Farm-level returns and costs of yellow catfish (Pelteobagrus fulvidraco) aquaculture in Guangdong and Zhejiang provinces, China

AbstractFreshwater aquaculture in China is expanding and intensifying as this country experiences rapid economic growth, and understanding farm-level profitability is necessary if farmers are to make reasonable decisions about their production plans. We conducted a survey of yellow catfish farmers in 2014 in Guangdong and Zhejiang provinces in order to estimate farm-level profitability of pond aquaculture. We selected representative prefectures from the 2 provinces as study areas and used convenience sampling. Eighty-seven farmers were interviewed between April and May 2014 and the questionnaire collected detailed information on: (1) farmers’ demographics (age, gender, education, training, and experience); (2) production inputs (land, labor, fingerlings, feed, chemicals, machinery, and other miscellaneous costs); and (3) outputs (weight and revenue of harvested fish). Responses of 61 farmers included in the data analysis were post-stratified into 3 categories of farm size (<1.47ha, 1.47–3.67ha, and >3.67ha). We calculated production cost components, returns, and returns-costs ratios by farm size in each province. The overall returns-costs ratio was 1.31 in Guangdong and 1.17 in Zhejiang. Farmers in Guangdong invested more in land and machinery and had higher percentages of labor costs and chemical expenditures, but achieved better returns-costs ratios than farmers in Zhejiang. Higher land rent might be associated with greater yields of yellow catfish in Guangdong, which were almost twice those of Zhejiang

Spatial trends of breast and prostate cancers in the United States between 2000 and 2005

<p>Abstract</p> <p>Background</p> <p>Breast cancer in females and prostate cancer in males are two of the most common cancers in the United States, and the literature suggests that they share similar features. However, it is unknown whether the occurrence of these two cancers at the county level in the United States is correlated. We analyzed Caucasian age-adjusted county level average annual incidence rates for breast and prostate cancers from the National Cancer Institute and State Cancer Registries to determine whether there was a spatial correlation between the two conditions and whether the two cancers had similar spatial patterns.</p> <p>Results</p> <p>There was a significant correlation between breast and prostate cancers by county (r = 0.332, p < 0.001). This relationship was more pronounced when we performed a geographically-weighted regression (GWR) analysis (r = 0.552) adjusting for county unemployment rates. There was variation in the parameter estimates derived with the GWR; however, the majority of the estimates indicted a positive association. The strongest relationship between breast and prostate cancer was in the eastern parts of the Midwest and South, and the Southeastern U.S. We also observed a north-south pattern for both cancers with our cluster analyses. Clusters of counties with high cancer incidence rates were more frequently found in the North and clusters of counties with low incidence rates were predominantly in the South.</p> <p>Conclusion</p> <p>Our analyses suggest breast and prostate cancers cluster spatially. This finding corroborates other studies that have found these two cancers share similar risk factors. The north-south distribution observed for both cancers warrants further research to determine what is driving this spatial pattern.</p

Correlations between meteorological parameters and prostate cancer

<p>Abstract</p> <p>Background</p> <p>There exists a north-south pattern to the distribution of prostate cancer in the U.S., with the north having higher rates than the south. The current hypothesis for the spatial pattern of this disease is low vitamin D levels in individuals living at northerly latitudes; however, this explanation only partially explains the spatial distribution in the incidence of this cancer. Using a U.S. county-level ecological study design, we provide evidence that other meteorological parameters further explain the variation in prostate cancer across the U.S.</p> <p>Results</p> <p>In general, the colder the temperature and the drier the climate in a county, the higher the incidence of prostate cancer, even after controlling for shortwave radiation, age, race, snowfall, premature mortality from heart disease, unemployment rate, and pesticide use. Further, in counties with high average annual snowfall (>75 cm/yr) the amount of land used to grow crops (a proxy for pesticide use) was positively correlated with the incidence of prostate cancer.</p> <p>Conclusion</p> <p>The trends found in this USA study suggest prostate cancer may be partially correlated with meteorological factors. The patterns observed were consistent with what we would expect given the effects of climate on the deposition, absorption, and degradation of persistent organic pollutants including pesticides. Some of these pollutants are known endocrine disruptors and have been associated with prostate cancer.</p

