scholarly journals PRESENCIA DE UROTRYGON MICROPHTHALMUM (ELASMOBRANCHII: UROLOPHIDAE) EN AGUAS BAJAS DE MARANHÃO (BRASIL) Y NOTAS SOBRE SU BIOLOGIA

2016 ◽  
Vol 29 ◽  
Author(s):  
Zafira S. Almeida ◽  
Jorge S. Nunes ◽  
Clarissa L. Costa
Keyword(s):  
Sexual Dimorphism ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Total Length ◽  
Sexual Stages

From October 1997 to April, 1998 seventy-nine specimens of the ray Urotrygon microphthalmumwere captured, all of them showing sexual dimorphism. They were processed in order to study their morphometrics, feeding habits, and reproduction. The largest was 300 mm in total length and the smallest one 64.4 mm, weighing 103.4 g and 12.5 g respectively. They fed mainly on crustaceans and ploychaeta; of the stomach contents 94.5 % were shrimp and 5.49% polychaeta. 7.6% of the total had empty stomachs. As far as reproduction, three sexual stages were found:  51% juvenile, 30% adult and 19% pregnant, with an average of three embryos per uterus. Among the male fishes analysed 84.4% were juvenile and 16.6% adults

Feeding habits of thresher sharks Alopias sp. in northern Peru: predators of Humboldt squid (Dosidicus gigas)

2018 ◽  
Vol 99 (3) ◽  
pp. 695-702 ◽  
Author(s):  
Adriana González-Pestana ◽  
Nicolas Acuña-Perales ◽  
Francisco Córdova ◽  
Javier Coasaca ◽  
Eliana Alfaro ◽  
...  
Keyword(s):  
Feeding Habits ◽  
Stomach Contents ◽  
Dosidicus Gigas ◽  
Size Classes ◽  
Genus Level ◽  
Total Length ◽  
Northern Peru ◽  
Humboldt Squid ◽  
High Degree ◽  
Thresher Sharks

The stomach contents of thresher sharks (Alopias spp.; 162–385 cm total length) were collected from five landing points in northern Peru during 2015. A total of 128 thresher sharks were sampled, with 38 individuals identified as Alopias pelagicus and 90 aggregated to the genus level Alopias sp. to prevent any misidentification. The diet comprised 13 and 10 prey taxa for Alopias sp. and A. pelagicus, respectively. Humboldt squid Dosidicus gigas dominated the diet of both groups, with only minor differences in the diet in relation to size classes and location. The diet of Alopias shows a high degree of specialization and the average trophic positions were high for both groups, A. pelagicus (4.4 ± 0.13) and Alopias sp. (4.5 ± 0.14).

scholarly journals Relative feeding specialization may depress ontogenetic, seasonal, and sexual variations in diet: the endemic lizard Cnemidophorus littoralis (Teiidae)

2003 ◽  
Vol 63 (2) ◽  
pp. 321-328 ◽  
Author(s):  
P. F. Teixeira-Filho ◽  
C. F. D. Rocha ◽  
S. C. Ribas
Keyword(s):  
Sexual Dimorphism ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Analysis Of Covariance ◽  
Head Size ◽  
Head Width ◽  
Adult Males ◽  
Important Prey ◽  
Relative Contribution ◽  
Main Item

We investigated the feeding habits of the teiid lizard Cnemidophorus littoralis in the markedly seasonal habitat of Restinga da Barra de Maricá (22º57'S, 43º50'W), Rio de Janeiro State, Brazil, to evaluate to what extent its diet is ontogenetically, sexually, and/or seasonally conservative. Lizard stomach contents were analyzed, identified, counted, estimated for volume (in mm³), and grouped in four classes (active, sedentary, and clumped preys, and plant material). The relative contribution of each food class to the total prey volume consumed by adult males and females and juveniles was compared in three ways: between juveniles and adults, sexes, and seasons (wet and dry). Sexual dimorphism in head size was tested by comparing head width and jaw length using analysis of covariance (ANCOVA). Isopterans were the most important prey item, occurring in 93% of the lizard stomachs examined and corresponding to 96.4% of total prey content and 69.7% of total prey volume. They occurred in high frequencies in the stomachs of C. littoralis throughout all study months. We found no sexual, ontogenetic, or seasonal differences in C. littoralis diet although the sexes differed significantly in head width. We concluded that isopterans are the main item in the diet of C. littoralis in Restinga da Barra de Maricá, both for juveniles and adults. The lack of seasonal, sexual, or ontogenetic variation in its diet results from the massive consumption of these insects. Isopterans are small, occur in clumps, and are available year-round, and thus are an advantageous food item for the active forager C. littoralis. We also found sexual dimorphism in the head size of C. littoralis: males have wider heads than females. This dimorphism, however, does not seem to be related with the diet of the species, and is probably a result of sexual selection.

