Feeding habits of the sandskate Psammobatis extenta (Garman, 1913): sources of variation in dietary composition

2005 ◽  
Vol 56 (4) ◽  
pp. 395 ◽  
Author(s):  
J. Matías Braccini ◽  
Jorge E. Perez
Keyword(s):  
Feeding Habits ◽  
Seasonal Pattern ◽  
Seasonal Patterns ◽  
Dietary Composition ◽  
Important Prey ◽  
Eastern Brazil ◽  
Prey Diversity ◽  
Sources Of Variation ◽  
Males And Females ◽  
Prey Items

Understanding the variation in the diet of skates is crucial for determining their roles in marine ecosystems. The diet of 458 sandskates, Psammobatis extenta, from Puerto Quequén, Argentina was quantified to determine whether there was geographical, sexual, ontogenetic, and/or seasonal variation in dietary composition. Cumulative prey-diversity curves reached a stable level at ~30 stomachs and thus the sample size was large enough to describe the overall diet of the sandskate. The diet comprised a variety of small invertebrates, suggesting that the sandskate is a secondary consumer (trophic level of 3.5). The most important prey items were gammarids, shrimps and, to a lesser extent, polychaete worms. A significant correlation was found between the diets of sandskates from south-eastern Brazil and Puerto Quequén, suggesting that in both locations they used similar resources and would have similar ecological roles. No difference was found between the diets of males and females, but ontogenetic and seasonal patterns were detected. Small sandskates preyed largely on gammarids and shrimps but consumed fewer polychaetes and brachyurans than larger individuals. In summer and winter, the most important prey item by number was gammarids, whereas the consumption of shrimps peaked in autumn. This ontogenetic and seasonal pattern indicates that large and small sandskates are versatile predators that can shift their diets in response to prey abundance.

scholarly journals Sources of variation in the feeding ecology of the piked spurdog (Squalus megalops): implications for inferring predator–prey interactions from overall dietary composition

2005 ◽  
Vol 62 (6) ◽  
pp. 1076-1094 ◽  
Author(s):  
J. Matías Braccini ◽  
Bronwyn M. Gillanders ◽  
Terence I. Walker
Keyword(s):  
Spatial And Temporal Variation ◽  
Dietary Composition ◽  
Bootstrap Analysis ◽  
Predator Prey ◽  
Ecological Relationships ◽  
Wide Range ◽  
Opportunistic Predator ◽  
Sources Of Variation ◽  
Males And Females ◽  
Prey Items

Abstract Sources of variation in dietary composition were examined in the piked spurdog (Squalus megalops). The species is an opportunistic predator that consumes a wide range of prey items. When importance of prey was measured by weight or occurrence, S. megalops preyed largely on molluscs and teleosts. However, when number of prey was considered, the main items were crustaceans. A bootstrap analysis showed that considerable variability can be expected in the importance of prey items in the species' overall diet. Regional, seasonal, and ontogenetic differences in dietary composition were found, but there were no differences between mature and immature sharks or between males and females. The spatial and temporal variation in diet exhibited by S. megalops and the intrinsic natural variability of the dietary composition of this opportunistic predator suggest that studies that infer predator–prey interactions from overall diet are likely to miss information on the ecological relationships among species and thus account for only part of these interactions.

scholarly journals Feeding habits of oriental sole (Brachirus orientalis) on the Bushehr coast of the Persian Gulf

2020 ◽  
Vol 28 (3) ◽  
pp. 175-185
Author(s):  
Dima Alghada ◽  
Yazdan Keivany ◽  
Fatemeh Paykan-Heyrati
Keyword(s):  
Coastal Waters ◽  
Persian Gulf ◽  
Diet Composition ◽  
Prey Species ◽  
Feeding Habits ◽  
Male And Female ◽  
Important Prey ◽  
Males And Females ◽  
The Persian Gulf ◽  
Prey Items

AbstractThe feeding habits of oriental sole, Brachirus orientalis (Bloch & Schneider) were investigated using 300 male and female specimens collected from coastal waters of Bushehr Province (Persian Gulf) between June 2015 and July 2016. The total length of females and males ranged from 16.2 to 38.5 cm and 14.1 to 29.1 cm, respectively. Of the total number of stomachs examined, 225 were empty (vacuity index = 77%). This index varied significantly over the year (P < 0.05), with maximum values in April and September and minimum in October and May. The B. orientalis diet was composed of nine prey species belonging to five classes. The most important prey items were Crustacea and Mollusca (Bivalvia and Gastropoda). Diet composition showed little seasonal variation, and Crustacea, Bivalvia, and Gastropoda were the most important prey items in all seasons. Sex did not appear to have any significant effects on dietary composition, and the main prey items were consumed by both males and females (P > 0.05).

