Rafael Miranda

River channelization effects on fish population structure in the Larraun river (Northern Spain)

As a consequence of the construction of the A-15 highway between 1991 and 1995, some modifications affecting the Larraun River (Navarra, North of Spain) were made. One of the most important effects was the channelization of a section of the river in the middle zone. Fish were caught by electrofishing in August of 1996 in the channelized reach, as well as in non-modified stretches upstream and downstream. Physical and chemical variables and shelter availability were also analyzed. The captured fish were measured (total length) and released into the river. We calculated the density, biomass, length distribution and diversity, comparing the obtained results from the different stretches. The number of species was higher in the lower zones of the river and diversity increased progressively downstream. The fish density in the channelized section was slightly lower than in the other two points. Also biomass in the channelized section was about a factor of 10 smaller than the calculated biomass in unaltered points. Moreover, in comparison with the unaltered sections of the river, in the channelized area a major decrease in the presence of fish larger than 150 mm was detected. The low shelter availability in the channelized section, lack of bank vegetation and alterations in the substratum could explain the observed variations in the length distribution, biomass and the lower value of the density of European minnow, Phoxinus phoxinus (Linnaeus, 1758).

Morphological and biometric comparison of the scales of the barbels (Barbus Cuvier) of Spain

The scales of 386 specimens of the eight species of the genus Barbus present in Spain (B. bocagei, B. comiza, B. graellsii, B. guiraonis, B. haasi, B. meridionalis, B. microcephalus, and B. sclateri) were studied. Six scales were extracted from each specimen, measurements taken, and the number of radii noted. Indices were obtained from these data. Statistical analysis allowed two groups to be established: 1) B. meridionalis and B. haasi, living in the upper stretches of rivers and distributed in the north of Spain; and 2) the remaining species. Within both groups a latitudinal gradation in the elongation of the scales and in the proportion of radii of the lateral fields was observed. J. Morphol. 245:196–205, 2000.

Phylogenetic relationships and biogeography of Pseudoxiphophorus (Teleostei: Poeciliidae) based on mitochondrial and nuclear genes

Phylogenetic relationships of species of genus Pseudoxiphophorus have been only tackled in detail based on morphology so far. However, phylogenetic evidence based on molecular data is still lacking. In this study, we have used five molecular markers (mitochondrial cytb, 16S, atp6-8, and nuclear actB and S7) to reconstruct a robust, inclusive phylogeny of Pseudoxiphophorus. Our phylogenetic results strongly disagree with the main morphological hypothesis, and indicate different phylogenetic relationships among the recognized species of Pseudoxiphophorus. Pseudoxiphophorus jonesii is recovered as the sister group of all other Pseudoxiphophorus lineages, and this initial splitting may be associated to the extension of the Mexican Neovolcanic Plateau at the Punta del Morro site (event used to calibrate our dating analysis). The branch leading to all other Pseudoxiphophorus separated subsequently into two major groups, one comprising those lineages occurring in southern Mexico and Guatemala-Belize, and another with those lineages that extended further southwards to Honduras and Nicaragua. This event took place during the Pliocene, and is likely associated with periods of inundation of the Polochic-Motagua fault area. The Isthmus of Tehuantepec also appears to have been a strong biogeographic barrier triggering cladogenesis in Pseudoxiphophorus. Heterandria formosa (traditionally placed as sister to Pseudoxiphophorus) is not sharing the most recent common ancestor with Pseudoxiphophorus, and is recovered as more distantly related to them. Furthermore, Pseudoxiphophorus bimaculatus (the most cosmopolitan species) is also recovered as a polyphyletic assemblage that appears to comprise those Pseudoxiphophorus that have not been assigned to the other eight, more localized species. All this suggests that Pseudoxiphophorus needs a major taxonomic revision as a whole in order to incorporate all existing diversity.

An alien ectosymbiotic branchiobdellidan (Annelida: Clitellata) adopting exotic crayfish: a biological co-invasion with unpredictable consequences

Abstract Invasive alien species present a global threat to biodiversity, particularly where pathogens and symbionts are involved. Branchiobdellidans are clitellate annelids with an obligate ectosymbiotic association primarily on astacoidean crayfish. There are several examples of branchiobdellidan species adopting a geographically exotic host where endemic and exotic crayfishes cohabit the same water body. The first records of a western North American branchiobdellidan, Xironogiton victoriensis, adopting the eastern North American crayfish, Procambarus clarkii, in 2 river basins in Spain provide further evidence of the ectosymbionts’ tolerance to adopt an exotic host. Given worldwide translocations of these and other commercial crayfish species, limnologists and agency managers need to be alert for further introductions of X. victoriensis and other branchiobdellidans. Impacts of these exotic ectosymbionts on habitat and biota at a new location are unknown, as are their consequences on native biodiversity.

Communication gaps in knowledge of freshwater fish biodiversity: implications for the management and conservation of Mexican biosphere reserves.

To detect differences in the information available on freshwater fish species found in Mexican biosphere reserves, the number of species considered in three sources of information: management programmes, Global Biodiversity Information Facility (GBIF) and the scientific literature were compared. Additionally, management actions for the reserves were evaluated. More than 55% of freshwater fish species registered for the reserves were found only in one of the three sources of information, while just 12% was shared among all the three. Fifteen threatened species were registered in GBIF and the scientific literature that were not found in management programmes. Although all the management programmes described conservation actions, none of them gave details about how they would be implemented. Lack of communication among the sources studied, unawareness of the existence of threatened species and the absence of detailed management actions hinder the development of adequate conservation strategies.

