Spatial trophic variability of a coastal apex predator, the giant trevally Caranx ignobilis, in the western Indian Ocean

2020 ◽  
Vol 641 ◽  
pp. 195-208
Author(s):  
JR Glass ◽  
R Daly ◽  
PD Cowley ◽  
DM Post
Keyword(s):  
Indian Ocean ◽  
Trophic Ecology ◽  
Niche Breadth ◽  
Trophic Position ◽  
Western Indian Ocean ◽  
Trophic Niche ◽  
Niche Width ◽  
Apex Predator ◽  
Ontogenetic Changes ◽  
Top Predators

Top predators have substantial downstream effects on the structure, function, and resilience of ecosystems. The influence of top predators on an ecosystem can vary if they occur within multiple habitat types and have a wide niche breadth due to spatiotemporal changes in diet. We examined spatial patterns in trophic position and niche width for an economically important reef-associated fishery species, the giant trevally Caranx ignobilis. We sampled 4 localities in the western Indian Ocean representing different habitats: coral atolls, coastal reefs, and granitic islands. We analyzed isotopic ratios of carbon (13C/12C) and nitrogen (15N/14N), and performed compound-specific amino acid stable isotope analysis (AA-CSIA) to control for baseline nitrogen variation. Our analysis of 12 juveniles and 43 adults revealed wide variation in trophic niche breadth between sampling sites and an offshore to coastal gradient in carbon that drove niche distinctiveness between localities. We observed niche width patterns suggestive of ontogenetic changes in diet and habitat utilization and larger niche sizes at the oceanic island sites than the coastal site. Trophic position estimates ranged from 3.5-5, expanding the trophic range of C. ignobilis relative to previous studies using AA-CSIA and placing it at the equivalent trophic level as many predatory sharks. Our study corroborates prior evidence that C. ignobilis is an important apex predator in reef and island ecosystems. Additionally, we show how evaluating spatiotemporal components of trophic ecology of marine predators is critical for characterizing their functional role and ecosystem influence, allowing for targeted conservation efforts.

scholarly journals Trophic ecology of two piranha species, Pygocentrus nattereri and Serrasalmus marginatus (Characiformes, Characidae), in the floodplain of the Negro River, Pantanal

2014 ◽  
Vol 26 (4) ◽  
pp. 381-391 ◽  
Author(s):  
Fabiane Silva Ferreira ◽  
Wagner Vicentin ◽  
Fábio Edir dos Santos Costa ◽  
Yzel Rondon Súarez
Keyword(s):  
Trophic Ecology ◽  
Niche Breadth ◽  
Feeding Activity ◽  
Interspecific Variation ◽  
Dry Season ◽  
Ontogenetic Changes ◽  
Flood Season ◽  
Negro River ◽  
Main River ◽  
Main River Channel

AIM: This study aimed to evaluate influence of hydrological variation, ontogeny and interspecific variation in the feeding activity and diet composition for P. nattereri and S. marginatus in floodplain of Negro River, South Pantanal. METHODS: The samples were taken with the use of gillnets and cast nets of different sizes, from October/2005 to August/2008. RESULTS: We sampled 748 specimens, 442 of P. nattereri and 306 of S. marginatus. We identified 31 items in the dry and 14 in the flood season for P. nattereri, and 29 items in the dry and eight in the flood season for S. marginatus. For both species, fish was the predominant food item in both seasons. The PERMANOVA results showed that the diet varied significantly between the two species (p<0.001), during ontogenetic development (p<0.001) and seasonally (p=0.024). The ancova results suggests that the intensity of food intake was higher in the dry season (p<0.001) for both species. The niche breadth varied only between studied species with S. marginatus presenting higher niche breadth than P. nattereri. CONCLUSION: Piranhas feed more during dry season, probably because in this period food is more varied and abundant, due to the concentration of fish in the main river channel. There were ontogenetic changes in the diet, with no feeding overlap between the two species, probably because of differences in preference for some items and differences in feeding behavior displayed during hunting attacks.

Feeding habits of the toothed flounder Cyclopsetta querna (Paralichthyidae) of the south-east Gulf of California

2010 ◽  
Vol 91 (6) ◽  
pp. 1225-1230 ◽  
Author(s):  
Felipe Amezcua ◽  
Alfonso Portillo ◽  
Felipe Amezcua-Linares
Keyword(s):  
Gulf Of California ◽  
Diet Composition ◽  
Niche Breadth ◽  
Feeding Habits ◽  
Demersal Fish ◽  
Trophic Niche ◽  
The South ◽  
Top Predators

