scholarly journals Diet composition and feeding habits of the eyespot skate, Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae), off Uruguay and northern Argentina

2016 ◽  
Vol 14 (3) ◽  
Author(s):  
Santiago A. Barbini ◽  
Luis O. Lucifora
Keyword(s):  
Body Size ◽  
Diet Composition ◽  
Prey Size ◽  
Prey Availability ◽  
Feeding Habits ◽  
Warm Season ◽  
Cold Season ◽  
The North ◽  
Multiple Hypothesis ◽  
Modelling Approach

ABSTRACT The eyespot skate, Atlantoraja cyclophora, is an endemic species from the southwestern Atlantic, occurring from Rio de Janeiro, Brazil, to northern Patagonia, Argentina. The feeding habits of this species, from off Uruguay and north Argentina, were evaluated using a multiple hypothesis modelling approach. In general, the diet was composed mainly of decapod crustaceans, followed by teleost fishes. Molluscs, mysidaceans, amphipods, isopods, lancelets and elasmobranchs were consumed in lower proportion. The consumption of shrimps drecreased with increasing body size of A. cyclophora. On the other hand, the consumption of teleosts increased with body size. Mature individuals preyed more heavily on crabs than immature individuals. Teleosts were consumed more in the south region (34º - 38ºS) and crabs in the north region (38º - 41ºS). Shrimps were eaten more in the warm season than in the cold season. Prey size increased with increasing body size of A. cyclophora , but large individuals also consumed small teleosts and crabs. Atlantoraja cyclophora has demersal-benthic feeding habits, shifts its diet with increasing body size and in response to seasonal and regional changes in prey availability and distribution.

Feeding habits of a large endangered skate from the south-west Atlantic: the spotback skate, Atlantoraja castelnaui

2012 ◽  
Vol 63 (2) ◽  
pp. 180 ◽  
Author(s):  
Santiago A. Barbini ◽  
Luis O. Lucifora
Keyword(s):  
Body Size ◽  
Prey Size ◽  
Feeding Habits ◽  
Warm Season ◽  
Cold Season ◽  
The South ◽  
The North ◽  
South West ◽  
Multiple Hypothesis ◽  
Modelling Approach

Elasmobranch predation has important effects on marine ecosystems. Identifying the main correlates of the feeding habits of skates is of paramount importance for determining their ecological role. We tested the hypotheses that the diet of the spotback skate, Atlantoraja castelnaui, off Uruguay and northern Argentina, changes with increasing body size, between seasons and regions and that prey size increased with predator’s size using a multiple-hypothesis modelling approach. A. castelnaui preyed mainly on teleosts, followed by cephalopods, elasmobranchs and decapods. Small individuals of A. castelnaui consumed decapods and large individuals ate elasmobranchs and cephalopods. The consumption of teleosts was constant along the ontogeny but differed between seasons; more demersal-benthic teleosts were consumed in the cold season, whereas more benthic teleosts were eaten in the warm season. Also, A. castelnaui consumed more cephalopods in the warm season than in the cold season. Benthic teleosts were consumed more in the south region, whereas decapods were eaten more in the north region. A. castelnaui is able to consume larger teleosts as it grows. We conclude that A. castelnaui is a versatile, mainly piscivorous, consumer that shifts its diet with increasing body size and in response to seasonal and regional changes in prey abundance or distribution.

Feeding habits of the Rio skate, Rioraja agassizi (Chondrichthyes: Rajidae), from off Uruguay and north Argentina

2010 ◽  
Vol 91 (6) ◽  
pp. 1175-1184 ◽  
Author(s):  
Santiago A. Barbini ◽  
Luis O. Lucifora
Keyword(s):  
Body Size ◽  
Linear Models ◽  
Feeding Habits ◽  
Warm Season ◽  
Cold Season ◽  
Maturity Stage ◽  
Ontogenetic Diet Shifts ◽  
Multiple Hypothesis ◽  
Diet Shifts ◽  
Modelling Approach

The feeding habits of the Rio skate, Rioraja agassizi, from off Uruguay and north Argentina were evaluated using a multiple-hypothesis modelling approach. Relationships between number of preys and sex, maturity stage, body size, season and region were assessed by building generalized linear models. Rioraja agassizi fed mainly upon crustaceans (shrimps, crabs and amphipods) and teleosts, but also upon isopods, cumaceans, lancelets and polychaetes. Ontogenetic diet shifts were found: small R. agassizi consumed amphipods, cumaceans and isopods and large individuals on shrimps, crabs and teleosts. The consumption of crustaceans (amphipods, shrimps, crabs, isopods and cumaceans) was higher in the northern (34°–38°S) than in the southern area (38°–41°S). Rioraja agassizi consumed more teleosts in the cold season and preyed more on lancelets in the warm season. Prey size increased with increasing body size of R. agassizi, but large individuals also consumed small prey. Ontogenetic shifts may be related to body size rather than other life-history traits. Rioraja agassizi adapts its feeding habits in response to regional and seasonal changes.

