Trophic Analysis of Ruffe (Gymnocephalus cernuus) and White Perch (Morone americana) in a Lake Superior Coastal Food Web, Using Stable Isotope Techniques

We used stable isotope analysis to derive trophic relationships and movement patterns for components of the western Lake Superior food web. Trophic linkages implied by previous gut content studies were only marginally supported by stable isotope data. Siscowet lake trout (Salvelinus namaycush siscowet) were the top predators, and trophic overlap between siscowet and lean lake trout (Salvelinus namaycush) was low. Exotic Pacific salmon (Oncorhynchus spp.) occupied a lower trophic position than native piscivores because the latter relied more on coregonids. To evaluate spatial heterogeneity of the food web, we assumed that the adjacent cities of Duluth and Superior (DS) were a point source of 15N, and we measured isotopes of organisms close to and far from DS. Slimy sculpin (Cottus cognatus) were enriched in the DS area relative to other sites, implying that they are relatively sedentary. Rainbow smelt (Osmerus mordax) showed no differences at any sites, implying high vagility. Other organisms showed differences that could not be attributed to DS, implying that other mechanisms, such as trophic ontogeny, were influencing their isotopic signatures.

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Diet and Food Web Support of the White Perch, Morone americana, in the Hackensack Meadowlands of New Jersey

Environmental Biology of Fishes ◽

10.1007/s10641-005-6466-0 ◽

2005 ◽

Vol 74 (1) ◽

pp. 109-113 ◽

Cited By ~ 14

Author(s):

Judith S. Weis

Keyword(s):

New Jersey ◽

Food Web ◽

White Perch ◽

Morone Americana ◽

Hackensack Meadowlands

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Long-term food web change in Lake Superior

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f09-151 ◽

2009 ◽

Vol 66 (12) ◽

pp. 2118-2129 ◽

Cited By ~ 39

Author(s):

Stephanie N. Schmidt ◽

M. Jake Vander Zanden ◽

James F. Kitchell

Keyword(s):

Stable Isotope ◽

Great Lakes ◽

Food Web ◽

Stable Isotope Analysis ◽

Native Species ◽

Trophic Position ◽

Lake Superior ◽

Isotope Analysis ◽

Food Web Structure

Restoration and rehabilitation of native species in the Laurentian Great Lakes is a priority for fisheries management agencies. Restoration efforts are increasingly incorporating a perspective that considers species within a broader food web context. We used stable isotope analysis and museum-preserved specimens to describe and quantify 100 years of food web changes in the Lake Superior fish community. We validated stable isotope analysis of museum specimens by showing a positive correlation between isotope- and diet-based estimates of trophic position. While introductions have created a more trophically diverse food web than historically found in Lake Superior, two separate metrics revealed little community-wide change in the food web. Our species-specific analysis revealed trophic niche differences between shortjaw ( Coregonus zenithicus ) and shortnose ( Coregonus reighardi ) ciscoes, two species previously argued to be indistinguishable based on morphological characteristics. By providing a historical context, our findings show the ability of the Lake Superior food web to accommodate non-native species introductions over the last century while still supporting native species populations. This long-term information about food web structure can help guide management and restoration goals in Lake Superior. Furthermore, Lake Superior can serve as a basis for comparing food web changes in other, more highly altered Great Lakes.

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Food Web Structure and Trophic Interactions Revealed by Stable Isotope Analysis in the Midstream of the Chishui River, a Tributary of the Yangtze River, China

Water ◽

10.3390/w13020195 ◽

2021 ◽

Vol 13 (2) ◽

pp. 195

Author(s):

Qiang Qin ◽

Fubin Zhang ◽

Fei Liu ◽

Chunling Wang ◽

Huanzhang Liu

Keyword(s):

Stable Isotope ◽

Carbon Source ◽

Food Web ◽

Food Chain ◽

Yangtze River ◽

Trophic Niche ◽

The Yangtze River ◽

Food Chain Length ◽

Trophic Pathways ◽

Chishui River

Understanding energy flow and nutrient pathways is crucial to reveal the dynamics and functions of riverine ecosystems and develop appropriate conservation strategies. In this study, we utilized stable isotopes of δ13C and δ15N to examine the fundamental characteristics of trophic position, trophic niche, and carbon source for the food web in the midstream of the Chishui River, a tributary to the Yangtze River. Our results showed that stable isotope signatures among different sorts of basal resources and consumers were significantly distinguishable and that the food chain consisted of four trophic levels, indicating the multiple trophic pathways and long food chain length here. The trophic guilds of fish were classified into four categories, in which herbivorous and carnivorous fish showed greater trophic diversity and omnivorous fish had higher trophic redundancy, which meant that there was a stable trophic niche structure in the study area. Phytoplankton and periphyton presented the largest contributions to consumers, indicating that autochthonous productivity was the dominant carbon source in the midstream of the Chishui River. Since the Chishui River is still in a natural condition without any dam constructions, the autochthonous productivity, stable trophic niche structure, multiple trophic pathways and long food chain length found here demonstrate its high conservation value. Therefore, the strategy to refrain from damming on this river should persist into the future.

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