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

2007 ◽  
Vol 87 (1) ◽  
pp. 255-264 ◽  
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.

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

2015 ◽  
Vol 63 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Gustavo Thompson ◽  
Roberta Callico Fortunato ◽  
Ignacio Chiesa ◽  
Alejandra Volpedo
Keyword(s):  
Trophic Ecology ◽  
Buenos Aires ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Benthic Fauna ◽  
Fine Sand ◽  
Coarse Sand ◽  
Buenos Aires Province ◽  
Southern Limit ◽  
Rates Of Growth

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).

Feeding of tub gurnard Chelidonichthys lucerna (Scorpaeniformes: Triglidae) in the north-east Mediterranean

2011 ◽  
Vol 92 (3) ◽  
pp. 605-612 ◽  
Author(s):  
Marco Stagioni ◽  
Stefano Montanini ◽  
Maria Vallisneri
Keyword(s):  
Diet Composition ◽  
Foraging Behaviour ◽  
Adriatic Sea ◽  
Feeding Habits ◽  
Feeding Activity ◽  
Stomach Contents ◽  
East Mediterranean ◽  
North East ◽  
The North ◽  
Important Prey

The stomach contents of 1096 specimens of Chelidonichthys lucerna were examined in order to analyse their diet composition according to fish size, sex, depth and season. Sampling was carried out from May 2005 to March 2007 during several bottom trawl surveys in the Adriatic Sea (north-east Mediterranean). Feeding activity was more intense in juveniles than in adults. The most important prey was Crustacea (mainly Decapoda: Brachyura, such as Goneplax rhomboides, Liocarcinus spp., Philocheras spp.) and Teleostei (mainly European anchovy Engraulis encrasicolus and black goby Gobius niger). There was no difference between male and female diet. Feeding habits varied with size, with fish dominating the stomach contents of larger specimens. Finally, fish increased in winter and crustaceans in summer. Chelidonichthys lucerna shows a generalist and opportunistic foraging behaviour, preying mainly epibenthic and nectobenthic organisms.

scholarly journals Pinnipeds, people and photo identification: the implications of grey seal movements for effective management of the species

2019 ◽  
Vol 99 (5) ◽  
pp. 1221-1230
Author(s):  
Sue Sayer ◽  
Rebecca Allen ◽  
Lucy A. Hawkes ◽  
Kate Hockley ◽  
Dan Jarvis ◽  
...  
Keyword(s):  
Regional Scale ◽  
Marine Species ◽  
Individual Variability ◽  
Grey Seal ◽  
Limited Information ◽  
Annual Life Cycle ◽  
Photo Identification ◽  
North East ◽  
Mobile Species ◽  
The Uk

AbstractGrey seals (Halichoerus grypus) of the North-east Atlantic are protected at designated European Marine Sites (Special Areas of Conservation, SACs) typically during their reproductive periods and in the UK at Sites of Special Scientific Interest (SSSI). As a mobile marine species, grey seals spend other parts of their annual life cycle in non-designated habitat. There is limited information on individual grey seal movements in south-west England. Citizen science photo identification (PID) revealed the movements of 477 grey seals at a regional scale (54 haul-outs up to 230 km apart) for over a decade. Reconstructed movements showed considerable individual variability. Four SACs were linked to up to 18 non-designated sites and two SSSIs in Cornwall were linked to a maximum of 41 non-designated sites. Observations support the value of existing SSSIs at both the well-connected West and North Cornwall sites. Thirteen Marine Protected Areas (MPAs) were visited by grey seals from four SACs and two SSSIs in Cornwall. As a mobile species, grey seals could be included in English MPA management plans. The application of functional linkage from SACs and SSSIs, informed by the movements evidenced in this research, could aid management efforts. This analysis reveals grey seal movements occur across a complex network of interconnected designated and non-designated sites that need to be managed holistically for this species for which the UK has a special responsibility.

scholarly journals Feeding habits of the Robber Frog Pristimantis paulodutrai (Bokermann, 1975) in northeastern Brazil

