Determining the causes behind the collapse of a small pelagic fishery using Bayesian population modeling.

Small pelagic fish species present complex dynamics that challenge population biologists and prevent effective management. Huge fluctuations in abundance have traditionally been associated with external environmental forcing on recruitment, exempting other processes from contributing to fisheries collapse. On the other hand, theory predicts that density dependence and overexploitation can increase the likelihood of population oscillations.

Seasonality of North Atlantic phytoplankton from space: impact of environmental forcing on a changing phenology (1998-2012).

Seasonal pulses of phytoplankton drive seasonal cycles of carbon fixation and particle sedimentation, and might condition recruitment success in many exploited species. Taking advantage of long-term series of remotely sensed chlorophyll a (1998-2012), we analyzed changes in phytoplankton seasonality in the North Atlantic Ocean. Phytoplankton phenology was analyzed based on a probabilistic characterization of bloom incidence.

Phytoplankton growth and microzooplankton grazing in the subtropical Northeast Atlantic.

Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E). Our design included two phytoplankton size fractions (0.2-5 µm and >5 µm) and five depths, allowing us to characterize differences in growth and grazing rates between size fractions and depths, as well as to estimate vertically integrated measurements.

Effects of the 'Prestige' oil spill on macroalgal assemblages: large-scale comparison.

An assessment of the effects of the 'Prestige' oil spill on intertidal, macroalgal assemblages was carried out comparing abundance data obtained before and after the spill. Four zones in the North and Northwest coast of Spain were sampled, one of them located at the immediate vicinity of the spill, the zone most heavily oiled. Macroalgal assemblages had similar structure between years.

Seasonal plankton dynamics along a cross-shelf gradient.

Much interest has recently been devoted to reconstructing the dynamic structure of ecological systems on the basis of time-series data. Using 10 years of monthly data on phyto- and zooplankton abundance from the Bay of Biscay (coastal to shelf-break sites), we demonstrate that the interaction between these two plankton components is approximately linear, whereas the effects of environmental factors (nutrients, temperature, upwelling and photoperiod) on these two plankton population growth rates are nonlinear. With the inclusion of the environmental factors, the main observed seasonal and inter-annual dynamic patterns within the studied plankton assemblage also indicate the prevalence of bottom-up regulatory control.

The effect of the "Prestige" oil spill on the plankton of the N-NW Spanish coast.

Chlorophyll, primary production, zooplankton biomass and the species composition of phytoplankton and zooplankton were studied in 2003, after the Prestige shipwreck. The information obtained was compared to previous data series available for the area affected by the spill. A large data series on plankton variables for the N-NW Spanish coast existed, and therefore a realistic evaluation of the effects by comparison with the range of natural variability could be carried out.