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Predatory impact of non-native rainbow trout on endemic fish populations in headwater streams in the Cape Floristic Region of South Africa

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Abstract

Non-native rainbow trout Oncorhynchus mykiss have been widely introduced in the Cape Floristic Region (CFR) at the south-western tip of Africa and may pose a serious threat to endemic freshwater fishes in the region. Quantitative information about trout impacts in the CFR is scarce but is urgently needed to guide legislation and management efforts. We used a combination of comparative and experimental approaches to evaluate impacts of introduced trout on native fish populations in headwater streams draining the upper Breede River catchment in the CFR. Fish populations were surveyed, and 19 environmental variables measured, in 24 minimally-disturbed streams, half of which had been invaded by trout. The mean densities of native Breede River redfin Pseudobarbus burchelli, Cape kurper Sandelia capensis and Cape galaxias Galaxias zebratus, were 89–97 % lower in invaded streams than in streams without trout. Furthermore, while native fish were present at all 12 sites without trout, they were not recorded at seven of the 12 invaded sites. None of the measured environmental variables differed significantly between sites with and without trout, and distance-based linear models identified trout density as the best predictor of redfin and kurper density, while galaxias density was best predicted by other environmental variables (riparian vegetation, canopy cover, substrate length, site slope). Native fish ≤40 mm in length were largely absent from invaded streams, but generally abundant in streams without trout, and a field experiment confirmed that trout selectively consume small redfin. Taken together, these findings constitute evidence that trout have depleted the abundance of CFR-endemic fishes through size-selective predation. It is recommended that managers aim to prevent new trout introductions and consider eradicating trout populations where they pose a threat to highly threatened native species.

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Notes

  1. In this study “Pseudobarbus burchelli” refers to a lineage currently known as Pseudobarbus sp. “burchelli Breede” which is regarded as Near Threatened (Tweddle et al. 2009), but is still awaiting formal taxonomic description (IUCN 2013).

References

  • Anderson MJ, Gorley RN, Clarke KR (2008) PERMANOVA+ for PRIMER: guide to software and statistical methods. PRIMER-E, Plymouth

    Google Scholar 

  • Bovee KD (1982) A guide to stream habitat analysis using the instream flow incremental methodology. USDI Fish and Wildlife Service Instream Flow Information Paper #12, FWS/OBS-82/26, Colorado

  • Burnham KP, Anderson DR (2002) Model selection and multimodel inference: a practical information-theoretic approach, 2nd edn. Springer, Colorado

    Google Scholar 

  • Cadwallader PL (1996) Overview of the impacts of introduced salmonids on Australian native fauna. Australian Nature Conservation Agency, Canberra

    Google Scholar 

  • Cambray JA (2003) The global impact of alien trout species: a review; with reference to their impact in South Africa. Afr J Aquat Sci 28:61–67

    Article  Google Scholar 

  • Chakona A, Swartz ER (2012) Contrasting habitat associations of imperilled endemic stream fishes from a global biodiversity hot spot. BMC Ecol 12:19. doi:10.1186/1472-6785-12-19

    Article  PubMed Central  PubMed  Google Scholar 

  • Chakona A, Swartz ER (2013) A new redfin species, Pseudobarbus skeltoni (Cyprinidae, Teleostei), from the Cape Floristic Region, South Africa. Zootaxa 3686:565–577

    Article  Google Scholar 

  • Clarke KR, Gorley RN (2006) PRIMER v6: user manual/tutorial. PRIMER-E, Plymouth

    Google Scholar 

  • Cowling RM, Holmes PM (1992) Flora and vegetation. In: Cowling RM (ed) The ecology of fynbos: nutrients, fire and diversity. Oxford University Press, Cape Town

    Google Scholar 

  • Cox JG, Lima SL (2006) Naiveté and an aquatic-terrestrial dichotomy in the effects of introduced predators. Trends Ecol Evol 21:674–680. doi:10.1016/j.tree.2006.07.011

    Article  PubMed  Google Scholar 

  • Crawford SS, Muir AM (2008) Global introductions of salmon and trout in the genus Oncorhynchus: 1870–2007. Rev Fish Biol Fish 18:313–344. doi:10.1007/s11160-007-9079-1

    Article  Google Scholar 

  • Crowl TA, Townsend CR, McIntosh AR (1992) The impact of introduced brown and rainbow trout on native fish: the case of Australasia. Rev Fish Biol Fish 2:217–241

