81 research outputs found
Edad, crecimiento y reproducción de Gobio gobio L. (Pisces, Cyprinidae) en un tramo regulado del río Segura (SE de España)
The age, growth and reproduction of Gobio gobio, were studied during a period of two years in a section of the Segura River regulated by the effect of a small upstream hydroelectric power station. A total of 254 specimens were caught monthly by electrofishing. The studied population showed a maximum of six age classes in females (0+–5+) and five in males (1+–5+). All females were mature at 2+ age class, whereas only 62.5% 2+ males showed mature gonads. During the studied period, both sexes showed maximum values of Gonadosomatic Index in May and spawn was different between the two studied periods. Compared with other populations, the studied population from a regulated locality is characterized by a non–seasonal body condition cycle and low captures of juvenile fish (0+, 1+) probably due to the effect of washing produced by drastic and unpredictable flow changes.La edad, crecimiento y reproducción de Gobio gobio, ha sido estudiada a lo largo de dos años en un tramo del río Segura regulado por una pequeña central hidroeléctrica. Mediante pesca eléctrica fueron capturados, mensualmente, un total de 254 ejemplares. Las hembras presentaron seis clases de edad (0+–5+) mientras que los machos presentaron cinco clases (1+–5+). Todas las hembras de clase de edad 2+ resultaron maduras mientras que los machos 2+ resultaron maduros en un 62,5% de los casos. Durante el periodo de estudio, ambos sexos presentaron los máximos valores del Índice Gonadosomático durante los meses de mayo aunque el desove resultó diferente entre los dos periodos estudiados. En comparación con otras poblaciones, la población estudiada en un tramo regulado del río se caracteriza por no presentar un ciclo estacional en la condición somática y bajas capturas de ejemplares juveniles (0+, 1+) debido, probablemente, al efecto de lavado provocado por los drásticos e impredecibles cambios en el caudal
Edad y crecimiento de Barbus graellsii Steindachner, 1866 y Chondrostoma miegii, Steindachner, 1866 (Pisces, Cyprinidae) en el río Cinca (cuenca hidrográfica del Ebro, NE España)
The age and growth of two endemic cyprinids from the lberian peninsula were studied for one year in a stretch of the Cinca River. There were caught by electrofishing 279 individuals of B. graellsii and 189 individuals of Ch. miegii. lmmature specimens of both species were not caught probably due to their migratory behaviour during the reproductive period. B. graellsii presented a maximum of 11 age classes in both sexes. Female Ch. miegii live for 8 years and males seven years. Growth was allometric in B. graellsii specimens whereas Ch. miegii showed isometric growth. Females were longer than males in both species. B. graellsii females showed higher growth rates than males whereas Ch. miegii
showed similar growth rates between sexes. B. graellsii males showed a significant increase in condition before the reproductive period and a decrease in condition during this period, while females only showed a significant decrease in condition in July. Ch. miegii females presented dynamics of condition very similar to B. graellsii males.
Key words: Age, Growth, Cyprinidae, Barbus graellsii, Chondrostoma miegii.The age and growth of two endemic cyprinids from the lberian peninsula were studied for one year in a stretch of the Cinca River. There were caught by electrofishing 279 individuals of B. graellsii and 189 individuals of Ch. miegii. lmmature specimens of both species were not caught probably due to their migratory behaviour during the reproductive period. B. graellsii presented a maximum of 11 age classes in both sexes. Female Ch. miegii live for 8 years and males seven years. Growth was allometric in B. graellsii specimens whereas Ch. miegii showed isometric growth. Females were longer than males in both species. B. graellsii females showed higher growth rates than males whereas Ch. miegii
showed similar growth rates between sexes. B. graellsii males showed a significant increase in condition before the reproductive period and a decrease in condition during this period, while females only showed a significant decrease in condition in July. Ch. miegii females presented dynamics of condition very similar to B. graellsii males.
Key words: Age, Growth, Cyprinidae, Barbus graellsii, Chondrostoma miegii.The age and growth of two endemic cyprinids from the lberian peninsula were studied for one year in a stretch of the Cinca River. There were caught by electrofishing 279 individuals of B. graellsii and 189 individuals of Ch. miegii. lmmature specimens of both species were not caught probably due to their migratory behaviour during the reproductive period. B. graellsii presented a maximum of 11 age classes in both sexes. Female Ch. miegii live for 8 years and males seven years. Growth was allometric in B. graellsii specimens whereas Ch. miegii showed isometric growth. Females were longer than males in both species. B. graellsii females showed higher growth rates than males whereas Ch. miegii
showed similar growth rates between sexes. B. graellsii males showed a significant increase in condition before the reproductive period and a decrease in condition during this period, while females only showed a significant decrease in condition in July. Ch. miegii females presented dynamics of condition very similar to B. graellsii males.