Seasonal Variation of Suicide in the City of São Paulo, Brazil, 1996–2010

Crisis ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 5-9 ◽  
Author(s):  
Daniel Hideki Bando ◽  
Fernando Madalena Volpe
Keyword(s):  
Seasonal Pattern ◽  
Total Sample ◽  
Sao Paulo ◽  
Seasonal Patterns ◽  
São Paulo ◽  
Health Statistics ◽  
Males And Females ◽  
June July ◽  
The City ◽  
Over Time

Background: In light of the few reports from intertropical latitudes and their conflicting results, we aimed to replicate and update the investigation of seasonal patterns of suicide occurrences in the city of São Paulo, Brazil. Methods: Data relating to male and female suicides were extracted from the Mortality Information Enhancement Program (PRO-AIM), the official health statistics of the municipality of São Paulo. Seasonality was assessed by studying distribution of suicides over time using cosinor analyses. Results: There were 6,916 registered suicides (76.7% men), with an average of 39.0 ± 7.0 observed suicides per month. For the total sample and for both sexes, cosinor analysis estimated a significant seasonal pattern. For the total sample and for males suicide peaked in November (late spring) with a trough in May–June (late autumn). For females, the estimated peak occurred in January, and the trough in June–July. Conclusions: A seasonal pattern of suicides was found for both males and females, peaking in spring/summer and dipping in fall/winter. The scarcity of reports from intertropical latitudes warrants promoting more studies in this area.

Trophic ecology of large pelagic fish in the Saint Peter and Saint Paul Archipelago, Brazil

2019 ◽  
Vol 70 (10) ◽  
pp. 1402 ◽  
Author(s):  
F. V. Albuquerque ◽  
A. F. Navia ◽  
T. Vaske ◽  
O. Crespo ◽  
F. H. V. Hazin
Keyword(s):  
Trophic Ecology ◽  
Feeding Habits ◽  
Saint Paul ◽  
Pelagic Fish ◽  
Trophic Niche ◽  
Trophic Relationships ◽  
Main Prey ◽  
Important Prey ◽  
Saint Peter ◽  
Prey Items

Trophic relationships of large pelagic predators can determine the structure and dynamics of oceanic food webs. The feeding habits and trophic ecology of five large pelagic fish (Acanthocybium solandri, Coryphaena hippurus, Elagatis bipinnulata, Thunnus albacares and Thunnus atlanticus) in the Saint Peter and Saint Paul Archipelago were evaluated to determine whether there is a trophic-niche overlap or resource partitioning among them. Eighty prey items found in 1528 stomachs were identified and grouped into Cephalopoda, Cnidaria, Crustacea, Gastropoda, Teleostei and Tunicata. Exocoetidae and Scombridae were the main prey in the diet of Acanthocybium solandri. In C. hippurus, Cheilopogon cyanopterus and Exocoetus volitans were the most important prey items, whereas C. cyanopterus was the main prey for T. albacares. Thunnus atlanticus consumed a great proportion of invertebrate species, with shrimps of Sergestidae family being particularly important. The gastropod Cavolinia sp. was the most important prey for E. bipinnulata. The five species had a high trophic specialisation and a high trophic level (&gt;4.4), whereas most dietary overlaps were consistently low. The most important factor for diet dissimilarity was the consumption of Exocoetidade. All species were classified as top predators with varied diets, indicating their structural and functional importance in the food web of the Archipelago.

