Infection conditions of <Emphasis Type="Italic">Fusarium graminearum</Emphasis> in barley are variety specific and different from those in wheat

Fusarium head blight is one of the most noxious cereal diseases. Worldwide, F. graminearum (FG) and the mycotoxin deoxynivalenol (DON) is the most dominant species/mycotoxin in barley and wheat. Barley is often produced as on farm feed and thus routine mycotoxin analyses similar to those of cereals for human consumption are not performed. Hence, an early prediction of mycotoxin levels is important for farmers to minimise the risk of contaminated feed but also of contaminated cereals entering the cereal supply chain. Therefore, climate chamber experiments with artificial FG infection of barley investigating the influence of different temperatures (10 °C, 15 °C, 20 °C) and durations (4 h, 8 h, 12 h) at 99% relative humidity were conducted to accumulate data to develop a forecasting system. An up to three times higher DON contamination in the 15 °C treatments for the feed barley variety Ascona was detected compared with the 10 °C and 20 °C treatments. For the malting barley variety Concerto, the prolonged humidity durations had a stronger effect under all tested temperatures and resulted in up to two times higher DON contaminations. In addition, field experiments where spore deposition during anthesis as well as disease incidence, fungal amount and mycotoxins were observed, showed that the overwintered straw treatment resulted, depending on the year, in a three times higher FG incidence and DON content compared with the control and freshly inoculated straw treatment.     

Rebuilding global fisheries: the World Summit Goal,costs and benefits

Many of the world’s fish stocks are depleted as a result of overexploitation, pollution and habitat loss. The 2002 World Summit on Sustainable Development (WSSD) sets a target for fisheries to maintain or restore stocks to levels that can produce the maximum sustainable yield (MSY) by 2015. We assessed the global stock status and found that 68% were at or above the MSY level in 2008 and that the 2015 target is unlikely to be met. We compiled data for eight indicators to evaluate the sustainability of fisheries and the gap to meet the WSSD target. These indicators show that the overall condition of global fisheries is declining, long‐term benefits are being compromised, and pressures on fisheries are increasing despite fisheries policy and management actions being taken by coastal States. We develop a bio‐economic model to estimate the costs and benefits of restoring overfished stocks. Our results show that the global fishing capacity needs to be cut by 36–43% from the 2008 level, resulting in the loss of employment of 12–15 million fishers and costing US$96–358 billion for buybacks. On the other hand, meeting the WSSD goal will increase annual fishery production by 16.5 million tonnes, annual rent by US$32 billion and improve biodiversity and functioning of marine ecosystems. However, progress towards rebuilding has been hindered by an unwillingness or inability to accept the short‐term socio‐economic consequences associated with rebuilding fisheries. Thus, there is a pressing need for integration of rebuilding plans into national political and economic decision‐making.     

Control mechanisms and ecosystem‐based management of fishery production

Fishery ecosystems are complex and influenced by various drivers that operate and interact at different levels and over multiple scales. Here, we propose a holistic methodology to determine the key mechanisms of fisheries, trophodynamics, and environmental drivers of marine ecosystems, using a multilevel model fitted to data on global catch, effort, trophic level, primary production, and temperature for 130 ecosystems from 1950 to 2012. The model describes the spatial‐temporal dynamics of world fisheries very well with a pseudo R² = 0.75 and estimates the effects of key drivers of fishery production. The results demonstrate the integrative operation of bottom‐up and top‐down regulated trophic interactions at the global level and great variations in their relative importance among different types of ecosystem. The estimation of key drivers’ effects on marine ecosystems provides practical mechanisms for informed ecosystem‐based fisheries management to achieve the sustainable objectives that are consistent with the needs of specific fisheries.     

