scholarly journals Application of Effective Day Degrees in the Assessment of Stable Isotope Patterns in Developing Seahorses under Different Temperatures

Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1571 ◽  
Author(s):  
Sonia Valladares ◽  
Miquel Planas
Keyword(s):  
Stable Isotope ◽  
Abiotic Factors ◽  
Experimental Period ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Developmental Progress ◽  
Temperature Regimes ◽  
Temperature Levels ◽  
Food Assimilation ◽  
Chronological Time

Relations between nutrient assimilation and growth rate in fishes may vary with abiotic factors such as temperature. The effects of feeding status, ontogeny and temperature regimes (15, 18 and 21 °C) on stable isotope (δ13C and δ15N) patterns were assessed in juveniles of the seahorse Hippocampus guttulatus. The use of effective day degrees (D°eff), day degrees (D°) and chronological time (age) were compared as development progress indices. Newborn seahorses were maintained at three temperature levels both deprived of food (5 days) or fed (30 days) on copepods or/and Artemia. Isotopic signatures in fed seahorses clearly differed from those in unfed juveniles. Temperature had a significant effect on δ13C values in fed juveniles throughout the experimental period. δ15N values also varied significantly with age, but not with temperature level. Faster growth and food assimilation in seahorses held at 18 and 21 °C were supported by faster variations in isotopic values. Our findings demonstrate that effective day degrees should be preferred over chronological time as index of developmental progress in temperature fluctuating scenarios or for comparative studios.

scholarly journals Application of Effective Day Degrees in the Assessment of Stable Isotope Patterns in Developing Seahorses under Different Temperatures

2020 ◽  
Author(s):  
Sonia Valladares ◽  
Miquel Planas
Keyword(s):  
Stable Isotope ◽  
Abiotic Factors ◽  
Experimental Period ◽  
Isotopic Signatures ◽  
Developmental Progress ◽  
Temperature Regimes ◽  
Different Temperatures ◽  
Temperature Levels ◽  
Food Assimilation ◽  
Chronological Time

Relations between nutrient assimilation and growth rate in fishes may vary with abiotic factors such as temperature. The effects of feeding status, ontogeny and temperature regimes (15, 18 and 21 °C) on stable isotope (δ13C and δ15N) patterns were assayed and modelled in juveniles of the seahorse Hippocampus guttulatus. The use of effective day degrees (D°eff) and chronological time (age) were compared as development progress indices. Newborn seahorses were maintained at three temperature levels both deprived of food (5 days) or fed (30 days) on copepods or/and Artemia. Isotopic signatures in fed seahorses clearly differed from those in unfed juveniles. Temperature had a significant effect on δ13C values in fed juveniles throughout the experimental period. δ15N values also varied significantly with age, but not with temperature level. Faster growth and food assimilation in seahorses held at 18 and 21 °C were supported by faster variations in isotopic values. Our findings demonstrate that effective day degrees should be preferred over chronological time as index of developmental progress in temperature fluctuating scenarios or for comparative studies.

Identification of local populations of Lake Biwa catfish Silurus biwaensis in Japan on the basis of δ13C and δ15N analyses

1999 ◽  
Vol 77 (2) ◽  
pp. 258-266 ◽  
Author(s):  
Noriyuki Takai ◽  
Wataru Sakamoto
Keyword(s):  
Stable Isotope ◽  
Lake Biwa ◽  
Local Population ◽  
Isotope Analysis ◽  
Lepomis Macrochirus ◽  
Δ13c And Δ15n ◽  
Eastern Area ◽  
Isotopic Signatures ◽  
Local Populations ◽  
Ultrasonic Tracking

Carbon and nitrogen stable isotope ratios were used to examine the mixing of adult Lake Biwa catfish, Silurus biwaensis, in different areas of the lake and to identify the local populations. The isotopic signatures of its prey, the bluegill, Lepomis macrochirus, were also examined as indicators of each local food web. We analyzed 141 Lake Biwa catfish and 60 bluegills captured in the lake. The differences in δ13C values indicated that the two groups of catfish captured in the northern- and the southern-most spawning areas did not mix with each other frequently and were thus identified as local populations. The catfish captured in the mid-eastern area, where no spawning ground was found, were considered to be a group of migrators from the southernmost area, not a local population. These results are consistent with those obtained using ultrasonic tracking. It was therefore clearly demonstrated that stable isotope analysis is useful for identifying local populations of aquatic animals.

scholarly journals Stable Isotope Analyses of Multiple Tissues of Great Shearwaters (Ardenna Gravis) Reveals Long-Term Dietary Stability, Short-Term Changes in Diet, and Can be Used as a Tool to Monitor Food Webs

Diversity ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 163 ◽  
Author(s):  
Hong ◽  
Wiley ◽  
Powers ◽  
Michener ◽  
Kaufman ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Food Webs ◽  
Trophic Level ◽  
Isotope Analysis ◽  
Diet Shift ◽  
Turnover Rates ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Over Time

