Use of endoscopy for gender and ovarian stage determinations in Russian sturgeon (Acipenser gueldenstaedtii) grown in aquaculture

The Russian sturgeon (Acipenser gueldenstaedtii) is native to the Caspian Sea, the Black Sea and the Azov Sea. It used to breed in the main incoming rivers, until dam construction in the mid 20th century blocked upriver spawning migration. Aquaculture of Russian sturgeon has only recently begun, prompted by their declining populations in natural habitats and the rise in meat and caviar prices. However, information on their gonadal development and puberty under culture conditions is incomplete.

Because sturgeons have no external sexual dimorphism and there are no external markers for sexing, internal examination of the gonads must be employed for gender identification as well as to monitor their development. The present study describes endoscopic and histological observations of the gonads of young Russian sturgeons aimed at identifying gender and monitoring ovarian developmental stage in females up to the age of 6 years, when they enter their first puberty cycle, as well as at 7 years of age, when they have completed vitellogenesis, under culture conditions. This information, as related to fish age and size, is of vital importance to commercial farming of Russian sturgeon for caviar production and reproduction.

For gonadal observations in both sexes, we used an endoscopic system consisting of a 4 mm, 14 cm long cystoscope sheath incorporated with fiber-optic light transmission, connected to a halogen cold light source and a miniature videocamera with a control unit attached to a color monitor. This system allowed us viewing of the fish's abdominal organs, and to save pictures of selected areas of the gonads on a computer as the fish's personal record. Ovarian biopsies were taken in parallel for histology at typical stages of gonadal development.

Gender could be identified with this system as early as at 3 years of age and the sex ratio under culture conditions of females, males and unidentified gender were 55, 40 and 5%, respectively.

Not only did large differences occur in the developmental stages of female of the same age group, but also ovarian development was highly asynchronous at the early vitellogenic stages. In late vitellogenesis, at the “gray egg” stage (1600–2600 μm diameter), the oocytes were quite regular in size and color, and remained so until the final stages of maturity.

Our study suggests that endoscopy is an efficient method for both gender identification at an early age, and for determination of gonadal development stage in sturgeon aquaculture. The ability to see the whole intact gonads of anesthetized fish can reveal important management and research information, with minimal damage or stress to the fish.     

Influence of wetland networks on bat activity in mixed-use landscapes

Parks and other protected lands can provide important source habitat and act as valuable dispersal corridors in urbanizing environments. However, most wetlands within protected areas are managed in isolation without consideration of the broader landscape connections. We studied the importance of wetland habitat connectivity and landscape context to bat activity in five National Parks along a gradient of increasing urbanization within the Mid-Atlantic United States. Ninety-six Anabat stations were set up throughout the parks, from which we derived the characteristic spatial scales at which bat activity was associated with wetlands. This information was used in a graph theoretic framework to construct network models of potential landscape connectivity for those species that had positive associations with wetland land cover. We found that the importance of wetlands as a predictor of bat activity varied on a species-by-species basis and increased when network measures were used that accounted for connected area in a broad spatial context. The results demonstrate that both area and connectivity of wetland foraging habitat may act as orthogonal variables to availability of roosting habitat in explaining the distribution of highly mobile species. We use the results to illustrate the value of network analysis to guide the coordinated management of two of the parks’ most valued natural resources - wetlands and bats.     

Industrial Structure and the Sources of Agglomeration Economies: Evidence from Manufacturing Plant Production

The impacts of agglomeration and local industrial structure are examined through an analysis of establishment‐level productivity. Using micro‐level data, measures of regional industrial specialization, economic diversity, and industrial competitive structure are incorporated together into a production function system estimated cross‐sectionally for three years and three manufacturing industries in the U.S. The findings demonstrate the importance of the influences of regional industrial competitive structure and diversity on performance.     

Role of sulfur and chloride in the dietary cation-anion balance equation for lactating dairy cattle

Ten Holstein cows averaging 120 d in lactation were arranged in replicated 5 x 5 Latin squares with 3-wk periods to evaluate the role of sulfur (S) in the dietary cation-anion balance equation. Diets were based on corn silage in Exp. 1 and sorghum silage in Exp. 2. Supplemental S and chloride (Cl) from the double sulfate of potassium and magnesium and CaCl2 were used to manipulate dietary cation-anion balance from 0 to +30 meq when expressed as meq [(Na + K)-(Cl + S)]/100 g diet DM and from +19 to +49 meq when expressed as meq [(Na + K)-Cl]/100 g diet DM. Blood pH was not affected by cation-anion balance, although both S and Cl supplementation tended to lower pH. Blood HCO3- and urine pH decreased and plasma calcium (Ca) and urinary Ca excretion increased as anion was added to the diet. Milk fat production tended to be increased by the low S supplementation. Dietary Cl and S had similar effects on acid-base status. Therefore, we suggest that S be included with Cl in the dietary cation-anion balance equation for lactating dairy cows as follows: meq [(Na + K)-(Cl + S)]/100 g diet DM. Although response of acid-base status to S and Cl was similar, as more data comparing the acidogenicity of S vs Cl become available, it may be necessary to include a modifying coefficient for S in the equation to adjust for differences between S and Cl in acid-generating potential. This coefficient may be further dependent on the dietary source of S.     

