Endemic Cyprinid Research Articles

Structural microhabitat use by endemic cyprinids in a Mediterranean‐type river: Implications for restoration practices

Abstract Endemic freshwater fish from the Mediterranean region are among the most threatened species in the world owing to increasing river degradation. Because of such threats, the number of river restoration projects has greatly increased. However, they are seldom planned with consideration of the species' life history, often resulting in erroneous practices that compromise their success. This study assessed the seasonal and size‐related microhabitat use by three endemic cyprinids (Iberian barbel, Luciobarbus bocagei; Iberian straight‐mouth nase, Pseudochondrostoma polylepis; and calandino, Squalius alburnoides) using a modified point electrofishing procedure in a Mediterranean river. A multivariate approach was then employed to analyse both structural resource use and availability data. All species showed non‐random microhabitat use. The barbel and nase shifted to faster‐flowing positions (>25 cm s−1) with a coarser substratum (>150 mm particle size) during spring and to sheltered positions (50–100% instream cover) during autumn. Calandino selected more covered areas in autumn (>60% cover) and shifted to shallower positions from this season (>40 cm) to summer (<35 cm). Significant size‐related differences in microhabitat use were consistent for the three species, with smaller individuals occupying on average shallower microhabitats. Significant resource‐use overlap between species size classes increased from autumn to summer, occurring mainly between juvenile and small adult barbel and calandino. The present study helped develop recommendations for river restoration practices that may have a wider application, particularly for other Mediterranean‐type rivers. Cover was found to be critical for all species, in particular for calandino, which could be classified as a shelter‐oriented eurytopic species. Restoration scenarios should therefore consider maintaining cover habitats during unfavourable flow conditions for these species. Lithophilic spawners, which were highly responsive to velocity and substratum, could particularly benefit from the creation of gravel bedforms and artificial riffles to enhance depth and flow variability.

Myxobolus linzhiensis n. sp. (Myxozoa: Myxobolidae) from the gill filament of Schizothorax oconnori Lloyd (Cyprinidae: Schizothoracinae) in Tibet, China: morphological and molecular characterization.

In this report, a new myxosporean species, Myxobolus linzhiensis n. sp. (Cnidaria: Myxozoa: Bivalvulida), was described from the endemic cyprinid Schizothorax oconnori inhabiting the Yarlung Tsangpo River in the Tibetan plateau, China. The whitish ellipsoidal plasmodia of M. linzhiensis n. sp. grew under the epithelium of gill filaments, 1.7-mm long and 0.4-mm wide, and were found in the 3 of 8 examined S. oconnori (37.5%). Mature spores appeared suborbicular in frontal view, fusiform shaped in lateral view with tapering anterior, measuring 11.4±0.7 (10.1-13.0) μm in length, 10.6±0.4 (10.0-11.3) μm in width, and 6.6±0.3 (6.2-7.0) μm in thickness. Two equal polar capsules were pyriform with an apophysis at its top end, measuring 5.7±0.5 (4.8-6.7) μm in length, 3.8±0.2 (3.2-4.2) μm in width, and polar filaments coiled 4 turns. Spore valves were symmetrical, and sutural ridge was straight and thin, running near the middle of the valves. Although Myxobolus linzhiensis n. sp. showed similar morphological characteristics with Myxobolus chushi Dar Kaur & Chishti 2017 from Schizothorax niger, Myxobolus kienweiensis Ma, 1976 from Schizothorax davidi, the new myxosporean was distinguished with them in spore shape, polar filament, and host-tissue tropism. Homology search by BLAST in GenBank indicated that the obtained 18S rDNA sequence of M. linzhiensis n. sp. (KY965935) did not match any available myxozoan sequence, most similar to Henneguya zikaweiensis, and showing less than 93% sequence similarity. Phylogenetical analyses demonstrated that M. linzhiensis n. sp. was firmly clustered in the clade consisting of myxosporeans Thelohanellus, Myxobolus, Henneguya from Asian cyprinids. This study is the first report on myxosporean parasitizing in endemic fish in the Tibetan Plateau, China.

A Common Eurasian Fish Tapeworm, Caryophyllaeides fennica (Cestoda), in Western North America: Further Evidence of 'Amphi-Pacific' Vicariance in Freshwater Fish Parasites.