scholarly journals Ecological Observations on Hybrid Populations of European Plethodontid Salamanders, Genus Speleomantes

Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 285
Author(s):  
Enrico Lunghi ◽  
Fabio Cianferoni ◽  
Stefano Merilli ◽  
Yahui Zhao ◽  
Raoul Manenti ◽  
...  
Keyword(s):  
Body Condition ◽  
Parental Species ◽  
Stomach Contents ◽  
Trophic Niche ◽  
Natural Hybrid ◽  
Ecological Information ◽  
Total Length ◽  
Plethodontid Salamanders ◽  
The Future ◽  
First Time

Speleomantes are the only plethodontid salamanders present in Europe. Multiple studies have been performed to investigate the trophic niche of the eight Speleomantes species, but none of these studies included hybrid populations. For the first time, we studied the trophic niche of five Speleomantes hybrid populations. Each population was surveyed twice in 2020, and stomach flushing was performed on each captured salamander; stomach flushing is a harmless technique that allows stomach contents to be inspected. We also assessed the potential divergence in size and body condition between natural and introduced hybrids, and their parental species. Previously collected data on Speleomantes were included to increase the robustness of these analyses. In only 33 out of 134 sampled hybrid Speleomantes we recognized 81 items belonging to 11 prey categories. The frequency of empty stomachs was higher in females and individuals from natural hybrid populations, whereas the largest number of prey was consumed by males. We compared the total length and body condition of 685 adult salamanders belonging to three types of hybrids and three parental (sub)species. Three group of salamanders (one hybrid and two parental species) showed significantly larger size, whereas no difference in body condition was observed. This study provided novel ecological information on Speleomantes hybrid populations. We also provided insights into the potential divergence between hybrids and parental species in terms of size and body condition. We discuss our findings, and formulate several hypotheses that should be tested in the future.

scholarly journals Morphometric characters and their relationship in estuarine catfish

1970 ◽  
Vol 6 (2) ◽  
pp. 349-353 ◽  
Author(s):  
M Begum ◽  
Abdullah Al-Mamun ◽  
ML Islam ◽  
MJ Alam
Keyword(s):  
Sexual Dimorphism ◽  
Linear Relationship ◽  
Standard Length ◽  
Head Length ◽  
Pectoral Fin ◽  
Morphometric Characters ◽  
Total Length ◽  
Length Standard ◽  
Eye Diameter ◽  
Males And Females

The morphometric observations were made on total length, standard length, pre-caudal length, head length, eye diameter and depth of body at pectoral fin base of estuarine catfish M. gulio. Males and females showed homogeneity in characters. A linear relationship was found between total length and morphometric characters. Regression of length and weight did not deviate significantly from cube law indicating isometric growth. The fish exhibited sexual dimorphism. Keywords: Morphometric characters; Estuarine catfish; Mystus gulio DOI: 10.3329/jbau.v6i2.4833 J. Bangladesh Agril. Univ. 6(2): 349-353, 2008

Stomach contents of the marine tucuxi dolphin (Sotalia guianensis) from Rio de Janeiro, south-eastern Brazil

2007 ◽  
Vol 87 (1) ◽  
pp. 253-254 ◽  
Author(s):  
Ana Paula Madeira Di Beneditto ◽  
Salvatore Siciliano
Keyword(s):  
Rio De Janeiro ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Additional Information ◽  
Sotalia Guianensis ◽  
South Eastern ◽  
Eastern Brazil ◽  
Trichiurus Lepturus ◽  
Cynoscion Guatucupa ◽  
Janeiro State

Along the central coast of Rio de Janeiro State (22°25′S–23°00′S), south-eastern Brazil, the marine tucuxi dolphin (Sotalia guianensis) feeds on neritic prey that are distributed through the water column and are abundant all year round. The most frequently found species were the teleost fish Trichiurus lepturus, Cynoscion guatucupa, Isopisthus parvipinnis and Porichthys porossisimus. Fish species were more important than cephalopod species in the diet of the marine tucuxi. Back calculations of prey sizes indicated that they feed mainly on young specimens. The present study provided additional information on the feeding habits of the marine tucuxi dolphin.

scholarly journals Reproductive biology of Sympterygia bonapartii (Chondrichthyes: Rajiformes: Arhynchobatidae) in San Matías Gulf, Patagonia, Argentina

2017 ◽  
Vol 15 (1) ◽  
Author(s):  
María L. Estalles ◽  
María R. Perier ◽  
Edgardo E. Di Giácomo
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Biology ◽  
Early Spring ◽  
Egg Laying ◽  
Reproductive Pattern ◽  
Reproductive Parameters ◽  
Egg Capsules ◽  
Northern Patagonia ◽  
Total Length