Effects of microalgae‐added diets on growth performance and meat composition of tilapia (Oreochromis mossambicus)

Two floating diets and one sinking diet were prepared for tilapia with local ingredients by extrusion or steam‐pelleting methods. Indoor and outdoor feeding trials were conducted to evaluate their effects on growth performance and quality of tilapia products. Local ingredients included defatted Haematococcus and Spirulina by‐products from Hawaii. The three diets, plus a commercial feed, were each assigned to three replicate tanks, and each tank (120 L) was stocked with 12 juvenile tilapia in an 8‐week indoor trial. The results showed that (1) the floating diet had significantly (P < 0.05) higher weight growth than the sinking diet; (2) increased inclusion of local microalgae by‐product (defatted Haematococcus) in floating diet from 12% to 24% significantly (P < 0.05) decreased tilapia weight growth; and (3) the three microalgae‐added diets obtained higher (P < 0.05) weight growth than the commercial feed, although they contained lower protein (36.9% to 37.7%) and lipid (7.1% to 8.1%) than the commercial feed (42.3%; 8.6%). The floating diet (containing 12% microalgae) and the commercial feed were also tested in outdoor green water tanks, simulating the commercial production conditions of local tilapia farms. Each diet had three replicate tanks (1200 L) stocked with 100 juvenile tilapia. The 12‐week trial showed that the local diet had significantly (P < 0.05) lower growth (12.0 g week^?1) than the commercial feed (14.8 g week^?1). All tilapia meat products were measured with low n‐3 fatty acid contents. These results provide important information for feed formulation and production using local ingredients for tilapia.     

The use of probiotics during the nursery rearing of the pink shrimp Farfantepenaeus brasiliensis (Latreille, 1817) in a zero exchange system

The present work evaluated the use of probiotics during the nursery rearing of the pink shrimp Farfantepenaeus brasiliensis, in a zero exchange aerobic heterotrophic culture system during 30 days. Three replicate tanks were randomly assigned to the following treatments: (1) Bacillus spp. mixture (Sanolife Pro‐‐W^®), (2) Bacillus sp., Enterococcus sp., Lactobacillus spp. mixture (Biomin Start‐grow^®), (3) Bacillus cereus var. toyoi and (4) control treatment (without probiotic addition). Bacteriological analysis monitored the abundance of presumptive Vibrio spp. in the water of experimental tanks. For the immunological analysis, shrimp haemolymph was collected to determine the granular haemocyte count and total protein concentration. Results showed that mean final weight and specific growth rate of shrimp in the probiotic treatments were significantly higher. Furthermore, shrimp reared in the probiotic treatments showed higher levels of total protein and granular haemocyte. The bacteriological analysis showed that the concentration of Vibrio spp. measured in probiotic treatment tanks was lower than that recorded in the control tanks.     

The critical period for weed competition in French bean (Phaseolus vulgaris L.) in Mediterranean areas

Field experiments were carried out in 2004 and repeated in 2005 and 2006 in central Italy to determine the effect of competition from a natural weed flora on growth and yield of French bean (Phaseolus vulgaris L.). Two treatments were applied; weeds were either allowed to infest the crop or plots were kept weed free for an increasing duration of time (0, 7, 21, 28, 35, 45 days) after crop emergence. To assess the critical period of weed competition (CPWC) and the influence of weed infestation on yield, the Gompertz and logistic equations were fitted to data which represented the increasing duration of weed-free and weed-infested periods, respectively. During the three years of the experiment weeds, allowed to interfere for the whole growing season, reduced fresh pods yields up to 60%, 65% and 59% of the weed-free bean plots. Based upon an arbitrary yield loss (AYL) of 5%, the CPWC was from 50 Growing Degree Days (GDD) to 284 GDD, i.e. from 11 days after emergence (DAE) to 28 DAE. These values correspond to the lowest and highest values observed in the three experiments respectively for the weed-infested and weed-free period.     

Mariculture for bacterial and organic waste removal: a field study of sponge filtering activity in experimental farming

Culture experiments in the field were performed on western Mediterranean populations of Ircinia variabilis and Agelas oroides. To evaluate culture and filtering performances among polluted and unpolluted sites in shallow waters, farming experiments were carried out in a harbour, a small tourist nautical base and a pristine biotope. Sponge explants were cultured onto nylon ropes, and in situ clearance rate tests were performed on farmed sponges to assess filtering ability under diverse farming conditions. At the harbour site, sponge survival and growth were similar to that observed in the two unpolluted sites until early summer, when a rapid increase in explant mortality occurred in response to extreme variations in environmental conditions. Filtering experiments revealed high retention and clearance rates of I. variabilis and A. oroides at all sites. The highest rates were observed at the polluted site, reflecting the optimal metabolic performance of explants in the first phase of culture under stressful conditions. Our results highlight the feasibility of sponge microcosms and the ability of I. variabilis and A. oroides to clear large volumes of water of organic and bacterial loads in polluted sites.