Perspectives from agriculture: advances in livestock breeding - implications for aquaculture genetics

In this paper we present livestock breeding developments that could be taken into consideration in the genetic improvement of farmed aquaculture species, especially in freshwater fish. Firstly, the current breeding objective in aquatic species has focused almost exclusively on the improvement of body weight at harvest or on growth related traits. This is unlikely to be sufficient to meet the future needs of the aquaculture industry. To meet future demands breeding programs will most likely have to include additional traits, such as fitness related ones (survival, disease resistance), feed efficiency, or flesh quality, rather than only growth performance. In order to select for a multi-trait breeding objective, genetic variation in traits of interest and the genetic relationships among them need to be estimated. In addition, economic values for these traits will be required. Generally, there is a paucity of data on variable and fixed production costs in aquaculture, and this could be a major constraint in the further expansion of the breeding objectives. Secondly, genetic evaluation systems using the restricted maximum likelihood method (REML) and best linear unbiased prediction (BLUP) in a framework of mixed model methodology could be widely adopted to replace the more commonly used method of mass selection based on phenotypic performance. The BLUP method increases the accuracy of selection and also allows the management of inbreeding and estimation of genetic trends. BLUP is an improvement over the classic selection index approach, which was used in the success story of the genetically improved farmed tilapia (GIFT) in the Philippines, with genetic gains from 10 to 20 per cent per generation of selection. In parallel with BLUP, optimal genetic contribution theory can be applied to maximize genetic gain while constraining inbreeding in the long run in selection programs. Thirdly, by using advanced statistical methods, genetic selection can be carried out not only at the nucleus level but also in lower tiers of the pyramid breeding structure. Large scale across population genetic evaluation through genetic connectedness using cryopreserved sperm enables the comparison and ranking of genetic merit of all animals across populations, countries or years, and thus the genetically superior brood stock can be identified and widely used and exchanged to increase the rate of genetic progress in the population as a whole. It is concluded that sound genetic programs need to be established for aquaculture species. In addition to being very effective, fully pedigreed breeding programs would also enable the exploration of possibilities of integrating molecular markers (e.g., genetic tagging using DNA fingerprinting, marker (gene) assisted selection) and reproductive technologies such as in-vitro fertilization using cryopreserved spermatozoa.

Length-weight relationships of Penaeus monodon reared in semi-intensive culture systems of Kerala, India

The results of a study on length-weight relationships of Penaeus monodon, reared in fertilized ponds in Kerala, India, and fed three different supplementary feeds are presented.

Problems in culturing black tiger shrimp (Penaeus monodon) the semi-intensive way: an Indian experience

This paper details some of the problems encountered in culturing black tiger shrimp (Penaeus monodon) the semi-intensive way in India, which include aquatic macrophytes; invasions by molluscs, jellyfish and frogs; predators; fouling organisms; and others.

Cypermethrin use in forestry and its impact on Welsh streams: An evaluation of the impact of cypermethrin use in forestry on Welsh streams

This is the Evaluation of the impact of cypermethrin use in forestry on Welsh streams from the University of Plymouth, published on September 2010 by the Environment Agency South West. The report focuses attention on Cypermethrin, a highly active synthetic pyrethroid insecticide effective against a wide range of pests in agriculture, public health, and animal husbandry. It is also used in forestry to control the pine weevil, Hylobius abietis. Cypermethrin is very toxic to aquatic invertebrates and fish at nanogram per litre concentrations. This project checks the effectiveness of current best practice measures in minimising the risk of pollution associated with the use of cypermethrin in forestry in Wales. Chemical results from the intensive studies show that cypermethrin entered minor watercourses draining treated areas at two of the eight sites. In one of these cases the level was well in excess of the short-term Predicted No Effect Concentration. The absence of a buffer area at the other site resulted in the cypermethrin reaching a main drain. However dilution appeared to be sufficient to prevent any impact on water quality or on the invertebrate community in the main stream. Invertebrate and chemical data from the extensive survey showed little evidence of pollution due to wider use of cypermethrin in Welsh forestry. Finally, a number of recommendations are made for further tightening controls on forestry practice to minimise the risk of cypermethrin entering the aquatic environment.

Economic and social impacts of Integrated Aquaculture-Agriculture technologies in Bangladesh

This study estimated the adoption rate of integrated aquaculture-agriculture (IAA) technologies in Bangladesh and their impact on poverty and fish and food consumption in adopting households. We used a novel, simulation-based approach to impact assessment called Tradeoff Analysis for Multi-Dimensional Impact Assessment (TOA-MD). We used the TOA-MD model to demonstrate how it is possible to use available data to estimate adoption rates in relevant populations, and to quantify impacts on distributional outcomes such as poverty and food security, thus demonstrating ex ante the potential for further investment in technology dissemination. The analysis used baseline and end-of-project survey data from WorldFish-implemented Development of Sustainable Aquaculture Project (DSAP), promoting IAA. This dataset was used to simulate adoption and assess its impacts on poverty and food security in the target population. We found that, if adopted, IAA had a significant positive impact on reducing poverty and improving food security and income.

