Trophic ecology of Mugil liza at the southern limit of its distribution (Buenos Aires, Argentina)

AbstractIn order to get to know the habitat and feeding habits of Mugil liza on the southern coast of Buenos Aires province, 65 specimens obtained at two sampling sites - the San Blas bay (SBB) and the mouth of the Quequén-Salado river (QSR) - during spring (November 2012) and summer (February 2013) were analyzed. Specimens were measured, sexed and weighed, their stomachs were removed and their stomach contents weighed and analyzed under the stereoscopic microscope. The specimens were adults, 28-49 cm in length and weighing 380-1100 g. Population growth was higher in the SBB (TW: 0.003*TL3.36), than in RQS (TW: 0.045*TL2.61). About 98% of the stomachs had some content, their repletion rate being of between 0.4 and 1.2%. About 75% of the stomachs contained very fine sand with few benthic organisms (algae, copepods, foraminifera), whereas the remaining 25% of stomachs contained coarse sand and a greater presence of benthic fauna (amphipods, bivalves, gastropods and coral organisms). The linear relationship between the weight of stomach contents and the total weight and length of the fish showed that the rates of growth (slope) were the same at both sites, but intercept values were significantly higher for San Blas bay (test parallelism; p < 0.001).

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Trophic ecology and diet of Hydra vulgaris (Cnidaria; Hydrozoa)

Animal Biology ◽

10.1163/15707563-00002537 ◽

2017 ◽

Vol 67 (3-4) ◽

pp. 287-300 ◽

Cited By ~ 4

Author(s):

María I. Deserti ◽

Karina S. Esquius ◽

Alicia H. Escalante ◽

Fabián H. Acuña

Keyword(s):

Nutritional Value ◽

Trophic Ecology ◽

Buenos Aires ◽

Feeding Habits ◽

Natural Habitat ◽

Buenos Aires Province ◽

Hydra Vulgaris ◽

Natural Diet ◽

Food Items ◽

Invertebrate Prey

Hydra is a genus of common, sessile, solitary freshwater cnidarians, which are defined as carnivorous and efficient predators. The purpose of this study was to obtain information on the feeding habits and diet of Hydra vulgaris collected from its natural habitat in Nahuel Rucá Lake (Buenos Aires Province, Argentina). We found three categories of food items in the coelenteron: algae, fungi, and small invertebrates. Algae dominated the diet in terms of abundance and frequency of occurrence, but their volumetric contribution was almost negligible, as was their possible nutritional value. Invertebrate prey captured, using active predation, represented the major volumetric contribution, with four different taxa found. The detection of phytoplankton in the gastral cavities reveals the input of some organisms present in the surrounding waters in addition to the invertebrates. This information is novel, since studies on the natural diet of Hydra are very scarce.

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Feeding habits of Lithobates megapoda (Anura: Ranidae), a threatened leopard frog used for human consumption, in Lake Chapala, Mexico

Phyllomedusa Journal of Herpetology ◽

10.11606/issn.2316-9079.v20i1p75-88 ◽

2021 ◽

Vol 20 (1) ◽

pp. 75-88

Author(s):

José Luis Barragán-Ramírez ◽

Benjamín Hernández ◽

María Guadalupe Velarde-Aguilar ◽

Oscar Pérez-Flores ◽

José Luis Navarrete-Heredia ◽

...

Keyword(s):

Trophic Ecology ◽

Dietary Diversity ◽

Feeding Habits ◽

Stomach Contents ◽

Prey Type ◽

Leopard Frog ◽

Human Consumption ◽

Relative Importance ◽

Prey Category ◽

Lake Chapala

The Big-footed Leopard Frog (Lithobates megapoda) is a threatened and endemic species from western Mexico. This species has aquatic habits and it is distinguished by its large size, particularly by the length of its legs, reason for which it is captured for human consumption. Also, knowledge about its natural history is scarce and incomplete. In this study, we analyzed the composition of the diet of L. megapoda on the shore of Lake Chapala, the largest lake in Mexico. A total of 69 adult individuals were collected lifeless in fishing nets, during the rainy season (June-October), of which 48 had stomach contents. A total of 96 prey items were identified, which correspond to 13 prey categories. Fish constituted the most dominant prey category in the diet in terms of number, volume, frequency of occurrence, and relative importance. No significant differences were found in the consumption by prey type (aquatic or terrestrial). However, the aquatic preys had a greater relative importance and were more voluminous than the terrestrial ones. The diversity of prey categories, in terms of prey volume, indicates males may have a higher dietary diversity than females, but we not evaluated possible bias. In addition, a significant effect was found in the interaction of size (SVL) of frogs with the average of prey volume. Females (that are larger than males) consumed prey within a wide volume range and, the larger they are, more voluminous are prey. In this way it is possible that intraspecific competition for trophic resources in the environment is reduced. This study helps us understand the trophic ecology of L. megapoda, a frog species that plays an important role in the food web where it lives, as a predator feeding on aquatic and terrestrial organisms.