Key words: Age, Growth, Cyprinidae, Barbus graellsii, Chondrostoma miegii
Amphibians in the Region of Murcia (SE Iberian peninsula): conservation status and priority areas
The conservation status of amphibian species was studied in the Region of Murcia, taking into consideration 10 variables concerning their biology and distribution. The results obtained show that the amphibian species exposed to the highest risk of extinction in the study area are those with long larval development and a restricted distribution range. According to this species classification, an index is proposed for assessing areas whose conservation is of the highest priority. In the Region of Murcia, most of these areas are located in the main mountain systems, primarily confined to the northwest. Regional Parks and proposed priority conservation areas overlap by only about 12%. The current isolation of these areas makes it necessary to undertake habitat restoration programmes to ensure their interconnection
Life strategy of Atherina boyeri Risso, 1810 (Pisces, Atherinidae) in the Mar Menor coastal lagoon (southeastern Iberian Peninsula)
The present study features the first findings on the biological traits of Atherina boyeri Risso, 1810 in the Mar Menor coastal lagoon (37º 38' N, 0º 42' W). A total of 4241 specimens were studied using samples taken from commercial catches obtained between November 1997 and September 1998. The maximum lengths were 94 mm fork length (LF) in females and 87 mm LF in males. Age determination based on scale readings and validated by length frequency analyses showed a 3-year life cycle. Females were significantly longer than males in each of the age classes. Both sexes attained approximately 56.2 % of their maximum fork length in their immature first year, after which the annual growth rate dropped quickly, probably because their energy was diverted to reproduction. The Von Bertalanffy growth parameters for all individuals were: L∞=83.56 mm, k=0.86 year˄-1, and t0=-0.13 year. Somatic condition was similar for both sexes, with a minimum in June and two maxima in April and November. The hepatic cycle peaked for both males and females in April. The overall sex ratio was 0.87:1 in favour of females. The reproductive period of the species is protracted (March to July), with maxima in April-May.Se presentan los primeros resultados sobre las características biológicas de Atherina boyeri Risso, 1810 en la laguna costera de Mar Menor (37º 38' N, 0º 42' O). Entre noviembre de 1997 y septiembre de 1998 fueron examinados 4 241 ejemplares procedentes de muestras obtenidas de capturas comerciales. Las longitudes máximas observadas fueron 94 mm de longitud furcal (LF) en las hembras y 87 mm LF en los machos. La determinación de la edad, basada en la lectura de escamas y contrastada mediante los análisis de las distribuciones de frecuencias de tallas, puso de manifiesto que la población está estructurada en cuatro clases de edad (máximo 3+). Las hembras fueron significativamente mayores que los machos en todas las clases de edad. Ambos sexos alcanzan aproximadamente el 56,2 % de su longitud furcal máxima en su primer año de vida, tras el cual la tasa de crecimiento anual decrece rápidamente, probablemente porque la mayor parte de la energía es destinada a la reproducción. Los coeficientes de crecimiento de Von Bertalanffy para todos los individuos fueron L∞83,56 mm, k = 0,86 años˄-1 y t0=-0,13 años. La condición somática fue similar en ambos sexos, con un mínimo en junio y máximos en abril y noviembre. En cuanto al ciclo hepático, machos y hembras mostraron un máximo en abril. La proporción de sexos resultó significativamente favorable a las hembras (0,87:1). El periodo reproductor de la especie es dilatado (de marzo a julio), con máximos en abril-mayo.Instituto Español de Oceanografí
Small ponds support high terrestrial bird species richness in a Mediterranean semiarid region
©2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
This document is the Accepted version of a Published Work that appeared in final form in Hydrobiologia. To access the final edited and published work see https://doi.org/10.1007/s10750-021-04552-7Ponds are among the world’s most endan gered freshwater ecosystems. A comprehensive
knowledge of pond biodiversity is urgently required
to inform effective pond management and conserva tion actions. Most studies about pond biodiversity
focus on aquatic taxa, while the terrestrial biodiver sity, especially of birds, has been little studied.
Moreover, the few studies existing on pond biodiver sity do not account for different detection rates of
species, thus yielding biased results. Here, we apply a
hierarchical Bayesian modelling technique to data
obtained from visual censuses to estimate bird species
richness associated with small ponds in a semiarid
region, considering the imperfect detection of species.
