Behaviour of price transmissions in vertically coordinated markets: The case of frozen black tiger shrimp (Penaeus monodon)*

Abstract

This study analyses the behaviour of the price transmission process for the leading cultured shrimp species, black tiger shrimp (Penaeus monodon), in both forward and backward directions between Thai and Indonesian shrimp packer markets and the Japan Tokyo wholesale market. The bivariate cointegration approach using the Engle‐Granger two‐stage estimation procedure is applied in this study. The results show that Tokyo wholesale prices appear to have stronger backward influences on the formation of overseas contract prices used by Japanese shrimp importers in the Thai and Indonesian shrimp packer markets. In addition, there is a tendency for the speed of price transmissions in the long term to increase with increasing size class (from 26 to 30–21–25 and 16–20 counts per pound) of black tiger shrimp, regardless of estimation specification in the direction of price transmissions and the shrimp country of origin.     

A simulation application to improve the operational efficiency of the wholesale fish market in Taiwan

Abstract

This paper presents the applications of two simulation models developed for the Pu‐Shin wholesale fish market: the current operational model and the alternative operational model. This study analyses the possible influence on the wholesale fish system by manipulating the number of porters in the alternative operational model. Cost‐benefit analysis is conducted to compare the two models. The results suggest ways to improve the operational efficiency of the wholesale fish market in Taiwan.     

海州湾海域鱼类分类多样性的时空变化及其与环境因子的关系

根据2011年3—12月在海州湾海域进行的5个航次的渔业资源综合调查,并结合相关的历史资料,研究海州湾海域鱼类分类多样性及其时空变化,并通过构建 GAM 模型分析平均分类差异指数(Δ+)和分类差异变异指数(Λ+)与环境因子之间的关系.结果表明,海州湾共有鱼类96种,隶属于2纲13目44科71属,其中Δ+的理论平均值为79.5,而Λ+的理论平均值为200.6.两个分类多样性指数均呈现明显的季节和空间变化,这可能与海州湾海域鱼类的季节性洄游和环境因子的差异有关.通过 GAM 模型分析发现,水深和底层溶氧对Δ+具有显著影响,而水深、底层溶氧、底层水温和月份则是影响Λ+的关键环境因子.通过比较中国近海不同纬度海域之间的鱼类分类多样性指数,发现Δ+和Λ+均呈现出“北高南低”的变化趋势,说明纬度变化对鱼类分类多样性的空间分布格局具有重要影响.     

Agglomeration externalities and technical efficiency: An empirical application to the pond aquaculture of Pangas and Tilapia in Bangladesh

This article analyzes the effects of agglomeration externalities on productivity and efficiency by applying a stochastic production frontier model with a technical inefficiency model to the aquaculture industry. Agglomeration externalities refer to the costs and benefits to firms from clustering. Agglomeration studies within aquaculture have focused on the intensive salmon industry, whereas this study focuses on low-technology, extensive pond aquaculture, representing most farmers in the developing world and using Bangladesh as an empirical case. The results show that there is a positive externality effect of regional industry size on the production possibility frontier and a negative effect on technical efficiency. Farm density enhances efficiency and the farm proximity to output markets decreases efficiency. Thus, policies aimed at increasing aquaculture pond production in developing countries should consider farm locations and their access to input and output markets, all of which affect farm productivity and efficiency.     

Data envelopment analysis for production efficiency improvement: An empirical application on brine shrimp Artemia franciscana culture in the Mekong Delta,Vietnam

Artemia culture in the Mekong Delta, Vietnam, is becoming more and more important to satisfy the global demands of cyst production. Nevertheless, Artemia cyst productivity in the Mekong Delta has been fluctuating largely due to not only technical inefficiencies and external factors but also farms’ characteristics. This study employed a data envelopment analysis to evaluate the production efficiencies in correlation with biological and cost inputs of Artemia culture in Vinh Chau and Bac Lieu located in the Mekong Delta. The key factors affecting technical efficiency (TE) were determined using ordinary least squares regression model. The empirical results indicated that production efficiencies of farms in Vinh Chau and Bac Lieu were similar with metatechnology ratios of 0.97 and 0.96 respectively. About 62.8% of surveyed farms were operating in technically inefficient circumstances. Farmers’ experience, educational level and culture technique training participation had positive effects on TE, while climate effects and water problems have been proved to have negative effects on TE. To improve production efficiency, inefficient farms are suggested to have moderately increasing combinations of organic fertilizer, chemical and feed. The use of probiotics should be reduced as it increases production cost and affects TE. Notably, a collaboration of scientists and feed processing companies is recommended to produce a specific formulated feed for Artemia in commercial scales. This study also proposes adaptive policies for local governments and cooperatives to assist coastal famers in the Mekong Delta overcome technical inefficiencies, improve cyst productivity and obtain economic sustainability in Artemia culture.