Genetic effects of introduced hatchery stocks on indigenous brown trout (<i>Salmo trutta</i> L.) populations in Spain

Cagigas, M. E.; Vázquez, Esther; Blanco, Gloria; Sánchez, José A.

doi:10.1111/j.1600-0633.1999.tb00065.x

Cited by 36 publications

(37 citation statements)

References 29 publications

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“…Thus, the populations from the Douro basin showed a scarce presence of foreign genes, which resembled that found in the North (mean S | =0·012) and Eastern Pyrenees (mean S | =0·079) basins (Morán et al, 1991(Morán et al, , 1995Martínez et al, 1993;Arias et al, 1995;García-Marín & Pla, 1996;Sanz et al, 2000). Moreover, the genetic introgression in the Douro basin was low compared with the Ebro (mean S | =0·421), Tagus (mean S | =0·233) and Jú car (mean S | =0·109) basins (García-Marín & Pla, 1996;García-Marín et al 1998;Cagigas et al, 1999;Machordom et al 1999). All these Spanish basins 72…”

Section: Discussionmentioning

confidence: 61%

Genetic introgression between wild and stocked brown trout in the Douro River basin, Spain

Almodóvar

Súarez

Nicola

et al. 2001

Journal of Fish Biology

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The genetic diversity of Spanish brown trout is currently threatened by stocking with exogenous brown trout from Central and Northern Europe. In the Douro River basin 25% of the analysed populations in the present study showed introgression by genes of hatchery origin. The mean introgression estimated by the single locus approach (S |) varied from 0 to 22% among populations, with a mean value of 3%. The hatchery allele markers were absent in populations where stocking ceased in 1993. However, the introgression effect was observed in all populations stocked until 1998. It seems that cessation of stocking is a good measure for restoring native populations. A thorough review of published and present data of genetic interactions between wild and stocked brown trout in Spanish rivers indicates different levels of introgression between basins. The absence of a clear geographical pattern in the introgression level suggests that ecological interactions and local stocking programmes may play an important role in stocking success. Finally, several guidelines are provided for conservation and management of native brown trout populations in Spanish rivers. 2001 The Fisheries Society of the British Isles

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Section: Discussionmentioning

confidence: 61%

Genetic introgression between wild and stocked brown trout in the Douro River basin, Spain

Almodóvar

Súarez

Nicola

et al. 2001

Journal of Fish Biology

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“…Our long-term study at Forks Creek, Washington, U.S.A., contributes to a growing literature examining differences in fitness and reproductive success among wild-hatchery and native-nonnative populations, and the consequences of allowing their sympatric spawning (steelhead Leider et al 1990); coho salmon, Oncorhynchus kisutch (Fleming and Gross 1992); brown trout, Salmo trutta (Skaala et al 1996;Cagigas et al 1999;Hansen 2002); Atlantic salmon, Salmo salar (McGinnity et al 1997;Crozier 2000;Fleming et al 2000)). Here we build on our previous results concerning the number of seaward-migrating smolts produced per female from sympatric, naturally spawning hatchery and wild steelhead populations (McLean et al 2003) by examining the differential fitness of these two groups through to the return of their adult offspring.…”

Section: Introductionmentioning

confidence: 99%

Differential reproductive success of sympatric, naturally spawning hatchery and wild steelhead trout (Oncorhynchus mykiss) through the adult stage

McLean¹,

Bentzen²,

Quinn³

2003

Can. J. Fish. Aquat. Sci.

