scholarly journals Using Stable Carbon and Nitrogen Isotopes to Evaluate Parrotfish Diet

2013 ◽  
pp. 108-123
Author(s):  
Maria Elisa Gerona ◽  
Florence Evacitas
Keyword(s):  
Stable Isotope ◽  
Nitrogen Isotopes ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Carbon Sources ◽  
Δ13c And Δ15n ◽  
Δ13c Values ◽  
Dual Isotope ◽  
Muscle Tissues ◽  
Carbon Intake

With limited inconclusive data provided by gut content analysis, stable isotope analysis has recently emerged to validate trophic position and dietary intake. In this study, a dual isotope approach was used to reveal parrotfish feeding. Comparisons of δ13C and δ15N values of muscle and liver among yellow barred (Scarus dimidiatus), rosy cheek (S. psittacus), and blue-barred (S. ghobban) parrotfishes from Canigao Island, Matalom, Leyte were made to track dietary shifting and to compare dietary carbon intake. Trophic assignment was based on the assumption that consumers are enriched by a factor of 3-4‰ for δ15N, relative to their diet. The δ13C values of muscle tissues of the three species of parrotfish were significantly higher (p=0.001) than those of their liver suggesting dietary shifting. The δ13C values of both muscle and liver tissues of S. dimidiatus were significantly (p<0.001) higher than those of S. psittacus and S. ghobban, but δ13C values of muscle and liver of S. psittacus and S. ghobban did not vary significantly. These mean that S. dimidiatus have different long term and recent dietary carbon intake compared to the other two species, while S. psittacus and S. ghobban have relatively the same dietary carbon intake. Considering the 1‰ δ13C trophic enrichment of consumers relative to their diet, possible dietary carbon sources of the sampled parrotfish include Dendronephthya spp., Ulva reticulata, Sargassum oligocystum, Dictyota sp., Digenea sp., Chlorodesmis sp., and Sargassum muticum suggesting that parrotfishes are generalist consumers. Mean stable isotope nitrogen ratios of S. dimidiatus (5.9‰), S. psittacus (6.9‰) and S. ghobban (6.7‰) together with their carbon isotope ratios confirmed that all sampled parrotfish species are generalist primary consumers.

Differentiation of Pigment in Eggs Using Carbon (13C/12C) and Nitrogen (15N/14N) Stable Isotopes

2016 ◽  
Vol 99 (4) ◽  
pp. 1032-1037
Author(s):  
Feng M Sun ◽  
Guang Y Shi ◽  
Hui W Wang
Keyword(s):  
Stable Isotope ◽  
Isotope Analysis ◽  
Stable Isotope Ratio ◽  
Strong Positive Correlation ◽  
Carbon Stable Isotope ◽  
Δ13c And Δ15n ◽  
Δ13c Values ◽  
Isotope Ratio Analysis ◽  
Stable Isotope Ratio Analysis ◽  
Yellow Pigments

Abstract Consumers prefer natural and healthy food, but artificial pigments are often abused in egg products. The study aimed at differentiating the origin of pigments in eggs by applying the technique of carbon (13C/12C) and nitrogen (15N/14N) stable isotope analysis. Five hundred sixty laying hens were randomly distributed into 14 treatments, which were divided into four groups: maize, carophyll red pigment, carophyll yellow pigment, and a mixture of carophyll red and yellow pigments. Eggs were collected and pretreated to determe the values of the Roche Yolk Color Fan (RCF), δ13C, and δ15N. With increasing maize content, the RCF and δ13C values of yolks increased. Moreover, the RCF values in the three pigment groups were significantly influenced by the artificial colors, but δ13C values were not significantly different, regardless of the existence of pigment. The δ15N values in all treatments did not vary as regularly as the carbon stable isotope. A strong positive correlation was found between RCF and δ13C in the maize group, but no such correlation was be observed in the pigment groups. It is concluded that carbon stable isotope ratio analysis (δ13C) of the yolk can be used to differentiate the origin of the pigment added to eggs.

