ◽  
Trade Offs ◽  
The Mean

scholarly journals Predation and associational refuge drive ontogenetic niche shifts in an arctiid caterpillar

Ecology ◽  
2015 ◽  
Vol 96 (1) ◽  
pp. 80-89 ◽  
Author(s):  
Patrick Grof-Tisza ◽  
Marcel Holyoak ◽  
Edward Antell ◽  
Richard Karban
Keyword(s):  
Ontogenetic Niche Shifts ◽  
Niche Shifts ◽  
Ontogenetic Niche ◽  
Associational Refuge

scholarly journals Predicting epidemics using search engine data: a comparative study on measles in the largest countries of Europe

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Loukas Samaras ◽  
Miguel-Angel Sicilia ◽  
Elena García-Barriocanal
Keyword(s):  
Competent Authority ◽  
Strong Relationship ◽  
Google Trends ◽  
Extensive Literature ◽  
The European Union ◽  
The United Kingdom ◽  
The Mean ◽  
The One ◽  
Relationship Of ◽  
Official Data

Abstract Background In recent years new forms of syndromic surveillance that use data from the Internet have been proposed. These have been developed to assist the early prediction of epidemics in various cases and diseases. It has been found that these systems are accurate in monitoring and predicting outbreaks before these are observed in population and, therefore, they can be used as a complement to other methods. In this research, our aim is to examine a highly infectious disease, measles, as there is no extensive literature on forecasting measles using Internet data, Methods This research has been conducted with official data on measles for 5 years (2013–2018) from the competent authority of the European Union (European Center of Disease and Prevention - ECDC) and data obtained from Google Trends by using scripts coded in Python. We compared regression models forecasting the development of measles in the five countries. Results Results show that measles can be estimated and predicted through Google Trends in terms of time, volume and the overall spread. The combined results reveal a strong relationship of measles cases with the predicted cases (correlation coefficient R= 0.779 in two-tailed significance p< 0.01). The mean standard error was relatively low 45.2 (12.19%) for the combined results. However, major differences and deviations were observed for countries with a relatively low impact of measles, such as the United Kingdom and Spain. For these countries, alternative models were tested in an attempt to improve the results. Conclusions The estimation of measles cases from Google Trends produces acceptable results and can help predict outbreaks in a robust and sound manner, at least 2 months in advance. Python scripts can be used individually or within the framework of an integrated Internet surveillance system for tracking epidemics as the one addressed here.

scholarly journals Single super-vortex as a proxy for ocean surface flow fields

2019 ◽  
Author(s):  
Imre M. Jánosi ◽  
Miklós Vincze ◽  
Gábor Tóth ◽  
Jason A. C. Gallas
Keyword(s):  
Kinetic Energy ◽  
Cross Correlation ◽  
Strong Relationship ◽  
Surface Flow ◽  
Coarse Grained ◽  
Cross Correlation Analysis ◽  
Energy Integrals ◽  
Ocean Region ◽  
The Mean ◽  
Westward Drift

Abstract. Empirical flow field data evaluation in a well studied ocean region along the U.S. West Coast revealed a surprisingly strong relationship between the surface integrals of kinetic energy and enstrophy (squared vorticity). This relationship defines a single isolated Gaussian super-vortex, whose fitted size parameter is related to the mean eddy size, and the square of the fitted height parameter is proportional to the sum of the square of all individual eddy amplitudes obtained by standard vortex census. This finding allows a very effective coarse-grained eddy statistics with minimal computational efforts. As an illustrative example, the westward drift velocity of eddies is determined from a simple cross correlation analysis of kinetic energy integrals.

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