Trophic spectrum of the sailfish Istiophorus platypterus caught off Acapulco in the southern Mexican Pacific

2012 ◽  
Vol 93 (4) ◽  
pp. 1097-1104 ◽  
Author(s):  
Sandra Berenice Hernández-Aguilar ◽  
Leonardo Andrés Abitia-Cárdenas ◽  
Xchel Gabriel Moreno-Sánchez ◽  
Marcial Arellano-Martínez ◽  
Eduardo González-Rodríguez
Keyword(s):  
Prey Species ◽  
Feeding Habits ◽  
Coastal Region ◽  
Important Species ◽  
Mexican Pacific ◽  
Istiophorus Platypterus ◽  
Important Prey ◽  
Males And Females ◽  
Index Of Relative Importance ◽  
Size Interval

The sailfish Istiophorus platypterus is one of the most common billfish species in the Mexican Pacific. Information about its feeding habits in the coastal region of Acapulco, Guerrero is extremely limited. In the present study we quantified the diet of sailfish, based on captures made from March 2008 to December 2009 by the sport fishing fleet of Acapulco. We analysed a total of 561 stomachs, of which 254 contained food (45%). The size interval of examined specimens was between 101 and 212 cm postorbital length and between 15 and 47 kg total weight. In general, teleosts were the most important prey, followed by cephalopods. According to index of relative importance, the most important species in the diet were the fish Auxis thazard (63.04%) and Fistularia commersonii (6.62%), followed by the cephalopod Octopus spp. (4.58%). There were no significant differences in the diet by sex (males and females), sexual maturity (immature and mature), or by season (warm and cold seasons). In all cases the most important prey species was A. thazard. We conclude that the sailfish I. platypterus off Acapulco behaves as a specialist predator because, despite the consumption of a high number of prey items, it feeds preferentially on a reduced number of prey species that form schools, and are available and abundant in the ocean.

scholarly journals Feeding habits of the franciscana dolphin (Pontoporia blainvillei) in south-eastern Brazil

2020 ◽  
Vol 100 (2) ◽  
pp. 301-313
Author(s):  
Laura Busin Campos ◽  
Xênia Moreira Lopes ◽  
Ednilson da Silva ◽  
Marcos César de Oliveira Santos
Keyword(s):  
Feeding Habits ◽  
Stomach Contents ◽  
Small Fish ◽  
South Eastern ◽  
Important Prey ◽  
Fishing Vessels ◽  
Eastern Brazil ◽  
Significant Difference ◽  
Pontoporia Blainvillei ◽  
Franciscana Dolphin

AbstractThis study evaluated the feeding habits of the franciscana dolphin (Pontoporia blainvillei) in south-eastern Brazil. Stomach contents were collected from a total of 145 dead specimens found incidentally caught by fishing vessels or stranded between 2005 and 2015. Fish otoliths, cephalopod beaks and whole non-digested prey were used for prey species identification. A total of 9337 prey items were identified, including 26 species of teleost fishes and three species of cephalopods. The most important prey families were Sciaenidae among fish and Loliginidae among cephalopods. Franciscana dolphins tended to feed on small fish (mean = 5.25 cm) and cephalopods (mean = 8.57 cm). The index of relative importance (IRI) showed that Pellona harroweri and Doryteuthis plei were the most important prey for both males and females. The PERMANOVA test confirmed that there is no significant difference between the feeding habits of different sexes, but detected a significant difference among seasons. Overall, our results show that franciscana dolphins are predominantly ichthyophagous and non-selective in relation to the type of prey, feeding on pelagic, demersal and pelagic-demersal prey.

Feeding ecology, growth and sexual cycle of the sand sole, Solea lascaris, along the Portuguese coast

2009 ◽  
Vol 89 (3) ◽  
pp. 621-627 ◽  
Author(s):  
Célia M. Teixeira ◽  
Ana Pinheiro ◽  
Henrique N. Cabral
Keyword(s):  
Feeding Habits ◽  
Gonadosomatic Index ◽  
Age And Growth ◽  
Sexual Cycle ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Portuguese Coast ◽  
Important Prey ◽  
Von Bertalanffy Growth Equation ◽  
Prey Items

Sand sole, Solea lascaris, were collected along the Portuguese coast, between October 2002 and July 2003, to examine feeding habits, age and growth and sexual cycle. The most important prey items were Mysidacea, Amphipoda and Polychaeta. Differences in diet according to season and length size were found: Amphipoda were very important in diet during winter, while Echinodermata were consumed mostly in summer; smaller individuals feed on Amphipoda while larger feed on Decapoda. Age of S. lascaris was determined from sagittae otoliths. The length of fish analysed ranged from 61 mm to 340 mm. The von Bertalanffy growth equation parameters differed significantly between sexes (L∞ = 342.3 mm, k = 0.50, t0 = −0.87 and L∞ = 264.5 mm, k = 0.82, t0 = 0.13, females and males, respectively). The highest values of the gonadosomatic index were obtained in winter and spring, when the highest proportion of individuals at spawning stage was recorded.