Ex-ante assessment of integrated aquaculture-agriculture adoption and impact in Southern Malawi

There are increasing requirements for impact assessment by development partners in order to increase the accountability and effectiveness of research and development projects. Impact assessment research has been dominated by conventional economic methods. This context challenges agricultural research organizations to develop and apply alternative impact assessment methods incorporating economic, social, and environmental impact components. In this study, we use the Tradeoff Analysis for Multi-Dimensional Impact Assessment (TOA-MD) model to evaluate the impact of integrated aquaculture-agriculture (IAA) adoption in Malawi. The study demonstrated that with a minimal data set, the TOA-MD model can be applied to predict and assess the adoption rates of new technologies and practices as well as their economic and non-economic impacts.

River Irk intensive survey

This is the River Irk intensive survey produced by the North West Water in 1986. This report focuses on the Intensive Survey carried out on the River Irk on 15 April 1986. The river Irk was one of the most polluted rivers in North West Water's area. In dry weather the bulk of the flow in the river originated from the 3 sewage works within the catchment (Castleton ETW, Royton ETW and Oldham ETW). The river Irk was badly affected by numerous unsatisfactory storm sewage overflows (SSOs) within the catchment. Several sewerage projects had been carried out within the Irk catchment especially in the Middleton area, where earlier major redevelopment of the old town centre took place between 1969 and 1976, at which time the main sewers were reconstructed. The survey was designed to investigate the changes in the water quality of the river Irk which take place during wet weather. Because of manpower and analytical restrictions the study on Wince Brook and the river Irk upstream of Wince Brook was limited to their bottom reaches.

Plan of the Lune Fishery District. Map of District sealed by the Board of agriculture & fisheries

Historic map of the River Lune Fishery District.

Intensive biological survey of the Glaze Brook catchment May 1981

This is the Intensive biological survey of the Glaze Brook catchment May 1981 report produced by the North West Water Authority in 1981. The aim of this report is to identify those pollution problems not identified during the routine biological water quality surveys, and to check the suitability of the routine biological sampling point. This report looks at an intensive biological water quality survey of the Glaze Brook catchment which was carried out by Biol. (S) on 13th-15th May, 1981. Kick samples of invertebrates were taken at 5 sites and all invertebrates were identified and counted in the field. The most significant water quality observations in the report were from: Borsdane brook, Pennington brook, Glaze brook, Amberswood brook, Cunningham brook, Old Mill brook, Shakerley brook, Astley brook and Shaw brook.

Intensive biological survey of the Glaze Brook catchment. Supplementary report on the water quality as indicated by macrophytes. August 1981

This is the Intensive biological survey of the Glaze Brook catchment: Supplementary report on the water quality as indicated by macrophytes produced by the North West Water Authority in 1981. This report describes the results of the macrophyte survey including data on their distribution and the prevailing water quality (nutrient status and toxic metal contamination) It supplements the initial report,TS-BS-81-3, which described the macroinvertebrate survey. The aim of this project is to describe the distribution of macrophytes within the river, paying attention to areas where weed growth may directly affect water quality or amenity usage, and describe the distribution of toxic metals. In the survey 16 sites of 500 m lengths of river were analysed, noting the relative abundance and percentage cover of the macrophytes present, plant score and Community Description Class (C.D.C.) were computed.

The effect of intensive line fishing on the virgin biomass of a tropical deepwater snapper, the crimson jobfish (Pristipomoides filamentosus)

An intensive commercial hook-and-line fishing operation targeted the demersal fisheries resources at Saya de Malha Bank in the Southwest Indian Ocean. Fishing was conducted with 12 dories that were equipped with echo sounders and electric fishing reels and supported by a refrigerated mothership. Over a 13-day period in the 55–130 m depth range, a total of 74.3 metric tons (t) of fish were caught, of which the crimson jobfish (Pristipomoides filamentosus) represented 80%. Catch rates decreased with time and could not be attributed to changes in location, climatic conditions, fishing depth, fishing method, or bait type. The initial virgin biomass of P. filamentosus available to a line fishery at the North Western promontory of Saya de Malha Bank was estimated at 72.6 t through application of the Leslie model to daily catch and effort data. Biomass densities of 2364 kg/km2 and 1206 kg/km were obtained by applying the initial biomass estimates to the surface area and to the length of the dropoff that was fished. The potential sustainable yield prior to exploitation was estimated at 567 kg/km2 per year. The quantity of P. filamentosus caught by the mother-ship-dory fishing operation represented 82% of the initial biomass available to a hook-and-line fishery, equivalent to more that three times the estimated maximum sustainable yield. The results of the study are important to fisheries managers because they demonstrate that intensive line fishing operations have the potential to rapidly deplete demersal fisheries resources.

Farmer-scientist research partnerships for integrated agriculture-aquaculture

A realistic alternative to traditional technology development and transfer has been utilized by the International Center for Living Aquatic Resources Management (ICLARM) to integrate pond fish culture into low-input farming systems in Malawi. Resource mapping was used to assess farm resources and constraints and introduce the concept of integrated resource management (IRM), the synergistic movement of resources between and among farm and household enterprises. Farmer-led IRM research projects are conducted on-farm and monitored by researchers through direct observation and on-station simulation of constraints and management practices. Technology-adoption rates by farmers involved in a pilot activity was 65% compared to 0% by farmers exposed only to top-down extension approaches. Within two years of adoption, every participating farmer had transferred the technology to an average of four other farmers without the involvement of the extension services.