Modeling and analysis of six-phase induction machine under fault condition

Analysis of six-phase induction motor drive system is presented with emphasis on the electrical faults of the inverter. A simple model has been described to analyses the dynamic behavior of the multi-phase machine under fault condition. Simulation and experimental results are presented to verify predicted behavior for different kinds of faults.

Setting priorities for existing conservation needs of crayfish and mink

According to Clavero (2014), the conservation in Spain of the white-clawed crayfish (Austropotamobius italicus) and the European mink (Mustela lutreola) to the detriment of 3 North American species (red swamp crayfish [Procambarus clarkii], signal crayfish [Pacifastacus leniusculus], and feral American mink [Neovison vison]) represents a case of shifting baseline syndrome (Pauly 1995; Papworth et al. 2009). Clavero argues there is clear evidence that all these species are nonnative to the Iberian Peninsula and therefore preserving the white-clawed crayfish and the European mink responds to an a priori social assimilation of these species as native and, thus, to a shift of the baseline of Spanish natural freshwater ecosystems. We question Clavero’s evidence on the nonnative status of these 2 species in the Iberian Peninsula and disagree with the importance he attributes to species’ native or nonnative status when setting conservation priorities. Nonnative species occur outside their historical natural range following intentional or accidental human introduction (Heywood 1995). Contrary to Clavero’s claim, evidence suggests the white-clawed crayfish and the European mink are native to the Iberian Peninsula (see below). Moreover, the current known European distribution for both species makes natural dispersion a plausible biogeographic process because the Pyrenean range is permeable at its extremes (e.g., Mart́ınezRica & Monserrat-Recoder 1990) and, at least for mustelids, mountains are not a barrier to dispersal (e.g., Zuberogoitia & Zabala 2003).

Biometrics of Iberian Dippers Cinclus cinclus: Environmental Sources of Among-Population Variation

Biometry of Iberian Dippers Cinclus cinclus has typically been addressed from a geographic perspective, often considering small local populations. In this work, we explored environmental correlates of among-population phenotypic variation in Dipper morphology throughout Iberia. We tested for effect of river slope, altitude, temperature and precipitation (summarized using Principal Component Analyses, PCA) on absolute and relative (controlling for tarsus length) wing length and tarsus length. We used data of 222 Dippers captured from 35 rivers in eight breeding areas in N and S Iberia. All biometric variables were larger for older birds and males, though tarsus length was not affected by age. Wing length was longer in S Iberia, even when controlling for tarsus length, All biometric variables co-varied negatively with one of the PCA components of abiotic factors, owing to large-scale environment differences between N and S Iberia (zone). The abiotic factors predicted mean tarsus length of birds within zones, with tarsus increasing with increasing river slope and decreasing temperatures and precipitation. Furthermore, Dippers from S Iberia were not larger but had longer absolute and relative wings than those from N Iberia. Altogether, these findings imply that the morphological diversification of Iberian Dippers is affected by the environment and that body size-wing length allometric relationship differs between N and S Iberia.

Spatial distribution patterns of fish assemblages relative to macroinvertebrates and environmental conditions in Andean piedmont streams of the Colombian Amazon

Abstract This work provides insight into an Andean–Amazonian river system by conducting a comprehensive study of the biodiversity and ecological processes in a poorly studied neotropical freshwater ecosystem. Hacha River in western Colombia harbours a rich and largely unknown biodiversity and is experiencing an increase in anthropogenic impacts from the city of Florencia. Changes in natural habitat characteristics and environmental quality were analysed and related to the distribution of fish and macroinvertebrates. Four environmental quality indices were applied, and concentrations of potential water pollutants were measured. All environmental quality indices used were reliable because they produced similar assessments of the ecological integrity of the study sites and were inversely related to the potential water pollutant concentrations. Fish and macroinvertebrate communities notably changed in response to differences in environmental quality, reinforcing the ecological integrity assessments. Nevertheless, natural gradients that influence fish and macroinvertebrate distributions showed an overlap with changes in environmental quality, thereby confounding the ability to discern the influence of natural and anthropogenic-induced alterations and to confirm an initials hift in fish assemblages due to anthropogenic impacts.

An experimental evaluation of the influence of water depth and bottom color on the Common kingfisher's foraging performance

To investigate how depth and bottom color affect prey selectivity in Common kingfisher (Alcedo atthis), we developed several experimental procedures using captive birds. We used 20 young kingfishers to test depth (25 or 50cm) and color (natural gravel or white) effects on foraging behavior. Live freshwater fish were used as target prey. To assess differences resulting from the natural behavior of different fish, we chose bottom-dwelling [Ebro barbel (Barbus graellsii)] and open-water benthopelagic species [Ebro nase (Parachondrostoma miegii) and Pyrenean minnow (Phoxinus bigerri)]. The number of attempts and captures, as well as the effects of hunger and experience, were assessed relative to feeding behavior. The effect of fish behavior, as observed in grouped vs. isolated fish, on the kingfishers performance was also tested. The results showed a significant effect of depth, with more attacks and greater success in shallow waters. No significant differences in catch success between natural- and white-colored bottoms were observed. Hunger had no effect on fishing success, but experience had a positive effect in shallow waters and on white bottoms. Both bottom- and open-water species were consumed equally. Kingfishers preyed more often upon grouped prey than upon isolated prey, although capture success did not vary between the two cases. Our results suggest that kingfishers prey upon the most accessible types of prey.