Ex-situ breeding of native unionids in Lake Banyoles (Spain) as part of a LIFE project

Póster presentado en: 2nd International Seminar Rearing of unionoid mussels (Clervaux, Luxembourg - Tuesday 24th November – Friday 27th November 2015)Lake Banyoles is the second largest natural lake in the Iberian Peninsula and is one of the first places in the Iberian Peninsula where massive planned fish introductions have taken place. The proliferation of alien fish species explains the current scarcity of the native species that are the natural hosts of the parasitic larvae of unionids. This situation has led to a dramatic regression in the four native unionid species found in this lake (Unio mancus, U. ravoisieri, Potomida littoralis and Anodonta anatina). As a result of management geared towards the preservation of natural heritage, the ecological quality of this site has improved in recent decades. However, the main challenge for the management of the lake and its surrounding areas is now posed by invasive alien species. Projecte Estany (LIFE 08/NAT/E/000078) was a four-year project (2010–2013) whose main aim was to design and implement a large-scale intervention actions that would combat, slow down and revert the decline in species and habitats of Community Interest via (1) the control of invasive alien species, (2) the strengthening of populations of seriously threatened native species, and (3) the restoration of key patches of riparian habitats. As part of the project to recover populations of two Unio species, a breeding laboratory was set up. During the first years of the project, several methodologies were tested to obtain mussel glochidia (larvae), optimize fish infection and design a methodology for fattening juveniles. Up to three different native fish species were tested as hosts for local Unio larvae: Barbus meridionalis, Squalius laietanus and Salaria fluviatilis. All demonstrated their capacity to act as hosts and release viable juveniles; however, due to their larger size, only the first two species are used for intensive mussel breeding, along with Luciobarbus graellsii. Between 2011 and 2013, a total of 108,875 U. mancus and 27,423 U. ravoisieri juveniles were produced via the artificial infection of host fish with larvae grown in a number of semi-natural sequential breeding systems fed by water and sediment from their natural habitats, pools, plastic outdoor channels, and/or cages. In the tested systems, U. mancus reached a mean length of 9.7 mm (SD_1.53) in one year and 12.4 mm (SD_1.55) in two years; for U. ravoisieri these values were 15.8 (SD_0.76) and 21.2 mm (SD_2.45). In the context of the further four years (2014-17) allotted to the project (LIFE Potamo Fauna, LIFE12 NAT/ES/001091), efforts to breed Unio species in this laboratory, which has been enlarged, will continue. We will describe the results of the different juveniles’ collection systems and the facilities created to improve their growth over the past six years. The protocols implemented, the current installations and the results of the captive breeding of Unio species are shown here.Peer reviewe

Fish ecology in Lake Banyoles (NE Spain): a tribute to Ramon Margalef

Lake Banyoles is the second largest lake in the Iberian Peninsula and due to this relative uniqueness, its peculiar geological origin, and its considerable age attracted the early attention of the late Professor Ramon Margalef. One of the first papers by Margalef was on the biota of Lake Banyoles and two of the first four Ph.D. theses that he supervised were about the limnology of this lake. Unfortunately, the uniqueness of this lake also implied that it was the first place of introduction into the Iberian Peninsula of several exotic fish species, early in the XXth Century and nowadays the lake fish assemblage is dominated by invasive species, and some native ones have been extirpated. Although the limnological studies in Lake Banyoles were pioneering within the Iberian Peninsula, studies on fish ecology of the lake did not start until 1989. Thereafter, four Ph.D. theses have been completed on different aspects of the fish assemblages of Lake Banyoles. The aim of this paper is to provide a short overview of this research, largely brought about by the considerable limnological information previously available for this lake, thanks to the insightful, pioneering work of Professor Margalef.El lago de Banyoles es el segundo mayor lago de la Península Ibérica y debido a su relativa singularidad, su peculiar origen geológico y su considerable edad atrajo la atención temprana del fallecido profesor Ramon Margalef. Uno de las primeras publicaciones de Margalef fue sobre la biota del lago de Banyoles y dos de las primeras cuatro tesis doctorales que dirigió fueron sobre la limnología del lago. Desgraciadamente, la singularidad de este lago implicó también que fue el primer lugar de introducción en la Península de varias especies exóticas de peces, a principios del siglo XX, y actualmente la comunidad de peces está dominada por especies invasoras y algunas nativas han sido extirpadas. Aunque los estudios limnológicos en el lago fueron pioneros en la península ibérica, la ecología de peces no se empezó a estudiar hasta 1989. Posteriormente, se han completado cuatro tesis doctorales sobre distintos aspectos de las comunidades de peces del lago de Banyoles. El objetivo de este artículo es proporcionar una breve sinopsis de estas investigaciones, que en gran medida surgieron de la considerable información limnológica existente sobre el lago, gracias al trabajo pionero y visionario del profesor Margalef

