Potential vector species of carp edema virus (CEV)

During a PCR‐based CEV survey in Poland in 2015–2017, the virus was detected in many farms both in clinical and asymptomatic cases and in common as well as in koi carp (Cyprinus carpio). In order to evaluate the potential carrier role of fish species that share the same habitats with carp, an experimental trial was performed. Investigations carried out on specimens of bleak (Alburnus alburnus), crucian carp (Carassius carassius), European perch (Perca fluviatilis), Prussian carp (Carassius gibelio), roach (Rutilus rutilus) and tench (Tinca tinca) cohabited with CEV‐infected carp yielded positive results. These species of fish were experimentally cohabited with CEV‐infected common carp at a temperature of 16°C ± 1. Material from the brain, gills, spleen, kidneys, intestine and skin was investigated for the presence of CEV DNA. Similar investigations were performed with uninfected fish designated controls. Samples were tested for CEV by qPCR.     

Age–length relationships in UK harbour seals during a period of population decline

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Ecological impacts of invasive carp in Australian dryland rivers

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Effect of the coupled action of ultrasonic waves and advanced oxidation reaction on the properties of bottom sediments originating from trout culture

The objective of this study was to determine the effect of preliminary ultrasound treatment of bottom sediments, a factor enhancing the reaction of advanced oxidation, on changes in the properties of sediments originating from the intensive aquaculture of rainbow trout. Experiments were conducted on a laboratory scale in model reactors with an active volume of 1.0 L, either under conditions of exposure to the ultrasonic field alone or under conditions of exposure to both the ultrasonic field and a chemical reagent: Fe³⁺/H₂O₂. The results we achieved showed that preliminary ultrasound treatment of bottom sediments increased the advanced oxidation reaction yield and consequently improved the physicochemical properties of the sediments. The highest yield was obtained upon 15‐min ultrasound treatment at a Fenton reagent dosage of 1.5 g Fe³⁺ L^?1 and g H₂O₂ L^?1. These conditions enabled a 43% reduction in the concentrations of organic compounds in the filtrate, shortened the capillary suction time (CST) by 93%, decreased the concentration of volatile substances in the sediments by 13% and decreased the levels of total nitrogen in sediments by 9% and of total phosphorus in the filtrate by 21%, and additionally caused a decrease in the mineral and dry matter content in the sediments.     

Foliar applications of calcium do not impact on fruit and leaf nutrient concentration or quality of ‘O’Neal’ blueberry

Calcium (Ca) has been considered a key element in maintaining fruit quality and extending the storage period of several fruits. The main blueberry (interspecific hybrids of Vaccinium corymbosum x V. darrowii) market for the Southern Hemisphere production involves a long transport between harvest and consumption. Foliar Ca sprays during the pre-harvest constitutes a common practice for improving Ca concentration [Ca] in fruits and therefore in alleviating the loss of firmness, dehydration and rot decay during postharvest. In this study, two formulations of Ca; Ca-nitrate [Ca(NO₃)₂] and chelate Ca-oxide (Ca-gluconate; Ca-Glu) were sprayed four times during pre-harvest of blueberry cv. O’Neal. [Ca] in the fruits was followed after each application and fruit quality parameters were determined at harvest and during 28 days of cold storage. Both formulations were ineffective in increasing [Ca] in the berries (or leaves) after any of the four applications. In fruits, [Ca] decreased from 0.32% at 25 days after full bloom (DAFB) to 0.11% Ca at harvest time. Other minerals such as magnesium (Mg), potassium (K), or nitrogen (N) remained unaffected by the treatments. Data shows that foliar pre-harvest applications of Ca, regardless of formula, were ineffective at increasing [Ca] or improving the quality of the fruit.     

Estimation of additive and epistatic gene effects of doubled haploid lines of winter oilseed rape (<Emphasis Type="Italic">Brassica napus</Emphasis> L.)

In this paper 60 doubled haploid lines of oilseed rape (Brassica napus L.) were studied. Genetic parameters as additive and epistasis effects were estimated for nine quantitative traits. The results indicate the importance of both additive and epistasis gene effects of number of branches per plant, number of siliques per plant, number of seeds per silique and silique length in this study.     

Diet of demersal fish species in relation to aquaculture development in Scottish sea lochs

The diets of demersal fish, principally haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus) and several flatfish species, sampled from four Scottish sea lochs (Hourn, Kishorn, Duich and Nevis) which support aquaculture sites, were examined in order to determine whether the impact of aquaculture on benthic biodiversity would affect the diets of demersal fish. Loch Kishorn had the highest maximum planned aquaculture production, loch Nevis follows and lochs Hourn and Duich have the lowest planned production. Samples were collected from locations less than and more than 2000 m from fish farm cages. Fish close to the fish farm cages were on average of greater individual weight than those further away from fish farms. Haddock ate predominantly Malacostracan crustacea, Ophiurid echinoderms and Polychaete annelids; whiting ate predominantly Malacostracan crustacea and teleost fish and flatfish ate Malacostracan crustacea, Polychaete annelids and Ophiurid echinoderms. A small number of saithe sampled had eaten mainly fish farm pellets. Dietary variation in each species was analysed in relation to loch, proximity to aquaculture facilities and fish size. Diet of whiting varied with body size. Dietary differences were observed between the lochs and between sites close to and far from farms in two lochs although these differences cannot be specifically attributed to aquaculture development. Controlling for differences between individual lochs, proximity to aquaculture facilities did not consistently affect diet composition.