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Thales Francisco S. S. Alves-dos-Santos ◽  
Lucas Rodriguez Forti ◽  
Marcelo Felgueiras Napoli
Keyword(s):  
Feeding Habits ◽  
Stomach Contents ◽  
Dry Mass ◽  
Northeastern Brazil ◽  
Generalist Predators ◽  
Predator Prey ◽  
North East ◽  
The North ◽  
Generalist Diet ◽  
Ecological Dominance

Abstract: Studying feeding habits is crucial to understand complex predator-prey interactions. Even though anurans play a fundamental role in the control of arthropods populations, the diet of several Neotropical species is poorly known. We describe the frequency and occurrence of prey items and their dry mass in stomach contents of the Robber Frog Pristimantis paulodutrai in the north east of the state of Bahia, Brazil. Based on the stomach contents of 30 individuals, Araneae, Isopoda, and Formicidae were found to be the most important food items. The generalist diet of this frog, which seems to be phylogenetically conserved among Pristimantis, is likely to be linked to its ecological dominance in the habitats surveyed. Our study corroborates the high trophic relevance of Robber Frogs in tropical forests as generalist predators.

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

2018 ◽  
Vol 75 (5) ◽  
pp. 1583-1590 ◽  
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.

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.

Stomach contents of bottlenose dolphins (Tursiops truncatus) in Scottish waters

2001 ◽  
Vol 81 (5) ◽  
pp. 873-878 ◽  
Author(s):  
M.B. Santos ◽  
G.J. Pierce ◽  
R.J. Reid ◽  
I.A.P. Patterson ◽  
H.M. Ross ◽  
...  
Keyword(s):  
Salmo Salar ◽  
Tursiops Truncatus ◽  
Gadus Morhua ◽  
Feeding Habits ◽  
Bottlenose Dolphins ◽  
Stomach Contents ◽  
Melanogrammus Aeglefinus ◽  
North East ◽  
Moray Firth ◽  
Merlangius Merlangus

Data on stomach contents of ten bottlenose dolphins (Tursiops truncatus) stranded and by-caught around Scotland (UK) between 1990 and 1999 are presented. Although the species is resident in the Moray Firth (north-east Scotland), little previous information exists on the feeding habits of the species in Scottish waters. Cod (Gadus morhua), saithe (Pollachius virens) and whiting (Merlangius merlangus) were found to be the main prey eaten although several other fish species were also found, including salmon (Salmo salar) and haddock (Melanogrammus aeglefinus), and also cephalopods.

Utilizing next-generation sequencing to identify prey DNA in western North Atlantic grey seal Halichoerus grypus diet

2020 ◽  
Vol 655 ◽  
pp. 227-240
Author(s):  
KR Flanders ◽  
ZH Olson ◽  
KA Ono
Keyword(s):  
Next Generation Sequencing ◽  
Feeding Habits ◽  
Atlantic Menhaden ◽  
Halichoerus Grypus ◽  
Frequency Of Occurrence ◽  
Grey Seal ◽  
Next Generation ◽  
Significant Difference ◽  
Generation Sequencing ◽  
Seal Diet

Increasing grey seal Halichoerus grypus abundance in coastal New England is leading to social, political, economic, and ecological controversies. Central to these issues is the foraging ecology and diet composition of the seals. We studied grey seal feeding habits through next-generation sequencing of prey DNA using 16S amplicons from seal scat (n = 74) collected from a breeding colony on Monomoy Island in Massachusetts, USA, and report frequency of occurrence and relative read abundance. We also assigned seal sex to scat samples using a revised PCR assay. In contrast to current understanding of grey seal diet from hard parts and fatty acid analysis, we found no significant difference between male and female diet measured by alpha and beta diversity. Overall, we detected 24 prey groups, 18 of which resolved to species. Sand lance Ammodytes spp. were the most frequently consumed prey group, with a frequency of occurrence (FO) of 97.3%, consistent with previous studies, but Atlantic menhaden Brevoortia tyrannus, the second most frequently consumed species (FO = 60.8%), has not previously been documented in US grey seal diet. Our results suggest that a metabarcoding approach to seal food habits can yield important new ecological insights, but that traditional hard parts analysis does not underestimate consumption of Atlantic cod Gadus morhua (FO = 6.7%, Gadidae spp.) and salmon Salmo salar (FO = 0%), 2 particularly valuable species of concern.

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.

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