ASSESSING HAWAII'S AQUACULTURE FARM AND INDUSTRY PERFORMANCE

This investigation uses farm-level data from the U.S. Census of Agriculture to evaluate the economic performance of the aquaculture industry in Hawaii. We first examine the entire aquaculture industry by assessing its profitability, efficiency, and input cost structure over time and across economic farm sizes; we then proceed to analyze the farms at the individual subsector levels of crustacean, Chinese catfish, other foodfish, and ornamental farms. The results reveal a wide variation in performance across farms, even within the same subsectors. In 2007, 57.6% of the aquafarms generated a profit; however 39.4% of the farms were found unable to cover their variable cash expenses. The presence of significant economies of scales were detected in performance with full-time operations being found more profitable and efficient than part-time operations. Finally, Hawaii's labor cost share for aquaculture enterprises is about 3.5 times greater than that found on the continental United States.     

Economic analysis of overwinter feeding regimens for channel catfish (Ictalurus punctatus)

Abstract

Overwintering is a major source of uncertainty for US catfish farmers, particularly decisions on feeding. To address this issue, economic analysis was undertaken using results from pond experiments. Three overwintering strategies (full‐feed, partial‐feed, and no‐feed) for two year classes of catfish were compared. Year 1 fin‐gerlings were 22 g and year 2 fish were 420 g at stocking. Winter feeding was based on temperature and body weight percentages; (1) full‐feeding followed the regime during the November to April period; (2) partial‐fed treatments followed the temperature/body weight regimen only during the months of November, March and April, with no feeding during the coldest months of December to February; and (3) no‐feeding treatments received no feed during the overwinter period. Cost and returns were estimated for each alternative and each alternative was assessed using: (1) overwinter period experimental results, (2) overwinter period experimental results extended through the grow‐out period, (3) overwinter period experimental results extended to minimally acceptable fish sizes, and (4) adjusted estimates to reflect commercial‐scale practices. Sensitivity analyses on feed conversion ratios, stocking rates and fish selling prices were also conducted on commercial‐scale enterprises. Results consistently showed partial‐fed overwinter practices to be most profitable. Secondly, year 1 fish always had higher returns than year 2 fish due largely to the additional overwintering period and associated variable and fixed costs incurred by the year 2 fish production practices. The data upon which this analysis was based do not include the possibility of having a harvest‐sized fish going into the winter period.     

Effects of temperature on fitness costs, insecticide susceptibility and heat shock protein in insecticide-resistant and -susceptible Plutella xylostella

Effects of high temperature on insecticide susceptibility and fitness were studied in the field population of Plutella xylostella (L.) (Lepidoptera: Plutellidae) (R DBM) and a susceptible field-insectarium population of P. xylostella (S DBM). R DBM displayed 18.3-fold resistance to methamidophos and 74.0-fold resistance to avermectin. The population growth tendency index (I) values were 41.8 (S DBM) and 27.7 (R DBM) at 25 °C, and 1.19 (S DBM) and 0.23 (R DBM) at 33.5 °C. The level of methamidophos resistance in the progenies of R DBM declined sharply when reared at high temperature for one generation. The increase of susceptibility to methamidophos appeared to pass from generation to generation. S DBM displayed higher up-regulation of Hsp70 expression at high temperature than R DBM. It was suggested that low fitness in R DBM caused by high temperature might be involved in the sharp decline of methamidophos resistance under high temperature conditions.     

Identifying and mapping biodiversity processes for conservation planning in islands: A case study in Réunion Island (Western Indian Ocean)

Over the last century, island biodiversity has become one of the most threatened in the world. Although many island conservation plans address biodiversity requirements at the species level, few plans address the spatial requirements of the biodiversity processes that underpin the persistence of these species. Using systematic conservation planning principles, we map the spatial components of biodiversity processes (SCBPs) and use these to design broad-scale conservation corridors for Réunion Island. Our method is based upon a literature review, expert knowledge, spatially explicit base data, conservation planning software, and spatial modelling. We combine a target-driven algorithm with least-cost path analyses to delineate optimal corridors for capturing key biodiversity processes while simultaneously considering biodiversity pattern targets, conservation opportunities, and future threats. We identify five SCBPs: the oceanic-terrestrial interface; riverine corridors; macrohabitat interfaces; the boundaries of isolated topographic units; and lowland-upland gradients. A large proportion of the SCBPs (81.3%) is currently untransformed, whereas 3% is irreversibly transformed by urbanisation and 15.7% is transformed but restorable. However, SCBPs are almost fully disrupted by urbanisation in the lowlands, thereby compromising functional corridors along full altitudinal gradients. This study is a contribution toward the reconciliation of conservation versus development objectives on Réunion Island but we believe that the delineation method is sufficiently general to be applied to other islands. Our results highlight the need for integrating marine, coastal and terrestrial conservation planning as a matter of urgency, given the rapid transformation of coastal areas on islands.     

景观设计"加减法"在精品城市建设中的运用

结合具体案例,详细阐述了景观设计"加减法"在精品城市建设中的运用,认为景观设计"加减法"为精品城市建设从宏观格局到细节的传承、降低成本及人文影响提出了高效的策略。     

中央级农业科研事业单位成本核算管理探析

近年来,国家对科学事业单位投入的经费大幅增加,但与之相应的成本核算模式落后、科研成本管理制度尚待建立。文章对我国科研事业单位现行成本管理现状进行了分析,并针对现有问题,结合工作经验和思考,从会计科目设置、成本核算方法选择,成本核算制度建立等方面,为中央级农业科研事业单位加强成本核算管理提出了初步改进建议。     

关于农村产权制度改革与农民财产性收入增长的研究

受到众多历史因素影响,我国的农村产权制度存在较多的漏洞,产权主体划分不明确, 这严重限制了农村的发展。基于此,本文先阐述了农村产权制度的改革历程及作用,然后分析 了不同产权制度改革与农民财产性收入增长之间的关系。