The freshwater fish faunas of the Palaearctic and Nearctic regions show similarities but also notable differences, resulting in diverse distributions of their parasites. Relatively few parasite species occur in both regions and fewer still have been examined using molecular data. We report a rare example of 'amphi-Pacific' distribution, involving the common Palaearctic parasite, the caryophyllidean cestode Caryophyllaeides fennica (Schneider, 1902), in the chiselmouth Acrocheilus alutaceus Agassiz and Pickering, 1855, an endemic cyprinid in northwestern Nearctic, Oregon. Available information on nonnative fish species in Oregon suggests that the parasite is native to the area and not introduced. Molecular data (18S ribosomal [r]DNA, 28S rDNA, internal transcribed spacer 2, and cytochrome c oxidase subunit 1 gene) indicate very little genetic divergence between representatives from the Palaearctic and Nearctic, and possibly a relatively more recent colonization of the Nearctic region by this cestode via the Beringian land bridge. This is remarkable considering that Acrocheilus has reportedly been in Oregon since the Miocene.

Life history traits and gonad histology of an endemic cyprinid fish, Mond spotted barb, Capoeta mandica from Southern Iran

The life history traits and gonad development of an endemic cyprinid fish, the spotted barb, Capoeta mandica (Bianco & Banarescu 1982), from southern Iran was investigated by regular monthly collections from February 2006 through January 2007 and on the basis of microscopic and macroscopic analyses. No information on the spawning characteristics of the fish are available to date. A total of 335 specimens were captured using electrofishing including 253 males and 102 females, resulting in 2.5:1 (male: female) sex ratio, which is significantly different from the expected ratio. The commonly known five standard maturation stages were determined based on the size, shape and weight of the gonads, degree of occupation of the body cavity, presence or absence of ripe oocytes, or milt, diameter of the oocytes in the ovary, and histological observations. These stages were correlated to the reproductive indices. The ovum diameters ranged from 0.04 to 1.31 mm, with the highest mean value in May. The condition factor of male and female specimens was the highest in April. The female GSI increased from March to May, peaking in the middle of spring and decreased significantly in June. Based on the gonad maturation stages, gonadosomatic index (GSI), modified GSI, mean egg diamete­r, condition factor (K) and Dobriyal index (DI), it was concluded that the spotted barbspawns during May and June. The provided data, contribute baseline data towards management ecology and conservation of this endemic fish species.

In vitro differentiation of fertile sperm from cryopreserved spermatogonia of the endangered endemic cyprinid honmoroko (Gnathopogon caerulescens)

Many endemic fish species are threatened with extinction. Conservation strategies and the restoration of endemic fish after extinction must therefore be investigated. Although sperm cryopreservation is indispensable for the conservation of endangered fishes, the limited number of mature fish and limited availability (volume and period) of sperm from small endemic fish hinders the optimization and practical use of this material. In this report, we demonstrate the in vitro differentiation of fertile sperm from cryopreserved spermatogonia of juveniles of the endangered small cyprinid honmoroko (Gnathopogon caerulescens), which is endemic to Lake Biwa in Japan. The entire process of spermatogenesis was recapitulated in vitro using cryopreserved spermatogonia of non-spawning adult and juvenile fish. The differentiation of sperm from spermatogonia was captured as a time-lapse video and confirmed by 5-ethynyl-2′-deoxyuridine (EdU) incorporation into sperm. Fertility was demonstrated by artificial insemination. These results suggest that the combination of cryopreservation of spermatogonia and in vitro sperm differentiation will provide a new and promising strategy for the preservation of paternal genetic materials.

Comparative phylogeography of two codistributed endemic cyprinids in southeastern Taiwan

Two cyprinid fishes, Spinibarbus hollandi and Onychostoma alticorpus, are endemic to southeastern Taiwan. This study examined the phylogeography of these two codistributed primary freshwater fishes using mitochondrial DNA cytochrome b sequences (1140 bp) to search for general patterns in the effect of historical changes in southeastern Taiwan. In total, 135 specimens belonging to these two species were collected from five populations. These two codistributed species revealed similar genetic variation patterns. The genetic variation in both species was very low, and the geographical distribution of the genetic variation corresponded neither to the drainage structure nor to the geographical distances between the samples. The results of a statistical dispersal-vicariance analysis suggested that the ancestral populations of these two species were distributed in southern Taiwan before their dispersal. Our study suggests that the initial colonization occurred in the Kaoping River followed by eastern and northward dispersal. Our results also indicate that the Central Range in Taiwan did not act as a barrier to the dispersal of S. hollandi or O. alticorpus.

