Naiads and fish, coupled destiny: the case of basins of north-eastern Catalonia

Póster presentado en: 2nd International Seminar Rearing of unionoid mussels (Clervaux, Luxembourg - Tuesday 24th November – Friday 27th November 2015)Native unionids are among the most threatened groups, as a whole, of the fauna of the Iberian continental waters. Most species are currently in regression, and in fact many of these are cataloged at some level of threat, whether international, national or regional level. Several factors explain this situation, including the destruction or alteration of river habitats and declining water quality, but also the degradation of fish communities. In north-eastern Catalonia four species of naiads are considered native: Potomida littoralis, Unio mancus, Unio ravoisieri and Anodonta anatina. The conservation status of these species in Catalonia is uneven, but generally we can consider all of them highly threatened, given the clear regression observed in their distribution. Much of the historical citations are probably missing at present, or have become residual populations with very low population densities and often on the verge of local extinction due to lack of recent recruitment. In north-eastern Catalonia P. littoralis is in the worst situation, with only four known small populations, with a few observed living animals in each site. On the other hand, recently has been detected an exotic naiad, Sinanodonta woodiana, which is currently expanding. We give a general revision of the known populations of naiads on the area, on the basis of their current structure, and in relation with the recent evolution of local fish communities. In general, it is confirmed that the few native unionid populations with current regular recruitment are placed on river stretches with not severely modified fish communities. These fish communities are characterized by a stable presence of at least one native fish species, and also in general by the absence of exotic fish species, or at most a not stable presence. In contrast, the exotic S. woodiana is now expanding in areas where original fish communities are nowadays strongly altered, often without native fish species.Peer reviewe

Expansion of the exotic unionid Sinanodonta woodiana in low Ter River flood plain (Catalonia)

Póster presentado en: 2nd International Seminar Rearing of unionoid mussels (Clervaux, Luxembourg - Tuesday 24th November – Friday 27th November 2015)In the northeast Catalonia, 4 native unionid species have been cited: Potomida littoralis (Cuvier, 1798), Unio mancus Lamarck, 1819, Unio ravoisieri Deshayes, 1847, and Anodonta anatina (L, 1758). Recently the exotic Sinanodonta woodiana (Lea, 1834), has been cited on Ter and Fluvià rivers. Between 1995 and 2014, several specific surveys were carried out, always below the Pasteral dam, both in the Ter river and in several of its tributaries, including Lake Banyoles. Moreover, from 2010 to 2014 a thorough freshwater bivalves prospection campaign was performed in the alluvial plain of lower Ter, including the river and secondary water masses, mainly irrigation channels associated with the traditional system of agricultural irrigation. The prospections were done by manually on the river bed bottom. All over since 2010 a total of 90 sampling stations has been surveyed in this alluvial plain. Status of native species is precarious, with populations intensely fragmented, and densities often low and heavily aged for lack of recruitment. This situation is clearly attributable to the severe rarefaction of native fish species, since in some areas even completely inexistent. In contrast, the exotic S. woodiana is expanding and occupies already the whole alluvial plain and the lower course of the Ter river, where it is very abundant. Moreover, S. woodiana presents a well-structured global population in the alluvial plain of Ter River and a regular recruitment can be observed thanks to the fact that several exotic fish species are abundant in the area, are potential hosts to them. This exotic unionoid appeared in most of the surveyed localities (81%), and was present in all the types of water bodies surveyed. In 16 % of the localities it was the only unionoid found, and it was present in all of the localities were other unionoid species were present. Specimens of this exotic species found alive constituted the 72 % of the total of alive unionoids collected during the surveying campaigns. Besides this species were quantitatively dominant in the whole of the alluvial plain. Therefore, it is the most spread and abundant unionoid species at present, often with very high densities. It presented a continuous distribution in the lower Ter river basin, as well as in the main irrigation canals.Peer reviewe

Eliminación de peces introducidos como medida de restauración de lagos de alta montaña

