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Non-native Fishes (non-native + fish)
Terms modified by Non-native Fishes Selected AbstractsRole of Genetic Refuges in the Restoration of Native Gene Pools of Brown TroutCONSERVATION BIOLOGY, Issue 4 2009ROSA M. ARAGUAS introgresión de piscifactoría; pautas de manejo; acervos génicas nativas; refugios genéticos; repoblación de peces Abstract:,Captive-bred animals derived from native, alien, or hybrid stocks are often released in large numbers in natural settings with the intention of augmenting harvests. In brown trout (Salmo trutta), stocking with hatchery-reared non-native fish has been the main management strategy used to maintain or improve depleted wild brown trout populations in Iberian and other Mediterranean regions. This measure has become a serious threat to the conservation of native genetic diversity, mainly due to introgressive hybridization. Aware of this risk, the agency responsible for management of brown trout in the eastern Pyrenees (Spain) created "brown trout genetic refuges" to preserve the integrity of brown trout gene pools in this region. Within refuge areas, the prerefuge status with respect to fishing activities has been maintained, but hatchery releases have been banned completely. We evaluated this management strategy through a comparison of the stocking impact on native populations that accounted for stocking histories before and after refuge designations and fishing activities. In particular we examined the relevant scientific, cultural, and political challenges encountered. Despite agency willingness to change fishery policies to balance exploitation and conservation, acceptance of these new policies by anglers and genetic monitoring of refuge populations should also be considered. To improve management supported by genetic refuges, we suggest focusing on areas where the public is more receptive, considering the situation of local native diversity, and monitoring of adjacent introgressed populations. We recommend the use of directional supportive breeding only when a population really needs to be enhanced. In any case, management strategies should be developed to allow for protection within the context of human use. Resumen:,Animales criados en cautiverio derivados de individuos nativos, exóticos o híbridos a menudo son liberados en grandes cantidades en ambientes naturales con la intención de incrementar su explotación. En la trucha común (Salmo trutta), la repoblación con peces no nativos criados en granjas ha sido la principal estrategia de manejo utilizada para mantener o mejorar poblaciones naturales de trucha común en la Peninsula Ibérica y otras regiones Mediterráneas. Esta medida se ha convertido en una seria amenaza para la conservación de la diversidad genética nativa, debido principalmente a la hibridación introgresiva. Consciente de este riesgo, la agencia responsable del manejo de la trucha común en los Pirineos orientales (España) creó"refugios genéticos de trucha común" para preservar la integridad de las acervos genéticos de trucha común en esta región. Dentro de las áreas de refugio, se ha mantenido el estatus previo al refugio con respecto a las actividades pesqueras pero las liberaciones de peces de piscifactoría han sido completamente prohibidas. Evaluamos esta estrategia de manejo mediante la comparación del impacto de la repoblación sobre las poblaciones nativas que registraron historias de repoblación antes y después de la designación de refugios y de actividades pesqueras. En particular, examinamos los significativos retos científicos, culturales y políticos que encontramos. A pesar de la disponibilidad de la agencia para cambiar las políticas de pesca hacia un equilibrio entre la explotación y la conservación, también se debe considerar la aceptación de estas nuevas políticas por los pescadores y el monitoreo genético de las poblaciones en los refugios. Para mejorar el manejo en los refugios genéticos sugerimos centrarse en las áreas donde el público es más receptivo, considerando la situación de la diversidad nativa local y el monitoreo de las poblaciones introgresadas adyacentes. Recomendamos la utilización de la cría de apoyo direccional solo cuando una población realmente requiera ser mejorada. En cualquier caso, se deberían desarrollar estrategias de manejo para permitir la protección en el contexto del uso por el hombre. [source] Indirect facilitation of an anuran invasion by non-native fishesECOLOGY LETTERS, Issue 4 2003Michael J. Adams Abstract Positive interactions among non-native species could greatly exacerbate the problem of invasions, but are poorly studied and our knowledge of their occurrence is mostly limited to plant-pollinator and dispersal interactions. We found that invasion of bullfrogs is facilitated by the presence of co-evolved non-native fish, which increase tadpole survival by reducing predatory macroinvertebrate densities. Native dragonfly nymphs in Oregon, USA caused zero survival of bullfrog tadpoles in a replicated field experiment unless a non-native sunfish was present to reduce dragonfly density. This pattern was also evident in pond surveys where the best predictors of bullfrog abundance were the presence of non-native fish and bathymetry. This is the first experimental evidence of facilitation between two non-native vertebrates and supports the invasional meltdown hypothesis. Such positive interactions among non-native species have the potential to disrupt ecosystems