The global contribution of forage fish to marine fisheries and ecosystems

Forage fish play a pivotal role in marine ecosystems and economies worldwide by sustaining many predators and fisheries directly and indirectly. We estimate global forage fish contributions to marine ecosystems through a synthesis of 72 published Ecopath models from around the world. Three distinct contributions of forage fish were examined: (i) the ecological support service of forage fish to predators in marine ecosystems, (ii) the total catch and value of forage fisheries and (iii) the support service of forage fish to the catch and value of other commercially targeted predators. Forage fish use and value varied and exhibited patterns across latitudes and ecosystem types. Forage fish supported many kinds of predators, including fish, seabirds, marine mammals and squid. Overall, forage fish contribute a total of about $16.9 billion USD to global fisheries values annually, i.e. 20% of the global ex‐vessel catch values of all marine fisheries combined. While the global catch value of forage fisheries was $5.6 billion, fisheries supported by forage fish were more than twice as valuable ($11.3 billion). These estimates provide important information for evaluating the trade‐offs of various uses of forage fish across ecosystem types, latitudes and globally. We did not estimate a monetary value for supportive contributions of forage fish to recreational fisheries or to uses unrelated to fisheries, and thus the estimates of economic value reported herein understate the global value of forage fishes.     

Evaluation of the aerosol transmission of a mixed infection of Mycoplasma hyopneumoniae and porcine reproductive and respiratory syndrome virus

To evaluate the transmission of Mycoplasma hyopneumoniae and porcine reproductive and respiratory syndrome virus (PRRSV) by aerosol as either a single or mixed infection, 28 pigs were inoculated intratracheally with M hyopneumoniae on day 0 and infected intranasally with PRRSV on day 35; they were housed together in a barn. To assess the aerosol transmission of M hyopneumoniae as a single infection, one trailer (A) containing 10 five-week-old sentinel pigs was placed along the south side of the infected barn (1 m from the fans) on day 28. To assess the mixed infection, two trailers (B and C), each containing 10 five-week-old sentinel pigs, were placed along each side of the barn on day 42. The sentinel pigs in the three trailers were exposed to the exhaust from the fans for seven days. No M hyopneumoniae infection was detected in the sentinel pigs in trailer A, but it was detected in the sentinel pigs in trailers B and C. No PRRSV was detected in any of the sentinel pigs.     

Associations between management, climate, and Escherichia coli O157 in the faeces of feedlot cattle in the Midwestern USA

Our objective was to generate hypotheses for potential on-farm control strategies for Escherichia coli O157 by identifying associations between management practices and climate, and the presence of E. coli O157 in feedlot cattle. Faeces were obtained from 10,622 cattle in 711 pens on 73 feedlots between May and August 2001. Management and climate information was obtained by questionnaire and observation at the time of sampling. The prevalence of E. coli O157 was 10.2% at the sample level, 52.0% at the pen-level, and 95.9% at the feedlot-level. The factors associated with the presence of E. coli O157 in cattle faeces were the frequency of observing cats in the pens or alleys (most common when observed daily), the presence of E. coli O157 in the water tanks (positive association), the historical use of injectable mass medication (positive association), the use of antibiotics in the ration or water (negative association), the wetness of the pen, number of cattle in the pen (negative association), wind velocity (positive association), and height of the feed bunk (positive association).     

中国沙塘鳢属(Odontobutis)鱼类之一新种 (鲈形目:沙塘鳢科)

报道采自长江中游，珠江水系及海南岛的水塘鳢属鱼类中有一种是新种，定名为：中华沙塘鳢Odontobutis sinensis Wu,Chen et Chong sp.nov。此新种眼后方无感觉管孔C，与仅产于的暗色水塘鳢Odontobutis obscura(Tamminck et Schlegel)想似，而与沙塘鳢属（Odontobutis)所有种类（其眼后方均有感觉管孔（C）易于区别。本新种与暗色沙塘鳢可以下列特征加以区别：第一背鳢具6鳍棘，胸鳍具14－15鳍条，纵列鳞39－42，横列鳞16－17，暗色沙塘鳢第一背鳍具7鳍棘，胸鳍具16鳍要，纵列鳞36－38，横列鳞13－15。新种模式标本与副模标本均存于上海水产大学鱼类研究室，其体长及采集地详见本文叙述，本文提供新种提供及讨论有相似种的关系。     