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Long-term spatio-temporal dynamics of the mosquito Aedes aegypti in temperate Argentina

Bulletin of Entomological Research ◽

10.1017/s0007485316000869 ◽

2016 ◽

Vol 107 (2) ◽

pp. 225-233 ◽

Cited By ~ 13

Author(s):

S. Fischer ◽

M.S. De Majo ◽

L. Quiroga ◽

M. Paez ◽

N. Schweigmann

Keyword(s):

Aedes Aegypti ◽

Buenos Aires ◽

Temporal Dynamics ◽

Spatial Dynamics ◽

Climatic Conditions ◽

Buenos Aires Province ◽

Southern Limit ◽

Spatio Temporal ◽

Lower Temperature

AbstractBuenos Aires city is located near the southern limit of the distribution of Aedes aegypti (Diptera: Culicidae). This study aimed to assess long-term variations in the abundance of Ae. aegypti in Buenos Aires in relation to changes in climatic conditions. Ae. aegypti weekly oviposition activity was analyzed and compared through nine warm seasons from 1998 to 2014, with 200 ovitraps placed across the whole extension of the city. The temporal and spatial dynamics of abundances were compared among seasons, and their relation with climatic variables were analyzed. Results showed a trend to higher peak abundances, a higher number of infested sites, and longer duration of the oviposition season through subsequent years, consistent with a long-term colonization process. In contrast, thermal favorability and rainfall pattern did not show a consistent trend of changes. The long-term increase in abundance, and the recently documented expansion of Ae. aegypti to colder areas of Buenos Aires province suggest that local populations might be adapting to lower temperature conditions. The steadily increasing abundances may have implications on the risk of dengue transmission.

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New records of Aedes aegypti at the southern limit of its distribution in Buenos Aires province, Argentina

Journal of Vector Ecology ◽

10.1111/jvec.12181 ◽

2015 ◽

Vol 40 (2) ◽

pp. 408-411 ◽

Cited By ~ 16

Author(s):

Gabriela Zanotti ◽

María Sol De Majo ◽

Iris Alem ◽

Nicolás Schweigmann ◽

Raúl E. Campos ◽

...

Keyword(s):

Aedes Aegypti ◽

Buenos Aires ◽

New Records ◽

Buenos Aires Province ◽

Southern Limit

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Grey seal diet at the southern limit of its European distribution: combining dietary analyses and fatty acid profiles

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s002531540705463x ◽

2007 ◽

Vol 87 (1) ◽

pp. 255-264 ◽

Cited By ~ 13

Author(s):

V. Ridoux ◽

J. Spitz ◽

C. Vincent ◽

M.J. Walton

Keyword(s):

