Feeding habits and ecological role of the freshwater stingray Potamotrygon magdalenae (Duméril 1865) (Myliobatiformes: Potamotrygonidae), combining gut-content and stable isotope analysis

Stable isotope analysis of tissues with different turnover rates allows for a broader temporal view of a species’ feeding habits. Epidermal mucus is a rapid to medium turnover ‘tissue’ in teleost fish, but its use in elasmobranch dietary studies is unknown. In the present study, we conducted stable isotope analysis on mucus and muscle from the giant manta ray Manta birostris. Mucus δ13C values were depleted and closer to surface zooplankton δ13C values compared with muscle, whereas there was no significant difference in δ15N values between these two tissue types. Using diet tissue discrimination factors from the literature, there was no significant difference in the expected prey profile between muscle and epidermal mucus. However, a broader range in δ13C values of expected prey was shown for mucus compared with muscle. The results suggest that if M. birostris mucus is indicative of recent dietary intake, resource use during aggregative behaviour off Ecuador is broader, but with no obvious resource switching. The present study is the first example of using bulk stable isotope analysis to evaluate mucus to investigate feeding ecology in elasmobranchs. However, the time course for the change in mucus isotope signature still needs to be determined through controlled feeding studies in an aquarium setting.

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Estimation of nutrient contributions from the ocean across a river basin using stable isotope analysis

Biogeosciences Discussions ◽

10.5194/bgd-12-5535-2015 ◽

2015 ◽

Vol 12 (7) ◽

pp. 5535-5557

Author(s):

K. Nakayama ◽

Y. Maruya ◽

K. Matsumoto ◽

M. Komata ◽

K. Komai ◽

...

Keyword(s):

Stable Isotope ◽

River Basin ◽

Stable Isotope Analysis ◽

Chum Salmon ◽

Ursus Arctos ◽

Isotope Analysis ◽

Oncorhynchus Gorbuscha ◽

River Ecosystem ◽

River Channels

Abstract. Since marine derived nutrients (MDN) are transported not only in river channels but also across the entire river basin, including via ground water and migratory animals, it is necessary to investigate the contribution of MDN to the forest floor (soils) in order to quantify the true role of MDN at the river ecosystem scale. This study investigated the contribution of pink (Oncorhynchus gorbuscha) and chum salmon (O. keta) to total oceanic nitrogen (TN) input across a river basin using stable isotope analysis (SIA) of nitrogen (δ15N). The contribution of TN entering the river basin by salmon was 23.8 % relative to the total amount of TN exported from the river basin, providing a first estimate of MDN export for a river basin. The contribution of nitrogen from the ocean to the river basin soils was between 22.9 and 23.8 %. Furthermore, SIA showed that the transport of oceanic TN by sea eagles (Haliaeetus spp.) was greater than that by bears (Ursus arctos), which had previously been that bears are thought to be the major animal transporter of nutrients in the northern part of Japan.

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A perspective on the evolving role of stable isotope analysis and the emergence of cavity enhanced spectroscopy as a potent tool

Journal of Analytical Atomic Spectrometry ◽

10.1039/d1ja00175b ◽

2021 ◽

Author(s):

Sanchi Maithani ◽

Abhijit Maity ◽

Manik Pradhan

Keyword(s):

Stable Isotopes ◽

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotopic Ratio ◽

Isotope Analysis ◽

Natural Environments ◽

Geological Samples ◽

Vast Array

The investigation of stable isotopes finds applications in a vast array of fields. The measurement of isotopic ratio in natural environments such as oceans, atmosphere and geological samples assists in...

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Trophic interactions of meso- and macrozooplankton and fish in the Iceland Sea as evaluated by fatty acid and stable isotope analysis

ICES Journal of Marine Science ◽

10.1093/icesjms/fss125 ◽

2012 ◽

Vol 69 (7) ◽

pp. 1277-1288 ◽

Cited By ~ 16

Author(s):

Hildur Petursdottir ◽

Stig Falk-Petersen ◽

Astthor Gislason

Keyword(s):

Fatty Acid ◽

Stable Isotope ◽

Stable Isotope Analysis ◽

Trophic Interactions ◽

Trophic Ecology ◽

Feeding Habits ◽

Isotope Analysis ◽

Trophic Levels ◽

Amphipod Species ◽

Blue Whiting

Abstract Petursdottir, H., Falk-Petersen, S., and Gislason, A. 2012. Trophic interactions of meso- and macrozooplankton and fish in the Iceland Sea as evaluated by fatty acid and stable isotope analysis. – ICES Journal of Marine Science, 69: . A trophic study was carried out in August of 2007 and 2008 on the pelagic ecosystem in the Subarctic Iceland Sea. Carbon and nitrogen stable isotopes and fatty acid biomarkers were used to study trophic linkages and the trophic ecology of the most important pelagic species in this ecosystem, with emphasis on capelin (Mallotus villosus). According to 15N enrichment results, there are 3–4 trophic levels in this ecosystem excluding organisms of the microbial loop and birds and mammals. The primarily herbivorous copepod Calanus hyperboreus occupies the lowest trophic level of the animal species studied, and adult capelin and blue whiting (Micromesistius poutassou) occupy the highest level. Calanus spp. proved to be an important dietary component of most of the species studied, the euphausiid species Thysanoessa inermis and T. longicaudata being exceptions. The chaetognath Eukrohnia hamata is a pure carnivore, feeding heavily on Calanus spp., whereas most of the other zooplankton species studied practice an omnivorous–carnivorous feeding mode. The amphipod species Themisto libellula is important in the diet of adult capelin. Adult capelin and blue whiting share the same feeding habits and could therefore be competing for food.

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Gut content and stable isotope analysis of tadpoles in floodplain wetlands

Australian Journal of Zoology ◽

10.1071/zo18043 ◽

2018 ◽

Vol 66 (4) ◽

pp. 261 ◽

Cited By ~ 1

Author(s):

J. F. Ocock ◽

K. J. Brandis ◽

B. J. Wolfenden ◽

K. M. Jenkins ◽

S. Wassens

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Management Strategies ◽

Isotope Analysis ◽

Food Sources ◽

Gut Contents ◽

Floodplain Wetlands ◽

Gut Content ◽

Larval Amphibians ◽

Aquatic Food

Larval amphibians (tadpoles) are an important link in aquatic food webs, as they can be highly abundant consumers and prey for a wide variety of predators. Most tadpoles are considered omnivores, predominately grazing on algae, detritus and macrophytes, though recent work has identified greater plasticity and breadth in diet than previously considered. We used gut content and stable isotope analysis (SIA) in a baseline study to determine the important dietary items (ingested material) and food sources (assimilated material) for tadpoles of two abundant generalist frog species in regulated floodplain wetlands of the Murrumbidgee River, south-east Australia. We identified a wide variety of dietary items in the gut contents, including whole microcrustaceans, filamentous algae and macrophytes. The composition of several ingested food items was correlated with their availability in each wetland. However, SIA identified biofilm as the food source most consistently assimilated across several wetlands, though microcrustaceans and algae contributed when abundant. Biofilm is likely the most important basal food item for tadpoles in floodplain wetlands because it is ubiquitous and has a high nutritional quality. Identifying important food sources is a crucial step towards developing management strategies for promoting tadpole recruitment in regulated wetlands.

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