Discharge-dependent covariation patterns in the population dynamics of brown trout (<i>Salmo trutta</i>) within a Cantabrian river drainage

Lobón‐Cerviá, Javier

doi:10.1139/f04-118

Cited by 83 publications

(77 citation statements)

References 50 publications

(77 reference statements)

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“…Hydrologic influences on brown trout year-class strength have been previously observed mostly in highgradient, mountainous streams in Europe (e.g., Jensen and Johnsen 1999; Cattanéo et al 2002;Lobón-Cerviá 2004;Lobón-Cerviá and Rincón 2004) and in introduced populations from the USA and New Zealand (e.g., Strange et al 1992;Hayes 1995), as well as in low-gradient streams in the USA (Zorn and Nuhfer 2007). All these works pointed out that 0?trout density was negatively influenced by high stream discharge during or shortly after emergence, resulting in weak year-classes.…”

Section: Discussionmentioning

confidence: 99%

“…However, some studies have shown that hydrological variability is also of major importance in determining juvenile density in temperate regions. For instance, functional links between recruitment and hydrological factors have been described for some brown trout populations (e.g., Solomon and Paterson 1980;Jensen and Johnsen 1999;Lobón-Cerviá 2004;Lobón-Cerviá and Rincón 2004). Nowadays, it is widely recognized that the impact of hydrological events does not depend only on their magnitude, but also on their timing and the life stage involved.…”

Section: Introductionmentioning

confidence: 99%

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Influence of hydrologic attributes on brown trout recruitment in low-latitude range margins

2009

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Factors controlling brown trout Salmo trutta recruitment in Mediterranean areas are largely unknown, despite the relevance this may have for fisheries management. The effect of hydrological variability on survival of young brown trout was studied during seven consecutive years in five resident populations from the southern range of the species distribution. Recruit density at the end of summer varied markedly among year-classes and rivers during the study period. Previous work showed that egg density the previous fall did not account for more than 50% of the observed variation in recruitment density. Thus, we expected that climatic patterns, as determinants of discharge and water temperature, would play a role in the control of young trout abundance. We tested this by analyzing the effects of flow variation and predictability on young trout survival during the spawning to emergence and the summer drought periods. Both hatching and emergence times and length of hatching and emergence periods were similar between years within each river but varied considerably among populations, due to differences in water temperature. Interannual variation in flow attributes during spawning to emergence and summer drought affected juvenile survival in all populations, once the effect of endogenous factors was removed. Survival rate was significantly related to the timing, magnitude and duration of extreme water conditions, and to the rate of change in discharge during hatching and emergence times in most rivers. The magnitude and duration of low flows during summer drought appeared to be a critical factor for survival of young trout. Our findings suggest that density-independent factors, i.e., hydrological variability, play a central role in the population dynamics of brown trout in populations from low-latitude range margins. Reported effects of hydrologic attributes on trout survival are likely to be increasingly important if, as predicted, climate change leads to greater extremes and variability of flow regimes.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of hydrologic attributes on brown trout recruitment in low-latitude range margins

2009

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“…Moreover, because of a strong temporal synchrony in the recruitment across sites and streams elucidated in previous studies on these very same year-classes and sites (Lobón-Cerviá 2004), calculating the mean annual recruitment (R a ) and the mean annual CV (CV a ) of juveniles size averaged across sites is pertinent and permits an overall comparison across temporal scales.…”

Section: Discussionmentioning

confidence: 99%

“…Conceivably, enhanced competition may force individuals to disperse in search of profitable sites elsewhere in the stream. However, this seems most unlikely because high densities at a given stream section are linked to high densities all along the streams caused by a strong temporal synchrony in recruitment (see Lobón-Cerviá 2004, 2008 and as a consequence, a full occupation of foraging sites all along the streams. Recent studies (Svanback and Bolnick 2005) have suggested that under the pressure of density dependence when preferred food items become scarce, individuals may feed opportunistically and increase the diversity of prey resulting in increased diet breadth.…”

Section: Discussionmentioning

confidence: 99%

Density dependence constrains mean growth rate while enhancing individual size variation in stream salmonids

Lobón‐Cerviá

2010

Oecologia

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The objective of this study was to elucidate the effects of density dependence on the individual size variation of brown trout (Salmo trutta) juveniles. Recruitment (the abundance of the youngest juveniles in May when they were 2 months old); the mean size attained by those individuals in September (6 months old) and the corresponding size variability around the mean size quantified with the coefficient of variation (CV) were examined in 22 year-classes at seven sites of two contrasting tributaries of the Rio Esva drainage (north-western Spain). Both mean size and CV tended to be site-specific but density dependence in the form of recruitment dependence affected both mean size and CV: the mean size depicted negative power relationships with increased recruitment whereas the CV increased positively with increased recruitment. However, this pattern differed among sites. At two out of seven sites, there was no obvious relationship between the mean size and recruitment. The CV increased positively with increased recruitment at all sites, although at several sites the CV described linear relationships and at others described power relationships. As a consequence, the stronger effects of density dependence on mean size occurred at low densities with minor effects at high densities, whereas density dependence operated on CV with continuous effects within the whole range of recruitment variation except at several sites where lower effects occurred at high densities. Thus, the occurrence, shape and intensity of competitive interactions underlying density dependence as a major cause of size variation differed across temporal and spatial scales.

