Francisco J. Oliva-Paterna

Diversification within glacial refugia: tempo and mode of evolution of the polytypic fish Barbus sclateri

A diversity of evolutionary processes can be responsible for generating and maintaining biodiversity. Molecular markers were used to investigate the influence of Plio‐Pleistocene climatic oscillations on the evolutionary history of taxa restricted to the freshwaters of a classical glacial refugium. Population genetic, phylogenetic and phylogeographical methods allowed the inference of temporal dynamics of cladogenesis and processes shaping present‐day genetic constitution of Barbus sclateri, a polytypic taxon found in several independent river drainages in southern Iberian Peninsula. Results from different analyses consistently indicate several range expansions, high levels of allopatric fragmentation, and admixture following secondary contacts throughout its evolutionary history. Using a Bayesian demographical coalescent model on mitochondrial DNA sequences calibrated with fossil evidence, all cladogenetic events within B. sclateri are inferred to have occurred during the Pleistocene and were probably driven by environmental factors. Our results suggest that glaciation cycles did not inhibit cladogenesis and probably interacted with regional geomorphology to promote diversification. We conclude that this polytypic taxon is a species complex that recently diversified in allopatry, and that Pleistocene glaciation–deglaciation cycles probably contributed to the generation of biological diversity in a classical glacial refugium with high endemicity.

Breeding habitat selection of Salamandra salamandra (Linnaeus, 1758) in the most arid zone of its European distribution range: application to conservation management

The influence of environmental variables on the selection of a water body as breeding habitat by Salamandra salamandra was studied in an arid zone located in the southwestern part of its distribution range. From November 2002 to October 2003, 50 water bodies were monitored in the south east of the Iberian Peninsula. Environmental data were submitted to a stepwise logistic regression analysis at macrohabitat, water body typology and microhabitat scales in order to establish the main factors influencing the use of a given water body as breeding habitat by this species. A significant degree of dependence between the reproduction of Salamandra salamandra and environmental variables was observed at all of these levels. These results should be taken into account when populations of this species are subjected to management and/or recovery programmes in arid areas.

Assessing the nursery role for marine fish species in a hypersaline coastal lagoon (Mar Menor, Mediterranean Sea)

Abstract The shallow inshore areas of coastal lagoons function as nursery grounds for the early life stages of marine fish. Multi-species approaches and the assessment of several population variables are of great value in studies focused upon the ecological importance of estuarine systems as fish nursery areas. Therefore, the objective of this study was to analyse the spatial differences in the abundance, biomass, growth and condition indexes of juveniles from three marine species: Sparus aurata, Liza aurata and Liza ramada, in order to assess the nursery role of the Mar Menor coastal lagoon for these species. Results showed high spatial variability of the studied variables, with higher abundance and biomass values at those sites closest to the inlet connecting the lagoon with the Mediterranean Sea. Moreover, there were significant relationships between the growth and condition of the fish with hydrographical circulation patterns within the lagoon, indicating the suitability of the Mar Menor as a nursery area for the three studied fish species.

Biology of the endangered cyprinodontid Aphanius iberus in a saline wetland (SE Iberian Peninsula)

For the last few decades, Aphanius iberus, an endemic cyprinodontid from the Iberian Peninsula and included in international red lists, has been declining despite several management efforts. In this study we present the biology of the species in an isolated wetland managed for salt exploitation (its most common habitat type in the southeastern Iberian Peninsula). The population studied is found under conditions of extreme high salinity and water temperature. We have examined the effects of extractive management on catchability, population structure, growth and reproduction traits. The stock was characterized by significant differences in abundance between seasons (higher values: end of summer and early autumn). Drastic changes in salinity and water level have negatively affected the species abundance. The population structure was characterized by three age groups (0+, 1+ and 2+ in both sexes), a high degree of group‐size overlapping into the 0+ (>2 groups), a short life span and a long reproductive period (April/May to September). Gonadal mass represented a maximum of 19.6±0.5% of the total mass in females. We detected changes in life‐history traits which could be related to the management of the salt extraction, variations in water level that increase the salinity should be indirect effects on fish population by reducing vegetation mats.

Removal control of the highly invasive fish Gambusia holbrooki and effects on its population biology: learning by doing

Abstract Context. For the success of future conservation and management programs, it is necessary to better understand the resilience mechanisms of invasive species and their invasive potential. In this sense, the study of the effects that management actions have on their biological traits is essential. Aims. The present study aimed to assess the effects of removal control on the abundance and biology of an isolated population of the top invasive fish Gambusia holbrooki (eastern mosquitofish). Methods. Experimental removal control with traps and handnets was carried out on a population of mosquitofish inhabiting a small semiarid stream in south-eastern Spain. Mosquitofish were periodically captured for more than 3 years. Temporal variations in abundance, fish somatic condition and reproductive investment, percentage of mature females, size at maturity and population recruitment were analysed. Key results. Individuals of the 1+ age class increased their reproductive investment when population abundance was lower, thus increasing recruitment rate during the first months of the recruitment period. Individuals of the 0+ age class were responsible for expanding the reproductive period in conditions of low fish abundance. Conclusions. The mosquitofish population showed variations of reproductive parameters that could indicate a compensatory density-dependent phenotypic response under diminished abundance conditions. However, its removal by the constant use of a combination of active and passive capture methods, reinforced by increased extraction effort according to its local biology, has led to an eradication of the population. The target mosquitofish population showed distinct ecological features that may have contributed to the effectiveness of local control, namely, low initial fish density, isolation in a headwater stretch and the prevalence of individuals in sunlit shallow ponds. Implications. The compensatory mechanisms of this invasive species in low-density conditions should be considered in the design of management programs. Moreover, further research into removal control methods for mosquitofish or similar species is also needed.