ABSTRACT This study estimates and analyses the reproductive parameters and cycle of Sympterygia bonapartii in San Matías Gulf, northern Patagonia, Argentina. A total of 827 males and 1,299 females were analysed. Males ranged from 185 to 687 mm of total length (TL) and females from 180 to 742 mm TL. Sexual dimorphism was detected; females were larger, heavier, exhibited heavier livers, wider discs and matured at lager sizes than males. Immature females ranged from 180 to 625 mm TL, maturing females from 408 to 720 mm TL, mature ones from 514 to 742 mm TL and females with egg capsules from 580 to 730 mm TL. Immature males ranged from 185 to 545 mm TL, maturing ones from 410 to 620 mm TL and mature males from 505 to 687 mm TL. Size at which 50% of the skates reached maturity was estimated to be 545 mm TL for males and 594 mm TL for females. According to the reproductive indexes analysed, S. bonapartii exhibited a seasonal reproductive pattern. Mating may occur during winter-early spring and the egg-laying season, during spring and summer.

scholarly journals FEEDING HABITS AND HELMINTH PARASITES OF SARDINE (S. PILCHARDUS) AND ANCHOVY (E. ENCRASICOLUS) IN THE ADRIATIC SEA

2015 ◽  
Vol 17 (1) ◽  
pp. 216 ◽  
Author(s):  
B. ZORICA ◽  
V. ČIKES KEČ ◽  
O. VIDJAK ◽  
I. MLADINEO ◽  
D. EZGETA BALIČ
Keyword(s):  
Diet Composition ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Stomach Content Analysis ◽  
Helminth Parasites ◽  
Significant Difference ◽  
Prey Composition ◽  
One Year ◽  
Paratenic Hosts ◽  
Hysterothylacium Aduncum

We examined the stomach contents of two of the most economically and ecologically important small pelagic fish species, the sardine, Sardina pilchardus and the anchovy, Engraulis encrasicolus, obtained monthly from commercial purse-seine catches operating on Croatian fishing grounds during a one-year period (January–December, 2011). Both species generally showed a similar diet, with copepod and decapod larvae as dominant prey groups. The composition of anchovy and sardine stomach contents was not size- or sex-related, but throughout the year, a significant difference in diet composition was observed for each species as well as between species. Two gastrointerstinal helminths; the digenean Parahemiurus merus and nematode Hysterothylacium aduncum, were recorded during the stomach content analysis. Differences in population dynamics between the two parasites are congruent with differences in the prey composition of sardine and anchovy, reflecting fine-tuned interactions in the trophic web between parasites and intermediate or paratenic hosts included in the sardine and anchovy diet.

scholarly journals Feeding habits of Cocobolo Andinoacara pulcher in the cienaga Grande de Lorica, Colombia

2016 ◽  
pp. 5189-5197
Author(s):  
Charles W Olaya-Nieto ◽  
Liquey Camargo-Herrera ◽  
Vanessa Díaz-Sajonero ◽  
Fredys F Segura-Guevara
Keyword(s):  
River Basin ◽  
Stomach Content ◽  
Feeding Habits ◽  
Frequency Of Occurrence ◽  
Relative Importance ◽  
Food Groups ◽  
Total Length ◽  
Length Relationship ◽  
Importance Index ◽  
Gut Length

ABSTRACTObjective. The feeding habits of Cocobolo (Andinoacara pulcher) in the cienaga Grande de Lorica, Sinu river basin, were studied. Materials and methods. The stomach content was analyzed using the Proportion of empty stomachs, Grade of digestion, Frequency of occurrence, numerical Frequency, Gravimetry, relative importance Index (RII) and the gut length-total length relationship. Results. 39.8% of stomachs were empty, 47.1% of preys were fresh and five food groups were identified. Vegetable remains was the most frequent group (63.8%) and the prey with greatest composition in weight (33.5%), while Rest of fishes was the most abundant group (34.7%). It was observed that in low and rising waters, fishes was the most consumed prey, while that in high and falling waters the most consumed prey was vegetable remains. Vegetable remains, detritus and fishes were food groups of secondary relative importance, while Insects and Others were circumstantial or incidental groups. Conclusions. The results achieved indicate that Cocobolo is a fish with omnivores feeding habits with a preference for fishes and vegetable remains. RESUMEN Objetivo. Se estudiaron los hábitos alimentarios de Cocobolo (Andinoacara pulcher) en la ciénaga Grande de Lorica, cuenca del río Sinú, Colombia. Materiales y Métodos. El contenido estomacal se evaluó con el Coeficiente de vacuidad, Grado de llenado, Grado de digestión, Frecuencia de ocurrencia, Frecuencia numérica, Gravimetría, Índice de importancia relativa y la relación longitud intestinal- longitud total. Resultados. El 39.8% de los estómagos se encontró vacío, el 47.1% de las presas en estado fresco y se identificaron cinco grupos alimentarios. Material vegetal fue el grupo más frecuente (63.8%) y con mayor composición por peso (33.5%), mientras que Restos de peces fue el más abundante (34.7%). Se observó que en aguas bajas y en aguas ascendentes, peces fue la presa más consumida, mientras que en aguas altas y aguas descendentes, fue material vegetal. Material vegetal, detritos y restos de peces fueron grupos alimentarios de importancia relativa secundaria, mientras que insectos y otros fueron circunstanciales o incidentales. Conclusiones. Los resultados alcanzados indican que Cocobolo es un pez de hábitos alimentarios omnívoros con preferencia por peces y material vegetal.

