A natural constant predicts survival to maximum age.

Information about the survival of species is important in many ecological applications. Yet, the estimation of a species' natural mortality rate M remains a major problem in the management and conservation of wild populations, often circumvented by applying empirical equations that relate mortality to other traits that are more easily observed. We show that mean adult M can be approximated from the general law of decay if the average maximum age reached by individuals in a cohort is known.

Elevated trawling inside protected areas undermines conservation outcomes in a global fishing hot spot.

Marine protected areas (MPAs) are increasingly used as a primary tool to conserve biodiversity. This is particularly relevant in heavily exploited fisheries hot spots such as Europe, where MPAs now cover 29% of territorial waters, with unknown effects on fishing pressure and conservation outcomes. We investigated industrial trawl fishing and sensitive indicator species in and around 727 MPAs designated by the European Union.

Estimating growth from tagging data: an application to north-east Atlantic tope shark Galeorhinus galeus.

This study addresses the inherent uncertainty when estimating growth from limited mark-recapture information. A selection procedure was developed utilizing 18 competing growth estimation methods. The optimal method for a given data set was identified by simulating the length at capture and recapture under different scenarios of measurement error and growth variability while considering the structure of observed data.

Plasma and erythrocyte lipid composition in normal pregnancy.

Variations of the plasma and erythrocyte lipid composition were studied in 110 clinically normal pregnant women at different gestational ages; a longitudinal study, carried out in 10 of these women, confirms the results of the cross-sectional study. The main changes observed in the plasma are a rise of the levels of triglycerides, phosphatidyl-cholines and to a lower extent of sphingomyelins; these increases are significantly correlated with the gestational age. The RBC lipid composition is faintly modified throughout pregnancy; the most important changes are observed close to term: after 35 weeks of gestation, the concentration of sphingomyelins, phosphatidyl-cholines and phosphatidyl-ethanolamines are higher and that of the cholesterol/phospholipids is lower than at the beginning of pregnancy.