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First record of a synergistic interaction between invasive salmonids in South America


Ecological interactions among multiple invaders can aggravate their effects on invaded systems. Many salmonids including rainbow trout Oncorhynchus mykiss and Chinook salmon O. tshawytscha have established naturalized populations and co-occur in rivers worldwide. Predation of eggs and juveniles has been well documented among salmonids in their native range in the Northern Hemisphere. It has been unclear to what extent these interactions exist in invaded rivers of the Patagonia. Here, we report and quantify rainbow trout predation of Chinook salmon eggs in the Cisnes River Basin, southern Chile. We used hook and line angling to sample rainbow trout (n = 80) around salmon spawning areas before, during, and after the spawning season of Chinook salmon. Stomach contents obtained during two consecutive years show consistent evidence that rainbow trout opportunistically prey on Chinook salmon eggs. Salmon eggs occurred in 75 and 50% of the trout stomachs analyzed in 2019 and 2020, respectively. The number of salmon eggs (mean ± SD) per trout stomach ranged between 17.95 ± 24.29 in 2019 and 7.45 ± 12.90 in 2020. We assumed that consumed eggs were primarily non-viable or would have had low probabilities of survival suggesting a synergistic interaction between rainbow trout and Chinook salmon. Our findings provide baseline information that contribute to demographic studies and the management of invasive salmonids in rivers of this region and elsewhere.

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Availability of data and material

Raw data are publicly available in Supplementary Material (Table S3 and S4).


  1. Arismendi I, Soto D, Penaluna B et al (2009) Aquaculture, non-native salmonid invasions and associated declines of native fishes in Northern Patagonian lakes. Freshw Biol 54:1135–1147

    CAS  Article  Google Scholar 

  2. Arismendi I, Penaluna BE, Dunham JB et al (2014) Differential invasion success of salmonids in southern Chile: patterns and hypotheses. Rev Fish Biol Fish 24:919–941

    Article  Google Scholar 

  3. Armstrong JB, Schindler DE, Omori KL, Ruff CP, Quinn TP (2010) Thermal heterogeneity mediates the effects of pulsed subsidies across a landscape. Ecology 91:1445–1454

    Article  Google Scholar 

  4. Ciancio JE, Pascual MA, Beauchamp DA (2007) Energy Density of Patagonian Aquatic Organisms and Empirical Predictions Based on Water Content. Trans Am Fish Soc 136:1415–1422

    Article  Google Scholar 

  5. Clarke KR, Gorley RN (2006) PRIMER v6. Plymouth, UK: User Manual/Tutorial. PRIMER–E. Version 6. PRIMER-E, UK

    Google Scholar 

  6. Correa C, Gross MR (2008) Chinook salmon invade southern South America. Biol Invasions 10:615–639

    Article  Google Scholar 

  7. Denton KP, Rich HB, Quinn TP (2009) Diet, movement, and growth of Dolly Varden in response to sockeye salmon subsidies. Trans Am Fish Soc 138:1207–1219

    Article  Google Scholar 

  8. Fierro P, Quilodrán L, Bertrán C et al (2016) Rainbow Trout diets and macroinvertebrates assemblages responses from watersheds dominated by native and exotic plantations. Ecol Indic 60:655–667

    CAS  Article  Google Scholar 

  9. Gomez-Uchida D, Sepúlveda M, Ernst B et al (2018) Chile’s salmon escape demands action. Science 361:857–858

    CAS  PubMed  Google Scholar 

  10. Greeley JR (1932) The Spawning Habits of Brook, Brown and Rainbow Trout, and the Problem of Egg Predators. Trans Am Fish Soc 62:239–248

    Article  Google Scholar 

  11. Heinimaa S, Heinimaa P (2004) Effect of the female size on egg quality and fecundity of the wild Atlantic salmon in the sub-arctic River Teno. Boreal Environ Res 9:55–62

