The diversity of juvenile salmonids does not affect their competitive impact on a native galaxiid

Young, Kyle A.; Stephenson, Jessica F.; Terreau, Alexandre; Thailly, A. F.; Gajardo, Gonzalo; Leániz, Carlos García de

doi:10.1007/s10530-008-9372-5

Cited by 27 publications

(24 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our surveys of island streams, we have encountered five native species: four galaxiids -Galaxias maculatus (ubiquitous and abundant in intertidal zones), Brachygalaxias bullocki (rare and scarce), Aplochiton zebra (variable), Aplochiton taeniatus (rare and scarce), and a native lamprey -Geotria australis (rare with juveniles locally common). Our study compares the impacts of rainbow and brown trout on Aplochiton spp., two diadromous drift feeders whose life histories, ecologies and conservation status remain poorly understood (McDowall & Nakaya, 1988;Dyer, 2000;Cussac et al, 2004;McDowall, 2006;Lattuca et al 2008;Young et al 2009). …”

Section: Study Areamentioning

confidence: 99%

A trial of two trouts: comparing the impacts of rainbow and brown trout on a native galaxiid

Young

Dunham

Stephenson

et al. 2010

Animal Conservation

View full text Add to dashboard Cite

Rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta are the world's two most widespread exotic fishes, dominate the fish communities of most coldtemperate waters in the southern hemisphere and are implicated in the decline and extirpation of native fish species. Here, we provide the first direct comparison of the impacts of rainbow and brown trout on populations of a native fish by quantifying three components of exotic species impact: range, abundance and effect. We surveyed 54 small streams on the island of Chilo´e in Chilean Patagonia and found that the rainbow trout has colonized significantly more streams and has a wider geographic range than brown trout. The two species had similar postyearling abundances in allopatry and sympatry, and their abundances depended similarly on reach-level variation in the physical habitat. The species appeared to have dramatically different effects on native drift-feeding Aplochiton spp., which were virtually absent from streams invaded by brown trout but shared a broad sympatric range with rainbow trout. Within this range, the species' post-yearling abundances varied independently before and after controlling for variation in the physical habitat. In the north of the island, Aplochiton spp. inhabited streams uninvaded by exotic trouts. Our results provide a context for investigating the mechanisms responsible for apparent differences in rainbow and brown trout invasion biology and can help inform conservation strategies for native fishes in Chilo´e and elsewhere.

show abstract

Section: Study Areamentioning

confidence: 99%

A trial of two trouts: comparing the impacts of rainbow and brown trout on a native galaxiid

Young

Dunham

Stephenson

et al. 2010

Animal Conservation

View full text Add to dashboard Cite

show abstract

“…Also, McDowall et al [44], [45] described the diet and morphological adaptations of putative AZ living in an endorheic, turbid lake on Falkland Islands, yet it turned out that when Vanhaecke et al [7] barcoded individuals from that same site (Red Pond), they only found AT. This is an example of likely misidentification, and, it is possible that other studies addressing the biogeography, ecology and biology of putative AZ might have inadvertently examined AT [4], [5], [43], [46]–[48]. Future work should critically reframe relevant background knowledge whenever Aplochiton species identity matters.…”

Section: Resultsmentioning

confidence: 99%

Diversity of Aplochiton Fishes (Galaxiidea) and the Taxonomic Resurrection of A. marinus

