WWW.WAS.ORG • WORLD AQUACULTURE • JUNE 2015 27 level against key indicators of resource use and thereby lessen negative impacts of aquaculture. This effort above will not be enough because, as Shell (2013) lamented, those responsible for making decisions about food production tend to ignore the results of censuses and surveys and follow courses of least resistance, particularly the most politically-expedient routes. Nevertheless, reliable data on resource use at the farm level is critical for making production of aquatic animals more efficient. Indicators Life Cycle Assessment (LCA) is gaining popularity for ascertaining the cumulative use of resources and the sum of negative environmental impacts incurred as a result of the production, use and disposal of products. Life Cycle Assessments have been made for the production of several aquaculture species (Boyd and McNevin 2015). Although LCA can assess the global, large-scale impacts of a particular product, it is difficult to conduct and some impacts of aquaculture production are beyond the control of the aquaculturist. For example, land and water use to produce aquaculture feed ingredients is a major impact of feed-based aquaculture but the aquaculturist has no control over practices used by marine fishers, grain and soybean farmers, fishmeal renderers, processors or feed mills. The only way that fish or shrimp farmers can influence the efficiency of resources used to produce feed is by using better practices to maximize feed conversion efficiency and lessen feeding wastes. This will lessen land and water use for feed ingredients, minimize wild fish use for fishmeal and fish oil in feeds and result in less waste per unit production. Moreover, less feed per unit production equates to lower production costs. In a comparison of the performance of farms participating and not participating in responsible aquaculture efforts, it will not be feasible to use LCA that considers all possible resource uses and impacts. It also will be impractical to base the comparison on better practices and standards in aquaculture improvement and certification programs. These standards tend to be all-inclusive with respect to coverage of possible impacts because it was necessary to obtain agreement among stakeholders and comply with the ISEAL Code for standard setting. For example, standards requiring numbers on buildings and use of warning signs are important for convenience and safety but they have nothing to do with resource use and production efficiency. Some certification programs require an aquatic animal health management plan to be on file but this is no substitute or proxy for knowing the percentage survival of farm stock, which is an actual indicator of how well a farm manages stock health. The approach in the WWF initiative will be to select a few indicators related to major impacts and benchmark performance against those indicators over time. Boyd et al. (2007) presented a review of indicators used for evaluating the efficiency of feed use, protein efficiency and fishmeal use in aquaculture and proposed methods for estimating land use and water use in aquaculture. Methods for estimating energy use, including embodied energy, in aquaculture are discussed by Boyd and McNevin (2015) and there are many online sources of information on estimating direct and embodied use of water, land and energy that may be applied to aquaculture. Thus, we will not provide methodologies for acquiring numerical values for indicators but merely indicate the features of the numerical values. The major impacts of aquaculture that rely on natural resource use requiring indicators are wild fish, land, water, nutrient and energy use that deplete major resources and cause perturbations such as eutrophication and negative impacts on biodiversity. The indicators selected for these impacts are listed in Table 1. Most of the data for these indictors will be available from compliance records kept by certified farms. Data from uncertified farms will be obtained through observation, measurement and interviews with farmers. Wild Fish Use Efficiency The major global impact of aquaculture is the huge quantities of fishmeal and fish oil included in feeds, mostly for a few highTABLE 1. Indicators for evaluation of resource use efficiency and waste production at aquaculture facilities. Indicator Units of measure Fish in: fish out ratio Forage fish in feed/production (kg/kg or t/t) Land use Total land area/production (ha/t) Water use (based on discharge) Effluent volume/production (m3/t) Survival Number stocked/number harvested x 100 (%) Energy use Energy use/production (GJ/t) Impact on receiving water Diurnal DO flux (afternoon DO - early morning DO = Δ mg/L) Feed conversion ratio Feed applied/production (kg/kg or t/t) (CONTINUED ON PAGE 28) The only way that fish or shrimp farmers can influence the efficiency of resources used to produce feed is by using better practices to maximize feed conversion efficiency and lessen feeding wastes. This will lessen land and water use for feed ingredients, minimize wild fish use for fishmeal and fish oil in feeds and result in less waste per unit production. Moreover, less feed per unit production equates to lower production costs.
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