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

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

Fish pass assessment in the rivers of Catalonia (NE Iberian Peninsula). A case study of weirs associated with hydropower plants and gauging stations

This study evaluated the effectiveness of fish passes in Catalan rivers (NE Iberian Peninsula). The aim was to test current functionality to enhance these structures for the purpose of optimising their management. We analysed river connectivity and fish pass facilities to generate information to improve the design, construction, management and assessment of solutions related to fish passage in Catalan rivers according to international best practices. In 2006, a preliminary evaluation of the locations and effectiveness of fish pass facilities in Catalonia was conducted through direct inspection of 78 fishways. Most of them were retro-fitted solutions using broad-spectrum technical structures, mainly pool fishway or pool pass facilities. An analysis of the effectiveness of 7 of the new fish passes (4, 2 and 1 passes in the Ter, Ebro and Tordera rivers, respectively) was performed between 2006 and 2009. The fish passes were located in weirs associated with hydropower plants and gauging stations. Our preliminary assessment of fish connectivity was based on a field visit and collection of information to populate a database of existing obstacles and associated fishways and calculation of the new version of the ICF index (river connectivity index) for all of them. Several methodologies were used to check the effectiveness of a selection of fish pass solutions, most of which were based on passage rates directly or indirectly estimated for each species. Direct estimation techniques involved the installation of fish traps upstream of the facility at the exit of the fish pass and visual counts. Indirect estimation techniques compared the fish population structure on each side of the obstacle in river sections with equivalent hydrology and habitat characteristics using electric fishing or trapping systems, group mark-recapture methods and individual mark-recapture methods (PIT tags). The results showed that (1) existing solutions to improve fish migration in Catalonia are insufficient (only present at approximately 8% of obstacles), and where they do exist, the fish passes are usually inadequate or poorly maintained. (2) Fish passes are generally inadequate or insufficient for the total native fish fauna from each water body. Additionally, with few exceptions, fish passage rates are too low, and in most cases, only fish with a high capacity to overcome obstacles or the largest individuals succeed in migrating. (3) Fish pass effectiveness agrees with the results of the new version of the ICF index.Este estudio evalua la eficacia de dispositivos o soluciones de paso para peces en los ríos de Catalunya (NE de la Península Ibérica). Se realizó con el propósito de comprobar su funcionalidad actual y también para poder mejorar elementos constructivos y/o para optimizar aspectos de gestión. El objetivo del estudio era analizar la conectividad de los ecosistemas fluviales y generar información para mejorar el diseño, construcción, gestión y evaluación de soluciones para el paso de peces en los ríos de Catalunya, de acuerdo con los estándares internacionales. El año 2006 se realizó un estudio de localización y evaluación preliminar de la eficacia de los dispositivos de paso para peces existentes en Catalunya mediante la inspección directa de 78 dispositivos. La mayor'ıa eran soluciones de rehabilitación por medio de estructuras técnicas de amplio espectro, como dispositivos de paso de estanques sucesivos. Entre 2006 y 2009 se efectuó un análisis de la eficacia de 7 de estos elementos (4, 2 y 1 en los ríos Ter, Ebro y Tordera, respectivamente). Los dispositivos de paso para peces estaban localizados en azudes para uso hidroeléctrico y estaciones de aforo. La evaluación preliminar de la connectividad para los peces se basó en una visita de campo y la recolección de información para completar una base de datos sobre los obstáculos existentes y las soluciones de paso para peces associadas. Para cada uno de estos casos analizados se calculó la nueva versión del Índice de Conectividad Fluvial (ICF). Posteriormente, se usaron varias metodologías para comprobar la eficacia de una selección de soluciones de paso para peces, la mayoría basadas en la estimación de la tasa de franqueo de cada especie. Las t'ecnicas de estimación directa consistieron en la instalación de trampas aguas arriba del obstáculo, a la salida del dispositivo de paso para peces, y los recuentos visuales. La estimación indirecta permitió la comparación de las estructuras poblacionales por especie de ambos lados del obstáculo en tramos fluviales de características hidrológicas y de hábitat equivalentes, a partir de muestreos con pesca eléctrica o trampeo, métodos de marcaje y recaptura de grupo, y métodos de marcaje y recaptura individualizados (con marcas PIT). Los resultados obtenidos indicaron (1) Las soluciones existentes en Catalunya para mejorar las migraciones de los peces resultan insuficientes (están presentes sólo alrededor del 8 % de los obstáculos). Cuando los hay, en general, los dispositivos de paso son inadecuados o con un mal mantenimiento. (2) Los dispositivos de paso para peces son generalmente inadecuados o insuficientes para el conjunto de las especies autóctonas de fauna piscícola de cada masa de agua. Las tasas de franqueo de los dispositivos de paso para peces son, con algunas excepciones, demasiado bajas y, en la majoría de los casos, sólo facilitan las migraciones de los peces con gran capacidad de superar obst'aculos o los individuos de mayor talla. (3) La eficacia de los dispositivos de paso para peces coincide con los resultados de la nueva versión del índice ICF