Feeding habits of the toothed flounder Cyclopsetta querna caught in the south-east Gulf of California were studied. Specimens were collected via demersal fish surveys. Results of this study show that C. querna is a predator that focuses on fish inhabiting the bottom and in particular on tonguefish (Symphurus sp.), midshipman fish (Porichthys sp.) and moray eels (Muraenidae). The diet of the toothed flounder did not vary significantly throughout the period of study, and neither size nor sex-related variations in diet composition were observed. Simpson's index indicates a limited trophic niche breadth with a diet dominated by a limited number of taxa. The estimated TROPH value for C. querna is similar to that estimated for other demersal top predators from the studied area; therefore, the toothed flounder can be considered a top carnivore from the demersal community in the Gulf of California.

scholarly journals Trophic ecology of the Patagonian skate, Bathyraja macloviana, on the Argentine continental shelf

2006 ◽  
Vol 63 (5) ◽  
pp. 867-874 ◽  
Author(s):  
L.B. Scenna ◽  
S.B. García de la Rosa ◽  
J.M. Díaz de Astarloa
Keyword(s):  
Sexual Dimorphism ◽  
Continental Shelf ◽  
Trophic Ecology ◽  
Niche Breadth ◽  
Feeding Strategy ◽  
Reproductive Behaviour ◽  
Trophic Niche ◽  
Important Prey ◽  
High Degree ◽  
Prey Items

Abstract The diet, feeding strategy, and dentition of the Patagonian skate, Bathyraja macloviana, on the northern continental shelf of Argentina were studied from specimens collected during research cruises in September and October 2001. Of a total of 81 stomachs examined, only 3.7% were empty. Cumulative prey curves showed that sample sizes were adequate to describe the main prey items of the diet. Quantitative analysis, a graphical method, and trophic niche breadth indicated the species to be a specialized feeder. The most important prey items were polychaetes, followed by gammarid amphipods, isopods, and crabs. Cumaceans, ophiuroids, and hydrozoans were likely incidentally consumed by mature females. Sexual dimorphism in dentition was observed; mature males had longer and sharper tooth cusps than females or immature males. However, there was a high degree of dietary overlap between mature males and mature females, indicating that dental sexual dimorphism in the species is more important in reproductive behaviour than in differential prey consumption.

scholarly journals Seasonal habitat and length influence on the trophic niche of co-occurring tropical tunas in the eastern Atlantic Ocean

2019 ◽  
Vol 76 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Fany Sardenne ◽  
N’Guessan Constance Diaha ◽  
Monin Justin Amandé ◽  
Iker Zudaire ◽  
Lydie I.E. Couturier ◽  
...  
Keyword(s):  
Trophic Position ◽  
Niche Partitioning ◽  
Niche Overlap ◽  
Monounsaturated Fatty Acids ◽  
Dry Mass ◽  
Trophic Niche ◽  
Top Predators ◽  
Thunnus Obesus ◽  
Eastern Atlantic Ocean ◽  
Tropical Tuna

In the Gulf of Guinea, bigeye tuna (Thunnus obesus; BET) and yellowfin tuna (Thunnus albacares; YFT) are an important part of commercial fisheries and play a prominent ecological role as top predators. Using fatty acid profiles and carbon and nitrogen stable isotopes, we examined their trophic niche partitioning in this understudied region. Trophic niche overlap was high (>70%), similar to percentages in other ocean basins. BET occupied a higher trophic position than YFT and fed on deeper prey (high δ15N values and high proportions of monounsaturated fatty acids). The trophic position of YFT decreased slightly in the last 15 years (δ15N values decreased by ∼0.5‰), suggesting a change in epipelagic communities, as observed in the eastern Pacific Ocean. Ontogenic changes were limited to BET. For both species, the dietary proportion of the diatom marker 20:5(n-3) increased in the seasonal upwelling area, highlighting the influence of seasonal habitat on the diet of tuna. The relatively lipid-rich muscle (∼6% dry mass) of Atlantic tropical tuna suggests a richer diet in this region than that of Indian Ocean tropical tuna and (or) differences in energy allocation strategies.

Pelagic cephalopods in the western Indian Ocean: New information from diets of top predators

2013 ◽  
Vol 95 ◽  
pp. 83-92 ◽  
Author(s):  
Frédéric Ménard ◽  
Michel Potier ◽  
Sébastien Jaquemet ◽  
Evgeny Romanov ◽  
Richard Sabatié ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
Top Predators ◽  
New Information

scholarly journals Sympatry with the devil? Niche-based approach explains the mechanisms allowing coexistence of native and non-native salmonids

2016 ◽  
Author(s):  
Camille Musseau ◽  
Simone Vincenzi ◽  
Dušan Jesenšek ◽  
Stéphanie Boulêtreau ◽  
Frédéric Santoul ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Native Species ◽  
Niche Breadth ◽  
Trophic Position ◽  
Isotope Analysis ◽  
Growth Period ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Niche Shift ◽  
Marble Trout