Feeding ecology of the apron rayDiscopyge tschudii(Elasmobranchii, Narcinidae) in San Jorge Gulf, Patagonia, Argentina

2015 ◽  
Vol 96 (5) ◽  
pp. 1093-1099 ◽  
Author(s):  
M. Cecilia Spath ◽  
Gabriela Delpiani ◽  
Daniel E. Figueroa
Keyword(s):  
Body Size ◽  
Feeding Habits ◽  
Marine Ecosystem ◽  
Warm Season ◽  
Cold Season ◽  
Maturity Stage ◽  
Multiple Hypothesis ◽  
Discopyge Tschudii ◽  
Modelling Approach

The study of the feeding habits of elasmobranch populations should help to elucidate the ecological role of these fishes in the marine ecosystem. Feeding habits of the apron ray,Discopyge tschudiifrom San Jorge Gulf were investigated. An evaluation of whether the diet ofD. tschudiichanges with body size, seasons, maturity stage and sex was performed using a multiple-hypothesis modelling approach.Discopyge tschudiipreyed mainly on polychaetes. The consumption of polychaetes was higher in males. Also, amphipods and siphons of clams were preyed more heavily in the cold season andMunida gregariain the warm season. Stomatopods were consumed more with increasing body size. All prey categories were independent of maturity stage. We concluded thatD. tschudiiis a benthic feeder.

Feeding habits of the apron ray,Discopyge tschudii(Elasmobranchii: Narcinidae), from off Uruguay and northern Argentina

2012 ◽  
Vol 93 (2) ◽  
pp. 291-297 ◽  
Author(s):  
M. Cecilia Spath ◽  
Santiago A. Barbini ◽  
Daniel E. Figueroa
Keyword(s):  
Body Size ◽  
Seasonal Changes ◽  
Feeding Habits ◽  
Cold Season ◽  
Relative Importance ◽  
Multiple Hypothesis ◽  
Index Of Relative Importance ◽  
Discopyge Tschudii ◽  
Modelling Approach

The feeding habits of the apron ray,Discopyge tschudii, were investigated, off Uruguay and northern Argentina, and we tested the hypothesis that the diet changes with increasing body size, between sexes and seasons using a multiple-hypothesis modelling approach.Discopyge tschudiipreys mainly on polychaetes (88.77% index of relative importance (IRI)) followed by siphons of the clamAmiantis purpurata(8.13% IRI) and amphipods (3.08% IRI). Ontogenetic, sexual and seasonal changes were found. Larger individuals ofD. tschudiiconsumed buried polychaetes more often. The consumption of errant polychaetes was higher in males and in the cold season. Also, amphipods were preyed on more heavily by females and the number of siphons ofA. purpurataconsumed was higher in the cold season.

scholarly journals Feeding habits of the cockfish, Callorhinchus callorynchus (Holocephali: Callorhinchidae) from off northern Argentina

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Jorge M. Roman ◽  
Melisa A. Chierichetti ◽  
Santiago A. Barbini ◽  
Lorena B. Scenna
Keyword(s):  
Body Size ◽  
Trophic Level ◽  
Coastal Waters ◽  
Diet Composition ◽  
Feeding Habits ◽  
Prey Abundance ◽  
Multiple Hypothesis ◽  
Species Shift ◽  
Brachyuran Crabs ◽  
Modelling Approach

ABSTRACT The feeding habits of Callorhinchus callorynchus were investigated in coastal waters off northern Argentina. The effect of body size, seasons and regions was evaluated on female diet composition using a multiple-hypothesis modelling approach. Callorhinchus callorynchus fed mainly on bivalves (55.61% PSIRI), followed by brachyuran crabs (10.62% PSIRI) and isopods (10.13% PSIRI). Callorhinchus callorynchus females showed changes in the diet composition with increasing body size and also between seasons and regions. Further, this species is able to consume larger bivalves as it grows. Trophic level was 3.15, characterizing it as a secondary consumer. We conclude that C. callorynchus showed a behavior of crushing hard prey, mainly on bivalves, brachyuran, gastropods and anomuran crabs. Females of this species shift their diet with increasing body size and in response to seasonal and regional changes in prey abundance or distribution.

scholarly journals CHROMOSOME STUDIES IN WILD POPULATIONS OF DROSOPHILA MELANOGASTER. II. RELATIONSHIP OF INVERSION FREQUENCIES TO LATITUDE, SEASON, WING-LOADING AND FLIGHT ACTIVITY

