The daily egg production method: recent advances, current applications and future challenges

More than 120 surveys over 25 years suggest that appropriate use of the daily egg production method (DEPM) provides unbiased but rather imprecise estimates of spawning biomass (coefficient of variation generally above 30%). Knowledge of species reproductive biology and early life history and a survey design adapted to local population dynamics are required to optimize DEPM performance in terms of bias, precision and cost. Clupeoid applications dominate worldwide (mainly for anchovies and sardines) and estimates are often used to tune indirect assessment models or to calibrate other fisheries‐independent methods. The method seems better adapted to the life history of anchovies than of sardines, leading to more precise estimates of anchovy spawning biomass and facilitating extensions of the method to estimate total biomass and numbers at age. The continuous underway fish egg sampler is often used as a secondary sampler in the ichthyoplankton survey of the DEPM to reduce the cost and improve the precision of egg production. Multinomial models were recently developed to analyse egg incubation data and used in a Bayesian procedure for egg ageing and delimitation of daily cohorts. These were incorporated in model‐based estimators to get spatially explicit estimates of egg production, daily fecundity parameters and spawning biomass that can improve the precision of DEPM. Uncertainty in daily fecundity estimation of clupeoids is mainly because of spawning fraction estimation by the post‐ovulatory follicle (POF) method. Exploration of recent histological and molecular techniques for POF characterization and laboratory experiments to test the effect of temperature on POF degradation can help to improve spawning fraction estimation. Available estimates of egg production and mortality, daily fecundity, spawning area and biomass from different populations, species and ecosystems are being used to improve the understanding of clupeoid spawning dynamics, their relation with ecosystem productivity and to build comprehensive population models. Finally, a counter‐intuitive finding of this review is that, although the DEPM is almost exclusively applied to clupeoids, recent evidence indicates that it may be easier and cheaper to use in other teleost families, including demersal species.     

New bricks on the wall of induced resistance: salicylic acid receptors and transgenerational priming

In nature, plants have to cope with different types of stress. Stress by pathogens can be avoided through a plant response called Systemic Acquired Resistance (SAR). SAR is regulated by salicylic acid amongst other signals. Recently, several findings help us to have a deeper knowledge of SAR. On one hand, two different research groups have reported three different putative salicylic acid receptors; on the other hand, another two groups of scientists have found evidence about the basis of transgenerational priming in inducing resistance against pathogens. All these discoveries are discussed in the frame of the recent literature.     

Distance to flood meadows as a predictor of use of <Emphasis Type="Italic">Nothofagus pumilio</Emphasis> forest by livestock and resulting impact,in Patagonia,Argentina

Seedling browsing by livestock has been indicated as major threat for forest sustainability use. Nothofagus pumilio forests are part of the livestock raising system in Patagonia, but because of the sparse understory cover, livestock graze mainly on flood meadows within the forest matrix. The complexity of the environment under study (forests and flood meadows) means that an adaptive predictor is needed to evaluate the intensity of resource use by livestock in order to assess its effect on the forest. Distance to flood meadows was evaluated as a predictor of the use intensity of the forest by livestock and its effect on the understory. The study was conducted at three sites in Chubut Province, Patagonia–Argentina. We established transects in the forest 320 m long, starting at the edge flood meadow-forest. In these transects, the livestock presence indicators (soil compaction, density of feces and trails) and composition of the understory were evaluated. Generalized Linear Model for repeated measures for longitudinal data were used. The indicators showed that distance is efficient for estimating forest use intensity by livestock. The understory varied with distance, the cover of exotic herbaceous was higher near the flood meadow. Far from the flood meadow, the cover was entirely composited of native species. The results support the use of distance to flood meadows as a tool for decision making in livestock and forest management in N. pumilio forests, and for further research on livestock effect on the forest.     

Response of <Emphasis Type="Italic">Piptatherum miliaceum</Emphasis> to co-culture with a legume species for the phytostabilisation of trace elements contaminated soils

Purpose

The presence of high concentrations of trace elements (TEs) in mine soils like those in the Sierra Minera of La Unión-Cartagena (SE Spain) limits the development of a vegetation cover on such sites, and pollution dispersion by water and wind erosion represents a serious risk for the surrounding ecosystems. The aim of this study was to evaluate different phytostabilisation procedures based on the co-culture of a legume (Bituminaria bituminosa) and a high-biomass (Piptatherum miliaceum) species for this type of soils.

Materials and methods

A pot experiment was carried out where B. bituminosa was tested as a soil pre-treatment strategy. Five different procedures were followed to study the growth stimulation or competition of both species in a contaminated soil from the Sierra Minera: (i) sowing of P. miliaceum without B. bituminosa (control treatment), (ii) sowing of P. miliaceum for co-cultivation of both species, (iii) sowing of P. miliaceum and co-cultivation of both species in soil with compost, (iv) harvesting and elimination of the aerial part of the plants before sowing of P. miliaceum and (v) harvesting and incorporation to the soil of the aerial part of B. bituminosa before sowing of P. miliaceum.

Results and discussion

The results showed that the co-culture of both species favoured the growth of P. miliaceum, whilst incorporating the aerial part of the legume to the soil increased nitrogen concentration in P. miliaceum but reduced its growth. The use of compost improved both the growth and N uptake of P. miliaceum and did not inhibit nodulation in B. bituminosa. TE extractability in the soils and accumulation in the plants were rather low and very little affected by the addition of the amendments or by co-culture of species.

Conclusions

Nitrogen availability plays an important role in P. miliaceum growth in TE-contaminated mine soils. The addition of compost together with legume cultivation is proposed as an effective combination for the cultivation of P. miliaceum in these soils, as both plant growth and soil conditions were improved following this procedure.

     

Selective and Apoptotic Action of Ethanol Extract of Annona cherimola Seeds against Human Stomach Gastric Adenocarcinoma Cell Line AGS

Plant Foods for Human Nutrition - Annona cherimola is a tree belonging to the family Annonacea, whose fruit (cherimoya) is very desirable, but its seeds are considered waste. Present in these seeds...     

Seroincidence of porcine T. solium infection in the Peruvian highlands

We performed repeated serological sampling of pigs in an endemic area of the Peruvian highlands (eight villages) to assess the feasibility of detecting incident cases of Taenia solium infection as indicators of ongoing transmission of the parasite. A total of 2245 samples corresponding to 1548 pigs were collected in three sampling rounds (n=716, 926, and 603, respectively). Village-period specific seroprevalences of antibodies by enzyme-linked immunoelectrotransfer blot (EITB) assay varied from 39% (95% CI: 34, 44) to 76% (95% CI: 72, 79). The prevalence of cysticercosis increased with the age of the pigs (similarly for both sexes). Around 40% of pigs were re-sampled at the end of each 4-month period. Crude incidence risks were 48% (57/120, 95% CI: 43–52) and 58% (111/192, 95% CI: 54–61) for each period. A proportion of seropositive animals became seronegative at the end of each period (23 and 15%). Incidence varied by the village, and the exposure period, and was higher in males than females (but did not differ by age).