Association of neonatal serum immunoglobulin G1 concentration with health and performance in beef calves

OBJECTIVE: To evaluate associations between neonatal serum IgG1 concentration and pre- and postweaning morbidity and mortality rates and average daily gains (ADGs) in beef calves and define a cutoff point for serum IgG1 concentration necessary for optimal health and performance of beef calves. DESIGN: Nonconcurrent cohort study. ANIMALS: 1,568 crossbred beef calves. PROCEDURE: Single radial immunodiffusion was used to quantitate IgG1 concentration in sera collected from calves between 24 and 72 hours after birth. Logistic regression, ANCOVA, and likelihood ratios were used to analyze data. RESULTS: In the preweaning period, lower perinatal IgG1 concentrations were significantly associated with higher morbidity rates, higher mortality rates, and lower ADGs. Calves with serum IgG1 concentration < 2,400 mg/dL were 1.6 times as likely to become ill before weaning and 2.7 times as likely to die before weaning as calves with higher serum IgG1 concentrations. Calves with serum IgG1 concentration of at least 2,700 mg/dL weighed an estimated 3.35 kg (7.38 lb) more at 205 days of age than calves with lower serum IgG1 concentration. No significant association of serum IgG1 concentration with feedlot morbidity, death, or ADG was identified. CONCLUSIONS AND CLINICAL RELEVANCE: By use of likelihood ratios, the threshold of serum IgG1 concentration for optimal health and performance of calves was higher than values reported previously. Implementation and maintenance of management and intervention strategies designed for early detection and treatment of calves at risk for failure of passive transfer will likely result in increases in preweaning health and performance parameters.     

鄱阳湖平原滩地杨树短周期工业原料林造林技术参数研究

通过实践较系统的总结了鄱阳湖区平原滩地营造杨树短周期工业原料林造林地海拔高程的选择、立地指数的判断、造林工程技术指标的确定及技术经济的指标评估方法。     

Interdependence of air,water, and soil pollution control strategies in a power plant and a kraft mill

An analysis of cross-media (air, water, and soil) emissions resulting from various control strategies is necessary in the evaluations of emission standards as well as control strategies. This paper presents such analysis on seven control strategies for a coal-fired power plant and ten control strategies for a kraft pulp and paper mill. The data illustrated include uncontrolled and controlled emissions to all three environmental media as well as power requirement, and capital and operating costs.     

Mechanical transmission of porcine reproductive and respiratory syndrome virus by mosquitoes, Aedes vexans (Meigen)

The objective of this study was to determine whether porcine reproductive and respiratory syndrome virus (PRRSV) could be transmitted to naïve pigs by mosquitoes following feeding on infected pigs. During each of 4 replicates, mosquito-to-pig contact took place on days 5, 6, and 7 after PRRSV infection of the donor pig. A total of 300 mosquitoes [Aedes vexans (Meigen)] were allowed to feed on each viremic donor pig, housed in an isolation room. After 30 to 60 s, feeding was interrupted, and the mosquitoes were manually transferred in small plastic vials and allowed to feed to repletion on a naïve recipient pig housed in another isolation room. Prior to contact with the recipient pig, the mosquitoes were transferred to clean vials. Swabs were collected from the exterior surface of all vials, pooled, and tested for PRRSV. Separate personnel handled the donor pig, the recipient pig, and the vial-transfer procedure. Transmission of PRRSV from the donor to the recipient pig occurred in 2 out of 4 replicates. The PRRSV isolated from the infected recipient pigs was nucleic-acid-sequenced and found to be 100% homologous with the virus used to infect the donor pigs. Homogenates of mosquito tissues collected in all replicates were positive by either polymerase chain reaction or swine bioassay. All control pigs remained PRRSV negative, and PRRSV was not detected on the surface of the vials. This study indicates that mosquitoes (A. vexans) can serve as mechanical vectors of PRRSV.