scholarly journals Trophic niches of sympatric tropical tuna in the Western Indian Ocean inferred by stable isotopes and neutral fatty acids

2016 ◽  
Vol 146 ◽  
pp. 75-88 ◽  
Author(s):  
Fany Sardenne ◽  
Nathalie Bodin ◽  
Emmanuel Chassot ◽  
Aurélien Amiel ◽  
Edwin Fouché ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Stable Isotopes ◽  
Indian Ocean ◽  
Western Indian Ocean ◽  
Tropical Tuna ◽  
Trophic Niches

scholarly journals High levels of halogenated natural products in large pelagic fish from the Western Indian Ocean

2021 ◽  
Author(s):  
Qiong Wu ◽  
Catherine Munschy ◽  
Yann Aminot ◽  
Nathalie Bodin ◽  
Walter Vetter
Keyword(s):  
Natural Products ◽  
Indian Ocean ◽  
Fish Species ◽  
Western Indian Ocean ◽  
Pelagic Fish ◽  
Negative Ion ◽  
Selected Ion Monitoring ◽  
Negative Ion Mass Spectrometry ◽  
Halogenated Natural Products ◽  
Tropical Tuna

AbstractConcentrations, profiles and muscle-liver distribution of halogenated natural products (HNPs) and anthropogenic persistent organic pollutants (POPs) were investigated in five large pelagic fish species and one smaller planktivore fish species from the Western Indian Ocean. Analysis of swordfish muscle from the Seychelles revealed the predominance of HNPs, with the highest concentrations found for 2′-methoxy-2,3′,4,5′- tetraBDE (2′-MeO-BDE 68 or BC-2), 6-methoxy-2,2′,4,4′- tetraBDE (6-MeO-BDE 47 or BC-3) and 2,3,3′,4,4′,5,5′-heptachloro-1′-methyl-1,2′-bipyrrole (Q1), along with varied contributions of further HNPs. The mean concentration of ∑HNPs (330 ng/g lw) was one or two orders of magnitude higher than ∑DDTs (60 ng/g lw) and ∑PCBs (6.8 ng/g lw). HNPs (BC-2, BC-3 and Q1) were also predominant in individual samples of three tropical tuna species from the Seychelles and from other regions of the Western Indian Ocean (Mozambique Channel, off Somalia and Chagos Archipelago). Non-targeted gas chromatography coupled with electron capture negative ion mass spectrometry operated in the selected ion monitoring mode (GC/ECNI-MS-SIM) analysis of one swordfish sample indicated low abundance of rarely reported HNPs (three hexachloro-1′-methyl-1,2′-bipyrrole (Cl6-MBP) isomers and pentabromo-1,1′-dimethyl-2,2′-bipyrroles (Br5-DBP)) but no further abundant unscreened polyhalogenated compounds.

scholarly journals Multidimensional trophic niche revealed by complementary approaches: gut content, digestive enzymes, fatty acids and stable isotopes in soil fauna

2020 ◽  
Author(s):  
Anton M. Potapov ◽  
Melanie M. Pollierer ◽  
Sandrine Salmon ◽  
Vladimír Šustr ◽  
Ting-Wen Chen
Keyword(s):  
Fatty Acids ◽  
Stable Isotopes ◽  
Food Web ◽  
Digestive Enzymes ◽  
Species Coexistence ◽  
Trophic Niche ◽  
List Type ◽  
Gut Content ◽  
Additional Value ◽  
Trophic Niches

AbstractThe trophic niche of an organism is tightly related to its role in the ecosystem and to interactions with other species. Thousands of species of soil animals feed on detritus and co-exist with apparently low specialisation in food resource use. Trophic niche differentiation may explain species coexistence in such a cryptic environment. However, most of the existing studies provide only few and isolated evidence on food resources, thus simplifying the multidimensional nature of the trophic niches available in soil.Focusing on one of the most diverse soil taxa – springtails (Collembola) – we aimed to reveal the additional value of information provided by four complementary methods: visual gut content-, digestive enzyme-, fatty acid- and stable isotope analyses, and to demonstrate the multidimensional nature of trophic niches.From 40 studies, we compiled fifteen key trophic niche parameters for 125 species, each analysed with at least one method. Focusing on interspecific variability, we explored correlations of trophic niche parameters and described variation of these parameters in different Collembola species, taxonomic groups and life forms.Correlation between trophic niche parameters of different methods was weak in 45 out of 64 pairwise comparisons, reflecting the complementarity of the multidimensional trophic niche approach. Gut content and fatty acids provided comparable information on fungivory and plant feeding in Collembola. Information provided by digestive enzymes differed from that gained by the other methods, suggesting its high additional value. Stable isotopes were mainly related to plant versus microbial feeding. Many parameters were affected by taxonomic affiliation but not life form. Furthermore, we showed evidence of bacterial feeding, which may be more common in Collembola than usually assumed.Different methods reveal different feeding dimensions, together drawing a comprehensive picture of the trophic niche in taxa with diverse feeding habits. Food web studies will benefit from simultaneously applying several joint approaches, allowing to trace trophic complexity. Future studies on the multidimensional trophic niche may improve understanding of food-web functioning and help to explain species coexistence in cryptic environments such as soil.