E. Carrillo, J. Ninot, T. Buchaca and M. Ventura. Blanes, LIFE+ LIMNOPIRINEUS Technical OfficeEntre los objetivos del proyecto LIFE+ LimnoPirineus (2014-2019) figuraban la restauración ecológica de ocho lagos pirenaicos y la recuperación o mejora de las poblaciones de diversas especies de interés comunitario de estos lagos, mediante la erradicación o el control intensivo de peces introducidos de hasta cuatro especies. En la mayor parte de lagos el objetivo operativo ha sido la erradicación, mientras que tan solo en uno de ellos el objetivo pasaba simplemente por llevar a cabo un control intensivo hasta alcanzar al menos una reducción del 75 % de la población inicial. A finales de 2019, estos objetivos se han alcanzado completamente para cinco de los lagos de actuación, mientras que en los otros tres lagos están cerca de alcanzarse, cosa que sucederá probablemente antes de finales de 2020. Se han puesto a punto métodos de extracción de peces basados en la combinación de hasta tres técnicas de captura principales: redes, trampas y pesca eléctrica. Se demuestra que la erradicación de los peces es factible en muchos lagos de alta montaña con una inversión suficiente en medios materiales y humanos, y con una adecuada planificación de las operaciones. Cuando no es factible la erradicación, el control intensivo mediante un esfuerzo sostenible en el tiempo es también una alternativa que cabe considerar a medio plazo.Peer reviewe

Síndrome de edema en Lissotriton helveticus salvajes del Pirineo y su entorno

Este artículo contiene 5 páginas, 2 figuras.Peer reviewe

Fluid composition changes in crystalline basement rocks from ductile to brittle regimes

The relationships between deformation and fluid flow have been investigated in the Paleozoic basement of an isolated horst of the Catalan Coastal Ranges. A structural, petrological and geochemical study has been performed in a complex fracture network that resulted from a long-lived tectonic history (from Carboniferous to Miocene). Nine fracture types, developed from a ductile regime in the greenschist facies to a shallow brittle regime, have been characterized in order to establish P, T and fluid compositions during the evolution of the horst. Syn-cleavage and late-cleavage quartz veins (qtz1-chl1 ± mu and late qtz2-chl2-dol1) formed during the Hercynian ductile deformation. These minerals precipitated from metamorphic fluids, possibly evolved from seawater, at temperatures between 240 and 340 °C. En-echelon albite vein arrays (ab-qtz3-chl3 ± ti-an) and NE-SW normal faults generating breccias mark the change from ductile to brittle, from compression to extension and from a closed to an open hydrologic regime. This paragenesis precipitated from the mixing of metamorphic and magmatic fluids at temperatures between 180 and 290 °C during the early Permian extension. Dolomite veins (dol2-chl4-qtz4), precipitated at 210–280 °C from the mixing of previous fluids with hypersaline oxidizing external brines, possibly during the late stage of the early Permian extension. Reverse faults and calcite veins (Cc1-ba) formed either during the Paleogene compression or during the Langhian to early Serravallian minor compression. Calcite and barite precipitated from meteoric or marine waters in an open hydrological system at temperatures below 50 °C. The Miocene extension is represented by NE-SW normal faults with fault gouges and NNW-SSE normal faults cemented by calcite 2 that precipitated at temperatures below 50 °C from meteoric fluids in an open basin-scale hydrological system. The studied horst was part of a relay zone between two segments of the NNW-SE Llobregat fault during the early Permian, explaining the high fracture density and the fast upflowing of hydrothermal fluids at that time, thus controlling the development of albite veins exclusively in this area

Minnow introductions in mountain lakes result in lower salmonid densities

Este artículo contiene 5 páginas, 3 figuras.Small fish species such as minnows (Phoxinus sp.) are introduced into mountain lakes by anglers that use them as live bait for fishing salmonids that were previously introduced in these naturally fishless habitats. Introduced fish severely impact native biota but minnows are nevertheless released believing to provide forage for game fish, i.e., salmonids. However, our results indicate that minnows negatively interact with game fish, reducing their relative densities. On some occasions, minnows can remain the only present fish following trout extinction. We believe that this information should be urgently disseminated among anglers as a pragmatic argument to also convince anglers less sensitive to conservation issues that carrying minnows to the mountains is not a good idea whatever the main interest is, e.g., nature conservation or outdoor recreation.Funding was provided by the EU Projects LIFE BIOAQUAE (LIFE11 BIO/IT/000020) and LIFE LIMNOPIRINEUS (LIFE13 NAT/ES/001210), LIFE RESQUE ALPYR (LIFE20 NAT/ES/000369), MONOCLE (H2020-CLIMATE/ 0357), and Biodiversa FISHME (BiodivRestor-280), and by the Spanish Government projects FUNBIO (RTI2018- 096217-B-I00) and BIOOCULT (2413/2017).Peer reviewe