Genetics ◽  
1980 ◽  
Vol 95 (1) ◽  
pp. 211-223
Author(s):  
Harrison D Stalker
Keyword(s):  
Drosophila Melanogaster ◽  
Warm Season ◽  
Cold Season ◽  
South Texas ◽  
Temperature Adaptation ◽  
Wing Loading ◽  
Ambient Temperatures ◽  
The North ◽  
Wing Load ◽  
Relationship Of

ABSTRACT In the midwestern and eastern U.S. populations of Drosophila melanogaster, the Standard gene arrangements show higher frequencies in the north than in the south. In a Missouri population, and to a lesser extent in a south Texas population, the frequencies of Standard chromosomes regularly rise during the cold season and drop during the warm season, thus paralleling the north-south frequency differences. In the Missouri population in 1976 and 1978, wild males were tested far their ability to fly to bait at different ambient temperatures. In both years, males flying in nature in the temperature range of 13° to 15° showed significantly higher frequencies of Standard chromosomes than did those flying in the 16° to 28° range. Wild males flying at 13° to 15° also have different tharax/wing proportions and significantly lower wingloading indices than do those flying at 16° to 28°. Moreover, wild flies homozygous Standard in 2R and/or 3R have significantly lower wing-loading indices than flies carrying inversions in these arms. Thus, wild flies with high frequencies of Standard chromosommes are karyotypically northern, are selectively favored during the cold season, have a relatively low wing-load and are most capable of flying at critically low ambient temperatures.—In summary, in Missouri, presence or absence of the common cosmopolitan inversions is an important factor in low temperature adaptation, and at least part of the adaptive mechanism involves control of thorax/wing proportions and thus control of wing-loading.

scholarly journals Diet of Ameerega braccata (Steindachner, 1864) (Anura: Dendrobatidae) from Chapada dos Guimarães and Cuiabá, Mato Grosso State, Brazil

2011 ◽  
Vol 71 (1) ◽  
pp. 189-196 ◽  
Author(s):  
LR. Forti ◽  
ASO. Tissiani ◽  
T. Mott ◽  
C Strüssmann
Keyword(s):  
Body Size ◽  
Niche Breadth ◽  
Prey Availability ◽  
Feeding Habits ◽  
Close Association ◽  
Mato Grosso ◽  
Important Prey ◽  
Phylogenetic Perspective ◽  
Toxic Alkaloids ◽  
Two Populations

The understanding of feeding habits is important for anurans in general, both from an ecological and a phylogenetic perspective. For diurnal poison frogs belonging to the Dendrobatidae family, diet aspects play a crucial role in their defense and survival. Herein, we investigated feeding habits, foraging behaviour, and overall effects of habitat, sex, and body size on the diet of individuals of Ameerega braccata, a poorly known dendrobatid species. Specimens were observed and collected in the type-locality, Chapada dos Guimarães, and in the neighbouring municipality of Cuiabá, both in the State of Mato Grosso, Midwestern Brazil. The most important prey categories for A. braccata were Formicidae, Isoptera, and Acari, whose representatives were caught during active foraging. Individuals from Chapada dos Guimarães population consumed more Acari but fewer Isoptera than individuals from Cuiabá. Despite this, niche breadth values were narrow and similar for the two populations. Individuals from two distinct habitats (campo sujo and cerrado stricto sensu) showed differences in their diet, probably as an effect of differential prey availability. Females consumed more Isoptera than males. The number of prey categories used as food was not influenced by the variation of body size of the target species. However, the abundance and the volume of consumed Acari were statistically correlated with body size. The main results suggest that Ameerega braccata has a narrow niche breadth, as well as a specialised diet in ants, termites, and mites, which reinforces the hypotheses of close association between Acari consumption and the presence of skin toxic alkaloids, already found in other species of Dendrobatidae. Although differences in prey consumption between sexes are uncommon among poisonous frogs, differences in the diet composition between age classes, which probably reduce intraspecific competition, are frequently reported.

Feeding habits of cockfish, Callorhinchus callorhynchus (Holocephali: Callorhynchidae), in Patagonian waters (Argentina)

1996 ◽  
Vol 47 (6) ◽  
pp. 801 ◽  
Author(s):  
EE Di Giacomo ◽  
MR Perier
Keyword(s):  
Prey Size ◽  
Prey Availability ◽  
Feeding Habits ◽  
Food Composition ◽  
Commercial Fishing ◽  
Bivalve Molluscs ◽  
Invertebrate Prey ◽  
Selective Foraging ◽  
Predator Size ◽  
Two Factors