The Complete Mitogenome and Phylogenetic Analysis of Acrossocheilus wuyiensis (Osteichthyes Cyprinidae)

Acorssocheilus wuyiensis is an endemic south China stream-dwelling cyprinid species. In this study, we decoded the complete mitogenome of Acorssocheilus wuyiensis for the first time by using whole genome sequencing approach. The complete mitogenome is 16,594 bp in length, consisting of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and one D-loop control region. Only ND6 and other eight tRNA genes are encoded on the L-strand while most of these genes are located in the H-strand. Its overall base composition is A: 31.1%, C: 28.0%, G: 16.2% and T: 24.7%. The complete mitogenome of the Chinese barred species of Cyprinidae could provide a basic data for further phylogenetic and conversational analysis.

Genetic Analysis Shows that Morphology Alone Cannot Distinguish Asian Carp Eggs from Those of Other Cyprinid Species

AbstractFish eggs and embryos (hereafter collectively referred to as “eggs”) were collected in the upper Mississippi River main stem (~300 km upstream of previously reported spawning by invasive Asian carp) during summer 2013. Based on previously published morphological characteristics, the eggs were identified as belonging to Asian carp. A subsample of the eggs was subsequently analyzed by using molecular methods to determine species identity. Genetic identification using the cytochrome‐c oxidase 1 gene was attempted for a total of 41 eggs. Due to the preservation technique used (formalin) and the resulting DNA degradation, sequences were recovered from only 17 individual eggs. In all 17 cases, cyprinids other than Asian carp (usually Notropis sp.) were identified as the most likely species. In previously published reports, a key characteristic that distinguished Asian carp eggs from those of other cyprinids was size: Asian carp eggs exhibited diameters ranging from 4.0 to 6.0 mm and were thought to be much larger than the otherwise similar eggs of native species. Eggs from endemic cyprinids were believed to rarely reach 3.0 mm and had not been observed to exceed 3.3 mm. However, many of the eggs that were genetically identified as originating from native cyprinids were as large as 4.0 mm in diameter (at early developmental stages) and were therefore large enough to overlap with the lower end of the size range observed for Asian carp eggs. Researchers studying the egg stages of Asian carp and other cyprinids should plan on preserving subsets of eggs for genetic analysis to confirm morphological identifications.Received July 30, 2015; accepted April 22, 2016 Published online August 31, 2016

First report of monogenean flatworms from Lake Tana, Ethiopia: gill parasites of the commercially important Clarias gariepinus (Teleostei: Clariidae) and Oreochromis niloticus tana (Teleostei: Cichlidae).

BackgroundLake Tana is the largest lake in Ethiopia and the source of the Blue Nile. The lake harbours unique endemic cyprinid fish species, as well as the commercially important endemic Nile tilapia subspecies Oreochromis niloticus tana and the North African catfish Clarias gariepinus. Its endemicity, especially within the Labeobarbus radiation, its conservation importance and its economic indispensability attract scientific interest to the lake’s ichthyofauna. Fish parasites of Lake Tana, however, are hitherto poorly known, and no formal report exists on its monogenean flatworms. For sustainable aquaculture and fisheries development, it is essential to study monogenean fish parasites in these economically most important fish species. Moreover, it remains to be verified whether this unique ecosystem and its endemicity gave rise to a distinct parasite fauna as well.ResultsNile tilapia and North African catfish hosts were collected from Lake Tana in 2013. Nine species of monogenean parasites of two orders, Gyrodactylidea Bychowsky, 1937 and Dactylogyridea Bychowsky, 1937, were recovered. Gyrodactylus gelnari Přikrylová, Blažek & Vanhove, 2012, Macrogyrodactylus clarii Gussev, 1961, Quadriacanthus aegypticus El-Naggar & Serag, 1986 and two undescribed Quadriacanthus species were recovered from C. gariepinus. Oreochromis niloticus tana hosted Cichlidogyrus cirratus Paperna, 1964, C. halli (Price & Kirk, 1967), C. thurstonae Ergens, 1981 and Scutogyrus longicornis (Paperna & Thurston, 1969).ConclusionsExcept for M. clarii, all species represent new records for Ethiopia. This first study on the monogenean fauna of Lake Tana revealed that the lake’s North African catfish, as well as its endemic Nile tilapia subspecies, harbour parasites that are known from these host species elsewhere in Africa.