Estrogen receptor positive breast cancers and their association with environmental factors

<p>Abstract</p> <p>Background</p> <p>Epidemiological studies to assess risk factors for breast cancer often do not differentiate between different types of breast cancers. We applied a general linear model to determine whether data from the Surveillance, Epidemiology, and End Results Program on annual county level age-adjusted incidence rates of breast cancer with and without estrogen receptors (ER+ and ER-) were associated with environmental pollutants.</p> <p>Results</p> <p>Our final model explained approximately 38% of the variation in the rate of ER+ breast cancer. In contrast, we were only able to explain 14% of the variation in the rate of ER- breast cancer with the same set of environmental variables. Only ER+ breast cancers were positively associated with the EPA's estimated risk of cancer based on toxic air emissions and the proportion of agricultural land in a county. Meteorological variables, including short wave radiation, temperature, precipitation, and water vapor pressure, were also significantly associated with the rate of ER+ breast cancer, after controlling for age, race, premature mortality from heart disease, and unemployment rate.</p> <p>Conclusions</p> <p>Our findings were consistent with what we expected, given the fact that many of the commonly used pesticides and air pollutants included in the EPA cancer risk score are classified as endocrine disruptors and ER+ breast cancers respond more strongly to estrogen than ER- breast cancers. The findings of this study suggest that ER+ and ER- breast cancers have different risk factors, which should be taken into consideration in future studies that seek to understand environmental risk factors for breast cancer.</p

Open Access

Background and methods: Idiopathic autism, suspected to be caused by exposure of genetically susceptible individuals to unknown environmental triggers, has increased dramatically in the past 25 years. The objectives of our study were to determine, using a linear regression model, whether the county prevalence of autism in the Pacific Northwest of the United States was associated with the source of drinking water for that county and whether this relationship was dependent on the level of environmental pollutants and meteorological factors in the county. Results: We found the previously reported relationship between precipitation and autism in a county was dependent on the amount of drinking water derived from surface sources in the county. We also found a positive association between the EPA’s risk of neurological disease and autism, but this relationship was only present in warm areas. Conclusions: Our study provides evidence for the hypothesis that environmental factors are associated with autism and that meteorological factors play a role in this relationship

Control of Vibrio parahaemolyticus (AHPND strain) and improvement of water quality using nanobubble technology

Nanobubble technology is used in wastewater treatment, but its disinfectant properties in aquaculture have not been clearly demonstrated. This study investigated the ability of nanobubbles to reduce Vibrio parahaemolyticus (AHPND strain) and to improve water quality. Two laboratory experiments were conducted over a one‐week period, that is (a) assessing the effects of air and oxygen nanobubbles for 60 minutes per day and (b) comparing effects of ozone nanobubble treatments for 2, 4 and 6 minutes per day. Experiments were done in triplicate 100 L tanks with 15‰ saline water, inoculated with an initial bacterial concentration of 106 CFU/ml. At the end of experiment 1, the bacterial concentration of the air and oxygen nanobubble groups was counted for 69% and 46% of the control group respectively. At the end of experiment 2, the bacterial concentration of the 2‐, 4‐ and 6‐minute ozone nanobubble groups were counted for 23%, 2.2% and 0% of the control group respectively. Oxygen and ozone nanobubbles significantly increased oxygen reduction potential and oxygen values. Results indicate that under effective dosages nanobubbles can be used in the production farms to control V.parahaemolyticus and increase oxygen levels

A case study of time-series regression modeling: Risk factors for pond-level mortality of farmed grass carp (Ctenopharyngodon idella) on a southern Chinese farm

