Is genetic variability so important? Non‐native salmonids in South America

Valiente, America G.; Juanes, Francis; Núñez, Pablo; García‐Vázquez, Eva

doi:10.1111/j.1095-8649.2007.01674.x

Cited by 16 publications

(20 citation statements)

References 35 publications

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“…Based on reduced genetic variability of Patagonian brown trout, Valiente et al (2007) suggested founder effects and bottlenecks that were not an obstacle for its expansion. The objectives of the present study were two-fold.…”

Section: Introductionmentioning

confidence: 98%

“…Although the region has experienced intense damming during the last 30 years (Mugetti et al 2004), which is a priori a potential risk for long-term survival of salmonids (Mesquita et al 2005;Whiteley et al 2006;Layman et al 2007), they have successfully adapted to South American ecosystems (Valiente et al 2007). This species exhibits a consistent ability of adapting to adverse environmental conditions, including damming (Ayllon et al 2006a).…”

Section: Introductionmentioning

confidence: 99%

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Brown trout (Salmo trutta) invasiveness: plasticity in life-history is more important than genetic variability

Valiente

Juanes

Núñez³

et al. 2009

Biol Invasions

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Brown trout of German origin were introduced into Patagonian National Parks in 1905, where they acclimatized and underwent population expansion endangering populations of native species like Galaxiidae. Spawning adults of two populations were sampled in 2004. Their age, length-at-age and migratory behaviour were assessed from scale samples, as well as their variation at the coding LDH-C1* and eight non coding microsatellite loci. Betweenpopulation differentiation for life history (spawning time, migratory behaviour, length and weight at age) and reduced genetic variation were revealed. Based on genetic variation, effective population size smaller than 50 individuals has been estimated for the founder stock, and its German origin has been genetically traced. Flexibility in migratory behaviour and spawning time were identified as key factors conferring competitive advantage on those brown trout populations.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Brown trout (Salmo trutta) invasiveness: plasticity in life-history is more important than genetic variability

Valiente

Juanes

Núñez³

et al. 2009

Biol Invasions

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“…Salmonids are typical examples of deliberate humanmediated stock movements. For the purposes of fishing and aquaculture, they have been transferred to exotic regions such as South America and New Zealand, where they have adapted and in some cases become invaders (Pascual et al, 2002;Townsend, 2003;Valiente et al, 2007). Large-scale human-mediated stock movements have also occurred between regions within the natural geographic range of a species; for example, in the second half of the XX century farmed salmon and trout from central and north European countries have been transplanted to south European rivers, where native populations already existed (e.g.…”

Section: Introductionmentioning

confidence: 99%

Impact of climate change and human-mediated introgression on southern European Atlantic salmon populations

Hórreo

Machado‐Schiaffino

Ayllón

et al. 2010

Global Change Biology

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This study focuses on temporal changes in Atlantic salmon (Salmo salar) populations from the vulnerable periphery of the species range (northern Spain). Using microsatellite markers to assess population structuring and introgression of exogenous genes in four different temporal samples collected across 20 years, we have determined the relative weights of climate and stocking practices in shaping contemporary regional population genetic patterns. Climate, represented by the North Atlantic Oscillation Index, was identified as the main factor for determining the level of population genetic differentiation. Populations within the region have become homogenized through gene flow enhanced by straying of adult salmon from natal rivers and subsequent interchange of genes among rivers due to warmer temperatures. At the same time, and in line with documented changes in stock transfer strategies, evidence of genetic introgression from past stock transfers has decreased throughout the study period, becoming a secondary factor in erasing population structuring. The ability to disentangle the effects of climatic changes and anthropogenic factors (fisheries management practices) is essential for effective long-term conservation of this iconic species. We emphasize the importance of evaluating all factors which may be linked to stocking practices in vulnerable species, particularly those sensitive to climate change.