    Google Scholar 

  12. Hureau J (1970) Biologie comparée de quelques poissons antarctiques (Nototheniidae). Bull Inst Oceanogr 68:1–244

    Google Scholar 

  13. Jackson MC (2015) Interactions among multiple invasive animals. Ecology 96:2035–2041

    CAS  Article  Google Scholar 

  14. Johnson JH, Ringler NH (1979) Predation on Pacific Salmon Eggs by Salmonids in a Tributary of Lake Ontario. J Great Lakes Res 5:177–181

    Article  Google Scholar 

  15. Johnson JH, Chalupnicki MA, Abbett R, Verdoliva F (2016) Predation on Pacific salmonid eggs and carcass’s by subyearling Atlantic salmon in a tributary of lake Ontario. J Great Lakes Res 42:472–475

    Article  Google Scholar 

  16. Moore JW, Schindler DE, Ruff CP (2008) Habitat saturation drives thresholds in stream subsidies. Ecology 89:306–312

    Article  Google Scholar 

  17. Penaluna BE, Arismendi I, Soto D (2009) Evidence of interactive segregation between introduced trout and native fishes in Northern Patagonian Rivers, Chile. Trans Am Fish Soc 138:839–845

    Article  Google Scholar 

  18. Ricker WE (1975) Computation and Interpretation of Biological Statistics of Fish Populations. Fisheries and Marine Service

  19. Sepúlveda M, Arismendi I, Soto D et al (2013) Escaped farmed salmon and trout in Chile: incidence, impacts, and the need for an ecosystem view. Aquac Environ Interact 4:273–283

    Article  Google Scholar 

  20. Shepard B, Arismendi I, David B et al (2019) Global perspectives on the management of trout and char. In: Kershner J, Williams J, Gresswel R, Lobon-Cervia J (eds) Trout and char of the world. American Fisheries Society, Bethesda, p 40

    Google Scholar 

  21. Simberloff D, Von Holle B (1999) Positive interactions of nonindigenous species: invasional Meltdown? Biol Invasions 1:21–32

    Article  Google Scholar 

  22. Soto D, Arismendi I, González J et al (2006) Southern Chile, trout and salmon country: invasion patterns and threats for native species. Rev Chil Hist Nat 79:97–117

    Article  Google Scholar 

  23. Soto D, Arismendi I, Prinzio CD, Jara F (2007) Establishment of Chinook salmon (Oncorhynchus tshawytscha) in Pacific basins of southern South America and its potential ecosystem implications. Rev Chil Hist Nat 80:81–98

    Article  Google Scholar 

  24. Tagliaferro M, Arismendi I, Lancelotti J, Pascual M (2015) A natural experiment of dietary overlap between introduced Rainbow Trout (Oncorhynchus mykiss) and native Puyen (Galaxias maculatus) in the Santa Cruz River, Patagonia. Environ Biol Fish 98:1311–1325

    Article  Google Scholar 

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Orlando Raín, Williams Díaz, Matías Santander, Cristobal Sánchez, Matías Raín and Catalina Méndez helped during fish collection and sampling processing. Manuel Díaz made the map and Brooke Penaluna provided feedback on the final version of this manuscript. Two anonymous reviewers and the Associate Editor provided thoughtful discussions that improved our manuscript. This research was supported by Núcleo Milenio INVASAL funded by Chile’s ANID – Programa Iniciativa Científica Milenio – NCN16_034. We also acknowledge grants 4136 − 2018, FEQUIP2019-INRN-03 from Vice-Rectory for Research and Postgraduate of Catholic University of Temuco and FONDECYT 1191256 from Chile’s Agencia Nacional de Investigación & Desarrollo. Student support came from CONICYT-PFCHA/Magíster Nacional/2020-22200247 scholarship to GFM.

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GFM, IV and IA contributed to study conception and design. GFM and PF led stomach contents analysis. IA and GFM analyzed the data. GFM and IA led the writing and review. Preparation of the first draft was completed by GFM, DGU and IA. All authors contributed to editing and have approved the final manuscript.

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Correspondence to Ivan Arismendi.

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Figueroa-Muñoz, G., Gomez-Uchida, D., Fierro, P. et al. First record of a synergistic interaction between invasive salmonids in South America. Biol Invasions (2021).

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  • Salmon
  • Trout
  • Predation
  • Marine-derived nutrients
  • River
  • Southern Chile