Limited research has been done using multivariable statistical methods to assess factors associated with fish mortality in warm-water finfish aquaculture in China. We carried out a case study to test the hypothesized association between pond-level daily mortality of farmed grass carp and predisposing environmental and husbandry factors. Based on logbook data from a single farm in Guangdong province (China) in 2013, two-stage time-series regression (TSR) analyses were conducted to estimate the lagged effect of these predisposing factors on grass carp mortality. Factors assessed included temperature fluctuations, movement of fish into and out of ponds, and 3 types of treatments (antibiotics-antiparasitics, traditional Chinese medicine-probiotics, and chemicals to improve water quality). First, coefficients were estimated using a generalized linear negative-binomial model for each pond, and these coefficient estimates were combined using meta-analytic techniques. Sensitivity analyses were done to compare effects of changes in the 3 modeling components: distributional forms, number of spline knots, and types of autocorrelation terms. Model results in the case study indicated 2 risk factors might be associated with increased mortality of grass carp: (1) movements-in of new fish during the previous 14 days; and (2) increasing water temperature during the previous 7 days. Sensitivity analyses indicated good consistency of the estimates with different modeling components. Our findings highlight the utility of assessing daily farm records using TSR to develop hypotheses about potential risk factors for grass carp mortality in China

Survey of Parasites In Threatened Stocks of Coho Salmon (Oncorhynchus kisutch) In Oregon By Examination of Wet Tissues and Histology

We are conducting studies on the impacts of parasites on Oregon coastal coho salmon (Oncorhynchus kistuch). An essential first step is documenting the geographic distribution of infections, which may be accomplished by using different methods for parasite detection. Thus, the objectives of the current study were to (1) identify parasite species infecting these stocks of coho salmon and document their prevalence, density, and geographic distribution; (2) assess the pathology of these infections; and (3) for the first time, determine the sensitivity and specificity of histology for detecting parasites compared with examining wet preparations for muscle and gill infections. We examined 576 fry, parr, and smolt coho salmon in total by histology. The muscle and gills of 219 of these fish also were examined by wet preparation. Fish were collected from 10 different locations in 2006–2007. We identified 21 different species of parasites in these fish. Some parasites, such as Nanophyetus salmincola and Myxobolus insidiosus, were common across all fish life stages from most basins. Other parasites, such as Apophallus sp., were more common in underyearling fish than smolts and had a more restricted geographic distribution. Additional parasites commonly observed were as follows: Sanguinicola sp., Trichodina truttae, Epistylis sp., Capriniana piscium, and unidentified metacercariae in gills; Myxobolus sp. in brain; Myxidium salvelini and Chloromyxum majori in kidney; Pseudocapillaria salvelini and adult digenean spp. in the intestine. Only a few parasites, such as the unidentified gill metacercariae, elicted overt pathologic changes. Histology had generally poor sensitivity for detecting parasites; however, it had relatively good specificity. We recommend using both methods for studies or monitoring programs requiring a comprehensive assessment of parasite identification, enumeration, and parasite-related pathology.This is the publisher’s final pdf. The published article is copyrighted by the American Society of Parasitologists and can be found at: http://www.journalofparasitology.org/

Differential characterization of emerging skin diseases of rainbow trout - a standardized approach to capturing disease characteristics and development of case definitions

Farmed and wild salmonids are affected by a variety of skin conditions, some of which have significant economic and welfare implications. In many cases, the causes are not well understood, and one example is cold water strawberry disease of rainbow trout, also called red mark syndrome, which has been recorded in the UK since 2003. To date, there are no internationally agreed methods for describing these conditions, which has caused confusion for farmers and health professionals, who are often unclear as to whether they are dealing with a new or a previously described condition. This has resulted, inevitably, in delays to both accurate diagnosis and effective treatment regimes. Here, we provide a standardized methodology for the description of skin conditions of rainbow trout of uncertain aetiology. We demonstrate how the approach can be used to develop case definitions, using coldwater strawberry disease as an example