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“…1995, Jensen et al 2000, Valiente et al 2007). However, a review of the applicability of Bergmann's rule (i.e.…”

Section: Discussionmentioning

confidence: 99%

“…Broadly speaking, several factors strongly influence salmonid growth, including temperature, trophic status, population density, and latitude (Elliott et al 1995, Jensen et al 2000, Valiente et al 2007). However, a review of the applicability of Bergmann's rule (i.e.…”

Section: Discussionmentioning

confidence: 99%

Variation in size-at-age between native cutthroat and introduced brown trout in allopatry and sympatry: implications for competitive interaction

Rasmussen¹,

Belk²,

Habit³

et al. 2011

Aquat. Biol.

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Brown trout Salmo trutta have been introduced into aquatic ecosystems throughout the western United States and have been implicated in the extirpation of many native cutthroat trout Oncorhynchus clarkii populations. We document patterns of size-at-age among multiple populations of brown trout and cutthroat trout in allopatry and sympatry. Comparisons were based on data from 48 allopatric populations (9 brown trout and 39 cutthroat trout) and 2 sympatric populations gathered from published reports and field collections. Brown trout are significantly larger than same-age cutthroat trout at all ages in both sympatry and allopatry. Size-at-age was also significantly negatively influenced with increasing latitude and elevation. The size-at-age for both species is reduced when in sympatry, but the reduction is more pronounced for brown trout. Cutthroat trout may be able to persist in the presence of brown trout in these instances because of the limited competitive ability of brown trout due to the reduced size, which may be a result of suboptimal conditions of the habitat. The fact that brown trout are unable to exclude cutthroat trout when growth is restricted suggests that size is an important mechanism of competitive exclusion of cutthroat trout by brown trout. KEY WORDS: Otoliths · Size-at-age · Introduced species · Competitive exclusion · SympatryResale or republication not permitted without written consent of the publisher Aquat Biol 13: 285-292, 2011 Taniguchi et al. 2002). Relatively small size differences, e.g. 20% of biomass, can facilitate eviction of smaller individuals from higher quality feeding territories in young trout (Johnsson et al. 1999). Limited resource availability often results in reduced growth and relatively small size-at-age in fishes (Jones 1986), which may act as a negative feedback loop for competitively inferior individuals or species.Cutthroat trout Oncorhynchus clarkii populations have de clined throughout much of their range (Behnke 1992, Kruse et al. 2000, and several subspecies are considered by state and federal agencies to be threatened or endangered within the USA (Quist & Hubert 2004). Although cutthroat trout are often considered a headwater species, the species historically inhabited a variety of habitats throughout many western drainages, including lakes and relatively low elevation areas (Quist & Hubert 2004), but their range has been drastically restricted for several reasons. Interaction with non-native salmonids is one of the main causes of decline and range restriction of cutthroat trout (Allendorf & Leary 1988, Young 1995, Dunham et al. 2002, Peterson et al. 2004.Brown trout Salmo trutta have been introduced widely in the western USA, often on top of native cutthroat trout populations (Fuller et al. 1999). In general, this species is relatively similar in habitat use and diet to native cutthroat trout (Dare & Hubert 2003, McHugh et al. 2008) and, in most introduction cases, the cutthroat trout are extirpated (Behnke 1992, Young 1995, especially in the ...

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Is genetic variability so important? Non‐native salmonids in South America

Cited by 16 publications

References 35 publications

Brown trout (Salmo trutta) invasiveness: plasticity in life-history is more important than genetic variability

Brown trout (Salmo trutta) invasiveness: plasticity in life-history is more important than genetic variability

Impact of climate change and human-mediated introgression on southern European Atlantic salmon populations

Variation in size-at-age between native cutthroat and introduced brown trout in allopatry and sympatry: implications for competitive interaction

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Is genetic variability so important? Non‐native salmonids in South America

Cited by 16 publications

References 35 publications

Brown trout (Salmo trutta) invasiveness: plasticity in life-history is more important than genetic variability

Brown trout (Salmo trutta) invasiveness: plasticity in life-history is more important than genetic variability

Impact of climate change and human-mediated introgression on southern European Atlantic salmon populations

Variation in size-at-age between native cutthroat and introduced brown trout in allopatry and ­sympatry: implications for competitive interaction

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Product

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Variation in size-at-age between native cutthroat and introduced brown trout in allopatry and sympatry: implications for competitive interaction