by amplifying invasions, and our study shows they can occur via indirect mechanisms. [source] Non-salmonids in a salmonid fishway: what do 50 years of data tell us about past and future fish passage?FISHERIES MANAGEMENT & ECOLOGY, Issue 5 2007M. MALLEN-COOPER Abstract, Salmonid fishways have been used in many countries for non-salmonid fishes, including Australia, but generally with poor results. Trapping the entrance and exit of a 1:9 gradient salmonid fishway on the Murray River confirmed very poor passage of native fish, with <1% of the most abundant species ascending. Fifty years of fish passage monitoring showed the numbers of three native species declining by 95,100% and non-native fish becoming dominant. Fishways are now being designed for native fish and being quantitatively assessed, but daily flow management also needs to be addressed. The ecological model for passage of potamodromous fishes has changed from passing adults of a few species to one that incorporates the whole fish community, specifically: immature fish of large-bodied species that dominate numbers migrating upstream; a diverse range of movement strategies; and small-bodied species, crustaceans and low numbers of less-mobile species. [source] A molecular approach to detect hybridisation between crucian carp (Carassius carassius) and non-indigenous carp species (Carassius spp. and Cyprinus carpio)FRESHWATER BIOLOGY, Issue 3 2005B. HÄNFLING Summary 1. Releases of non-native fish into the wild is an increasing problem posing considerable ecological and genetic threats through direct competition and hybridisation. 2. We employed six microsatellite markers to identify first generation hybrids and backcrosses between native crucian carp (Carassius carassius) and introduced goldfish (C. auratus) and common carp (Cyprinus carpio) in the U.K. We also investigated the genetic characteristics of the taxonomically controversial gibel carp (Carassius spp.) from sites across Europe. 3. Natural hybridisation between goldfish and crucian carp occurs frequently, although hybrids between all other species pairs were observed. Only 62% of British crucian carp populations (n = 21) consisted exclusively of pure crucian carp. In some populations hybrids were so frequent, that no pure crucian carp were caught, indicating a high competitive ability of hybrids. 4. Most hybrids belonged to the F1 generation but backcrossing was evident at a low frequency in goldfish × crucian carp hybrids and goldfish × common carp hybrids. Furthermore, some local populations had high frequencies of backcrosses, raising the opportunity for introgression. 5. Gibel carp from Germany and Italy belonged to two triploid clonal lineages that were genetically closely related to goldfish, whereas all individuals identified from British populations proved to be crucian carp × goldfish hybrids. 6. Our study suggests that the release of closely related exotic cyprinids not only poses a threat to the genetic integrity and associated local adaptations of native species, but may also contribute to shifts in community structure through competitive interactions. [source] Indirect facilitation of an anuran invasion by non-native fishesECOLOGY LETTERS, Issue 4 2003Michael J. Adams Abstract Positive interactions among non-native species could greatly exacerbate the problem of invasions, but are poorly studied and our knowledge of their occurrence is mostly limited to plant-pollinator and dispersal interactions. We found that invasion of bullfrogs is facilitated by the presence of co-evolved non-native fish, which increase tadpole survival by reducing predatory macroinvertebrate densities. Native dragonfly nymphs in Oregon, USA caused zero survival of bullfrog tadpoles in a replicated field experiment unless a non-native sunfish was present to reduce dragonfly density. This pattern was also evident in pond surveys where the best predictors of bullfrog abundance were the presence of non-native fish and bathymetry. This is the first experimental evidence of facilitation between two non-native vertebrates and supports the invasional meltdown hypothesis. Such positive interactions among non-native species have the potential to disrupt ecosystems by amplifying invasions, and our study shows they can occur via indirect mechanisms. [source] To be, or not to be, a non-native freshwater fish?JOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2005G. H. Copp Summary We examine the evolving concept of what constitutes a non-native (or alien) freshwater fish. In an attempt to distinguish between biogeographical and socio-political perspectives, we review the patterns in the introduction and dispersal of non-native fishes in Europe and North America, and especially the recent expansion of Ponto-Caspian gobies in Europe. We assess patterns in the development of national policy and legislation in response to the perceived threat of non-native fish introductions to native species and ecosystems. We review, and provide a glossary of, the terms and definitions associated with non-native species. Finally, we discuss perspectives as regards the future treatment of naturalized species. [source] A review of changes in the fish assemblages of Levantine inland and marine ecosystems following the introduction of non-native fishesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2005M. Goren Summary The arrival of non-native fishes in the Levant Basin began in the late 19th century. Whereas the presence of most