Spatial and temporal variabilities of δ13C and δ15N within lower trophic levels of a large lake: implications for estimating trophic relationships of consumers

Wrack accumulates commonly in surf zones of sandy beaches and can be a semipermanent feature. Very few studies have investigated the trophic pathways associated with wrack accumulations in sandy beach surf zones, despite their potential importance to nearshore food webs. In the present study, we were specifically interested in determining the fish–wrack trophic associations in the nearshore. Macrophytes, macroinvertebrates and fish were sampled from drifting wrack at two sites with different macrophyte compositions (i.e. algae v. an algae–seagrass mix) in South Australia. The gut contents of fish were sampled, and the δ13C and δ15N stable isotope signatures of fish, macroinvertebrates and macrophytes were analysed. Using both the stable isotope and diet data, we identified that fish are feeding among wrack accumulations, but some unexplained trophic pathways suggest that fish are also likely to be foraging over multiple habitats elsewhere for food. In contrast, there was more evidence that grazing macroinvertebrates may be feeding on and around macrophytes within the accumulations, as well as using them as habitat. Thus, the present study established some baseline trophic pathways associated with wrack accumulations in sandy beach surf zones. Given the modest evidence for use of wrack as a food source, the lower trophic levels of the food webs identified remain unknown and should be an area for future research.

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A review on macrobenthic trophic relationships along subtropical sandy shores in southernmost Brazil

Biota Neotropica ◽

10.1590/1676-06032014006914 ◽

2014 ◽

Vol 14 (3) ◽

Cited By ~ 7

Author(s):

Raphael Mathias Pinotti ◽

Diogo Marroni Minasi ◽

Leonir André Colling ◽

Carlos Emílio Bemvenuti

Keyword(s):

Surf Zone ◽

Fish Assemblages ◽

Trophic Levels ◽

Trophic Relationships ◽

Intermediate Type ◽

Sandy Shores ◽

Macrobenthic Assemblages ◽

High Species Richness ◽

Asterionellopsis Glacialis

Main trophic relationships that occur along the exposed sandy shores in southernmost Brazil (∼33° S) are established taking into account several biological compartments operating at morphodynamically distinct environments. Beaches are predominantly of the intermediate type but some stretches of coastline are truly dissipative (Cassino Beach) or tending-to-reflective (Concheiros Beach), presenting thus diverse biological compartments and inhabitant macrobenthic assemblages. Dense concentrations of the surf-zone diatom Asterionellopsis glacialis are responsible - at least for the intermediate shorelines - for the most year-round primary production, sustaining several consumers up to tertiary level. Among them, bivalves Amarilladesma mactroides, Donax hanleyanus and the hippid crabEmerita brasiliensis can account for more than 95% of all the surf-zone secondary production, in addition to the elevated biomass of the suspension-feeder polychaete Spio gaucha and the scavenger isopod Excirolana armata. Crabs, whelks, carnivorous polychaetes, seabirds and surf-zone fishes may also be present and occupy superior trophic levels depending on the beach morphodynamics. Based on the high species richness, abundance and the role of macrobenthic fauna in transferring matter and energy to seabirds and the surf-zone fish assemblages, we address this important issue on the Southwestern Atlantic ecology. Conservation efforts should be implemented for the southernmost Brazilian sandy shores, at least for those non urbanized areas.

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‘Taking Fishers’ Knowledge to the Lab’: An Interdisciplinary Approach to Understand Fish Trophic Relationships in the Brazilian Amazon

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.723026 ◽

2021 ◽

Vol 9 ◽

Author(s):

Paula Evelyn Rubira Pereyra ◽

Gustavo Hallwass ◽

Mark Poesch ◽

Renato Azevedo Matias Silvano

Keyword(s):