et al. 2013

View full text Add to dashboard Cite

Aplochiton is a small genus of galaxiid fishes endemic to Patagonia and the Falkland Islands whose taxonomy is insufficiently resolved. Recent genetic analyses confirmed the existence of only two closely related species, Aplochiton taeniatus and Aplochiton zebra, while a third controversial species, Aplochiton marinus, remained lost to synonymy with A. taeniatus. Using an integrative taxonomy framework, we studied original samples and published sequences from a broad range in western Patagonia and the Falkland Islands, and generated robust species hypotheses based on single-locus (Cytochrome Oxidase subunit I; COI) species-delineation methods and known diagnostic morphological characters analyzed in a multivariate context. Results revealed three distinct evolutionary lineages that morphologically resemble, in important respects, existing nominal species descriptions. Interestingly, the lineage associated with A. marinus was unambiguously identifiable (100% accuracy) both from the genetic and morphological viewpoints. In contrast, the morphology of A. taeniatus and A. zebra overlapped substantially, mainly due to the high variability of A. taeniatus. Discriminant function analysis aided the identification of these species with 83.9% accuracy. Hence, for their unambiguous identification, genetic screening is needed. A. marinus has seldom been documented, and when recorded, it has always been found in sites with clear marine influence. It is possible that only A. marinus preserves a life cycle related to the sea akin to the hypothesized ancestral galaxiid. We did not find evidence of claimed diadromy in A. taeniatus or A. zebra, and, therefore, these should be regarded as freshwater species. Finally, a lack of phylogeographic patterns and overrepresentation of uncommon haplotypes suggested demographic expansions in recent evolutionary time, especially of A. zebra, in line with the hypothesis of large-scale range expansion and lineage spread in western Patagonia.

show abstract

“…Galaxiids are confined to the Southern Hemisphere and are evolutionarily naive with respect to the salmonid predators that have been deliberately introduced from the Northern Hemisphere (Cox & Lima, 2006;Mcdowall, 2006). Although direct predation is probably the leading cause of these negative effects, some indirect effects have also been documented, including habitat shifts (Mcintosh, Townsend & Crowl, 1992;Edge, Townsend & Crowl, 1993;Penaluna, Arismendi & Soto, 2009) and reduced growth (Young et al, 2008). Although direct predation is probably the leading cause of these negative effects, some indirect effects have also been documented, including habitat shifts (Mcintosh, Townsend & Crowl, 1992;Edge, Townsend & Crowl, 1993;Penaluna, Arismendi & Soto, 2009) and reduced growth (Young et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Reciprocal trophic niche shifts in native and invasive fish: salmonids and galaxiids in Patagonian lakes

2012

View full text Add to dashboard Cite

Summary 1. Rainbow (Oncorhynchus mykiss) and brown trout (Salmo trutta) are widespread and invasive salmonids with important lethal effects as predators, although indirect effects are also possible. We used stable isotope analyses (δ15N, δ13C) to explore how the density of invasive trout in 25 Patagonian lakes alters the trophic niche (TN) of a widespread native fish, Galaxias platei (Galaxiidae). We also explored how the density of the galaxiid influences the TN of invasive trout. 2. We quantified two aspects of the TN: (i) the proportion of littoral carbon (PL) and (ii) trophic height (TH) (i.e. the ‘height’ at which the fish feeds in the food web). We related these measures of TN in a given species to the density of other species (as estimated by catch‐per‐unit‐effort). 3. As G. platei body size increased, their PL increased (increasing littoral feeding) in several lakes. However, none of the fish species investigated showed changes in PL with increasing density of the other fish species. TH increased with body size in all three species. In addition, the TH of large G. platei declined with increasing trout density and, reciprocally, the TH of large S. trutta decreased with decreasing G. platei density. 4. The reciprocal effects of native and the invasive fish on TH were as large as a shift of one trophic level. This pattern is consistent with an exhaustion of galaxiid prey for both piscivorous G. platei and S. trutta in lakes with high trout density. 5. These finding support the suggested management strategy of culling trout from overpopulated lakes, which should simultaneously protect native fish and enhance a lucrative sport fishery for large trout.

show abstract

The diversity of juvenile salmonids does not affect their competitive impact on a native galaxiid

Cited by 27 publications

References 40 publications

A trial of two trouts: comparing the impacts of rainbow and brown trout on a native galaxiid

A trial of two trouts: comparing the impacts of rainbow and brown trout on a native galaxiid

Diversity of Aplochiton Fishes (Galaxiidea) and the Taxonomic Resurrection of A. marinus

Reciprocal trophic niche shifts in native and invasive fish: salmonids and galaxiids in Patagonian lakes

Contact Info

Product

Resources

About