Stable isotope analysis indicates resource partitioning and trophic niche overlap in larvae of four tuna species in the Gulf of Mexico

Niche specificity can predispose species to population declines during periods of resource limitation, yet trophic niche specificity is poorly known for many small-bodied freshwater fishes. Applying a two-tiered approach involving stomach content and stable isotope analyses, we examined the diet and trophic niche of the threatened eastern sand darter (Ammocrypta pellucida (Putnam, 1863)) and co-occurring fishes in the Thames River, Ontario, Canada. As with previous studies, stomach content analysis revealed that eastern sand darter consumed a variety of benthic organisms including Chironomidae, Cladocera, Ostracoda, Oligochaeta, and Ephemeroptera; however, proportional contributions of prey groups differed based on stable isotope analysis, highlighting the potential for seasonal variation in prey consumption. Despite evidence of a generalist strategy, stable isotope analysis indicated eastern sand darter exhibited a relatively narrow trophic niche relative to co-occurring fishes. Trophic niche overlap was relatively minor between eastern sand darter and drift-feeding fishes (spotfin shiner (Cyprinella spiloptera (Cope, 1867)), emerald shiner (Notropis atherinoides Rafinesque, 1818), and buffalo sp. (genus Ictiobus Rafinesque, 1820)), but was more evident between eastern sand darter and benthic and benthopelagic fishes (johnny darter (Etheostoma nigrum Rafinesque, 1820) and blackside darter (Percina maculata (Girard, 1859))), indicating that competition with these species may be more likely during periods of prey scarcity.

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Trophic ecology of sea urchins in coral-rocky reef systems, Ecuador

PeerJ ◽

10.7717/peerj.1578 ◽

2016 ◽

Vol 4 ◽

pp. e1578 ◽

Cited By ~ 8

Author(s):

Nancy Cabanillas-Terán ◽

Peggy Loor-Andrade ◽

Ruber Rodríguez-Barreras ◽

Jorge Cortés

Keyword(s):

Stable Isotope ◽

Trophic Ecology ◽

Habitat Degradation ◽

Sea Urchins ◽

Relative Proportion ◽

Isotope Analysis ◽

Niche Overlap ◽

Trophic Niche ◽

Rocky Reef ◽

Trophic Overlap

Sea urchins are important grazers and influence reef development in the Eastern Tropical Pacific (ETP).Diadema mexicanumandEucidaris thouarsiiare the most important sea urchins on the Ecuadorian coastal reefs. This study provided a trophic scenario for these two species of echinoids in the coral-rocky reef bottoms of the Ecuadorian coast, using stable isotopes. We evaluated the relative proportion of algal resources assimilated, and trophic niche of the two sea urchins in the most southern coral-rocky reefs of the ETP in two sites with different disturbance level. Bayesian models were used to estimate the contribution of algal sources, niche breadth, and trophic overlap between the two species. The sea urchins behaved as opportunistic feeders, although they showed differential resource assimilation.Eucidaris thouarsiiis the dominant species in disturbed environments; likewise, their niche amplitude was broader than that ofD. mexicanumwhen conditions were not optimal. However, there was no niche overlap between the species. The Stable Isotope Analysis in R (SIAR) indicated that both sea urchins shared limiting resources in the disturbed area, mainlyDictyotaspp. (contributions of up to 85% forD. mexicanumand up to 75% forE. thouarsii). The Stable Isotope Bayesian Ellipses in R (SIBER) analysis results indicated less interspecific competition in the undisturbed site. Our results suggested a trophic niche partitioning between sympatric sea urchin species in coastal areas of the ETP, but the limitation of resources could lead to trophic overlap and stronger habitat degradation.

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Stable isotope analysis of trophic niche in two co-occurring native and invasive terrapins, Emys orbicularis and Trachemys scripta elegans

Biological Invasions ◽

10.1007/s10530-016-1251-x ◽

2016 ◽

Vol 18 (12) ◽

pp. 3611-3621 ◽

Cited By ~ 10

Author(s):

Paride Balzani ◽

Salvatrice Vizzini ◽

Giacomo Santini ◽

Alberto Masoni ◽

Claudio Ciofi ◽

...

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Trophic Niche ◽

Trachemys Scripta ◽

Trachemys Scripta Elegans ◽

Emys Orbicularis

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Stable isotope analysis reveals variation in trophic niche depending on altitude in an endemic alpine gecko

Basic and Applied Ecology ◽

10.1016/j.baae.2014.05.005 ◽

2014 ◽

Vol 15 (4) ◽

pp. 362-369 ◽

Cited By ~ 11

Author(s):

Mar Comas ◽

Daniel Escoriza ◽

Gregorio Moreno-Rueda

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Trophic Niche

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Multi-tissue stable isotope analysis reveals resource partitioning and trophic relationships of large reef-associated predators

Marine Ecology Progress Series ◽

10.3354/meps12915 ◽

2019 ◽

Vol 615 ◽

pp. 159-176 ◽

Cited By ~ 2

Author(s):

M Espinoza ◽

J Matley ◽

MR Heupel ◽

AJ Tobin ◽

AT Fisk ◽

...

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Resource Partitioning ◽

Isotope Analysis ◽

Trophic Relationships

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Stable isotope analysis reveals that humpback whales (Megaptera novaeangliae) primarily consume capelin (Mallotus villosus) in coastal Newfoundland, Canada

Canadian Journal of Zoology ◽

10.1139/cjz-2020-0257 ◽

2021 ◽

Author(s):

Kelsey Johnson ◽

Gail Davoren

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Niche Overlap ◽

Prey Type ◽

Megaptera Novaeangliae ◽

Humpback Whales ◽

Mallotus Villosus ◽

Δ13c And Δ15n ◽

Capelin Mallotus Villosus

On the Newfoundland, Canada foraging ground, humpback whales (Megaptera novaeangliae (Borowski, 1781)) are found associated with a dominant forage fish species, capelin (Mallotus villosus (Müller, 1776), that experienced a population collapse in the early 1990s and has not recovered. Our primary goal was to reconstruct dietary proportions of humpback whales on their summer foraging grounds off the northeastern Newfoundland coast during July-August, 2016 and 2017 using a Bayesian stable isotope mixing model (MixSiar). Modelled dietary proportions were similar in both years, with capelin comprising ~90% of the diet. However, both δ13C and δ15N in humpback whale skin differed significantly between years, resulting in minimal dietary niche overlap (9%). Lipid-extracted and nonlipid-extracted skin samples were used to develop a lipid normalization equation: ∆13C = – 3.184 + 1.011(C:N). Overall, findings suggest that capelin is the primary prey type of humpback whales in coastal Newfoundland, despite the continued collapsed state of the capelin population. Findings also reiterate that dietary reconstruction from stable isotope analysis of cetacean skin can be misinterpreted without concurrently sampled isotopic ratios of potential prey types.

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