Length-length and length-weight relationships for four endemic Cyprinid species in Küçük Menderes River Basin, Turkey

Length–length and length–weight relationships were studied for four endemic Cyprinid species from the Küçük Menderes River Basin located in the Western Anatolian region of Turkey. Fish were sampled from Tahtalı and Beydağı reservoirs, Bulgurca, Şaşal and Azmak streams during 2013–2014, using multimesh gillnets in the reservoirs and by electrofishing in the streams. First records of length–weight relationships for Barbus pergamonensis Karaman, 1971, Squalius kosswigi (Karaman, 1972) and Petroleuciscus smyrnaeus (Boulenger, 1896) are reported in addition to three new maximum total lengths for Chondrostoma holmwoodii (Boulenger, 1896), Squalius kosswigi (Karaman, 1972) and Petroleuciscus smyrnaeus (Boulenger, 1896).

Development of novel microsatellite loci and analyses of genetic diversity in the endangered Tanakia somjinensis

Somjin bitterling (Tanakia somjinensis), an endemic cyprinid on the Korean Peninsula, is critically endangered with only a few small populations found in limited areas in a single drainage, raising concerns that this species has likely suffered low levels of genetic variability. In the current study, 23 polymorphic microsatellite markers were developed using Illumina paired-end sequencing for quantification of the genetic diversity in this species and to determine their amplification efficiency in other bitterling species. A total of 50 somjin bitterlings collected from two localities were genotyped using these 23 loci. This species showed a remarkably high level of genetic variability, with an average number of alleles per locus of 17.30 and mean observed and expected heterozygosity values of 0.758 and 0.802, respectively. Our relatedness analyses for all pairs of individuals clearly indicated that the two somjin bitterling populations were completely outbred. No signature of drastic demographic decline was detected using our analytical methods. Many of our loci were validated as successfully transferable within and between genera and could potentially be used for genetic and demographic studies in other bitterling species.

Environmental changes in a Mediterranean river: implications for the fish assemblage

AbstractThis study examined the impacts of climate change on hydrology and fish population dynamics in a river in central Spain. The objectives were to (i) contextualize long‐term trends in the hydrology (1943–2012) and climate (1985–2011) of the study area and (ii) identify the environmental factors driving fish population dynamics (1998–2012). Air and water temperatures progressively increased over the study period, whereas there were substantial reductions in mean spring river discharges but increases in peak‐flow discharges during the spawning and early larval period of endemic cyprinids in recent decades. In particular, the changes in spring river discharges could have fundamental implications for the future status of the endemic cyprinids because this study revealed a positive influence of stable and low‐flow conditions during the spawning and early larval period (in late spring) on recruitment success (young‐of‐the‐year densities). The density of young‐of‐the‐year Salmo trutta appeared most influenced by flow conditions during fry emergence and the early larval period (in early spring), with the highest densities associated with low peak‐flow hydrological pulses. Overall, fish abundances were significantly influenced by the frequency and duration of high and low hydrological pulses, but there were interspecific and ontogenetic differences in their influence. We conclude that although it is widely accepted that global warming should favour cyprinid over salmonid species, future shifts in hydrology due to climate change could negatively affect some cyprinids, including endemic species. Copyright © 2016 John Wiley & Sons, Ltd.

A Review on the Ecology and Biodiversity of Lake Lanao (Mindanao Is., The Philippines)

