Diversity, biogeography, evolutionary relationships, and conservation of Eastern Mediterranean freshwater mussels (Bivalvia: Unionidae).

Located at the junction between Europe, Africa, and Asia, with distinct evolutionary origins and varied ecological and geographical settings, together with a marked history of changes in orogeny and configuration of the main river basins, turned the Eastern Mediterranean into a region of high diversity and endemism of freshwater taxa. Freshwater mussels (Bivalvia, Unionidae) from the Western Palearctic have been widely studied in their European range, but little attention has been dedicated to these taxa in the Eastern Mediterranean region and their diversity and phylogeography are still poorly understood. The present study aims to resolve the diversity, biogeography, and evolutionary relationships of the Eastern Mediterranean freshwater mussels. To that end, we performed multiple field surveys, phylogenetic analyses, and a thorough taxonomic revaluation. We reassessed the systematics of all Unionidae species in the region, including newly collected specimens across Turkey, Israel, and Iran, combining COI + 16S + 28S and COI phylogenies with molecular species delineation methods. Phylogeographical patterns were characterized based on published molecular data, newly sequenced specimens, and species distribution data, as well as ancestral range estimations. We reveal that Unionidae species richness in the Eastern Mediterranean is over 70% higher than previously assumed, counting 19 species within two subfamilies, the Unioninae (14) and Gonideinae (5). We propose two new species, Anodonta seddonisp. nov. and Leguminaia anatolicasp. nov. Six additional taxa, Unio delicatusstat. rev., Unio eucirrusstat. rev., Unio huetistat. rev., Unio sesirmensisstat. rev., Unio terminalisstat. rev. removed from the synonymy of Unio tigridis, as well as Unio damascensisstat. rev. removed from the synonymy of Unio crassus, are re-described. The nominal taxa Unio rothi var. komarowi O. Boettger, 1880 and Unio armeniacus Kobelt, 1911 are proposed as new synonyms of Unio bruguierianus, and Anodonta cyrea Drouët, 1881 and Anodonta cilicica Kobelt & Rolle, 1895 as new synonyms of Anodonta anatina. Also, the presence of Unio tumidus in the Maritza River is confirmed. The phylogeographic patterns described here are interpreted concerning major past geological events. Conservation needs and implications are presented, together with populations and species conservation priorities.

Is salinity an obstacle for biological invasions?

Invasions of freshwater habitats by marine and brackish species have become more frequent in recent years with many of those species originating from the Ponto-Caspian region. Populations of Ponto-Caspian species have successfully established in the North and Baltic Seas and their adjoining rivers, as well as in the Great Lakes-St. Lawrence River region. To determine if Ponto-Caspian taxa more readily acclimatize to and colonize diverse salinity habitats than taxa from other regions, we conducted laboratory experiments on 22 populations of eight gammarid species native to the Ponto-Caspian, Northern European and Great Lakes-St. Lawrence River regions. In addition, we conducted a literature search to survey salinity ranges of these species worldwide. Finally, to explore evolutionary relationships among examined species and their populations, we sequenced the mitochondrial cytochrome c oxidase subunit I gene (COI) from individuals used for our experiments. Our study revealed that all tested populations tolerate wide ranges of salinity, however, different patterns arose among species from different regions. Ponto-Caspian taxa showed lower mortality in fresh water, while Northern European taxa showed lower mortality in fully marine conditions. Genetic analyses showed evolutionary divergence among species from different regions. Due to the geological history of the two regions, as well as high tolerance of Ponto-Caspian species to fresh water, whereas Northern European species are more tolerant of fully marine conditions, we suggest that species originating from the Ponto-Caspian and Northern European regions may be adapted to freshwater and marine environments, respectively. Consequently, the perception that Ponto-Caspian species are more successful colonizers might be biased by the fact that areas with highest introduction frequency of NIS (i.e., shipping ports) are environmentally variable habitats which often include freshwater conditions that cannot be tolerated by euryhaline taxa of marine origin.

Dietary administration of Pontogammarus maeoticus extract affects immune responses, stress resistance, feed intake and growth performance of caspian roach (Rutilus caspicus) fingerlings.