scholarly journals Fish behaviour from fishers’ knowledge: the case study of tropical tuna around drifting fish aggregating devices (DFADs)

2007 ◽  
Vol 64 (11) ◽  
pp. 1517-1528 ◽  
Author(s):  
Gala Moreno ◽  
Laurent Dagorn ◽  
Gorka Sancho ◽  
David Itano
Keyword(s):  
Indian Ocean ◽  
Local Ecological Knowledge ◽  
Western Indian Ocean ◽  
Future Research ◽  
Ecological Knowledge ◽  
Fish Behaviour ◽  
Planning And Design ◽  
Tropical Tuna ◽  
Fish Aggregating Devices

Purse-seining for tropical tuna is one of the most technologically advanced fisheries in the world. The purpose of this study was to apply local ecological knowledge (LEK) to assist in the planning of future in situ studies of fish behaviour around drifting fish aggregating devices (DFADs) by prioritizing research topics, thereby reducing the number of potential hypotheses to explore. Interviews of fishing masters of the purse-seine fleets working in the western Indian Ocean provided an alternate, independent, and previously unexplored source of behavioural information, specifically on the attraction, retention, and departure behaviours of tuna schools in relation to DFADs. Most fishing masters agreed that the maximum attraction distance of a DFAD is approximately 10 km and generally agreed to the following statements. Tuna form distinct schools under FADs, commonly segregated by species and size. The main reasons for the departure of tuna aggregations from FADs are changes in currents or FAD movements and location in relation to physical or oceanographic features. The number of actively monitored DFADs at sea in the western Indian Ocean was estimated at approximately 2100. Incorporating fishers into the planning and design stages of future research projects will facilitate collaborative and integrated approaches.

scholarly journals Spatial variation in stable isotopes and fatty acid trophic markers in albacore tuna (Thunnus alalunga) from the western Indian Ocean

2020 ◽  
Vol 161 ◽  
pp. 103286
Author(s):  
Zahirah Dhurmeea ◽  
Heidi Pethybridge ◽  
Clothilde Langlais ◽  
Christopher J. Somes ◽  
Natacha Nikolic ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Fatty Acid ◽  
Indian Ocean ◽  
Spatial Variation ◽  
Western Indian Ocean ◽  
Albacore Tuna ◽  
Thunnus Alalunga ◽  
Trophic Markers

Editorial Introduction

2020 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Editors of the JIOWS
Keyword(s):  
Nineteenth Century ◽  
Indian Ocean ◽  
Western Indian Ocean ◽  
Late Nineteenth Century ◽  
Fourth Volume ◽  
History Of ◽  
The Indian Ocean ◽  
Complex Relationships ◽  
Indian Ocean World ◽  
Shed Light

The editors are proud to present the first issue of the fourth volume of the Journal of Indian Ocean World Studies. This issue contains three articles, by James Francis Warren (Murdoch University), Kelsey McFaul (University of California, Santa Cruz), and Marek Pawelczak (University of Warsaw), respectively. Warren’s and McFaul’s articles take different approaches to the growing body of work that discusses pirates in the Indian Ocean World, past and present. Warren’s article is historical, exploring the life and times of Julano Taupan in the nineteenth-century Philippines. He invites us to question the meaning of the word ‘pirate’ and the several ways in which Taupan’s life has been interpreted by different European colonists and by anti-colonial movements from the mid-nineteenth century to the present day. McFaul’s article, meanwhile, takes a literary approach to discuss the much more recent phenomenon of Somali Piracy, which reached its apex in the last decade. Its contribution is to analyse the works of authors based in the region, challenging paradigms that have mostly been developed from analysis of works written in the West. Finally, Pawelczak’s article is a legal history of British jurisdiction in mid-late nineteenth-century Zanzibar. It examines one of the facets that underpinned European influence in the western Indian Ocean World before the establishment of colonial rule. In sum, this issue uses two key threads to shed light on the complex relationships between European and other Western powers and the Indian Ocean World.

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