Morphology of the main digestive features of cockfish, Callorhinchus callorhynchus, is described and linked to feeding habits. Composition of the diet and size-selective foraging of this species on scallops was studied in northern Patagonian waters and analysed in relation to depth, sex and size. Three species of bivalve molluscs (Pitar rostratus, Aequipecten tehuelchus and Ennucula puelcha) and flabelligerid polychaetes were predominant in the diet of males. The scallop Zygochlamys patagonica dominated the diet of females. The diet of juveniles consisted of small gastropods (Olivella sp.), bivalves with fragile shells (e.g. Pandora cistula), amphipods and polychaetes. Differences in food composition between sexes and between juveniles and adults are attributed to two factors: extrinsic (concerning prey availability) and intrinsic (concerning the morphology and behaviour of the predator). Size-selective foraging on two species of scallops, Aequipecten tehuelchus (subject to commercial fishing) and Zygochlamys patagonica, was found in adults; it is argued that maximum scallop prey size is constrained by the strength of the crushing apparatus of the cockfish. The diet of the cockfish is compared with that of other holocephalans. It is concluded that species of Callorhinchus can be generally characterized as benthic foragers that specialize in crushing shelled invertebrate prey.

scholarly journals Forecast of Hourly Airport Visibility Based on Artificial Intelligence Methods

Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 75
Author(s):  
Jin Ding ◽  
Guoping Zhang ◽  
Shudong Wang ◽  
Bing Xue ◽  
Jing Yang ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Prediction Models ◽  
Warm Season ◽  
Northwest China ◽  
Cold Season ◽  
Central China ◽  
The North ◽  
Hourly Data ◽  
Artificial Intelligence Algorithm ◽  
Good Visibility

Based on the hourly visibility data, visibility and its changes during 2010–2020 at monthly and annual time scales over 47 international airports in China are investigated, and nine artificial-intelligence-based hourly visibility prediction models are trained (hourly data in 2018–2019) and tested (hourly data in 2020) at these airports. The analyses show that the visibility of airports in eastern and central China is at a poor level all year round, and LXA (in Lhasa) has good visibility all year round. Airports in south and the northwest China have better visibility from May to October and poorer visibility from November to April. In all months, the increasing visibility mainly occurs in the central, northeast and coastal areas of China, while decreasing visibility mainly appears in the western and northern parts of China. In spring, summer and autumn, the changes difference between east and west is particularly obvious. This East–West distribution of trends is obviously different from the North–South distribution shown by the mean. For all airports, good visibility mainly occurs from 14:00–18:00 p.m. Beijing Time, while poor visibility mainly concentrates from 22:00 p.m. to 12:00 p.m. the next day, especially between 3:00–9:00 a.m. Our proposed artificial intelligence algorithm models can be reasonably used in airport visibility prediction. In particular, most algorithm models have the best results in the visibility prediction over HFE (in Hefei) and SJW (in Shijiazhuang). On the contrary, the worst forecast results appear at LXA and LHW (in Lanzhou) airports. The prediction results of airport visibility in the cold season (October–December) are better than those in the warm season (May–September). Among the algorithm models, the prediction performance of the RF-based model is the best.

scholarly journals Assessing the Efficacy of A Marine Reserve to Protect Sharks With Differential Habitat Use

2020 ◽  
Author(s):  
Cesar Peñaherrera-Palma ◽  
Alistair Hobday ◽  
Alex Hearn ◽  
Eduardo Espinoza ◽  
George Shillinger ◽  
...  
Keyword(s):  
Marine Reserve ◽  
Warm Season ◽  
Environmental Parameters ◽  
Marine Species ◽  
Cold Season ◽  
Utilization Distribution ◽  
The North ◽  
South Central ◽  
Central Regions ◽  
Hammerhead Sharks

Abstract Spatial management through the implementation of marine protected areas is one strategy to limit the extraction of sensitive marine species. Understanding the area used by marine life is thus a key step towards the evaluation of the management framework and efficacy of a protected area. To provide information of the protective coverage of the Galapagos Marine Reserve (GMR), we assessed the habitat utilization distribution (UD) of hammerhead and blacktip sharks in the GMR. Fifteen hammerhead sharks and 27 blacktip sharks were tagged with SPOT and SPLASH satellite tags in the north and south-central regions of the GMR between 2007 and 2012. Our results show nearly 90% of hammerhead shark’s UD was enclosed by the reserve boundary during the cold season (June-October), yet this decreased to only ~30% with the advent of the warm season (December-April). Conversely, blacktip sharks’ UD was 100% enclosed by the reserve boundaries in all seasons. Season and depth were the most important environmental parameters defining the UD of hammerhead sharks; whilst year and eddy kinetic energy were the most important parameters for blacktip sharks. These findings suggest the size of the GMR may be effective for blacktip sharks but seasonally effective for hammerhead sharks.

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