The Effects of Salivary Gland Extracts from <Emphasis Type="Italic">Boophilus microplus</Emphasis> Ticks on Mitogen-stimulated Bovine Lymphocytes

The effect of salivary gland extract (SGE) from the tick Boophilus microplus was examined in mitogen-stimulated lymphocytes in vitro. SGE was added to lymphocytes of seven cattle together with the mitogens concanavalin A (ConA), phytohaemagglutinin (PHA) and pokeweed mitogen (PWM). Semi-purified B cells from another seven cattle were stimulated with the mitogen lipopolysaccharide (LPS). PHA and ConA stimulated proliferation of lymphocytes to the same extent, but the inhibition due to SGE of Boophilus microplus on the proliferative response stimulated by PHA (39.0% ± 9.3%) was less than the inhibition of proliferative response stimulated by ConA (75.4% ± 6.9%). In contrast, SGE of B. microplus stimulated the proliferation of B cells in the presence of LPS in a dose-dependent manner. Enhanced stimulation of B cells by SGE at >4 μg in culture was greater than twice that observed when B cells were stimulated by LPS alone. SGE does not have a direct suppressive effect on bovine B cell proliferation; however, in vivo the effectiveness of B cell responses might be influenced by other immune factors, such as cytokine profiles.     

Does Biochar Improve Establishment of Tree Seedlings in Saline Sodic Soils?

Reforestation of saline sodic soil is increasingly undertaken as a means of reclaiming otherwise unproductive agricultural land. Currently, restoration of degraded land is limited to species with high tolerances of salinity. Biochar application has the potential to improve physical, biological and chemical properties of these soils to allow establishment of a wider range of plants. In a glasshouse trial, we applied biochar made from Acacia pycnantha (5 Mg ha⁻¹) or no biochar to either a low (EC_e 4·75 dS m⁻¹, ESP 6·9), a moderate (EC_e 27·6 dS m⁻¹, ESP 29·3) or a high (EC_e 49·4 dS m⁻¹, ESP 45·1) saline sodic soil. The regional common reforestation species Eucalyptus viminalis and Acacia mearnsii were planted as tubestock in to the soils. Early establishment indicators, including growth, plant condition and nutrition, were assessed at the end of a simulated growing season, 108 days after biochar application. Application of biochar increased height, and decreased root : shoot and the concentration of Mn, N and S in plants of E. viminalis when grown in the highly saline sodic soil. Biochar application increased the concentration of B in leaves of E. viminalis and increased the concentration of P, K and S in leaves of A. mearnsii when grown in the low saline sodic soil. The results confirm that there is potential for biochar to assist in reforestation of saline sodic soils. Copyright © 2015 John Wiley & Sons, Ltd.     

Changing positions and interests of stakeholders in environmental conflict: A New Zealand transport infrastructure case

Abstract: Stakeholders are an integral part of environmental conflict. Analysing the positions and interests of stakeholders is vital in effective environmental conflict management. This paper reviews the literature related to stakeholders and their dynamics in environmental conflict. It also presents the results of a study relating to a New Zealand transport infrastructure project where the positions and interests of stakeholders have kept on changing during the life of the project. This study plots the changing positions of some of the key stakeholders, towards this project. These stakeholders include a policy manager, a community stakeholder, an environmental stakeholder and a political stakeholder. The paper also analyses the changing positions by identifying and classifying the key drivers for these changes.     

Genetic relationships between attributes in sugarcane clones closely related to Saccharum spontaneum

Summary Saccharum spontaneum is being used in sugarcane breeding programs in attempt to improve characteristics such as ratooning ability and stress tolerance. A population of F₁ (Saccharum officinarum or commercial variety x S. spontaneum) and F₁ x F₁ sugarcane clones was evaluated for sugar yield and a range of yield components in a plant and two ratoon crops. The aim was to determine genetic correlations between attributes in clones with a large component of S. spontaneum, that could be used to help derive appropriate selection indices in such populations.There were close associations between the same attributes measured in different crop-years and the associations between different attributes were generally similar across crop-years. Stalk number and fibre content were positively correlated, as were stalk weight and CCS. The latter two attributes (which are low in S. spontaneum but high in S. officinarum) were negatively correlated with the former two (high in S. spontaneum, low in S. officinarum). Sugar yield was more closely associated with stalk weight and CCS than with stalk number but became more closely associated with stalk number with successive ratoon crops.CCS was positively correlated (r_g=0.55) with cane yield in the plant crop but showed a small negative correlation with cane yield (r_g=–0.20) in the second ratoon crop. CCS (measured in any crop) also had a negative correlation with cane yield in the ratoon crops expressed as a percentage of plant cane yield. This suggests that CCS is negatively correlated with levels of traits contributing to ratooning ability. Intensive selection among such populations for CCS without consideration of ratooning performance may reduce the frequency of favourable specific ratooning characteristics.Abbreviations CCS commercial cane sugar     

利用AFLP进行“甘蔗属复合体”系统演化和亲缘关系研究

采用AFLP分子标记技术，对“甘蔗属复合体”中4个属16个种的69份来自中国和澳大利亚的甘蔗种质资源材料进行系统演化和亲缘关系分析。2对AFLP引物共检测到173个标记，其中172个为多态标记，多态率达99.4%；通过计算Jaccard相似性系数，用UPGMA和PCA法构建了分子系统树和效应图。结果表明：(1)属间亲缘关系中，甘蔗属与芒属较