Stable Isotopes ◽

Food Webs ◽

Fish Species ◽

Trophic Interactions ◽

Brazilian Amazon ◽

Trophic Levels ◽

Trophic Relationships ◽

Ecological Knowledge ◽

Data Limitations ◽

Combining Data

Trophic levels can be applied to describe the ecological role of organisms in food webs and assess changes in ecosystems. Stable isotopes analysis can assist in the understanding of trophic interactions and use of food resources by aquatic organisms. The local ecological knowledge (LEK) of fishers can be an alternative to advance understanding about fish trophic interactions and to construct aquatic food webs, especially in regions lacking research capacity. The objectives of this study are: to calculate the trophic levels of six fish species important to fishing by combining data from stable isotopes analysis and fishers’ LEK in two clear water rivers (Tapajós and Tocantins) in the Brazilian Amazon; to compare the trophic levels of these fish between the two methods (stable isotopes analysis and LEK) and the two rivers; and to develop diagrams representing the trophic webs of the main fish prey and predators based on fisher’s LEK. The fish species studied were Pescada (Plagioscion squamosissimus), Tucunaré (Cichla pinima), Piranha (Serrasalmus rhombeus), Aracu (Leporinus fasciatus), Charuto (Hemiodus unimaculatus), and Jaraqui (Semaprochilodus spp.). A total of 98 interviews and 63 samples for stable isotopes analysis were carried out in both rivers. The average fish trophic levels did not differ between the stable isotopes analysis and the LEK in the Tapajós, nor in the Tocantins Rivers. The overall trophic level of the studied fish species obtained through the LEK did not differ from data obtained through the stable isotopes analysis in both rivers, except for the Aracu in the Tapajós River. The main food items consumed by the fish according to fishers’ LEK did agree with fish diets as described in the biological literature. Fishers provided useful information on fish predators and feeding habits of endangered species, such as river dolphin and river otter. Collaboration with fishers through LEK studies can be a viable approach to produce reliable data on fish trophic ecology to improve fisheries management and species conservation in tropical freshwater environments and other regions with data limitations.

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Temporal variabilities of δ13C and δ15N in an ecosystem from the Central-East Gulf of California: estimating trophic relationships

Aquatic Ecosystem Health & Management ◽

10.1080/14634988.2018.1547581 ◽

2019 ◽

Vol 22 (1) ◽

pp. 40-52

Author(s):

Martha Del Rio-Salas ◽

Angel Martínez-Durazo ◽

Reina Castro-Longoria ◽

Martín E. Jara-Marini

Keyword(s):

Gulf Of California ◽

Trophic Relationships ◽

Δ13c And Δ15n

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South American sea lions Otaria byronia as biological samplers of local cephalopod fauna in the Patagonian shelf marine ecosystem

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315419000432 ◽

2019 ◽

Vol 99 (06) ◽

pp. 1459-1463

Author(s):

R. L. Bustos ◽

G. A. Daneri ◽

E. A. Varela ◽

A. Harrington ◽

A. V. Volpedo ◽

...

Keyword(s):

Marine Mammals ◽

Marine Ecosystem ◽

Isotopic Signature ◽

Trophic Levels ◽

Trophic Relationships ◽

South American ◽

Sea Lions ◽

Patagonian Shelf ◽

Important Prey ◽

Top Predators

AbstractCephalopods are important prey in the diet of top predators, such as marine mammals and seabirds. However, detailed information on their trophic relationships in the Patagonian marine ecosystem is scarce, including those cephalopod species with commercial interest. The aims of this study were to evaluate the composition of the cephalopod component in the diet of Otaria byronia and determine the habitat use and trophic levels of their main cephalopod prey by measuring the stable isotopic signature of cephalopod beaks. Between May 2005 and February 2009, fresh faecal samples were collected from two sea lions rookeries in San Matias Gulf. Cephalopods occurred in 39.4% of the 1112 samples collected during the whole period of study. The dominant prey species was Octopus tehuelchus, which occurred in 45.8% of scats containing cephalopod remains, and represented 58.7% in terms of numerical abundance and 52.0% in mass of cephalopods consumed. The second species most consumed was the myopsid Doryteuthis gahi. The significant higher δ15N values of O. tehuelchus beaks in comparison with those of D. gahi showed that these two species have different trophic levels while occupying similar habitat (δ13C values) in neritic waters of the Patagonian shelf.

