scholarly journals Subcolony Variation in Breeding Success in the Tufted Puffin (Fratercula Cirrhata): Association With Foraging Ecology and Implications

The Auk ◽  
2007 ◽  
Vol 124 (4) ◽  
pp. 1149-1157
Author(s):  
J. Mark Hipfner ◽  
Mathieu R. Charette ◽  
Gwylim S. Blackburn
Keyword(s):  
Stable Isotope ◽  
Breeding Success ◽  
Large Scale ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Egg Yolk ◽  
Foraging Strategies ◽  
Small Scale ◽  
Carbon And Nitrogen ◽  
Tufted Puffin

Abstract Large-scale oceanographic processes are the main drivers of seabird breeding success, but small-scale processes, though not as well understood, can also be important. We compared the success of Tufted Puffins (Fratercula cirrhata) breeding at two subcolonies only 1.5 km apart on Triangle Island, British Columbia, Canada, 2002–2005. In addition, we used stable-isotope analysis to test the hypothesis that parental foraging strategies differed between the two subcolonies, potentially underlying the variation in breeding success. Success was concordant across years at the two sites but, overall, Tufted Puffins bred more successfully at Strata Rock than at Puffin Rock. They raised chicks in all four years at Strata Rock, but in only three years at Puffin Rock; in two of those three years, Strata Rock chicks were, on average, 60 g and 100 g heavier than Puffin Rock chicks just before fledging. Discriminant analysis of carbon and nitrogen stable-isotope ratios in egg yolk and chick blood in 2004 and 2005 indicated that parental foraging differed between the two subcolonies, with both spatial (δ13C) and trophic-level (δ15N) differences involved. Thus, our study demonstrates the existence of foraging asymmetries in a pelagic seabird at a small spatial scale (between subcolonies), complementing patterns found at larger scales (between colonies). Moreover, the foraging asymmetries were associated with inequalities in fitness measures. We conclude that small-scale processes—in this case, systematic differences in the foraging ecology of local groups—can interact with large-scale oceanographic processes to determine seabird breeding success. Variation sous-coloniale du succès de reproduction de Fratercula cirrhata: Association avec l'écologie de la quête alimentaire et implications

scholarly journals Manta birostris , predator of the deep? Insight into the diet of the giant manta ray through stable isotope analysis

2016 ◽  
Vol 3 (11) ◽  
pp. 160717 ◽  
Author(s):  
Katherine B. Burgess ◽  
Lydie I. E. Couturier ◽  
Andrea D. Marshall ◽  
Anthony J. Richardson ◽  
Scarla J. Weeks ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Large Scale ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Stomach Contents ◽  
Foraging Strategies ◽  
Manta Birostris ◽  
Elusive Species ◽  
Manta Ray

The characterization of diet for the giant manta ray Manta birostris has been problematic given their large-scale movement patterns and the difficulty in obtaining stomach contents from this species. The large majority of existing information is based on observational data limited to feeding events at the sea surface during daylight. Recently discovered aggregation sites for the giant manta ray off mainland Ecuador are some of the most accessible to date and provide a unique opportunity for researchers to gather much needed information on this elusive species. To assess how important surface zooplankton is to giant manta ray diet, we conducted stable isotope analysis ( 15 N and 13 C) on M. birostris muscle and surface zooplankton. Trophic position estimates placed M. birostris overall at a secondary consumer level of approximately 3.4 but there was large variation in δ 15 N and δ 13 C values among individuals. Manta birostris muscle tissue δ 13 C values were also not consistent with this species feeding predominantly on surface zooplankton and suggest that the majority of dietary intake is of mesopelagic origin. Given the conservative life history and fisheries pressure on large planktivores, knowledge of their trophic role and foraging strategies is essential to better understand their ecology and develop effective conservation measures.

scholarly journals Stable Isotope Analysis and Persistent Organic Pollutants in Crustacean Zooplankton: The Role of Size and Seasonality

