Invasive predatory fish occupies highest trophic position leading to expansion of isotopic niches in a riverine food web.
| Title: | Invasive predatory fish occupies highest trophic position leading to expansion of isotopic niches in a riverine food web. |
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| Authors: | Hodgson OC; Pennsylvania Cooperative Fish and Wildlife Research Unit, The Pennsylvania State University, University Park, Pennsylvania, USA.; Stark S; Pennsylvania Cooperative Fish and Wildlife Research Unit, The Pennsylvania State University, University Park, Pennsylvania, USA.; Schall MK; Department of Biology, Pennsylvania State University Hazleton, Hazleton, Pennsylvania, USA.; Smith GD; Pennsylvania Fish and Boat Commission, Division of Fisheries Management, Bellefonte, Pennsylvania, USA.; Smalling KL; U.S. Geological Survey, New Jersey Water Science Center, Lawrenceville, New Jersey, USA.; Wagner T; U.S. Geological Survey, Pennsylvania Cooperative Fish and Wildlife Research Unit, The Pennsylvania State University, University Park, Pennsylvania, USA. |
| Source: | Ecology [Ecology] 2025 Sep; Vol. 106 (9), pp. e70180. |
| Publication Type: | Journal Article |
| Language: | English |
| Journal Info: | Publisher: Ecological Society of America Country of Publication: United States NLM ID: 0043541 Publication Model: Print Cited Medium: Internet ISSN: 1939-9170 (Electronic) Linking ISSN: 00129658 NLM ISO Abbreviation: Ecology Subsets: MEDLINE |
| Imprint Name(s): | Publication: Washington, DC : Ecological Society of America; Original Publication: Brooklyn, NY : Brooklyn Botanical Garden |
| MeSH Terms: | Predatory Behavior*/physiology ; Catfishes*/physiology ; Fishes*/physiology ; Food Chain* ; Introduced Species* ; Rivers*; Animals ; Nitrogen Isotopes ; Carbon Isotopes |
| Abstract: | Invasive species are drivers of ecological change with the potential to reshape the structure and function of terrestrial and aquatic ecosystems. The invasive flathead catfish (Pylodictis olivaris) is an opportunistic predator that has established a rapidly growing population in the Susquehanna River, Pennsylvania, USA, since they were first detected in 2002. Although the predatory effects of invasive catfishes on native fish communities have been documented, the effects of invasion on riverine food webs are poorly understood. This study quantified the effects of invasive flathead catfish on the trophic position (TP) and isotopic niche of the river's food web by comparing invaded and non-invaded sites. In addition to flathead catfish, the food web components examined included crayfish, minnows, and two ecologically and socioeconomically important fish species: the smallmouth bass (Micropterus dolomieu) and channel catfish (Ictalurus punctatus). We found that flathead catfish occupied the highest TP, with a posterior mean TP of 3.08 (95% credible interval = [2.71, 3.42]), exceeding that of the two resident fish predators, the smallmouth bass and channel catfish. The TP of the resident channel catfish, which occupies a similar ecological niche, declined after flathead catfish invasion. In fact, there was a 0.92 posterior probability that channel catfish TP was lower in invaded sites than at non-invaded sites. Using a Bayesian bivariate ellipses analysis, we found overwhelming evidence of isotopic niche expansion and overlap for all components of the food web in the presence of flathead catfish. These findings support the "trophic disruption hypothesis," where an introduced species prompts resident species to change diets in an attempt to avoid competition and predation following invasion. Our results indicate that flathead catfish invasion is altering food web structure and energy flow in a large riverine ecosystem and contributes to the breadth of knowledge regarding how ecosystems may respond to the introduction of a large predatory fish species.; (© 2025 The Author(s). Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America.) |
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| Grant Information: | NA22OAR4170119 Pennsylvania Sea Grant, Pennsylvania State University; U.S. Geological Survey |
| Contributed Indexing: | Keywords: Pylodictis olivaris; food web; invasion ecology; river; trophic dispersion; trophic displacement; trophic disruption hypothesis; trophic position flathead catfish |
| Substance Nomenclature: | 0 (Nitrogen Isotopes); 0 (Carbon Isotopes) |
| Entry Date(s): | Date Created: 20250905 Date Completed: 20250905 Latest Revision: 20250908 |
| Update Code: | 20260130 |
| PubMed Central ID: | PMC12411813 |
| DOI: | 10.1002/ecy.70180 |
| PMID: | 40908753 |
| Database: | MEDLINE |
Journal Article