AbstractNiche-based hypotheses have been proposed to explain processes and mechanisms of success in the establishment of non-native species into native communities. Competition due to niche overlap may lead to native species niche shift and to native species replacement. To understand the ecological consequences of trophic interactions between non-native rainbow trout and native and endangered marble trout, we used as model system the Idrijca river (Western Slovenia) in which marble trout occurs either in allopatry (MTa) or in sympatry (MTs) with rainbow trout (RTs). We focused on different metrics of niche change such as centroid shift, niche overlap and trophic niche breadth using stable isotope analysis (δ15N and δ13C). Our results showed plasticity in niche overlap between MTs and RTs and niche shift of marble trout when occurring in sympatry with RTs, but not due to a niche replacement of MTs by RTs. Niche breadth of marble trout increases in sympatry and the trophic position during the growth period was higher for MTs than MTa.

scholarly journals Ontogenetic variation in the diet of the anuran community from a semi-arid environment in the southeastern Chihuahuan Desert

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7908
Author(s):  
Ricardo Luría-Manzano ◽  
Aurelio Ramírez-Bautista
Keyword(s):  
Arid Environment ◽  
Sympatric Species ◽  
Trophic Niche ◽  
Niche Width ◽  
Ontogenetic Variation ◽  
Dietary Composition ◽  
Ontogenetic Changes ◽  
Species Identity ◽  
Predator Size ◽  
Semi Arid

Although ontogeny influences dietary composition and trophic niche breadth in many anurans, its effects on diet have been little analyzed in sympatric species. In this study, we analyzed interspecific and ontogenetic variation in dietary composition and trophic niche width in an anuran community from a semi-arid environment. We found a more profound effect of species identity than body size on dietary composition, with the diet of four species dominated by formicids, that of two others by coleopterans and formicids, and that of the remaining species not dominated by specific prey types. We found ontogenetic changes in dietary composition in three of four species analyzed, in which consumption of some small insects decreased as predator size increased, regardless of species. Additionally, we did not find ontogenetic change in prey number consumed in any of the four species, but prey size increased with increasing predator size in all of them. Most species exhibited a narrow trophic niche, which was even narrower in adults in three of the four species analyzed. Costello’s modified plots revealed a high variation among individuals in termite consumption in Anaxyrus punctatus, and in more prey types in Spea multiplicata. Our results suggest that this community is not size-structured, and that ontogenetic diet shifts are mainly caused by passive sampling toward prey of different sizes. Finally, comparisons with previous data revealed an interpopulation pattern, in which trophic niche width contracts as aridity increases, possibly because of an increase in interspecific competition for trophic resources.

scholarly journals Trophic partitioning between abundant demersal sharks coexisting in the North Aegean Sea

2019 ◽  
Vol 99 (5) ◽  
pp. 1213-1219 ◽  
Author(s):  
Emre Yemisken ◽  
Joan Navarro ◽  
Manuela Forero ◽  
Persefoni Megalofonou ◽  
Lutfiye Eryilmaz
Keyword(s):  
Stable Isotope ◽  
Trophic Position ◽  
Feeding Strategy ◽  
Aegean Sea ◽  
Trophic Niche ◽  
Niche Width ◽  
Isotopic Niche ◽  
Shark Species ◽  
The North ◽  
Eastern Aegean

AbstractWe examined the feeding ecology (diet, trophic width and trophic position) of five demersal shark species (Mustelus mustelus Linnaeus, 1758, Galeus melastomus Rafinesque, 1810, Scyliorhinus canicula Linnaeus, 1758, Scyliorhinus stellaris Linnaeus, 1758, Squalus blainville, Risso, 1826) coexisting in the north-eastern Aegean Sea (around Gökçeda Island) by combining stomach content and stable isotope analyses. The results indicate clear differences in diet between the five sharks. Cephalopods were mainly found in diet of S. stellaris and M. mustelus and the stomachs of G. melastomus, S. canicula and S. blainville included fish. S. blainville showed the highest trophic position in respect of stable isotope analysis (TPsia = 4.89) around Gökçeada Island. It was followed by G. melastomus (TPsia = 4.57). Direct isotopic values (both stable nitrogen and carbon) and isotopic niche width based on the Standard Ellipse Area (SEA) clearly differed among the five shark species. In particular, S. blainville was isotopically segregated from the other shark species studied, showing a narrow isotopic trophic niche and higher trophic level. In contrast, M. mustelus had the widest trophic niche of the five species studied. The niche width of S. stellaris was narrower than M. mustelus and S. canicula but wider than S. blainville and G. melastomus. SEA showed that G. melastomus has a specialized feeding strategy in the area. There is no overlap between S. canicula and S. stellaris in trophic width.

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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