The sparse body of information on the ecology and biodiversity of one of the world’sancient lakes, Lake Lanao, was reviewed to arrive at objective insights that may be useful for an ecosystem-based management of the Lake Lanao Watershed. The terrestrial portion of the watershed is relatively rich in flora and fauna that mostly inhabit the remaining intact forests which provides 60% cover, but a thorough species inventory is wanting. Nearly 90% of the alienable and disposable lands including most of the lake shoreline and the adjacent lowland forest areas have now yielded to agriculture (87%), but only 0.4% to urban and rural settlements. Major rivers and numerous intermittent tributaries that sustain lake water are unstudied. Within a span of 30 years since a rich indigenous community of fish species was first described, the lake’s fisheries ecosystem has undergone a regime shift featuring the dominance of invasive fish species and the catastrophic disappearance of 16 endemic cyprinid species. Analysis of nutrient levels when the lake was at its relatively pristine state indicated a high sensitivity to levels of dissolved nitrogen with a pelagic ecosystem that is bottom-up or resource controlled. Most recent water quality analyses indicate a eutrophic, coliform-contaminated, and invasive species-colonized state with anthropogenic input as the possible main driver. Hence, apart from biodiversity conservation in the lake watershed, the flux of nutrients and pollutants should be a top priority of an ecosystem-based management that needs to employ innovative socio-environmental approaches involving participatory, multisectoral, multidisciplinary, integrated and co-management efforts. The looming climate change, which may undoubtedly lead to further loss of biodiversity services, needs to be incorporated in the watershed modelling and management framework.

Phylogeography and genetic structure of the endemic cyprinid fish Microphysogobio brevirostris in northern Taiwan

This study used the mitochondrial DNA cytochrome b and control region sequences to examine the population genetic structure of Microphysogobio brevirostris, an endemic cyprinid species in northern Taiwan. In total, 90 specimens were collected from six populations belonging to four major rivers. All haplotypes were identified as two major clades (Clades N and S), exhibiting a southern and a northern distribution. The results of statistical dispersal-vicariance analysis (S-DIVA) revealed that two vicariance events and one dispersal event shaped the phylogeographic pattern of M. brevirostris. These results suggest that the ancestral populations of M. brevirostris are widely distributed throughout northern Taiwan, north of the Miaoli Plateau. The ancestral populations then diverged into two clades (N and S) by the raising of the Taoyuan Plateau. Finally, two major rivers of the S clade diverged and dispersed into adjacent rivers. Besides, our results revealed that Microphysogobio alticorpus and M. brevirostris colonized Taiwan during the same ice age through different colonization routes.

Factors shaping contemporary patterns of genetic diversity of the Portuguese endemic cyprinids

Event Abstract Back to Event Factors shaping contemporary patterns of genetic diversity of the Portuguese endemic cyprinids Carla Sousa Santos1*, Joana I. Robalo1, Ana M. Pereira1, Paulo Branco2, 3, José M. Santos2, Maria T. Ferreira2, Monica Sousa4 and Ignacio Doadrio5 1 ISPA, Portugal 2 CEF—Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, Portugal 3 CERis—Civil Engineering Research and Innovation for Sustainability, Instituto Superior Técnico, Portugal 4 Instituto da Conservação da Natureza e das Florestas, I.P., Portugal 5 Museo Nacional de Ciencias Naturales, CSIC, Portugal Iberian cyprinids are currently highly endangered, with over 68% of the species raising some level of conservation concern. Population declines were reported in the last decades, however, it was unknown if it was coupled with the depletion of gene pools. In order to assess the genetic diversity distribution patterns of native cyprinid species, the Portuguese hydrographical network was extensively covered (all the 34 river basins and 47 sub-basins). A total of 188 populations belonging to 16 cyprinid species of Squalius, Luciobarbus, Achondrostoma, Iberochondrostoma, Anaecypris and Pseudochondrostoma were characterized, for a total of 3,678 cytochrome b gene sequences. We found differences among populations from the same species and between species with identical distribution areas. Factors shaping the contemporary patterns of genetic diversity were explored and the results revealed the role of latitude, inter-basin connectivity, migratory behaviour, species maximum size, species range and other species intrinsic traits in determining the genetic diversity of sampled populations. Contrastingly, drainage area and hydrological regime (permanent vs. temporary) seem to have no significant effect on genetic diversity. Species intrinsic traits, maximum size attained, inter-basin connectivity and latitude explained over 30% of the haplotype diversity variance and, generally, the levels of diversity were significantly higher for smaller sized species, from connected and southerly river basins. Keywords: Haplotype diversity, Nucleotide diversity, fish conservation, Genetic diversity drivers, Endangered Species Conference: IMMR | International Meeting on Marine Research 2016, Peniche, Portugal, 14 Jul - 15 Jul, 2016. Presentation Type: Poster presentation Topic: Biodiversity, Conservation and Coastal Management Citation: Sousa Santos C, Robalo JI, Pereira AM, Branco P, Santos JM, Ferreira MT, Sousa M and Doadrio I (2016). Factors shaping contemporary patterns of genetic diversity of the Portuguese endemic cyprinids. Front. Mar. Sci. Conference Abstract: IMMR | International Meeting on Marine Research 2016. doi: 10.3389/conf.FMARS.2016.04.00072 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 28 Apr 2016; Published Online: 13 Jul 2016. * Correspondence: PhD. Carla Sousa Santos, ISPA, Lisboa, Portugal, csousasantos@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Carla Sousa Santos Joana I Robalo Ana M Pereira Paulo Branco José M Santos Maria T Ferreira Monica Sousa Ignacio Doadrio Google Carla Sousa Santos Joana I Robalo Ana M Pereira Paulo Branco José M Santos Maria T Ferreira Monica Sousa Ignacio Doadrio Google Scholar Carla Sousa Santos Joana I Robalo Ana M Pereira Paulo Branco José M Santos Maria T Ferreira Monica Sousa Ignacio Doadrio PubMed Carla Sousa Santos Joana I Robalo Ana M Pereira Paulo Branco José M Santos Maria T Ferreira Monica Sousa Ignacio Doadrio Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