Effects of Shoreline Urban Modification on Habitat Structure and Fish Community in Littoral Areas of a Mediterranean Coastal Lagoon (Mar Menor, Spain)

The shallow habitats of coastal lagoons play an invaluable role for fish communities as nursery areas and provide essential habitats for threatened fish species. Shoreline modification is an anthropogenic coastal stressor that can negatively affect aquatic communities through the modification of nearshore habitats. The aim of the present study was to quantify the effects of two types of shoreline conditions on habitat structure and fish community of littoral habitats. Unmodified shorelines adjacent to saltmarshes and recreational beaches in urbanised areas of the Mar Menor coastal lagoon were compared. The results showed that there were significant differences in habitat structure, fish community structure and fish species abundance by shoreline type. Recreational beaches were characterised by higher water depth and homogeneous substrata, while unmodified shorelines showed high substrata heterogeneity and supported well developed meadows of submerged vegetation. The latter shoreline type provided an important nursery habitat for marine species such as Sparus aurata and Liza saliens, and represented critical habitats for species of conservation concern such as Aphanius iberus and Syngnathus abaster. Littoral areas adjacent to modified shorelines were dominated by Pomatoschistus marmoratus. We suggest that urbanisation has impacted fish assemblages through degradation of habitat structure (loss of complexity and refuge areas).

The effects of competitors on fitness of marbled goby Pomatoschistus marmoratus (Pisces, Gobiidae) in the Mar Menor coastal lagoon (SE Iberian Peninsula)

We investigated the relationship, at local level, between fitness (measured as fish condition) of Pomastoschistus marmoratus and environmental variables of shallow areas in the Mar Menor lagoon (Spain, Mediterranean Sea): water temperature (°C), water salinity (‰), depth (cm), submerged vegetation cover (%), submerged vegetation volume, substrate size, substrate heterogeneity, fish species richness, potential competitor fish species abundance, potential competitor fish species biomass, P. marmoratus abundance and P. marmoratus biomass. The mass–length relationships were used to test differences in fish condition between nine sampling sites. The ecological variable that accounted for most of the variation in condition was the abundance of potential competitor fish species, wich was related to interspecific fish interactions. The condition of P. marmoratus populations may be a good indicator of fish density interactions in coastal lagoons and could be considered when such populations are subjected to recovery plans or any other management programmes.

Threatened Fishes of the World: Aphanius baeticus (Doadrio, Carmona & Fernández Delgado, 2002) (Cyprinodontidae)

Francisco J. Oliva-Paterna, Ignacio Doadrio & Carlos Fernandez-Delgado Department of Zoology and Anthropology, University of Murcia, E-30100, Murcia, Spain (E-mail: fjoliva@ um.es) Department of Biodiversity, Natural Museum of Natural Science, C/ Gutierrez Abascal, 2, 28006, Madrid, Spain Department of Animal Biology. Faculty of Sciences, University of Cordoba, Campus Rabanales, Edf. Charles Darwin 3a pl, 14071, Cordoba, Spain

Catch and selectivity parameters of the anastomid fish Schizodon nasutus using gillnets in the Jurumirim reservoir (São Paulo, Brazil)

Abstract Catch and selectivity parameters using gillnets were calculated for Schizodon nasutus in the Jurumirim reservoir on the Parana‐panema River in southern Brazil. The simple gillnets used were made of monofilament nylon of 30 to 140 mm mesh size and of different heights. The relative abundance of the S. nasutus caught was analysed monthly and a positive relationship was found be tween catches per unit effort in number and biomass. The relative catches were more abundant for the nets of 40 and 50 mm mesh size. Catches were characterized by clear temporal variations and a predominance of medium size fish throughout the study period. The selectivity curve of gillnets for S. nasutus in this ecosystem was obtained. The catch obtained was compared with the avail able catch for each mesh size, and the available catch for a cer tain length of fish was calculated starting from the theoretical se lectivity curve. The 50 mm mesh size gillnet showed the best fit between real and available captures and was considered the most suitable, because a smaller mesh size resulted in a catch of pre dominantly immature specimens. It is expected that these results will contribute to improving management strategies for conserva tion of resources. Parameters such as the minimum catch length advisable or the mesh size permitted for a given species are indis pensable for such decision‐making.

Threatened fishes of the world: Valencia hispanica (Valenciennes, 1846) (Valenciidae)

Common names: Valencia toothcarp; Samaruc (Spanish). Conservation status: CR A2ace (IUCN 2008); EN B1+2abcde (Spanish Red List; Doadrio 2002). Identification: Adult males show a grey-blue coloration with narrow dark transversal bars, borders of the pectoral and caudal fins are yellow to orange (Kottelat and Freyhof 2007). Males (total length< 67 mm) are smaller than females (total length< 71 mm) (Caiola et al. 2001a). Picture by F.J. OlivaPaterna. Distribution: It is restricted to the eastern Spanish coastline where independent conservation units were established (Fernández-Pedrosa et al. 1995; Perdices et al. 1996). Abundance: Only ten wild populations exist, no more than five are in good conservation status (Caiola 2006). Ecology: V. hispanica inhabits small coastal freshwater systems locally known as “ullals”. Exceptionally, it may live in some wetlands like coastal lagoons and swamps. The species is characterized by slow growth and high longevity (4+females; 3+males) when compared to other Cyprinodontiformes (Caiola et al. 2001a). It has a narrow trophic spectrum (gammarids, midges and isopods) (Caiola et al. 2001b; Caiola and De Sostoa 2002). Reproductive strategy: Low reproductive effort, relatively late maturity and multiple spawning between April and July. Current threats include punctuated distribution, habitat loss, water pollution and the introduction of exotic Environ Biol Fish (2009) 85:275–276 DOI 10.1007/s10641-009-9486-3