Longitudinal connectivity in hydromorphological quality assessments of rivers. The ICF index : a river connectivity index and its application to Catalan rivers

The Water Framework Directive urges assessment of river continuity as an input for the evaluation of hydromorphological quality. The existence of transverse obstacles in river beds has serious ecological consequences because it blocks the natural flow of water, sediments and biota, and this is considered one of the major causes of declines in many continental fish species. The index of river connectivity (ICF, from the Catalan name Index de Connectivitat Fluvial) evaluates obstacle effects on fish movement alone and does not take into account other elements affected by the obstacles. However, it can be used as a complementary element in hydromorphological condition assessments. The index is based on comparison of obstacle and fish pass (if any) characteristics with the capabilities of the fishes potentially present in the considered river section to overcome the obstacle. In this study, we present a new version of the ICF improved from its earlier version that was tested by different consultants and research centres for several obstacles from 2006 to 2009. The new version of the ICF is divided into three blocks that encompass assessment of (1) the obstacle and (2) the fish pass (if any) as well as (3) the estimation of certain modulators. Finally, the ICF classifies connectivity into five levels from very good to bad depending on the degree of permeability for different fish groups. This new version of the ICF has been tested for 101 transverse obstacles in rivers in Catalonia (NE Iberian Peninsula) both with and without fish passes, obtaining representation of the five expected quality levels (from very good to bad), and it is considered coherent with the real permeability of the obstacles. Its ease of application compared to in situ measurements of fish movements and the detailed information recorded by the index make it a very useful tool for the diagnosis of the longitudinal connectivity of rivers and for guiding measures for hydromorphological quality improvement.La Directiva Marco del Agua define que para evaluar la calidad hidromorfológica de los ríos hay que valorar, entre otros factores, la continuidad fluvial. La existencia de obstáculos transversales al cauce fluvial tiene importantes consecuencias ecológicas, y se considera una de las causas principales del declive de muchas especies continentales de peces. Por ello se ha diseñado el Índice de Conectividad Fluvial (ICF), que aunque sólo considera los peces y no otros compartimentos afectados (agua y sedimentos), puede ser utilizado como parte integrante del protocolo completo de evaluación de la calidad hidromorfológica de los ríos en Catalunya (protocolo HIDRI). El ICF se basa en la comparación de las características de un determinado obstáculo y de los dispositivos de paso para peces (si dispone de ellos) con las capacidades para superarlo de las distintas especies de peces autóctonos potencialmente presentes en el tramo. En este estudio se presenta una versión mejorada del ICF, que ha sido probada por distintos equipos de consultorías y centros de investigación entre 2006 y 2009. La nueva versión consta de tres grandes bloques que incluyen la evaluación de (1) el obstáculo, (2) el o los dispositivos de paso de peces, en caso que los haya, y (3) la estimación de distintos moduladores. Finalmente, el ICF clasifica el nivel de conectividad en cinco rangos, de muy bueno a malo, en función del grado de franqueabilidad para los distintos grupos de especies potencialmente presentes en el tramo. La nueva versión del ICF ha sido aplicada en 101 obstáculos transversales de distintos ríos de Catalunya (NE de la península Ibérica), con y sin dispositivos de paso para peces. En los resultados se encuentran representados los cinco rangos de calidad posibles (desde muy bueno a malo), resultados que se consideran coherentes con la permeabilidad real del obstáculo. Su fácil aplicación, en comparación con la evaluación in situ de los movimientos de los peces, así como los detalles de la información recogida en las hojas de campo, sugieren que el ICF es una buena herramienta tanto para diagnosticar la conectividad longitudinal como para orientar las medidas a tomar para la mejora de la calidad hidromorfológica

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