Movements and spatial distribution of an endangered fish (Sciaena umbra) within a marine protected area.

The brown meagre (Sciaena umbra) is an endangered species, which requires specific protection measures to ensure its conservation. These measures need to be informed by high-quality scientific knowledge on their space use patterns. Here, we used acoustic telemetry to assess its seasonal movement patterns and habitat use within a marine protected area (MPA). Our results suggested that S. umbra is a highly sedentary species (home range < 1.0 km2) and, therefore, the MPA is extensive enough to protect the local population. Their population was discretely distributed in two main areas within the MPA, which was likely a result of habitat segregation and density-dependent movements. The temporal variability of their movements further uncovered when and where spawning occurs (mainly, but probably not only, in the fully protected area in June) and indicated that spillover of this species is limited but still possible. Overall, we highlight the importance of MPAs in the recovery of S. umbra, we advocate the need to perpetuate the current national fishing bans and extend it to other countries in the Mediterranean region, and we emphasize that considering the fine-scale movements of S. umbra in future management actions is key to achieving a successful recovery of their populations.

Seasonal influence on the bathymetric distribution of an endangered fish within a marine protected area.

The spatio-temporal variability of fish distribution is important to better manage and protect the populations of endangered species. In this sense, the vertical movements of a vulnerable and protected species, Sciaena umbra, were assessed in a marine protected area (the Réserve Naturelle Marine de Cerbère-Banyuls, south of France) to study the variability of their bathymetric distribution at different time scales. Twenty adults were marked with acoustic transmitters and acoustically monitored over 2.5 years. This revealed that some individuals remained at shallow waters (< 8 m) all year round, while others presented vertical segregation at deeper waters during the cold months (mean depth of 22.5 ± 0.04 m) and all aggregated in shallow waters during the warm months. The brown meagre was more active during the night, except in June and July when peaks of activity were observed at dusk. These patterns are likely associated with foraging and reproductive behavior during the cold and warm periods, respectively, and likely regulated by water temperature and the depth of the thermocline. Here, we provide valuable information on when and where in the water column critical periods of S. umbra life cycle are expected to occur, which should be considered in management and protection plans.

Estudio comparativo de la capacidad destructiva de los terremotos de Chile y México de 1985

En este trabajo se compara la capacidad destructiva de los terremotos de Chile y México de 1985 empleando como criterio el potencial destructivo PD. Ambos terremotos tienen la particularidad de haber sido registrados por acelerógrafos en su área epicentral y en la zona de mayores daños, pero tienen a su vez la gran diferencia de que siendo ambos terremotos de gran magnitud de Richter : Chile Ms =7.8 y México Ms = 8.1 los potenciales de daños son significativamente diferentes. El terremoto de Chile se caracterizó por un nivel de dañ moderado en su área ipecentral, en tanto el de México por un bajo nivel de daño en la misma área. El de Chile tuvo daños relativamente menores que el de México, no obstante sus mayores aceleraciones máximas y ordenadas y espectrales de aceleraciones, en sus zonas de mayores daños (AU)

Response spectra and building response in Chile

The seismic behavior of 45 reinforced concrete building between 11 and 23 stories and the response spectra measured in Viña del Mar City for the 1985 Chilean earthquake are used to estimated the design spectra in epicentral zone of Chile. Since most of the response of these buildings was almost elastic. Their good behavior can not be only explained through ductility reductions due to nonlinear incursions. Therefore an additional reduction factor due to earthquake source mechanism between 4 to 5 is proposed to obtain the design spectra (AU)