As a result of the stagnation of commercial fishery landings, aquaculture activities are expected to increase over the next decades to match the growing demand for marine protein. Overall, it is ...expected that the aquaculture sector could reduce some of the fishing pressure applied to wild stocks. However, this development is likely to be limited by the availability of key aquaculture inputs, specifically fishmeal and fish oil products (FMFOP). Aquaculture provided 60 % (fish meal) and 80 % (fish oil) of the world total consumption of these products in 2007. FMFOP are generally derived from small pelagic fish species, but can also be derived from other sources. Identifying the origin of FMFOP is crucial to understanding the effects of this new pressure on marine social-ecological systems. Two factors are of particular importance in the reduction sector transforming wild fish into fishmeal or fish oil: the two “conversion ratios” (i.e. the ratio between the quantity of wild fish harvested and the resulting quantity of FMFOP, and the ratio between the quantity of FMFOP and aquaculture production), and the type of raw material used by the reduction sector. Based on trade and production databases from FAO and the International Fishmeal and Fish oil Organisation (IFFO), this paper proposes an approach to identify the origin of FMFOP. It shows that whereas different countries use different pelagic resources to produce FMFOP, other countries use non-pelagic sources, and some countries use pelagic resources for human consumption.
The dynamics and evolution of rifts and continental rifted margins have been the subject of intense study and debate for many years and still remain the focus of active investigation. The 2006 AGU ...Fall Meeting session “Extensional Processes Leading to the Formation of Basins and Rifted Margins, From Volcanic to Magma-Limited” included several contributions that illustrated recent advances in our understanding of rifting processes, from the early stages of extension to breakup and incipient seafloor spreading. Following this session, we aimed to assemble a multi-disciplinary collection of papers focussing on the architecture, formation and evolution of continental rift zones and rifted margins. This
Tectonophysics Special Issue “Role of magmatism in continental lithosphere extension” comprises 14 papers that present some of the recent insights on rift and rifted margins dynamics, emphasising the role of magmatism in extensional processes. The purpose of this contribution is to introduce these papers.
Background: Lactose malabsorption is normally evaluated by measuring exhaled H2 produced by intestinal flora, from unabsorbed lactose. However, differing microbiome composition can lead to the ...production of CH4 instead of H2; hence, some authors challenge the H2 method sensitivity and favor the evaluation of both intestinal gases. Aim: To compare different approaches to usage of a lactose breath test for lactose malabsorption diagnosis, after medical evaluation of gastrointestinal symptoms. Methods: In a retrospective observational study, we compared the 2 approaches in a population of 282 subjects in Northern Italy. Following oral lactose administration, exhaled samples were harvested every 30 minutes for 4 hours and prepared for H2 and CH4 analysis. Basal gas levels were subtracted from H2 and CH4 ppm and values at 4 hours and peaks were considered for analysis.Results: Applying the standard methodology, which takes separately into consideration H2 and CH4 produced in the intestinal lumen, the results indicated that 11.7% of the patients were diagnosed “positive” for hypolactasia, differently from what was expected. Conversely, taking into consideration the sum of H2 and CH4, the percentage increased to 62.8%, closer to the expected one. No significant differences were found when comparing the 2 groups for age, gender, or symptoms. The sizable difference between the 2 approaches is likely linked to gut microbiome variability, and consequently the different production of the 2 gases, in the population. Conclusion: The threshold normally used for lactose breath test should be reconsidered and changed, merging H2 and CH4 stoichiometric values to increase sensitivity.