The impact of wildfire on stream fishes in an Atlantic-Mediterranean climate: evidence from an 18-year chronosequence

The predicted increase in wildfires associated with climate change poses a risk to freshwater biodiversity that may be exacerbated by river regulation. We studied the effects of wildfire and river management on the fish assemblages of Atlantic-Mediterranean streams in northern Portugal. Employing a chronosquence survey covering an 18-year gradient of impact-recovery from major fire events (ca. 100% catchment burnt), we assessed the ecological response with respect to time since wildfire, interpreting fish assemblages in the context of species traits and characteristics of the river habitat. Non-burnt sites (N = 18; surveyed 4 years previously) were compared to burnt sites (N = 14), two of which were part of the non-burnt set, thus providing a Before-After Impact comparison (BAI; N = 2). Across burnt sites richness and abundance were not related to time since wildfire. BAI revealed a contrast in the response of different species that corresponded to descriptive evidence from the chronosequence of burnt sites. As resource specialists, Salmo trutta were negatively impacted by wildfire; Iberian endemic cyprinids, characterized by generalist traits, demonstrated resistance. Habitat structure was a key determinant of wildfire-impact, increasing with channel slope and the degree of channelization. The low abundance of migratory taxa (S. trutta and Anguilla anguilla ) at burnt sites suggested the importance of fish mobility to post-fire recovery. These data demonstrate that trait profiles and habitat descriptions provide pragmatic information for the management of rivers in fire-susceptible regions and suggest that the rehabilitation of these upland stream habitats might enhance ecological resistance and resilience to catchment wildfire.

When Anthropogenic River Disturbance Decreases Hybridisation between Non-Native and Endemic Cyprinids and Drives an Ecomorphological Displacement towards Juvenile State in Both Species.

Understanding the impact of non-native species on native species is a major challenge in molecular ecology, particularly for genetically compatible fish species. Invasions are generally difficult to study because their effects may be confused with those of environmental or human disturbances. Colonized ecosystems are differently impacted by human activities, resulting in diverse responses and interactions between native and non-native species. We studied the dynamics between two Cyprinids species (invasive Chondrostoma nasus and endemic Parachondrostoma toxostoma) and their hybrids in 16 populations (from allopatric to sympatric situations and from little to highly fragmented areas) corresponding to 2,256 specimens. Each specimen was assigned to a particular species or to a hybrid pool using molecular identification (cytochrome b and 41 microsatellites). We carried out an ecomorphological analysis based on size, age, body shape, and diet (gut vacuity and molecular fecal contents). Our results contradicted our initial assumptions on the pattern of invasion and the rate of introgression. There was no sign of underperformance for the endemic species in areas where hybridisation occurred. In the unfragmented zone, the introduced species was found mostly downstream, with body shapes similar to those in allopatric populations while both species were found to be more insectivorous than the reference populations. However, high level of hybridisation was detected, suggesting interactions between the two species during spawning and/or the existence of hybrid swarm. In the disturbed zone, introgression was less frequent and slender body shape was associated with diatomivorous behaviour, smaller size (juvenile characteristics) and greater gut vacuity. Results suggested that habitat degradation induced similar ecomorphological trait changes in the two species and their hybrids (i.e. a transition towards a pedomorphic state) where the invasive species is more affected than the native species. Therefore, this study reveals a diversity of relationships between two genetically compatible species and emphasizes constraints on the invasion process in disturbed areas.