scholarly journals Diet and foraging of the endemic lizard Cnemidophorus littoralis (Squamata, Teiidae) in the restinga de Jurubatiba, Macaé, RJ

2006 ◽  
Vol 66 (3) ◽  
pp. 803-807 ◽  
Author(s):  
V. A. Menezes ◽  
V. C. Amaral ◽  
M. V. Sluys ◽  
C. F. D. Rocha
Keyword(s):  
Adult Male ◽  
Stomach Contents ◽  
Important Prey ◽  
Potential Source ◽  
Morphological Variables ◽  
Males And Females ◽  
Active Forager ◽  
Hemidactylus Mabouia ◽  
Prey Items

We investigated the diet and foraging of the endemic teiid lizard Cnemidophorus littoralis in a restinga habitat in Jurubatiba, Macaé - RJ. The stomach contents were removed, analyzed and identified to the Order level. There was no relationship between C. littoralis morphological variables and number, length or volume of preys. Termites (48.7%) and larvae (35.5%) were the most important prey items which occurred in the examined lizards´ stomachs. The diet did not differ between males and females. Cnemidophorus littoralis is an active forager and predominantly consumes relatively sedentary prey or prey that is aggregated in the environment. We also found an intact and undigested hatchling of the crepuscular/nocturnal gekkonid lizard Hemidactylus mabouia in the stomach of an adult male of C. littoralis, which indicates that C. littoralis is a potential source of mortality for individuals of H. mabouia in the restinga de Jurubatiba.

scholarly journals Feeding habits of the blue shark (Prionace glauca) off the coast of Brazil

2009 ◽  
Vol 9 (3) ◽  
pp. 55-60 ◽  
Author(s):  
Teodoro Vaske Júnior ◽  
Rosangela Paula Lessa ◽  
Otto Bismarck Fazzano Gadig
Keyword(s):  
Feeding Habits ◽  
Southern Region ◽  
Brazilian Coast ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Northeastern Region ◽  
Frequent Item ◽  
Important Prey ◽  
Prey Items ◽  
Reproductive Migration

Stomachs from 222 blue sharks collected along the Brazilian coast were analyzed - 116 from the northeastern region and 106 from the southern region. A total of 51 prey taxa were identified. The most important prey items in the southern region were Mysticeti whales, teleosteans, the gempylid Ruvettus pretiosus and the nomeid Arioma bondi. Cephalopods were more diverse, with dominance of vertical migrants Histioteuthis spp., Cranchiidae and the epipelagic octopus Ocythoe tuberculata. In the northeastern region, blue sharks consumed mainly teleosteans, including the alepisaurid Alepisaurus ferox and the gempylid Gempylus serpens. Among cephalopods, Histioteuthis spp. and the epipelagic octopus Tremoctopus violaceus were the dominant items. Predation upon schooling prey was occasional, as observed on Arioma bondi. Birds also were consumed in both regions; Puffinus gravis was the fifth most frequent item in the northeastern region. During the reproductive migration cycle, blue sharks likely prey in the thermocline, which is deeper in the northeastern region and closer to the surface in the southern region.

scholarly journals Feeding habits of the shortnose guitarfish, Zapteryx brevirostris (Müller and Henle, 1841) (Elasmobranchii, Rhinobatidae) in southeastern Brazil

2011 ◽  
Vol 71 (1) ◽  
pp. 83-89 ◽  
Author(s):  
C. Marion ◽  
T. Vaske-Junior ◽  
OBF. Gadig ◽  
IA. Martins
Keyword(s):  
Feeding Habits ◽  
Sao Paulo ◽  
Southeastern Brazil ◽  
Small Fish ◽  
São Paulo ◽  
Southeast Brazil ◽  
Males And Females ◽  
Prey Items

The feeding habits of the shortnose guitarfish, Zapteryx brevirostris, were studied based on 382 specimens from the northern São Paulo coast, southeast Brazil. The diet showed a predominance of crustaceans (carideans and amphipods), polychaete annelids, and occasionally small fish, sipunculids, and cephalopods. The diets of males and females were similar; however, differences in the proportion of prey items were found among juveniles, subadults, and adults. Differences in the ingestion of prey items were found during the year, probably influenced by oceanographic parameters, although in general, the species feeds mostly on crustaceans and polychaetes.

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