    Article  Google Scholar 

  • de Moor FC, Bruton MN (1988) Atlas of alien and translocated indigenous aquatic animals of southern Africa. S Afr Nat Sci Prog Rep No 144, CSIR, Pretoria, pp 78–133

  • de Moor FC, Day JA (2013) Aquatic biodiversity in the mediterranean region of South Africa. Hydrobiologia. doi:10.1007/s10750-013-1488-7

  • Dunham JB, Pilliod DS, Young MK (2004) Assessing the consequences of nonnative trout in headwater ecosystems in western North America. Fisheries 29:18–26

    Article  Google Scholar 

  • Ellender BR, Becker A, Weyl OLF, Swartz ER (2012) Underwater video analysis as an non-destructive alternative to electrofishing for sampling imperilled headwater stream fishes. Aquat Conserv 22:58–65. doi:10.1002/aqc.1236

    Article  Google Scholar 

  • Fausch KD (2007) Introduction, establishment and effects of non-native salmonids: considering the risk of rainbow trout invasion in the United Kingdom. J Fish Biol 71:1–32. doi:10.1111/j.1095-8649.2007.01682.x

    Article  Google Scholar 

  • Fletcher AR (1979) Effects of Salmo trutta on Galaxias olidus and macroinvertebrates in stream communities. M.Sc. Dissertation, Monash University

  • Garcia de Leaniz C, Gajardo G, Consuegra S (2010) From best to pest: changing perspectives on the impact of exotic salmonids in the southern hemisphere. Syst Biodivers 8:447–459. doi:10.1080/14772000.2010.537706

    Article  Google Scholar 

  • Habit E, Piedra P, Ruzzante DE, Walde SJ, Belk MC, Cussac VE, Gonzalez J, Colin N (2010) Changes in the distribution of native fishes in response to introduced species and other anthropogenic effects. Glob Ecol Biogeogr 19:697–710. doi:10.1111/j.1466-8238.2010.00541.x

    Google Scholar 

  • Hankin DG, Reeves GH (1988) Estimating total fish abundance and total habitat area in small streams based on visual estimation methods. Can J Fish Aquat Sci 45:834–844

    Article  Google Scholar 

  • Hardie SA, Barmuta LA, White RWG (2006) Comparison of day and night fyke netting, electrofishing and snorkelling for monitoring a population of the threatened golden galaxias (Galaxias auratus). Hydrobiologia 560:145–158. doi:10.1007/s10750-005-9509-9

    Article  Google Scholar 

  • Harrison AC (1950a) Introduction of exotic fishes to the Cape Province: the prelude. Piscator 16:125–128

    Google Scholar 

  • Harrison AC (1950b) Trout and minnows. Piscator 13:2–6

    Google Scholar 

  • Harrison AC (1952) Cape minnows. Piscator 24:117–128

    Google Scholar 

  • Hey D (1926) Fisheries survey 1925–1926: inland waters. Department of Mines and Industries, Report No. 2. Cape Town

  • Impson ND (2001) Threatened fishes of the world: Barbus andrewi Barnard, 1937 (Cyprinidae). Environ Biol Fishes 61:212

    Article  Google Scholar 

  • IUCN (2013) IUCN red list of threatened species. Version 2013.2. http://www.iucnredlist.org. (Downloaded on 26 Feb 2014)

  • Januchowski-Hartley F, Graham N, Cinner J, Russ G (2013) Spillover of fish naivete from marine reserves. Ecol Lett 12:191–197

    Article  Google Scholar 

  • Kitano S (2004) Ecological impacts of rainbow, brown and brook trout in Japanese inland waters. Glob Environ Res 8:41–50

    Google Scholar 

  • Lescak EA, von Hippel F (2011) Selective predation of threespine stickleback by rainbow trout. Ecol Freshw Fish 20:308–314. doi:10.1111/j.1600-0633.2011.00497

    Article  Google Scholar 

  • Linder HP, Johnson SD, Kuhlmann M, Matthee CA, Nyffeler R, Swartz ER (2010) Biotic diversity in the southern African winter-rainfall region. Environ Sustain 2:109–116. doi:10.1016/j.cosust.2010.02.001

    Google Scholar 

  • Lintermans M (2000) Recolonization by the mountain galaxias Galaxias olidus of a montane stream after the eradication of rainbow trout Oncorhynchus mykiss. Mar Freshw Res 51:799–804

    Article  Google Scholar 

  • Lowe S, Browne M, Boudjelas S, De Poorter M (2000) 100 of the world’s worst invasive alien species: a selection from the global invasive species database. The Invasive Species Specialist Group (ISSG), Aliens 12, Aukland