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Rigoberto Rosas-Luis ◽  
Nancy Cabanillas-Terán ◽  
Carmen A. Villegas-Sánchez
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Middle Level ◽  
Food Sources ◽  
Thunnus Albacares ◽  
Katsuwonus Pelamis ◽  
Δ13c And Δ15n

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.

Investigating the diet of the omnivorous mirid Dicyphus hesperus using stable isotopes

2009 ◽  
Vol 99 (4) ◽  
pp. 347-358 ◽  
Author(s):  
J.A. Bennett ◽  
D.R. Gillespie ◽  
S.L. VanLaerhoven
Keyword(s):  
Nitrogen Isotopes ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Isotopic Signature ◽  
Encarsia Formosa ◽  
Verbascum Thapsus ◽  
Diet Variability ◽  
Feeding Trials ◽  
Plant Sources ◽  
Over Time

AbstractOmnivory involves numerous feeding relationships and a complex web of interactions. When using omnivores in biocontrol, these interactions need to be understood to maximize feeding on the target species and minimize non-target interactions. Dicyphus hesperus is used along with Encarsia formosa for biocontrol of whiteflies in greenhouse tomato crops. Dicyphus hesperus is a generalist omnivore which feeds on all components of the system. To quantify these interactions, stable isotope analysis was used to identify trophic position with nitrogen isotopes (δ15N) and plant sources with carbon isotopes (δ13C). Feeding trials were used to establish baseline isotopic data for D. hesperus and their diet, including Verbascum thapsus, an alternative plant food. Cage trials were used to monitor population abundances and the isotopic signature of D. hesperus. In feeding trials, D. hesperus were enriched relative to their food, suggesting an elevated trophic position. However, large amounts of isotopic variation were found within all diet components, with only V. thapsus exhibiting a distinct signature. In cage trials, the average δ15N and δ13C of the omnivore declined over time, coinciding with declines in total available prey, though it may be confounded by changes in temperature. The range of δ13C, but not the range of δ15N, also declined over time. This suggests a change in the plant source within the diet, but also some unquantified variability within the population. We suggest that diet variability exists within D. hesperus populations, declining as prey become less abundant.

Trophic relationships of the platypus: insights from stable isotope and cheek pouch dietary analyses

2016 ◽  
Vol 67 (8) ◽  
pp. 1196 ◽  
Author(s):  
Melissa Klamt ◽  
Jenny A. Davis ◽  
Ross M. Thompson ◽  
Richard Marchant ◽  
Tom R. Grant
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Trophic Relationships ◽  
Cheek Pouch ◽  
Insect Larvae ◽  
Top Down ◽  
Δ13c And Δ15n ◽  
Eastern Australia ◽  
Wide Range

The unique Australian monotreme, the platypus (Ornithorhynchus anatinus) potentially exerts a strong top-down influence on riverine food webs in eastern Australia. However, despite considerable interest in the evolutionary history and physiology of the platypus, little is known of its trophic relationships. To address this lack of knowledge we used stable isotope analysis, in combination with the analysis of food items stored in cheek pouches, to determine its position in a typical riverine food web. This was the essential first step in the process of designing a larger study to investigate the relative importance of top-down and bottom-up effects in rivers where the platypus occurs. We found that platypuses were feeding on a wide range of benthic invertebrates, particularly insect larvae. The similarity of δ13C and δ15N values recorded for the platypus, a native fish (Galaxias sp.) and the exotic mosquitofish (Gambusia holbrooki) indicated dietary overlap and potential competition for the same resources. Although cheek pouch studies identify most of the major groups of prey organisms, the potential for contribution of the soft-bodied organisms such as larval dipterans, is suggested by stable isotope analysis, indicating that the use of both techniques will be important in future ecological investigations.

Use of epidermal mucus in elasmobranch stable isotope studies: a pilot study using the giant manta ray (Manta birostris)

2018 ◽  
Vol 69 (2) ◽  
pp. 336 ◽  
Author(s):  
K. B. Burgess ◽  
M. Guerrero ◽  
A. J. Richardson ◽  
M. B. Bennett ◽  
A. D. Marshall
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Time Course ◽  
Feeding Habits ◽  
Isotope Analysis ◽  
Δ13c Values ◽  
Significant Difference ◽  
Manta Birostris ◽  
Epidermal Mucus ◽  
Manta Ray

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.