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Trophic relationships of breeding Red-necked Grebes (Podiceps grisegena) on wetlands with and without fish in the Aspen Parkland

Canadian Journal of Zoology ◽

10.1139/z09-132 ◽

2010 ◽

Vol 88 (2) ◽

pp. 186-194 ◽

Cited By ~ 7

Author(s):

C. E. McParland ◽

C. A. Paszkowski ◽

J. L. Newbrey

Keyword(s):

Egg Production ◽

Trophic Position ◽

Isotope Analysis ◽

Trophic Levels ◽

Trophic Relationships ◽

Breeding Sites ◽

Top Predators ◽

Aspen Parkland ◽

Wintering Areas ◽

Podiceps Grisegena

Dietary overlap between waterbirds and fish in many freshwater systems can lead to competition for food resources and changes in the trophic position of top predators. We used stable isotope analysis of carbon and nitrogen from egg tissues to document differences in the trophic position of breeding Red-necked Grebes ( Podiceps grisegena (Boddaert, 1783)) on wetlands with and without fish in the Aspen Parkland of Alberta, Canada. Grebes occupied higher trophic levels in the presence of fish than in their absence, suggesting that small-bodied fish in Aspen Parkland food webs may lengthen food chains in which grebes are top predators. A mixed diet of invertebrates and fishes may be adaptive for grebes in this highly variable ecosystem where fish colonize wetlands in wet years and are extirpated in dry years. Carbon analyses indicated that female grebes likely obtained resources for egg production from breeding sites and not from wintering areas, as eggs had similar δ13C values to wetland primary producers, invertebrates, and fishes.

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Trophic relationships of the platypus: insights from stable isotope and cheek pouch dietary analyses

Marine and Freshwater Research ◽

10.1071/mf15004 ◽

2016 ◽

Vol 67 (8) ◽

pp. 1196 ◽

Cited By ~ 7

Author(s):

Melissa Klamt ◽

Jenny A. Davis ◽

Ross M. Thompson ◽

Richard Marchant ◽

Tom R. Grant

Keyword(s):

Stable Isotope ◽

Stable Isotope Analysis ◽

Isotope Analysis ◽

Trophic Relationships ◽

Cheek Pouch ◽

Insect Larvae ◽

Top Down ◽

Δ13c And Δ15n ◽

Eastern Australia ◽

Wide Range

The unique Australian monotreme, the platypus (Ornithorhynchus anatinus) potentially exerts a strong top-down influence on riverine food webs in eastern Australia. However, despite considerable interest in the evolutionary history and physiology of the platypus, little is known of its trophic relationships. To address this lack of knowledge we used stable isotope analysis, in combination with the analysis of food items stored in cheek pouches, to determine its position in a typical riverine food web. This was the essential first step in the process of designing a larger study to investigate the relative importance of top-down and bottom-up effects in rivers where the platypus occurs. We found that platypuses were feeding on a wide range of benthic invertebrates, particularly insect larvae. The similarity of δ13C and δ15N values recorded for the platypus, a native fish (Galaxias sp.) and the exotic mosquitofish (Gambusia holbrooki) indicated dietary overlap and potential competition for the same resources. Although cheek pouch studies identify most of the major groups of prey organisms, the potential for contribution of the soft-bodied organisms such as larval dipterans, is suggested by stable isotope analysis, indicating that the use of both techniques will be important in future ecological investigations.

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Trophic ecology of the blue shark (Prionace glauca) based on stable isotopes (δ13C and δ15N) and stomach content

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315415001393 ◽

2015 ◽

Vol 96 (7) ◽

pp. 1403-1410 ◽

Cited By ~ 13

Author(s):

Sandra Berenice Hernández-Aguilar ◽

Ofelia Escobar-Sánchez ◽

Felipe Galván-Magaña ◽

Leonardo Andrés Abitia-Cárdenas

Keyword(s):

Stable Isotope ◽

Stomach Content ◽

Trophic Ecology ◽

Baja California ◽

Marine Ecosystem ◽

Isotope Analysis ◽

Trophic Levels ◽

Baja California Sur ◽

Δ13c And Δ15n ◽

Prionace Glauca

Occupying the upper levels of trophic webs and thus regulating prey at lower levels, sharks play an important role in the trophic structure and energy dynamics of marine ecosystems. In recent years, the removal of these individuals from upper trophic levels as a result of overfishing has negatively affected ecosystems. We analysed the diet of blue sharks (Prionace glauca) caught off the west coast of Baja California Sur, Mexico, during the months of February–June in 2001, 2005 and 2006. We employed both stomach content and stable isotope analyses as each method provides distinct yet important information regarding the role of blue sharks in marine food webs, allowing us to estimate the relative contribution of different prey items to this predator's diet. Of the 368 stomachs analysed, 210 contained food (57%) and 158 (43%) were empty. Based on stomach contents and the index of relative importance (IRI), the pelagic red crab (Pleuroncodes planipes) was the most important prey, followed by the squids Gonatus californiensis (34.1%) and Ancistrocheirus lesueurii (10.4%). The mean (±SD) values for δ15N (16.48 ± 0.94‰) and δ13C (−18.48 ± 0.63‰) suggest that blue sharks prefer feeding in oceanic waters. The trophic level based on stomach content analysis was 4.05, while that based on the stable isotope analysis was 3.8, making blue sharks top consumers in the marine ecosystem of Baja California Sur, Mexico.

