Marine Biodiversity and Ecosystem Functioning
EU Network of Excellence

 
Main Menu

· Home
· Contacts
· Data Systems
· Documents
· FAQ
· Links
· MarBEF Open Archive
· Network Description
· Outreach
· Photo Gallery
· Quality Assurance
· Register of Resources
· Research Projects
· Rules and Guidelines
· Training
· Wiki
· Worldconference

 

Register of Resources (RoR)

 People  |  Datasets  |  Literature  |  Institutes  |  Projects 

[ report an error in this record ]basket (0): add | show Print this page

Ontogenetic characterization of the feeding habits of Franciscanas, Pontoporia blainvillei, based on stable carbon and nitrogen isotopes
Cibele Troina, G. (2013). Ontogenetic characterization of the feeding habits of Franciscanas, Pontoporia blainvillei, based on stable carbon and nitrogen isotopes. MSc Thesis. Universiteit Antwerpen/Universiteit Gent/VUB: Antwerpen, Gent, Brussel. 16, 45 pp.

Thesis info:

Available in  Author 
Document type: Dissertation

Keyword
    Marine/Coastal

Author  Top 
  • Cibele Troina, G.

Abstract
    We characterized sex- and age-related resource exploitation and ontogenetic dietary shifts in franciscana dolphins (Pontoporia blainvillei), by-caught between 1992 and 2010 in Rio Grande (RS), Brazil. Carbon and nitrogen stable isotope ratios, expressed as d13C and d15N, were measured in the tooth dentin of dolphins from different age classes (calves, juveniles, first adults and adults). d15N values were negatively correlated with Total Body Length (TBL) and age which was attributed to decreasing influence of the suckling period. Correlations of d13C with TBL and age were small but significant, with slight enrichment in 13C in older animals. No significant differences were found in isotope signatures between females and males, indicating that both sexes forage upon the same resources. The isotopic compositions of main prey species in the diet of these dolphins were also analyzed. Bayesian isotopic mixing models were applied to estimate the fractional contribution of prey items to each ontogenetic class. Prey groups had high similarities in their isotope signals, which hindered the ability of the models to isolate the proportional contribution of prey groups separately. The effectiveness of Stable Isotope Analysis to assess foraging ecology was compared to that of Stomach Content Analysis (SCA). Stomach contents have been extensively used to infer the diet of franciscanas in this region for several years, and it is therefore considered representative of their diet. SIAR results indicated that ES_fish and squid had a high contribution to calves and juveniles. However, SCA revealed that squid was more frequent in adults, although their IRI could not be compared to that of fishes through that method due to the different digestion rates of otoliths vs beaks. Results obtained for the younger age classes may be biased due to the high relative contribution of the wide deposition of the first year dentine. Therefore, caution is necessary when interpreting these results. On the other side, adult SIAR results seemed to be more coincident with that of SCA, although some differences in the relative contribution of the main prey were found. The present study is a first attempt to characterize the ontogenetic dietary shifts in franciscanas through the analysis of their isotopic signatures. The results presented here emphasize the importance of integrating previous information about the species’ feeding habits, instead of relying exclusively on the model’s outcome.

All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy Top | Author 


If any information here appears to be incorrect, please contact us
Back to Register of Resources
 
Quick links

MarBEF WIKI

Erasmus Mundus Master of Science in Marine Biodiversity and Conservation (EMBC)
Outreach

Science
Responsive Mode Programme (RMP) - Marie Nordstrom, copyright Aspden Rebecca

WoRMS
part of WoRMS logo

ERMS 2.0
Epinephelus marginatus Picture: JG Harmelin

EurOBIS

Geographic System

Datasets

 


Web site hosted and maintained by Flanders Marine Institute (VLIZ) - Contact data-at-marbef.org