Trophic ecology of the blue shark (Prionace glauca) based on stable isotopes (δ13C and δ15N) and stomach content

2015 ◽  
Vol 96 (7) ◽  
pp. 1403-1410 ◽  
Author(s):  
Sandra Berenice Hernández-Aguilar ◽  
Ofelia Escobar-Sánchez ◽  
Felipe Galván-Magaña ◽  
Leonardo Andrés Abitia-Cárdenas
Keyword(s):  
Stable Isotope ◽  
Stomach Content ◽  
Trophic Ecology ◽  
Baja California ◽  
Marine Ecosystem ◽  
Isotope Analysis ◽  
Trophic Levels ◽  
Baja California Sur ◽  
Δ13c And Δ15n ◽  
Prionace Glauca

Occupying the upper levels of trophic webs and thus regulating prey at lower levels, sharks play an important role in the trophic structure and energy dynamics of marine ecosystems. In recent years, the removal of these individuals from upper trophic levels as a result of overfishing has negatively affected ecosystems. We analysed the diet of blue sharks (Prionace glauca) caught off the west coast of Baja California Sur, Mexico, during the months of February–June in 2001, 2005 and 2006. We employed both stomach content and stable isotope analyses as each method provides distinct yet important information regarding the role of blue sharks in marine food webs, allowing us to estimate the relative contribution of different prey items to this predator's diet. Of the 368 stomachs analysed, 210 contained food (57%) and 158 (43%) were empty. Based on stomach contents and the index of relative importance (IRI), the pelagic red crab (Pleuroncodes planipes) was the most important prey, followed by the squids Gonatus californiensis (34.1%) and Ancistrocheirus lesueurii (10.4%). The mean (±SD) values for δ15N (16.48 ± 0.94‰) and δ13C (−18.48 ± 0.63‰) suggest that blue sharks prefer feeding in oceanic waters. The trophic level based on stomach content analysis was 4.05, while that based on the stable isotope analysis was 3.8, making blue sharks top consumers in the marine ecosystem of Baja California Sur, Mexico.

Benthic and pelagic contributions to Mysis nutrition across Lake Superior

2011 ◽  
Vol 68 (6) ◽  
pp. 1051-1063 ◽  
Author(s):  
Michael E. Sierszen ◽  
John R. Kelly ◽  
Timothy D. Corry ◽  
Jill V. Scharold ◽  
Peder M. Yurista
Keyword(s):  
Stable Isotope ◽  
Contaminant Transport ◽  
Trophic Position ◽  
Lake Superior ◽  
Multiple Source ◽  
Stable Isotope Ratios ◽  
Dual Isotope ◽  
Mysis Diluviana ◽  
Benthic Food ◽  
Benthic Pelagic Coupling

Quantifying nutritional sources for Mysis diluviana will help to clarify the basis for production in lakes with Mysis and improve models of migration-driven nutrient and contaminant transport. We sampled Mysis, plankton, and benthos across Lake Superior using a stratified-random design that provided a statistically valid representation of the lake across depths. We then estimated nutritional contributions to Mysis using stable isotope ratios of Mysis, zooplankton, Bythotrephes , Diporeia , oligochaetes, and detritus in a multiple-source, dual-isotope mixing model. Lake-wide, small (<1.0 cm) mysids relied almost exclusively upon plankton, whereas large mysids occupied a higher trophic position and obtained nutrition among sources. Model estimates of mean benthic contributions to large Mysis ranged from 27% to 58%. We predicted the importance of benthos to Mysis to track declining benthic biomass with depth. Model results indicated that if Diporeia were the only benthic food eaten, benthic contributions would decline to 40% with depth, but inclusion of detritus in the model resulted in consistent importance of benthic food across depths. The importance of benthos to mysid nutrition suggests strong benthic–pelagic coupling at all lake depths and might limit the ability of Mysis to support fisheries in systems that have lost Diporeia.

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