Fatty Acid ◽

Feeding Habits ◽

Stomach Contents ◽

Individual Variability ◽

Foraging Strategies ◽

Grey Seal ◽

Adult Males ◽

Southern Limit ◽

North East ◽

Conger Eel

The north-east Atlantic grey seal, Halichoerus grypus, is widely distributed along the European coastline from northern Russia to France, with the core population centred around Scotland. To date, very little is known of the diet of the species at the southern margin of the species range. However, because grey seal numbers have been increasing over the last few decades in France, the issue of their potential interactions with coastal fisheries is frequently raised. The diet of grey seal in the Molène Archipelago was investigated by combining scat, stomach content and fatty acid analyses, since all three approaches have complementary potentials to reveal feeding habits of a predator. A total of 145 scats mostly of moulting adult males, 14 stomach contents of yearlings and 14 blubber samples from animals of all ages were analysed following standard methodologies. Scats revealed a diet mainly constituted of 50.6% by mass (M) of wrasse, Labridae (mostly Labrus bergylta), 20.7%M conger eel, Conger conger, and 11.9%M sea bass, Dicentrarchus labrax. Stomach contents were made up of 52.3%M cuttlefish, Sepia officinalis, 9.5%M sole, Solea solea, and 9.4 %M conger eel. All these prey are different from the diet observed in core areas. Fatty acid analysis from the blubber confirmed that the diet differed between the Molène Archipelago and one of the Scottish breeding sites. It also showed that most of the inter-individual variability was explained by variation in seal body masses, which could be linked to behavioural ontogeny of foraging strategies. Most of the prey species identified in the food of the grey seal in Brittany are also targeted by professional and/or recreational fisheries in the area; additionally, several prey size-ranges also partly overlap with marketed size-ranges for several species.

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Variaciones Antropogenicas de las Playas del Sudeste de Buenos Aires, Argentina

Pesquisas em Geociências ◽

10.22456/1807-9806.20165 ◽

2001 ◽

Vol 28 (1) ◽

pp. 27 ◽

Cited By ~ 1

Author(s):

FEDERICO ISLA ◽

GERMAN BERTOLA ◽

MARCELO FARENGA ◽

LUIS CORTIZO

Keyword(s):

Buenos Aires ◽

Morphological Changes ◽

Beach Nourishment ◽

Fine Sand ◽

Storm Tracks ◽

Buenos Aires Province ◽

Sand Mining ◽

The South ◽

Southeastern Coast ◽

Sand Accumulation

The southeastern coast of Buenos Aires Province is subject to natural and critic erosion problems induced mainly by storm tracks from the south. Man tried to minimize these problems by the construction of groin fields and recently by beach-nourishment programs. Sand exploitation was very intense and was prohibited at the end of the eighties (there are still local exploitations where sand accumulation is induced at the base of the southern jetty of the Mar del Plata harbor). Comparing beach surveys carried out at different periods (1983-84, 1991-93 and 1997-2000), significant changes in beach morphodynamics have been detected. At the northern beaches of La Perla region, the prolongation of old groins have caused convex profiles and accumulation of coarser foreshores. The erosive beach of Playa Grande changed dramatically due to nourishment jobs carried out in 1998. Since that time, the beach face became composed of fine sand and has been receding at a faster rate. At the Alfar beach, the interruption of sand mining provoked the accumulation of fine-sand berms. The Chapadmalal beach recorded the more significant morphological changes within this last period (1997-2000). The beaches within the groin field of Miramar city have steep profiles during winter, recovering the berms during the rest of the year, with variations of the coastline of more than 30 m.

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Investigating diet patterns of highly mobile marine predators using stomach contents, stable isotope, and fatty acid analyses

ICES Journal of Marine Science ◽

10.1093/icesjms/fsy025 ◽

2018 ◽

Vol 75 (5) ◽

pp. 1583-1590 ◽

Cited By ~ 5

Author(s):

Talia Young ◽

Jennifer Pincin ◽

Philipp Neubauer ◽

Sofía Ortega-García ◽

Olaf P Jensen

Keyword(s):

Fatty Acid ◽

Stable Isotope ◽

Trophic Ecology ◽

Feeding Habits ◽

Stomach Contents ◽

Short Term ◽

Predator Species ◽

Diet Patterns ◽

Marine Predators

Abstract Determining what animals eat is simultaneously challenging and yet also critical for ecologists, fisheries scientists, and resource managers. The tools of trophic ecology have expanded considerably in the last half century in pursuit of this goal. In this study, we combined stomach contents, stable isotope, and fatty acid analyses to investigate trophic patterns in three species of highly mobile, pelagic predators: striped marlin (Kajikia audax), blue marlin (Makaira nigricans), and common dolphinfish (Coryphaena hippurus). We were particularly interested in examining individual diet specialization among these species. We compared the short-term stomach contents with long-term diet proportions estimated from stable isotope ratios and fatty acid profiles using a Bayesian mixing model. Our results indicate that all three species feed on a mix of prey types. This work furthermore suggests that individuals of all three predator species demonstrate generalist feeding habits, with minimal differences in long-term (weeks, months) diet estimates between individuals with different short-term (hours, days) stomach contents. This novel, three-part analytical approach can elucidate complex and otherwise elusive trophic dynamics.

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