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1490 ◽  
Author(s):  
Roberta Piscia ◽  
Michela Mazzoni ◽  
Roberta Bettinetti ◽  
Rossana Caroni ◽  
Davide Cicala ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Standing Stock ◽  
Fish Predation ◽  
Crustacean Zooplankton ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Pollutant Concentrations ◽  
Stock Biomass

Zooplankton is crucial for the transfer of matter, energy, and pollutants through aquatic food webs. Primary and secondary consumers contribute to the abundance and standing stock biomass, which both vary seasonally. By means of taxa- and size-specific carbon and nitrogen stable isotope analysis, the path of pollutants through zooplankton is traced and seasonal changes are addressed, in an effort to understand pollutant dynamics in the pelagic food web. We analyzed zooplankton plurennial changes in concentration of polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane and its relatives (DDTs) and in taxa-specific δ15N signatures in two size fractions, ≥450 µm and ≥850 µm, representative of the major part of zooplankton standing stock biomass and of the fraction to which fish predation is mainly directed, respectively. Our work is aimed at verifying: (1) A link between nitrogen isotopic signatures and pollutant concentrations; (2) the predominance of size versus seasonality for concentration of pollutants; and (3) the contribution of secondary versus primary consumers to carbon and nitrogen isotopic signatures. We found a prevalence of seasonality versus size in pollutant concentrations and isotopic signatures. The taxa-specific δ15N results correlated to pollutant concentrations, by means of taxa contribution to standing stock biomass and δ15N isotopic signatures. This is a step forward to understanding the taxa-specific role in pollutant transfer to planktivores and of zooplankton enrichment in PCBs and DDTs.

scholarly journals Application of stable isotope analysis to differentiate shrimp extracted by industrial fishing or produced through aquaculture practices

2014 ◽  
Vol 71 (10) ◽  
pp. 1520-1528 ◽  
Author(s):  
Julián Gamboa-Delgado ◽  
César Molina-Poveda ◽  
Daniel Enrique Godínez-Siordia ◽  
David Villarreal-Cavazos ◽  
Denis Ricque-Marie ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotope Analysis ◽  
Pacific White Shrimp ◽  
Trophic Levels ◽  
White Shrimp ◽  
Nitrogen Stable Isotope ◽  
Carbon And Nitrogen ◽  
Open Sea ◽  
Clear Differentiation ◽  
Shrimp Farms

Carbon and nitrogen stable isotope values were determined in Pacific white shrimp (Litopenaeus vannamei) with the objective of discriminating animals produced through aquaculture practices from those extracted from the wild. Farmed animals were collected at semi-intensive shrimp farms in Mexico and Ecuador. Fisheries-derived shrimps were caught in different fishing areas representing two estuarine systems and four open sea locations in Mexico and Ecuador. Carbon and nitrogen stable isotope values (δ13CVPDB and δ15NAIR) allowed clear differentiation of wild from farmed animals. δ13CVPDB and δ15NAIR values in shrimps collected in the open sea were isotopically enriched (−16.99‰ and 11.57‰), indicating that these organisms belong to higher trophic levels than farmed animals. δ13CVPDB and δ15NAIR values of farmed animals (−19.72‰ and 7.85‰, respectively) partially overlapped with values measured in animals collected in estuaries (−18.46‰ and 5.38‰, respectively). Canonical discriminant analysis showed that when used separately and in conjunction, δ13CVPDB and δ15NAIR values were powerful discriminatory variables and demonstrate the viability of isotopic evaluations to distinguish wild-caught shrimps from aquaculture shrimps. Methodological improvements will define a verification tool to support shrimp traceability protocols.

Stable Isotope Analysis Enhances Our Understanding of Diamondback Terrapin (Malaclemys terrapin) Foraging Ecology

2018 ◽  
Vol 42 (2) ◽  
pp. 596-611 ◽  
Author(s):  
Mathew J. Denton ◽  
Amanda W. J. Demopoulos ◽  
John D. Baldwin ◽  
Brian J. Smith ◽  
Kristen M. Hart
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Foraging Ecology ◽  
Isotope Analysis ◽  
Diamondback Terrapin ◽  
Malaclemys Terrapin
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