The model incorporates specific responses to site
characteristics (pond typology), landscape (environ mental heterogeneity) and at regional scale (mean
annual precipitation). The studied ponds were used by
two thirds of the terrestrial breeding bird community
of the study region. Our modelling approach increased
by an average of 7.5 species the observed site-specific
richness. Drinking troughs supported a greater rich ness than other pond types. Environmental hetero geneity was positively related with species richness,
whereas no clear relation was observed between
richness and precipitation. In addition to ecosystem
services provided by ponds to human welfare, our
results suggest these small isolated habitats may act as
key landscape elements for terrestrial birds in semiarid
regions
Habitat quality affects the condition of Luciobarbus sclateri in the Guadiamar River (SW Iberian Peninsula): Effects of disturbances by the toxic spill of the Aznalcóllar mine
This study analyzes the somatic condition of southern Iberian barbel Luciobarbus sclateri (Günther, 1868) in the Guadiamar River (SW Iberian Peninsula). This river was seriously affected by a toxic spill of about 4 million cubic meters of acidic water and 2 million cubic meters of mud rich in heavy metals. Once the spill removal works concluded, sites affected and unaffected by the accident were sampled to study its effects on the fish fauna. The ecological variables registered were related to water quality, physical state of reaches, ecological quality, resources exploited by fish, and potential intra-specific interactions. From an initial 15 ecological variables, seasonal water flow and pH explained most of the variation in barbel condition. This study shows that the Guadiamar River, 56 months after the accident, is still undergoing a recovery process where, beyond ecological variables, proximity to the affected area is the most influential factor for fish condition. © 2012 Springer Science+Business Media B.V
Awareness and Prevention of Aquatic Invasive Alien Species in the Iberian Peninsula by LIFE INVASAQUA: Midterm Outcomes
The Iberian society has a limited understanding of the threats posed by invasive alien species (IAS) in aquatic ecosystems. This lack of knowledge and awareness about IAS problems hampers any management policy proposed by public administration and stakeholders, contributing to missing an IAS management strategy. We present the midterm outcomes of the Environmental Governance and Information LIFE project—LIFE INVASAQUA—that will run between 2018 and 2023 in the Iberian Peninsula. The main goal of INVASQUA is to increase the Iberian public and stakeholders’ awareness of aquatic IAS problems and to develop tools that will improve an efficient early warning and rapid response (EWRR) framework for new IAS in freshwater and estuarine habitats in the Iberian Peninsula. We focus on new challenges and outcomes of the project to explore some of the problems and solutions encountered in the project implementation
Strategic Recommendations for the Transnational Management of Invasive Alien Crayfish and Crabs in Iberian Inland Waters
An important goal of LIFE INVASAQUA is to develop tools that will improve management and increase the efficiency of the Early Warning and Rapid Response framework for Invasive Alien Species (IAS) in the Iberian Peninsula. We developed a participative process with experts in order to obtain Strategic Recommendations for the
transnational management of invasive alien crayfish and crabs in inland waters of Spain and Portugal. They promote the coordinated management between Spain and Portugal, in order to facilitate implementation of international commitments and best practices and to support development of policies and targets on IAS management
at Iberian scale. They were designed to serve as a guiding tool seeking to identify a strategic direction for the
Spanish and Portuguese governance that is already being developed. The resulting Strategic Recommendations
are important tools supporting the implementation of the IAS EU Regulation. Ultimately, the information included can be used for achieving the target of the EU Biodiversity Strategy to 2030 for combatting IAS, and also for
implementing of other EU policies with requirements on alien species, such as the Birds and Habitats Directives,
and the Marine Strategy and Water Framework Directives
RECOMENDAÇÕES ESTRATÉGICAS PARA A GESTÃO TRANSNACIONAL DE LAGOSTINS E CARANGUEJOS EXÓTICOS INVASORES NAS ÁGUAS INTERIORES DA PENÍNSULA IBÉRICA
Um objetivo importante do LIFE INVASAQUA é desenvolver ferramentas que melhorem a gestão e aumentem a eficácia no Alerta Precoce e Resposta Rápida para Espécies Exóticas Invasoras (EEI) na Península Ibérica. Desenvolvemos um processo participativo com especialistas para obter recomendações estratégicas para a gestão transnacional de lagostins e caranguejos exóticos invasores em águas continentais de Espanha e Portugal. As recomendações foram concebidas para servir de instrumento orientador para identificar uma direção estratégica seguindo a governação espanhola e portuguesa que já está a ser desenvolvida. As recomendações resultantes são uma ferramenta importante para apoiar a implementação do Regulamento EEI da UE. Em última análise, as informações incluídas podem ser utilizadas para atingir a meta da Estratégia de Biodiversidade da UE para 2030 de combate às espécies exóticas invasoras, e também para a implementação de outras políticas da UE com requisitos relativos a espécies exóticas, como as Diretiva Aves e Habitats, Diretiva-Quadro da Estatégia Marinha (DQEM) e Diretiva-Quadro da Água (DQA)
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