scholarly journals Biometric sexual and ontogenetic dimorphism on the marine catfish Genidens genidens (Siluriformes, Ariidae) in a tropical estuary

2017 ◽  
Vol 43 (5) ◽  
pp. 895-903
Author(s):  
Larissa G. Paiva ◽  
Luana Prestrelo ◽  
Kiani M. Sant'Anna ◽  
Marcelo Vianna
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Difference ◽  
Body Measurements ◽  
Guanabara Bay ◽  
Sex Dimorphism ◽  
Total Length ◽  
Maturity Stages ◽  
Males And Females ◽  
Adipose Fin ◽  
Eye Depth

This paper aims to study the ontogenetic sexual dimorphism of Genidens genidens in Guanabara Bay, southeastern coast of Brazil. Altogether 378 specimens were anayzed (233 females and 145 males) with total length ranging from 13.3 to 43.5 cm. Specimens were measured for 12 body measurements, sex was identified and maturity stages were recorded and classified. Pearson’s linear correlation reveled a significant positive correlation between total length and all other body measures, except for base adipose fin, mouth depth and eye depth for immature females. Analyses nested PERMANOVA desing showed significant differences between maturity stages for each sex, between sexes considering or not maturity stages, indicating a variation in morphometric characteristics driven by sexual dimorphism. Differences among all maturity stages were also found, indicating an ontogenetic morphological difference. But immature individuals didn’t differ between sexes indicating that differentiation patterns starts with sexual development. The most important measures differing males and females were related to head characteristics, which appears to be key parameters to evaluate sexual differences. Due to male incubation of fertilized eggs and juvenile individuals <59 mm in their oral cavity, head measures are proposed to be sex dimorphism not related to reproduction, but with post reproductive fase due to ecological and biological needs.  [L1]Modificated  as suggested by Reviewer E.

scholarly journals Trophic habits of the invasive crab Libinia dubia H. Milne Edwards, 1834 from the Gulf of Gabès (Tunisia)

2020 ◽  
Author(s):  
AMANI CHAFFAI ◽  
WAFA RJIBA-BAHRI ◽  
ASMA ABIDI ◽  
FRANҪOISE DENIS ◽  
JAMILA BEN SOUISSI
Keyword(s):  
Feeding Habits ◽  
Carapace Width ◽  
Stomach Contents ◽  
Spider Crab ◽  
Gulf Of Gabes ◽  
Chi Square ◽  
Gulf Of Gabès ◽  
Chi Square Test ◽  
Herbivorous Species ◽  
Stomach Weight

Feeding habits of the invasive spider crab Libinia dubia from the Mediterranean Sea were studied in the Gulf of Gabès (Tunisia) using the frequency of occurrence and points methods. The population was sampled at least monthly between November 2015 and October 2016. Stomach contents of 384 specimens were analysed. Results indicate that L. dubia is an herbivorous species exhibiting clear preferences for algae (ALG) and Magnoliophyta (MAG) (62.03%, 7.13 points and 59.36%, 5.3 points respectively) although Echinodermata (ECH), Porifera (POR), Cnidaria (CNI), Mollusca (MOL), Polychaeta (POL), Crustacea (CRU) and fish (FIS) were accidentally consumed along with Bryozoa (BRY), sediment (SED), and unidentifiable materials (UNM). The diversity of ALG ingested was studied in detail: Chlorophyceae were found in 87.93% of stomachs containing ALG and contributed most of points to the stomach contents (4.18 points) followed respectively by Phaeophyceae (81.03%, 2.27 points) and Rhodophyceae (40.95%, 0.68 points).Very low Vacuity Index was recorded (VI = 2.6%). Ingested items varied significantly with regard to the season (Chi-square test, χ2calculated = 87.86 > χ2theoretical = 7.81, df = 3, p < 0.05) and crab size (χ2calculated = 14.25 > χ2theoretical = 5.99, df = 2, p = 0.026). Insignificant differences were registered by studying Carapace Width-Stomach Weight (CW-SW) relationships (T-test, tcalculated < ttheoretical, p > 0.05). Kruskal-Wallis test was applied so that the composition of crab diet among groups could be compared (H = 1.1, df = 3, p = 0.77). 

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