of the 40 non-native freshwater fishes stem from intentional introductions, either for aquaculture or pest control, the 62 species of non-native marine fishes arrived by natural dispersal via the Suez Canal. Of the non-native freshwater species, five have established successful breeding populations (mosquitofish Gambusia affinis, common carp Cyprinus carpio, crucian carp Carassius carassius, swordtail Xiphophorus hellerii and rainbow trout Oncorhynchus mykiss), and seven are regularly stocked in natural habitats (thinlip mullet Liza ramada, flathead mullet Mugil cephalus, European eel Anguilla anguilla, grass carp Ctenopharyngodon idella, Asian silver carp Hypophthalmichthys molitrix, bighead carp Aristichthys nobilis, black carp Mylopharyngodon piceus). Some non-native species appear to have out-competed native species. Gambusia affinis may have caused the extirpation of two native cyprinid fishes from the Qishon River basin (Levant silver carp Hemigrammocapoeta nana and common garra Garra rufa) and the southern Dead Sea (endemic Sodom's garra G. ghoerensis). The opening of the Suez Canal in 1869 allowed entry into the eastern Mediterranean of Indo-Pacific and Erythrean biota, with the latter now dominating the community structure (50,90% of fish biomass) and function (altered native food web) of the Levantine littoral and infra-littoral zones. The process has accelerated in recent years concurrent with a warming trend of the seawater. Record numbers of newly discovered non-native species is leading to the creation of a human-assisted Erythrean biotic province in the eastern Mediterranean. [source] The demography of introduction pathways, propagule pressure and occurrences of non-native freshwater fish in EnglandAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2010G. H. Copp Abstract 1.Biological invasion theory predicts that the introduction and establishment of non-native species is positively correlated with propagule pressure. Releases of pet and aquarium fishes to inland waters has a long history; however, few studies have examined the demographic basis of their importation and incidence in the wild. 2.For the 1500 grid squares (10×10,km) that make up England, data on human demographics (population density, numbers of pet shops, garden centres and fish farms), the numbers of non-native freshwater fishes (from consented licences) imported in those grid squares (i.e. propagule pressure), and the reported incidences (in a national database) of non-native fishes in the wild were used to examine spatial relationships between the occurrence of non-native fishes and the demographic factors associated with propagule pressure, as well as to test whether the demographic factors are statistically reliable predictors of the incidence of non-native fishes, and as such surrogate estimators of propagule pressure. 3.Principal coordinates of neighbour matrices analyses, used to generate spatially explicit models, and confirmatory factor analysis revealed that spatial distributions of non-native species in England were significantly related to human population density, garden centre density and fish farm density. Human population density and the number of fish imports were identified as the best predictors of propagule pressure. 4.Human population density is an effective surrogate estimator of non-native fish propagule pressure and can be used to predict likely areas of non-native fish introductions. In conjunction with fish movements, where available, human population densities can be used to support biological invasion monitoring programmes across Europe (and perhaps globally) and to inform management decisions as regards the prioritization of areas for the control of non-native fish introductions. © Crown copyright 2010. Reproduced with the permission of her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. [source] Fish movements: the introduction pathway for topmouth gudgeon Pseudorasbora parva and other non-native fishes in the UKAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2010G. H. Copp Abstract 1.The contamination of fish consignments (for stocking or aquaculture) is a major pathway by which non-native organisms, including fish, are introduced to new areas. One of the best examples of this is the topmouth gudgeon Pseudorasbora parva, which was accidentally imported into Romania and then throughout Europe in consignments of Asian carp species. 2.The introduction and spread of topmouth gudgeon in the UK has been linked to imports and movements of the ornamental variety (golden orfe) of ide Leuciscus idus. To examine this hypothesis, relationships between authorized movements of both native and non-native fish species (in particular ide) and the occurrence in England of topmouth gudgeon were tested at the 10×10,km scale. 3.Topmouth gudgeon occurrence in the wild was significantly correlated with the trajectories of movements of ornamental fish species (ide/orfe, sunbleak Leucaspius delineatus) as well as a few non-ornamental fish species (European catfish Silurus glanis, Atlantic salmon Salmo salar and grass carp Ctenopharyngodon idella). 4.These results highlight the mechanism by which non-native fish species disperse from the point of first introduction, and especially that movements of fish within the country represent an important mechanism for accidental introductions of non-native species. © Crown copyright 2010. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. [source] | |||||||||||||