Pluvial Drainage Patterns and Holocene Desiccation Influenced the Genetic Architecture of Relict Dace, Relictus solitarius (Teleostei: Cyprinidae).

Changing drainage patterns have played a significant role in the evolution of western North American aquatic taxa. Relict dace, Relictus solitarius, is a Great Basin endemic cyprinid with a native range that is restricted to four valleys in eastern Nevada. Relictus solitarius now occupies spring systems that are the remnants of Pleistocene-era pluvial lakes, although it may have occurred in the area for much longer. Here we use mitochondrial DNA sequence data to assess range-wide genetic diversity of R. solitarius, and to estimate divergence times to determine whether pluvial drainages played an important role in shaping intraspecific genetic diversity. Genetic diversification within R. solitarius began during the early to mid-Pleistocene, separating populations within two sets of valleys (Butte/Ruby and Goshute/Steptoe). Additional diversification in each of the two sets of valleys occurred more recently, in the mid- to late-Pleistocene. Holocene desiccation has further isolated populations, and each population sampled contains unique mtDNA haplotypes. Pluvial drainage patterns did contribute to the genetic structure observed within R. solitarius, but most of the intraspecific diversification does not appear to be associated with the Last Glacial Maximum. Holocene desiccation has also contributed to the observed genetic structure. The relict dace populations we sampled are all unique, and we recommend that future management efforts should strive to preserve as much of the genetic diversity as possible.

Phylogeography, historical demography and habitat suitability modelling of freshwater fishes inhabiting seasonally fluctuating Mediterranean river systems: a case study using the Iberian cyprinid Squalius valentinus.

The Mediterranean freshwater fish fauna has evolved under constraints imposed by the seasonal weather/hydrological patterns that define the Mediterranean climate. These conditions have influenced the genetic and demographic structure of aquatic communities since their origins in the Mid-Pliocene. Freshwater species in Mediterranean-type climates will likely constitute genetically well-differentiated populations, to varying extents depending on basin size, as a consequence of fragmentation resulting from drought/flood cycles. We developed an integrative framework to study the spatial patterns in genetic diversity, demographic trends, habitat suitability modelling and landscape genetics, to evaluate the evolutionary response of Mediterranean-type freshwater fish to seasonal fluctuations in weather. To test this evolutionary response, the model species used was Squalius valentinus, an endemic cyprinid of the Spanish Levantine area, where seasonal weather fluctuations are extreme, although our findings may be extrapolated to other Mediterranean-type species. Our results underscore the significant role of the Mediterranean climate, along with Pleistocene glaciations, in diversification of S.valentinus. We found higher nuclear diversity in larger drainage basins, but higher mitochondrial diversity correlated to habitat suitability rather than basin size. We also found strong correlation between genetic structure and climatic factors associated with Mediterranean seasonality. Demographic and migration analyses suggested population expansion during glacial periods that also contributed to the current genetic structure of S.valentinus populations. The inferred models support the significant contribution of precipitation and temperature to S.valentinus habitat suitability and allow recognizing areas of habitat stability. We highlight the importance of stable habitat conditions, fostered by typical karstic springs found on the Mediterranean littoral coasts, for the preservation of freshwater species inhabiting seasonally fluctuating river systems.

Occurrence of Lernaea cyprinacea (Crustacea: Copepoda) in an endemic cyprinid fish, Chondrostoma orientale Bianco & Banarescu, 1982 from the Kor River Basin, southwestern Iran

Occurrence of Lernaea parasite in a narrow distributed endemic fish, Chondrostoma orientale (Oriental nase) restricted to the Kor river basin, Southwestern Iran is reported. Based on the obtained results, all three collected specimens (TL= 174-192mm, SL= 148-169mm) were infested with Lernaea parasites which were attached to the base of dorsal, pectoral, caudal and pelvic fins and also body muscles. The prevalence and intensity of parasite was 100% and 10.3, respectively. Due to effects of Lernaea , a long term monitoring of the parasites and fishes in the Kor River basin is highly recommended.