  • Macchi PJ, Cussac VE, Alonso MF, Denegri MA (1999) Predation relationships between introduced salmonids and the native fish fauna in lakes and reservoirs in northern Patagonia. Ecol Freshw Fish 8:227–236

    Article  Google Scholar 

  • Marr SM (2012) An assessment of a proposal to eradicate non-native fish from priority rivers in the Cape Floristic Region, South Africa. Afr J Aquat Sci 37:141–142. doi:10.2989/16085914.2012.666654

    Article  Google Scholar 

  • McDowall RM (2006) Crying wolf, crying foul, or crying shame: alien salmonids and a biodiversity crisis in the southern cool-temperate galaxioid fishes? Rev Fish Biol Fish 16:233–422. doi:10.1007/s11160-006-9017-7

    Article  Google Scholar 

  • McDowall RM, Allibone RM, Chadderton WL (2001) Issues for the conservation and management of Falkland Islands freshwater fishes. Mar Freshw Ecosyst 11:473–486

    Article  Google Scholar 

  • McIntosh AR (2000) Habitat- and size-related variations in exotic trout impacts on native galaxiid fishes in New Zealand streams. Can J Fish Aquat Sci 57:2140–2151. doi:10.1139/cjfas-57-10-2140

    Article  Google Scholar 

  • McIntosh AR, McHugh PA, Dunn NR, Goodman JM, Howard SW, Jellyman PG, Brien LKO, Nyström P, Woodford DJ (2010) The impact of trout on galaxiid fishes in New Zealand. N Z J Ecol 34:195–206

    Google Scholar 

  • McVeigh SJ (1977) Galaxias minnow: a trout food. Piscator 99:7

    Google Scholar 

  • Mullner SA, Hubert WA, Weshe TA (1998) Snorkelling as an alternative to depletion electrofishing for estimating abundance and length class frequencies of trout in small streams. N Am J Fish Manag 18:947–953

    Article  Google Scholar 

  • Peterson DP, Fausch KD, White GC (2004) Population ecology of an invasion: effects of brook trout on native cutthroat trout. Ecol Appl 14:754–772

    Article  Google Scholar 

  • Quinn GP, Keough MJ (2002) Experimental design and data analysis for biologists. Cambridge University Press, Cambridge

    Book  Google Scholar 

  • Raleigh RF, Hickman T, Solomon RC, Nelson PC (1984) Habitat suitability information: rainbow trout. US Fish and Wildlife Service, Report no. USFWS-BSP, Colorado, pp 1–39

  • Rebelo AG, Boucher C, Helme N, Mucina L, Rutherford MC (2006) Fynbos biome. In: Mucina L, Rutherford MC (eds) The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria

  • Reznick D, Endler J (1982) The impact of predation on life history evolution in Trinidadian guppies (Poecilia reticulata). Evolution 36:160–177

    Article  Google Scholar 

  • Reznick D, Butler M IV, Rodd F, Ross P (1996) Life-history evolution in guppies (Poecilia reticulata) 6. Differential mortality as a mechanism for natural selection. Evolution 50:1651–1660

    Article  Google Scholar 

  • RHP (2011) River health programme state of rivers report: rivers of the Breede water management area. Institute for Water Quality Studies, Pretoria

    Google Scholar 

  • Rowntree KM, Wadeson RA (1999) A hierarchical geomorphological model for the classification of selected South African rivers. Water Research Commission, Report No. 497/1/99, Pretoria

  • Skelton PH (1987) South African red data book: fishes. Afr Nat Sci Prog Rep No 137, CSIR, Pretoria, pp 60–62

  • Skelton PH (2001) A complete guide to the freshwater fishes of Southern Africa, 2nd edn. Struik, Cape Town

    Google Scholar 

  • SPSS (2011) IBM SPSS statistics, version 20.0. SPSS Inc., Chicago

    Google Scholar 

  • Steynor AC, Hewitson BC, Tadross MA (2009) Projected future runoff of the Breede River under climate change. Water SA 35:433–440

    Google Scholar 

  • Swartz ER, Flemming AF, Mouton P (2004) Contrasting genetic patterns and population histories in three threatened redfin species (Cyprinidae) from the Olifants River system, western South Africa. J Fish Biol 64:1153–1167. doi:10.1046/j.1095-8649.2004.00375.x