Both evolutionary ecologists and wildlife managers make inference based on how fitness and demography vary in space. Spatial variation in survival can be difficult to assess in the wild because (1) ...multisite study designs are not well suited to populations that are continuously distributed across a large area and (2) available statistical models accounting for detectability less than 1.0 do not easily cope with geographical coordinates. Here we use penalized splines within a Bayesian state-space modeling framework to estimate and visualize survival probability in two dimensions. The approach is flexible in that no parametric form for the relationship between survival and coordinates need be specified a priori. To illustrate our method, we study a game species, the Eurasian Woodcock
Scolopax rusticola
, based on band recovery data (5000 individuals) collected over a >50 000-km
2
area in west-central France with contrasted habitats and hunting pressures. We find that spatial variation in survival probability matches an index of hunting pressure and creates a mosaic of population sources and sinks. Such analyses could provide guidance concerning the spatial management of hunting intensity or could be used to identify pathways of spatial variation in fitness, for example, to study adaptation to changing landscape and climate.
The development of a Sauvignon Blanc wine sealed under screwcap and cork was undertaken using different fill heights and initial levels of free SO2 (20, 25, and 30 mg/L) over 2 years. More SO2 was ...lost for wines under cork over the first 3 months, corresponding to a higher level of dissolved oxygen at bottling. From this time wines under cork and screwcap lost SO2 at a similar rate and retained dissolved CO2 equally well, indicating that both types of closure presented a similar effective barrier to gas movement. After 2 years in the bottle, the different treatments retained similar levels of the volatile thiols 3-mercaptohexyl acetate (3MHA) and 3-mercaptohexanol (3MH) responsible for fruity aromas, with initial SO2 levels having no effect, but the thiol concentrations were 18−23% lower under cork, which may be due to absorption of volatiles into the cork. Levels of polyphenols such as caftaric acid and the absorbance at 420 nm were the same for wines under cork and screwcap, whereas some indication was given that more oxidation occurred with a lower level of initial free SO2. Although the different treatments were not readily distinguished by a sensory panel, the data for individual wines showed a positive correlation between passion fruit descriptors and levels of 3MHA and 3MH. Keywords: Sauvignon Blanc; screwcap; cork; closure; wine aging; sensory analysis; polyphenols; volatile thiols
Researchers often rely on capture-mark-recapture (CMR) data to study animal dispersal in the wild. Yet their spatial coverage often does not encompass the entire dispersal range of the study ...individuals, sometimes producing misleading results. Information contained in population surveys and variation in population spatial structure can be used to overcome this issue. We build an integrated model in a multisite context in which CMR data are only collected at a subset of sites, but numbers of breeding pairs are counted at all sites. In a Black-headed Gull
Chroicocephalus ridibundus
population, the integrated-modeling approach induces an increase in precision for the demographic parameters of interest (variances, on average, were decreased by 20%) and provides a more precise extrapolation of results from the CMR data to the whole population. Patterns of condition-dependent dispersal are therefore made easier to detect, and we obtain evidence for colony-size dependence in recruitment, dispersal, and breeding success. These results suggest that first-time breeders disperse to small colonies in order to recruit earlier. The exchange of experienced breeders between colonies appears as a main determinant of the observed variation in colony sizes.
Life-history theory predicts that traits involved in maturity, reproduction and survival correlate along a fast–slow continuum of life histories. Evolutionary theories and empirical results indicate ...that senescence-related traits vary along this continuum, with slow species senescing later and at a slower pace than fast species. Because senescence patterns are typically difficult to estimate from studies in the wild, here we propose to predict the associated trait values in the frame of life-history theory. From a comparative analysis based on 81 free-ranging populations of 72 species of birds and mammals, we find that a nonlinear combination of fecundity, age at first reproduction and survival over the immature stage can account for ca two-thirds of the variance in the age at the onset of actuarial senescence. Our life-history model performs better than a model predicting the onset based on generation time, and it only includes life-history traits during early life as explanatory variables, i.e. parameters that are both theoretically expected to shape senescence and are measurable within relatively short studies. We discuss the good-fit of our life-history model to the available data in the light of current evolutionary theories of senescence. We further use it to evaluate whether studies that provided no evidence for senescence lasted long enough to include the onset of senescence.
PDF