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Elucidating trophic pathways of the most abundant fish larvae in northern Patagonia using δ13C and δ15N isotopes

Marine Ecology Progress Series ◽

10.3354/meps13374 ◽

2020 ◽

Vol 650 ◽

pp. 253-267

Author(s):

A Bernal Bajo ◽

LR Castro ◽

D Costalago

Keyword(s):

Organic Matter ◽

Particulate Organic Matter ◽

Fish Larvae ◽

Trophic Position ◽

Trophic Levels ◽

Feeding Strategies ◽

Late Winter ◽

Terrestrial Organic Matter ◽

Δ13c And Δ15n ◽

Northern Patagonia

The alternation of the classic and microbial food-webs in spring and winter, respectively, and the trespass towards higher trophic levels represented by fish early stages, are not well understood in Patagonia. These trophic routes were investigated in the inner Sea of Chiloe, an estuary of high ecological relevance in northern Patagonia. The isotopic values of δ13C and δ15N of ichthyoplankton and particulate organic matter were analyzed in late winter and spring 2017 to evaluate whether seasonal changes (e.g. in the composition of the freshwater discharge) were reflected in the isotopic signals of fish larvae. For this purpose, larvae of dominant fish species with contrasting feeding strategies were collected up to 100 m depth. The inshore zone of northern Patagonia was characterized by a dominance of marine carbon production, with increasing input of terrestrial organic matter during winter. δ13C values < -25 ‰ at the outermost estuary stations indicated the influence of allochthonous carbon exported from the inshore area in spring. The δ13C-larval signature of the species of the lightfish Maurolicus parvipinnis, the pipefish Leptonotus blainvilleanus, and the rockfish Sebastes oculatus followed the isotopic signature of the particulate organic matter in both seasons, at inshore and the exchange (outer) zone. Food partitioning was detected between species, with Merluccius spp. at the highest trophic position and L. blainvilleanus at the lowest. The fish larval community reached more diverse and higher δ15N values in winter, when larvae likely fed on prey items of higher trophic level, or instead when the food-web was partly sustained by microbial sources. Our results showed seasonal variations in δ13C values, suggesting differences in the source of organic carbon incorporated by the studied fish larvae. Moreover, trophic plasticity at larval stages may be an important characteristic of this type of estuarine environment.

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Trophic studies in a high-latitude fjord ecosystem — a comparison of stable isotope analyses (δ13C and δ15N) and trophic-level estimates from a mass-balance model

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f08-180 ◽

2008 ◽

Vol 65 (12) ◽

pp. 2791-2806 ◽

Cited By ~ 44

Author(s):

Marianne Nilsen ◽

Torstein Pedersen ◽

Einar Magnus Nilssen ◽

Stein Fredriksen

Keyword(s):

Food Web ◽

Mass Balance ◽

High Latitude ◽

Carbon Sources ◽

Trophic Levels ◽

Food Sources ◽

Balance Model ◽

Ecological Groups ◽

Mass Balance Model ◽

Δ13c And Δ15n

Stable isotopes of δ13C and δ15N were used to examine food sources and trophic structure of 65 taxa, representing 19 ecological groups, in a high-latitude ecosystem. Discrimination was made between pelagic and benthic carbon sources, where feeding in most cases reflected the habitat. Trophic levels from these analyses, TLN, were compared with corresponding levels estimated by an Ecopath mass-balance model, TLE, constructed independently of the isotope data. The good correlation between the two methods (r2 = 0.72) supports the diet composition and the grouping of taxa into ecological groups in the model. However, when estimates diverged, this was often explained by the analyses of few taxa, taxa that were not the most representative for the group, or the analyses of specimens from a limited size range. Some assumed detrivores were assigned high TLN in favour of an abundant microbial community in the sediments. High TLN estimates for many invertebrate taxa, combined with relatively low TLN for fishes, suggest that parts of the benthic food web are decoupled from the classical food web.

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