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“…Por un lado, se han estudiado las relaciones denso-independientes (procesos exógenos) de la trucha común. En este sentido, la influencia hidrológica sobre las clases de edad con altos o bajos periodos de caudales pueden afectar a las densidades de la especie, especialmente a los alevines durante época de incubación o emergencia de las larvas Alonso-González et al, 2008;, al reclutamiento (Lobón-Cerviá y Rincón, 2004;) y a las clases adultas (Lobón-Cerviá, 2004). También se ha averiguado que ciertos modelos de índices de calidad de hábitat para salmones en Canadá, los cuales definen la calidad del hábitat para la especie a partir de las propiedades físicas, explican una pequeña proporción de la variación de las densidades juveniles (Hedger et al, 2004).…”

Section: En Ríos Mediterráneos Resumenunclassified

Estado de las poblaciones de trucha en los ríos de la Comunidad Valenciana y caracterización de sus hábitats

Hernández¹,

Diego²

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Queda prohibida la reproducción, distribución, comercialización, transformación, y en general, cualquier otra forma de explotación, por cualquier procedimiento, de todo o parte de los contenidos de esta obra sin autorización expresa y por escrito de sus autores.A Gisela y Arturo.Mi pequeño clan. AGRADECIMIENTOSMe acuerdo el día en el que conocí a Paco, mi tutor. Él acababa de llegar a la Universidad Politécnica de Valencia como profesor interino, era joven y apenas tenía unos pocos años más que yo. Iba buscando a una persona para trabajar con él. Bastaron unas pocas palabras para convencerme y juntos formamos un pequeño grupo de investigación muy joven, casi adolescentes, si nos comparamos con las largas trayectorias de los científicos. Se debió correr la voz de la creación de este nuevo grupo por lo largo y ancho del planeta, porque al poco llego desde las costas de Chile, un nuevo doctorando, Matías. Mano a mano, estuvimos trabajando durante más de año antes de que llegara Aina (para los amigos Divaina). Paco me introdujo en el fascinante mundo de los ríos y de los peces. A él le debo el que yo haya realizado esta tesis. Mis socios en esta empresa, Paco, Matías y Aina compartieron conmigo mis sueños y mis desvelos, solventados muchas veces con una copita de pacharán. Con el tiempo y poco a poco, el grupo fue creciendo paulatinamente aumentando la calidez humana. Las nuevas incorporaciones de Virginia, Marta, Manu, Rui, Rafa y Julia me aportaron nuevas ideas e ilusiones. A todos ellos, mil gracias.En el largo peregrinaje que es el hacer una tesis me encontré por el camino a mucha gente, que sin pedir nada a cambio me ayudaron desinteresadamente, muchas veces sin que ni ellos lo supieran o se dieran cuenta. Entre ellos está la guardería forestal del Rincón de Ademuz, especialmente a los agentes medioambientales Germán Francés y José Urbano, que aportaron profesionalidad en los trabajos de campo. A Carlos Alonso González, por su ayuda en el cálculo de densidades. De la misma manera, quisiera mencionar a Toni Pradillo y Roberto Coll que consiguieron trasmitirme su gran pasión, la pesca. Además, quisiera agradecer a Roberto Coll por luchar, desde su blog pescaturia, por la dignidad de los ríos mediterráneos y por el estudio genético de las poblaciones de trucha común en ríos valencianos. A Mercedes Arenas, Consuelo Pérez, Pau Lucio, Rafa Casas, Rosa de la Salud, Pascual Puerto, Javier Izquierdo, Jaime Ramos, Laura Gómez, Fran Pardavila, Sasa Plestenjak y Bego Monroig (perdonadme si a alguien no nombro) por transformarse, en las infinitas salidas al campo, en tramperos por unos días para realizar la pesca eléctrica o incluso en buzos (sin escafandra).No quisiera olvidarme de Juan Theureau que desde la Consellería de Medio Ambiente, Agua, Urbanismo y Vivienda de la Generalitat Valenciana de la Generalitat Valenciana consiguió gran parte de la financiación para que esta aventura, que partió con un estudio para la administración, llegara a buen puerto. Como tampoco del profesor Derek H. Orgle (Northland Collage, EE.UU)...

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Discharge-dependent covariation patterns in the population dynamics of brown trout (Salmo trutta) within a Cantabrian river drainage

Cited by 83 publications

References 50 publications

Influence of hydrologic attributes on brown trout recruitment in low-latitude range margins

Influence of hydrologic attributes on brown trout recruitment in low-latitude range margins

Density dependence constrains mean growth rate while enhancing individual size variation in stream salmonids

Estado de las poblaciones de trucha en los ríos de la Comunidad Valenciana y caracterización de sus hábitats

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