Dietary administration of immunostimulants showed promising results for elevation of immune responses and disease resistance. The aim of the present study was to investigate the effects of dietary Pontogammarus (Pontogammarus maeoticus) extract on innate immune response, stress resistance, feed intake and growth performance of the Caspian roach fingerling. Two levels of P. maeoticus extract dilution with distilled water 1:25 [T1] and 1:50 [T2] were prepared. Experimental diets were prepared by top-spraying the basal diet with equal amount (2%) of diluted extracts. One hundred and eighty Caspian roach fingerlings (4.30 ± 0.10 g) were supplied, stocked in nine 100-L tanks (three treatment repeated in triplicates) and fed on experimental diets for 8 weeks. At the end of the trial, serum innate immune parameters (Total Ig, ACH50, and lysozyme activity), resistance against salinity stress, feed intake and growth parameters were measured. The results revealed remarkable increase of innate immune parameters and resistance against salinity stress in roach fed P. maeoticus extracts (P < 0.05). Also, growth performance and food intake were notably improved in P. maeoticus extracts fed fish (P < 0.05). These results revealed beneficial effects of P. maeoticus extract on innate immune response, resistance, feed intake as well as growth performance of the Caspian roach.

Assessment of trace-metal concentrations in Western Reef heron (Egretta gularis) and Siberian gull (Larus heuglini) from southern Iran.

The objective of the present study was to investigate the levels of heavy metals, namely, chromium, copper, cobalt, nickel, and iron, in Western Reef heron (Egretta gularis) (n = 15) and Siberian gull (Larus heuglini) (n = 15) to (1) compare metal concentrations between two bird species with different trophic level, molting pattern, and life strategy; (2) examine species- and sex-related variations in trace-metal accumulation; and (3) determine the significance between heavy-metal concentrations in kidney, liver, and pectoral muscle. Bird samples were collected from November to December 2010 throughout the Hara Biosphere Reserve, and heavy metals were assayed by using a Shimadzu AA 680 flame atomic absorption spectrophotometer; the results were given as µg/g dry weight. Metal concentrations were different between the bird species as well as among bird tissues, but there was no difference (except chromium and iron in kidney) between sex (male vs. female). Mean levels in kidney of Western Reef heron and Siberian gull were chromium (0.96, 2.32 µg/g), copper (6.31, 10.55 µg/g), cobalt (0.12, 0.14 µg/g), nickel (1.13, 1.32 µg/g), and iron (37.92, 39.64 µg/g), respectively, whereas in liver they were chromium (1.05, 2.75 µg/g), copper (8.93, 12.63 µg/g), cobalt (0.09, 0.17 µg/g), nickel (1.1, 2.27 µg/g), and iron (34.03, 44.21 µg/g), respectively. Results showed that heavy-metal concentrations in Western Reef heron were decreased in the sequence iron > copper > nickel > chromium > cobalt, whereas in Siberian gull they were decreased in the sequence iron > copper > chromium > nickel > cobalt. Results also showed that in both species, the highest chromium and nickel concentrations were measured in female birds and the lowest in male birds, whereas the highest copper, cobalt, and iron (except iron in liver) concentrations were measured in male birds and the lowest in female birds.

Use of 13C and 15N for the determination of the metal flux in the Caspian Sea fishes.

Biomagnification of metals (Cd, Cr, Cu, Mn, Ni, Zn, Fe) was investigated in 14 species of Caspian Sea commercial fishes using 13C and 15N analyses to decode their trophic position (TP). The stable nitrogen isotope ratios varied among the Caspian Sea fish species from 8.7 to 13.8‰ while the stable carbon isotope ratios varied from -23.7 to -17.6‰. The TPs varied between 2.2 and 4.9. Clupeonella caspia had the lowest average TP, and Acipenseridae species (except Acipenser persicus) and Sander lucioperca had higher average TPs. Wide intra- and inter-specific differences were observed in metal concentrations. The stable isotope results were relatively coordinated with feeding behaviour of species. However, some exceptions were observed particularly in Alburnus chalcoides and S. lucioperca. By comparing logarithmic concentration of metals vs. TPs, no metal biomagnification was observed. The estimated daily intakes of metals were lower than the provisional tolerable daily intakes and, thus, these amounts do not pose any threat on human health.