Comparative genetic structure in two high-dispersal prawn species from the south-west Indian Ocean

The penaeid prawns Fenneropenaeus indicus and Metapenaeus monoceros support shallow-water prawn fisheries in the south-west Indian Ocean. They are sympatric and have similar life histories, including developmental stages that depend on estuarine and marine habitats and a short dispersal duration. Nevertheless, M. monoceros juveniles display a more generalist habitat preference in estuaries and recruit to offshore habitats during a different season than F. indicus. We hypothesised that these differences would affect dispersal patterns, leading to dissimilar geographic genetic structure between the two taxa. Given their short dispersal phase, we also hypothesised that the Mozambique Channel would form a barrier to dispersal between the southeastern African mainland and Madagascar sites. Population differentiation was assessed based on analysis of mitochondrial DNA control-region sequences. Both species displayed high haplotype and low nucleotide diversity. Pairwise ?_ST statistics supported the existence of admixed populations along the African mainland sites for both species, with geographic distance isolating populations at the extremes of the sampled range (Kenya and east coast of South Africa). The Madagascar population differed significantly from African mainland populations. The concordant patterns in population differentiation suggest that F. indicus and M. monoceros can be considered as single African stocks, or fisheries management units.     

Water-level changes in the wells of Kamchatka at the time of the <Emphasis Type="Italic">M</Emphasis><Subscript><Emphasis Type="Italic">w</Emphasis></Subscript> 7.6, April 20, 2006 Olyutorskii earthquake

The seismic waves excited by the M _w 7.6 Olyutorskii earthquake that occurred on April 20, 2006 in the Koryak Upland gave rise to water-level changes in five wells situated in continental areas of Kamchatka at hypocentral distances of 750–1150 km. We describe the effects due to seismic waves, as well as the water-level anomalies for February–April 2006 before the earthquake. We used an original technique for the processing of water-level records based on the study of barometric and tidal water-level responses in order to estimate the volume strain in water-saturated rocks during synchronous level variations at two wells. We discuss possible mechanisms for producing anomalous water-level changes due to elastic deformation of monitored groundwater reservoirs and to crack dilatancy in the water-saturated rocks.     

The influence of hydrometeorological factors on the results of geophysical monitoring conducted at the Petropavlovsk-Kamchatskii Geodynamic Test Site

A local model has been developed for the Petropavlovsk-Kamchatskii Geodynamic Test Site; the model is concerned with the transformation of atmospheric precipitation in the snow cover and in the active soil layer. The input parameters of the model are standard hydrometeorological observations, the output consists in the variation of moisture content in the soil and evaporation from it. Data from water level monitoring carried out at the Site for the purpose of earthquake prediction were used to show how the output parameters can be utilized to reveal the water level variations in a well due to the moisture content variation in the upper crust. The procedure makes the data interpretation more correct.