The development and expansion of a viable marine shrimp-farming industry in the USA has been a goal of the US Marine Shrimp Farming Program research consortium for many years. Production research has focused on the development of systems for open pond culture, and a small but stable industry has developed based on these technologies. New advances have facilitated the intensification of production, reduction or elimination of water exchange, application of biosecurity protocols and stocking of high-health and genetically improved shrimp, all of which currently serve as the foundation for the US shrimp-farming industry. Based on these research advances, consortium scientists have shifted resources over the past few years to re-evaluate super-intensive raceway production technologies. At the Waddell Mariculture Center (WMC) in South Carolina, and the Oceanic Institute (OI) in Hawaii, prototype and pilot-scale systems have been operated over the past 3 years. In recent WMC trials, production of up to 3 kg/m2 was demonstrated with survival ranging from 55 to 71%, and harvest sizes from 14.6 to 17.1 g in 137 days. At harvest, production results for the latest trial based on the stocking of nursed 1 g juveniles were: survival=91%; mean weight=16.6 g; FCR=1.54; mean growth/week=1.44 g; and yield=4.50 kg/m2. At OI, three trials have been conducted with increasing stocking densities ranging from 100 to 300/m2. In the most recent 85-day trial, juvenile shrimp (∼2 g) grew to a harvest weight of 19.9 g with a mean growth rate of 1.47 g/week. Productivity of the system reached 5.2 kg/m2 and survival was 86.3%. All of these trials are based on high-output, minimal water usage, enclosed raceway designs that assure biosecurity and provide excellent potential for application in non-traditional, urban and/or contaminated environments. The demonstration trials described in this chapter, along with supporting research on breeding, microbial dynamics, feeds, engineering, financial feasibility and marketing, have brought these technologies to the point of commercialization. Urban and peri-urban application of these technologies in the USA could offer opportunities for the development of integrated marketing initiatives to improve the outlook for financial viability.

Longitudinal studies in southeastern Cambodia of three different areas with differing water regimes indicated that the average amount of fish and other aquatic animals caught in rice fields and surrounding areas was over 380 kg per household per year-1. The amount varied significantly (P<0.001) between areas with better (mean 604 kg) and poorer (mean 158 kg) water resources. Despite this trend, the annual consumption of 37 kg per person and the amount of fish purchased annually did not vary significantly between the different areas. The amount of fish sold, however, increased almost tenfold between water-poor and water-rich areas, 34 and 356 kg, respectively. This suggests that the desirable level of per caput fish consumption in these areas is around 37 kg and most households will attain this one way or another. The value of the ricefield catch was on average over 80% of that of the rice harvest, though this varied significantly between areas with differing water resources. It can be argued that a one-third increase in rice production would be detrimental if it reduced local fish catches by 40% or more. Aquaculture is often promoted to fill the gap between declining fish production from natural sources and the increasing demand from the growing populations. We argue that this is a gross over-simplification, as sustainable management of the ricefield fishery and associated resources needs to be high on the national agenda for many countries such as Cambodia. This important resource should feature in any agricultural and infrastructure development initiatives aimed at addressing rural food security and helping the rural poor.

The Faculty of Fisheries of the University of Agriculture and Forestry (FoF-UAF) in collaboration with the Aqua Outreach programme of the Asian Institute of Technology has implemented since 1994 farmer-managed on-farm trials in two different agroecological (rainfed and irrigated) areas of four provinces (Tay Ninh, Binh Duong, Binh Phuoc and Long An) to develop fish culture in ponds of small-scale households in the southeast region of southern Vietnam. Baseline surveys carried out prior to the trials have pointed out problems of fish culture of farmers in the two selected areas, e.g. pond preparation, cultured fish selection, stocking density, and water quality management. After 3 years implementation of the on-farm trials, appropriate recommendations of low-cost fish culture for small-scale farmers in the two agroecological areas have been produced. The average fish yield of 56 project farms in three provinces (Tay Ninh, Binh Phuoc and Long An), has increased around 40, 25 and 70%, respectively. Since 1996 the project staff have collaborated with Agricultural Extension Centres (AECs) of the three provinces to train about 700 farmers on fish culture based on the proven recommendations. Moreover, three sets of leaflets on fish culture in ponds for different agroecological areas based on appropriate techniques have also been designed to support extension activities of the provincial AECs. To improve the efficiency of the AECs on aquacultural technique transfer, the FoF-UAF has organized several short training courses to upgrade knowledge and skills for AEC staff. In 1996, 64 extension staff of the three provinces were trained on integrated fish culture and extension methods and 41 extension workers have been trained on methods of fish culture on-farm trials and extension material production to date. The fish culture on-farm trials have been shown to be an efficient method to produce appropriate recommendations for small-scale farmers. However, some difficulties in implementation of the trials need to be overcome for further expansion.

An eco-technological survey was conducted in the central freshwater region of the Mekong Delta (Vietnam) involving around 260 fish farming households with different types of farming systems. The survey was carried out during the dry season of 1996 to describe and analyse the present state, structure and functioning, as well as constraints to, and management options of, integrated fish farming systems. Systems for the survey were selected to represent as wide a spectrum of farming conditions as possible among the high variety and combination of integrated fish farming systems existing in the central region of the Mekong Delta. Two basic types of integration were selected for the survey: AC/VAC systems of fishpond-livestock with/without a vegetable and/or fruit-tree garden; and AR system of rice-fish. A non-integrated system, namely fish culture in ponds and/or garden canals, was also investigated. Farmer-managed trials were conducted on 25 selected farms during the culture period of 1997-98 to test improved technologies based on the results of the survey by partial modification of the limiting technological parameters and management methods.

A working definition for urban aquaculture is presented that invokes concepts of land use planning, notions of urbanism, where trade links and markets, nucleated settlements, administrative organizations and specialist labour guilds are considered indicative of urban communities, and encompasses aquaculture closely linked with industrial activity. Early examples of 'proto-urban aquaculture' developed in association with Roman villas, monasteries, castles, manors and millponds are described, and important factors in the emergence of such practices, including technological advancement, demonstration of social status, declining or unreliable capture fisheries, growing market demand for aquaculture products and use of unexploited resources by entrepreneurs assessed. Pressures and events that contributed to the abandonment of these systems, notably the contraction and eventual fall of the Roman Empire, and economic decline and depopulation in the medieval period, are reviewed. Following this historical enquiry, pertinent accounts relating to contemporary urban aquaculture operations throughout Europe are presented, including production in intensively managed recirculation units, horizontally integrated marine aquaculture facilities and systems exploiting industrial by-products, in particular thermal effluents. This review suggests factors underlying the emergence of contemporary urban aquaculture are similar to those that gave rise to proto-urban systems. However, drawing on lessons learned regarding earlier declines, when considering prospects for contemporary urban aquaculture in Europe, it is recommended that a systems-based perspective is adopted.