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We used multilocus microsatellite analysis to compare the reproductive success of naturally spawning wild steelhead trout (Oncorhynchus mykiss) with a newly established sympatric hatchery population in Forks Creek, Washington, U.S.A. Hatchery steelhead spawning in the wild had markedly lower reproductive success than native wild steelhead. Wild females that spawned in 1996 produced 9 times as many adult offspring per capita as did hatchery females that spawned in the wild. Wild females that spawned in 1997 produced 42 times as many adult offspring as hatchery females. The wild steelhead population more than met replacement requirements (approximately 3.7-6.7 adult offspring were produced per female), but the hatchery steelhead were far below replacement requirements (<0.5 adults per female). The survival differential was greatest in the freshwater environment (i.e., production of seaward-migrating juveniles), but survival at sea favored the hatchery population in 1 year and the wild population in the next. The poor performance of the hatchery population may be a consequence of spawning too early in the winter, generations of inadvertent domestication selection, or a combination of these two. Résumé :Une analyse des microsatellites à plusieurs locus nous a permis de comparer le succès de la reproduction chez des truites arc-en-ciel anadromes (Oncorhynchus mykiss) sauvages qui frayent naturellement à celui d'une population sympatrique nouvellement établie provenant d'une pisciculture à Forks Creek, Washington, É.-U. Les truites de pisciculture qui frayent en nature ont un succès reproducteur nettement inférieur à celui des truites sauvages indigènes. Les femelles sauvages qui ont frayé en 1996 ont produit 9 fois plus de descendants adultes par femelle que les femelles de pisciculture qui se sont reproduites en nature. En 1997, les femelles sauvages ont produit 42 fois plus de descendants adultes que les femelles de pisciculture. La population sauvage de truite dépasse les taux nécessaires pour le remplacement de la population (environ 3,7-6,7 descendants adultes produits par femelle), mais les truites de pisciculture sont bien en deçà de ces taux (<0,5 adulte par femelle). La différence dans la survie est maximale dans les environnements d'eau douce (i.e., la production des jeunes qui migrent vers la mer), mais la survie en mer a été plus grande une année chez les truites sauvages et l'autre année chez les truites de pisciculture. Il se peut que la piètre performance de la population de pisciculture soit due à une fraye trop hâtive en hiver, ou à des générations de sélec-tion involontaire de domestication, ou alors à une combinaison de ces deux facteurs.[Traduit par la Rédaction] McLean et al. 440

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“…However, limitations in space and time associated with high effective costs have resulted many times in the low success rate of these activities. Furthermore, several studies have reported negative consequences of stocking such as the spread of parasites and diseases (MOFFIT et al, 1998), an increase of competitive interactions (NICKELSON et al, 1986;McMICHAEL and PEARSONS, 1997), and, more recently, genetic introgression (BLANCO et al, 1998;CAGIGAS et al, 1999;ALMODÓVAR et al, 2001). …”

Section: Introductionmentioning

confidence: 99%

Habitat Use by Native and Stocked Trout (Salmo Trutta L.) in Two Northeast Streams, Portugal

Teixeira¹,

Cortes²,

Oliveira³

2006

Bull. Fr. Pêche Piscic.

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Habitat use by stocked and native brown trout (Salmo trutta L.) was assessed in two headwater streams of North-eastern Portugal. Underwater observations were made during the summer season in three successive years to evaluate the effect of supplemental trout stocking. Multivariate analysis techniques applied to data sets on microhabitat use were exploited to identify the focal elevation (distance of fish from the bottom), total depth and cover as the variables that contribute most to the discrimination between stocked and native trout. Preference curves computed for native and stocked trout of the same age (1 + ), showed a distinct pattern in their ability to explore the available microhabitat resources. Stocked trout tended to occupy deeper pools (total depth > 100 cm vs. 60-100 cm for native trout), holding higher focal elevations (140-160 cm vs. < 20 cm for native) with lower water column velocities (< 10 cm.s -1 vs. 10-20 cm.s -1 for native) and no specific preference for cover. In contrast, native trout displayed a clear preference for microhabitats with coarse substrate (particle size > 22.5 cm) and cover (combination of boulders and overhanging vegetation or undercut banks). Furthermore, a high poststocking movement of 80% hatchery-reared fish was verified just one month after their release, suggesting that stocking did not contribute to the sustainable populations in either stream, and is far from being an adequate management technique. Key-words:Salmo trutta, snorkelling, restocking, microhabitat, preference curves. UTILISATION DE L'HABITAT PAR LA TRUITE COMMUNE (SALMO TRUTTA L.) SAUVAGE ET CELLE D'ÉLEVAGE, DANS DEUX RIVIÈRES DU NORD-EST DU PORTUGAL RÉSUMÉL'utilisation de l'habitat par la truite de repeuplement et par la truite commune (Salmo trutta) a été évaluée dans deux rivières du Nord-Est du Portugal. Des observations en plongée ont été faites en période estivale pendant trois années successives pour évaluer l'efficacité des repeuplements. Des techniques d'analyses multivariées appliquées à l'ensemble des données du microhabitat ont permis d'identifier la position Article available at

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Genetic effects of introduced hatchery stocks on indigenous brown trout (Salmo trutta L.) populations in Spain

Cited by 36 publications

References 29 publications

Genetic introgression between wild and stocked brown trout in the Douro River basin, Spain

Genetic introgression between wild and stocked brown trout in the Douro River basin, Spain

Differential reproductive success of sympatric, naturally spawning hatchery and wild steelhead trout (Oncorhynchus mykiss) through the adult stage

Habitat Use by Native and Stocked Trout (Salmo Trutta L.) in Two Northeast Streams, Portugal

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