    Article  CAS  Google Scholar 

  • Tankard AJ, Jackson MPA, Eriksson KA, Hobday DK, Hunter WEL, Minter DR (1982) The Cape trough: an aborted rift. In: Tankard AJ, Jackson MPA, Eriksson KA, Hobday DK, Hunter WEL, Minter DR (eds) Crustal evolution of Southern Africa: 3.8 billion years of earth history. Springer, New York, pp 333–335

    Chapter  Google Scholar 

  • Thurow RF (1994) Underwater methods for study of salmonids in the Intermountain West. General Technical Report INT-GTR-307, Ogden

  • Tweddle D, Bills R, Swartz ER, Coetzer W, Da Costa L, Engelbrecht J, Cambray JA, Marshall B, Impson ND, Skelton PH, Darwall WRT, Smith KG (2009) The status and distribution of freshwater fishes. In: Darwall WRT, Smith KG, Tweddle D, Skelton P (eds) The status and distribution of freshwater biodiversity in South Africa. IUCN, Gland, Switzerland and SAIAB (South African Institute for Aquatic Biodiversity), Information Press, Oxford, pp 21–37

  • van Rensburg BJ, Weyl OLF, Davies SJ, van Wilgen LJ, Peacock DS, Spear D, Chimimba CT (2011) Chapter 15: invasive vertebrates of South Africa. In: Pimentel D (ed) Biological invasions: economic and environmental costs of alien plant, animal, and microbe species, 2nd edn. CRC Press, Boca Raton, FL, pp 326–378

    Google Scholar 

  • Weyl OLF, Ellender BR, Woodford DJ, Jordaan MS (2013) Fish distributions in the Rondegat River, Cape Floristic Region, South Africa, and the immediate impact of rotenone treatment in an invaded reach. Afr J Aquat Sci 38:201–209. doi:10.2989/16085914.2012.753401

    Article  CAS  Google Scholar 

  • White JL, Harvey BC (2001) Effects of an introduced piscivorous fish on native benthic fishes in a coastal river. Freshw Biol 46:987–995. doi:10.1046/j.1365-2427.2001.00724.x

    Article  Google Scholar 

  • Woodford DJ (2009) Riverscape-mediated effects of introduced trout on non-diadromous galaxiid fishes in New Zealand. Ph.D. Dissertation, University of Cantebury

  • Woodford DJ, Impson ND (2004) Preliminary assessment of the impact of alien rainbow trout (Oncorhynchus mykiss) on indigenous fishes of the upper Berg River, Western Cape Province, South Africa. Afr J Aquat Sci 29:107–111

    Article  Google Scholar 

  • Woodford DJ, Impson ND, Day JA, Bills IR (2005) The predatory impact of invasive alien smallmouth bass, Micropterus dolomieu (Teleostei: Centrarchidae), on indigenous fishes in a Cape Floristic Region mountain stream. Afr J Aquat Sci 30:167–173. doi:10.2989/16085910509503852

    Article  Google Scholar 

  • Young KA, Dunham JB, Stephenson JF, Terreau A, Thailly AF, Gajardo G, Garcia de Leaniz C (2010) A trial of two trouts: comparing the impacts of rainbow and brown trout on a native galaxiid. Anim Conserv 13:399–410. doi:10.1111/j.1469-1795.2010.00354.x

    Article  Google Scholar 

  • Zar JH (1999) Biostatistical analysis, 4th edn. Prentice Hall, New Jersey

    Google Scholar 

Download references

Acknowledgments

Financial support was from the DST-NRF Centre of Excellence for Invasion Biology (CIB), the German Academic Exchange Service (DAAD), the University of Cape Town (UCT) and the Cape Tercentenary Foundation. JMS also acknowledges a UCT Postgraduate Publication Incentive Bursary. This research was conducted under permit 0035-AAA 007-00057 issued from CapeNature, and animal ethics clearance for the study was obtained from the University of Cape Town. We thank K Tilanus and MS Bird for field assistance, and ND Impson, SM Marr and SR Lowe for constructive discussions. H Waldron of the UCT Marine Research Institute at UCT conducted the nutrient analysis. We thank CL Moloney and D Pillay for analytical advice and I Hampton, OLF Weyl and two anonymous reviewers who provided valuable comments on the manuscript.

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Shelton, J.M., Samways, M.J. & Day, J.A. Predatory impact of non-native rainbow trout on endemic fish populations in headwater streams in the Cape Floristic Region of South Africa. Biol Invasions 17, 365–379 (2015). https://doi.org/10.1007/s10530-014-0735-9

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