Estat de conservació del cavilat (Cottus hispaniolensis) a la Val d’Aran

E. Carrillo, J. Ninot, T. Buchaca and M. Ventura. Blanes, LIFE+ LIMNOPIRINEUS Technical OfficeEl cavilat (Cottus hispaniolensis) és un dels peixos continentals més amenaçats de Catalunya i Espanya. La seva situació a la Val d’Aran va empitjorar dràsticament arran de les riuades del 2013, fins al punt d’arribar pràcticament a desaparèixer. Des d’aleshores, les poblacions s’han anat recuperant progressivament, amb un lent increment de la seva densitat mitjana i de les localitats ocupades. En part, aquesta recuperació s’ha produït gràcies a actuacions emmarcades en el projecte LIFE+ LimnoPirineus, que s’han dissenyat específicament per a la recuperació d’aquesta espècie dins l’espai de la xarxa Natura 2000 «Aigüestortes » (ES0000022).Peer reviewe

Estado de conservación del cavilat (Cottus hispaniolensis) en el valle de Arán

E. Carrillo, J. Ninot, T. Buchaca and M. Ventura. Blanes, LIFE+ LIMNOPIRINEUS Technical OfficeEl cavilat (Cottus hispaniolensis) es uno de los peces continentales más amenazados de Cataluña y España. Su situación en el valle de Arán empeoró drásticamente a raíz de las riadas del 2013, hasta el punto de llegar a su práctica desaparición. Desde entonces, sus poblaciones se han ido recuperando progresivamente, con un lento incremento de su densidad media y de las localidades ocupadas. En parte, esta recuperación se ha producido gracias a actuaciones enmarcadas dentro del proyecto LIFE+ LimnoPirineus, que se han diseñado específicamente para la recuperación de esta especie dentro del espacio de Red Natura 2000 de Aigüestortes (ES0000022).Peer reviewe

Conservation status of the pyrenean sculpin (cottus hispaniolensis) in the Aran Valley

E. Carrillo, J. Ninot, T. Buchaca and M. Ventura. Blanes, LIFE+ LIMNOPIRINEUS Technical OfficeThe Pyrenean sculpin (Cottus hispaniolensis) is one of the most threatened freshwater fish in Catalonia and Spain. Its status in the Aran Valley drastically deteriorated as a result of the floods of 2013, to the point of reaching its practical disappearance. Since then, their populations have been progressively recovering, with a slow increase in their average density and occupied localities. In part, this recovery has been produced thanks to actions framed within the LIFE+ LimnoPirineus project, which have been specifically designed for the recovery of this species within the Natura 2000 network space “Aigüestortes” (ES0000022).Peer reviewe

Evaluation of visual encounter surveys as a method for the rapid assessment of fish presence and relative density in high mountain lakes

Este artículo contiene 9 páginas, 5 figuras, 1 tabla.1. Introduced fish are a widespread ecological threat in originally fishless high mountain lakes. However, basic distribution data are largely missing for most high mountain regions. 2. Using time-consuming standard methods (e.g. Nordic standard fishing nets) to assess fish distribution and relative densities at a relevant spatial scale can be impracticable, because of the large number of high mountain lakes. To overcome this problem, alternative rapid monitoring methods would be helpful. 3. Visual encounter survey (VES) is a candidate method that enables observing fish from the shoreline. It takes only minutes to implement and is already widely used for amphibian monitoring in high mountain lakes and ponds. VES was evaluated as a method for monitoring introduced salmonids and cyprinids (the most widespread fish families) in 52 high mountain lakes. 4. The probability of detecting both families by VES rapidly approaches 100% as the relative densities of fish increase, and false absences are restricted to populations living at low relative densities. VES also provides simple indications about fish relative densities, distinguishing between high-density and low-density populations. 5. As VES usually does not enable fish species identifications, we propose VES as a useful method to describe large fish distribution inventories, not needing high taxonomic detail, but necessary for planning large-scale conservation measures.Funding was provided within the framework of the EU Projects LIFE BIOAQUAE (LIFE11 BIO/IT/000020), LIFE LIMNOPIRINEUS (LIFE13 NAT/ES/001210), LIFE RESQUE ALPYR (LIFE20 NAT/ES/000369), and Biodiversa FISHME (BiodivRestor-280), and of the Spanish Government projects FUNBIO (RTI2018-096217-B-I00) funded by MCIN/AEI/10.13039 and BIOOCULT (2413/2017) funded by MTERD/OAPN and by “ERDF A way of making Europe.” Additional funding was provided by the Confederaci on Hidrográfica del Ebro, Mont Avic Natural Park, and the University of Pavia.Peer reviewe