The great shearwater (Ardenna gravis) is a common pelagic bird with a distribution that spans almost the entire Atlantic basin, which in conjunction with its relatively high abundance, makes great shearwaters an effective bio indicator. We compared δ13C and δ15N values from the feathers, red blood cells (RBCs), and plasma of great shearwaters collected in 2014 and 2015 from the waters off Massachusetts and Cape Cod. The δ13C and δ15N values of RBCs were quite constant between sampling periods and years, suggesting a generally stable food web over that time period. However, the δ13C of plasma indicates a small seasonal change in diet between July and September for both years, with plasma δ15N values suggesting a slight increase in trophic level late in summer. Comparison of the δ15N of RBCs and plasma indicates that great shearwaters experienced a diet shift during the first few weeks of summer 2014, but not in 2015. Comparisons with other studies suggest that these shearwaters feed at a lower trophic level than great shearwaters sampled in the Bay of Fundy and that there is a decrease in δ13C with increasing latitude, which could indicate a more pelagic diet in northern waters. Stable isotope analysis of the sixth primary feathers provided evidence that these feathers are molted in the Northern Hemisphere and that the diet of great shearwaters shortly after arrival was different in 2014 and 2015. This study demonstrates that within species comparisons of tissue isotopic signatures over time and comparisons of isotopic signatures of tissues with different turnover rates, can detect changes in diet and be used as a tool to monitor for changes in marine food webs over time and space. The relevant signals remain informative even in the absence of species-specific data on tissue-diet discrimination factors, tissue turnover rates, or knowledge of dietary components and their stable isotopic signatures, suggesting dietary changes indicative of a corresponding change in the food web.

THE AFFECT OF LAND USE CHANGE ON STABLE ISOTOPE (δ13C AND δ15N) VALUES IN CONNECTICUT WETLANDS DURING THE HOLOCENE

2016 ◽  
Author(s):  
Caitlin T. McManimon ◽  
◽  
David P. Gillikin ◽  
William B. Ouimet ◽  
Michael T. Hren ◽  
...  
Keyword(s):  
Land Use ◽  
Stable Isotope ◽  
Land Use Change ◽  
Δ13c And Δ15n ◽  
The Holocene

scholarly journals Arsenic speciation in food chains from mid-Atlantic hydrothermal vents

2012 ◽  
Vol 9 (2) ◽  
pp. 130 ◽  
Author(s):  
Vivien F. Taylor ◽  
Brian P. Jackson ◽  
Matthew R. Siegfried ◽  
Jana Navratilova ◽  
Kevin A. Francesconi ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Deep Sea ◽  
Hydrothermal Vents ◽  
Arsenic Speciation ◽  
Inorganic Arsenic ◽  
Food Sources ◽  
Arsenic Compounds ◽  
Marine Animals ◽  
Δ13c And Δ15n ◽  
Organic Arsenic

Environmental contextArsenic occurs in marine organisms at high levels and in many chemical forms. A common explanation of this phenomenon is that algae play the central role in accumulating arsenic by producing arsenic-containing sugars that are then converted into simpler organic arsenic compounds found in fish and other marine animals. We show that animals in deep-sea vent ecosystems, which are uninhabited by algae, contain the same organic arsenic compounds as do pelagic animals, indicating that algae are not the only source of these compounds. AbstractArsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge hydrothermal vents. The shrimp species, Rimicaris exoculata, the vent chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (δ13C and δ15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the vent chimneys covered with microbial mat, which is a presumed food source for many vent organisms, contained high levels of total As, but organic species were not detectable. The formation of arsenosugars in pelagic environments is typically attributed to marine algae, and the pathway to arsenobetaine is still unknown. The occurrence of arsenosugars and arsenobetaine in these deep sea organisms, where primary production is chemolithoautotrophic and stable isotope analyses indicate food sources are of vent origin, suggests that organic arsenicals can occur in a foodweb without algae or other photosynthetic life.

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.

Biology and Management of Dogfish Sharks

2009 ◽  
Keyword(s):  
Stable Isotope ◽  
Isotope Composition ◽  
Feeding Habits ◽  
Important Species ◽  
Isotopic Signatures ◽  
Ecological Changes ◽  
Varied Diet ◽  
Commercially Important ◽  
C And N

Abstract.—Spiny dogfish <em>Squalus acanthias </em>are an abundant and commercially important species of fish off both the Atlantic and Pacific coasts of North America. They are opportunistic feeders and have a varied diet that can include many fish species, especially small forage fish such as herring, capelin, and sand lance as well as crustaceans, worms, euphausiids, gelatinous zooplankton, and cephalopods. The purpose of our present study is to investigate the utility of the second dorsal spine in providing multiyear information on the feeding habits of dogfish using stable isotope (C and N) analysis. The outer dentine and enamel layers of a spine from three dogfish (caught off the coast of British Columbia) were analyzed to obtain their stable nitrogen and carbon isotope composition (δ<sup>15</sup>N and δ<sup>13</sup>C, respectively). Each sample had annuli from multiple years, allowing possible seasonal migrations to be averaged over samples. The δ<sup>15</sup>N ranged from a low of 11.6‰ to a high of 14.9‰ over the three spines and δ<sup>13</sup>C ranged from –11.5‰ to –18.4‰. The variable isotopic signatures along the spine indicate that the method may be used to assess ecological changes. Stable isotope measurements of dogfish spines could be a valuable means of determining long-term changes in habitat usage and feeding ecology.

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