Searching for Solutions in Aquaculture: Charting a Sustainable Course

EG37CH10-Naylor ARI 6 October 2012 16:59 Searching for Solutions in Aquaculture: Charting a Sustainable Course Dane Klinger1,2 and Rosamond Naylor2 1Emmett Interdisciplinary Program in Environment and Resources, 2Center on Food Security and the Environment, Stanford University, Stanford, California 94305-6055; email: [email protected], [email protected] Annu. Rev. Environ. Resour. 2012. 37:247–76 Keywords First published online as a Review in Advance on RAS, aquaponics, IMTA, offshore aquaculture, feeds August 6, 2012 The Annual Review of Environment and Resources Abstract is online at environ.annualreviews.org Aquaculture is currently the fastest growing animal food production This article’s doi: sector and will soon supply more than half of the world’s seafood for 10.1146/annurev-environ-021111-161531 Annu. Rev. Environ. Resourc. 2012.37:247-276. Downloaded from www.annualreviews.org human consumption. Continued growth in aquaculture production is c by Stanford University - Main Campus Lane Medical Library on 11/15/12. For personal use only. Copyright 2012 by Annual Reviews. likely to come from intensification of fish, shellfish, and algae pro- All rights reserved duction. Intensification is often accompanied by a range of resource 1543-5938/12/1121-0247$20.00 and environmental problems. We review several potential solutions to these problems, including novel culture systems, alternative feed strategies, and species choices. We examine the problems addressed; the stage of adoption; and the benefits, costs, and constraints of each solution. Policies that provide incentives for innovation and environmental improvement are also explored. We end the review by identify- ing easily adoptable solutions and promising technologies worth further investment. 247 EG37CH10-Naylor ARI 6 October 2012 16:59 economies, spurred further growth in seafood Contents consumption. Most of the additional demand for seafood is now met by aquaculture, as global INTRODUCTION.................. 248 catches from wild fisheries have stagnated or BACKGROUND..................... 249 decreased since the mid-1980s (2, 3). Trends in Aquaculture Production . 249 Aquaculture is currently the fastest growing Social and Environmental Benefits . 249 animal food production sector and is poised to Environmental, Resource, supply over half of the world’s seafood in 2012 and Social Problems . 249 (3, 4). Global production of cultured finfish, Solutions, Opportunities, and crustaceans, and mollusks rose from 1 million Limitations to Growth . 250 metric tons (mmt) in 1950 to 52.5 mmt in CULTURE SYSTEM 2008. The growth in aquaculture production IMPROVEMENTS . 250 has far outpaced human population growth; Recirculating Aquaculture Systems. 251 aquaculture production has increased by an Aquaponic Systems . 253 annual average of 8.3% since 1970, while Integrated Multitrophic Aquaculture 254 human population has increased by an an- Offshore Aquaculture . 255 nual average of only 1.6% (3). In 2008, the FEEDSTRATEGIES................ 257 production of cultured aquatic plants reached Commercial Replacement of Fish 15.8 mmt in live weight equivalent, further MealandFishOil............... 258 enhancing aquaculture’s contribution to world Fish Meal and Fish Oil food production (3). Intensification of fish and Replacements in Experimental shellfish production for human consumption and Early-Development Phases . 260 will no doubt dominate any growth in wild SPECIESSELECTION.............. 262 catch volumes in the future, just as intensifi- SelectiveBreeding................. 262 cation of the world’s agricultural and livestock Genetic Modification . 263 systems—reflected in the use of advanced Farming Down the Food Chain. 264 technology and added inputs to achieve high POLICY AND INFORMATION yields—has generated most of the growth in APPROACHES................... 264 terrestrial food production during the past half THEPATHFORWARD............. 266 century. The question we pose in this review is whether or not the aquaculture sector can avoid some of the large resource and environmen- INTRODUCTION tal problems that have plagued the agricultural The global demand for seafood1 is rising and livestock sectors during the past several rapidly with a growing population consuming decades. What technological and management Annu. Rev. Environ. Resourc. 2012.37:247-276. Downloaded from www.annualreviews.org larger amounts of fish in their diets. The solutions are being developed, or have been by Stanford University - Main Campus Lane Medical Library on 11/15/12. For personal use only. world’s population more than doubled be- adopted in commercial systems, to set the aqua- tween the early 1960s and 2008, rising from culture sector on a more sustainable path? And 3 billion to 6.5 billion, and over this same pe- what are the main socioeconomic, institutional, riod, the average annual seafood consumption health, and technological barriers to adopting increased from 9 kg to 17 kg per capita (1). The these solutions? Our goals are to review the global population surpassed the 7 billion mark available evidence on a wide range of solutions in late 2011, and rising per capita incomes in aquaculture from the peer-reviewed litera- Aquaculture: the in many countries, especially in emerging ture and to identify some of the most promis- cultivation of algae ing pathways toward sustainable growth in the and aquatic plants and animals 1In this review, “seafood” includes food produced in fresh, future. Our main challenge is to evaluate such brackish, and saltwater. a dynamic sector—one that is rapidly growing, 248 Klinger · Naylor EG37CH10-Naylor ARI 6 October 2012 16:59 evolving, and improving—without being obso- production sectors (10, 11), but the benefits lete within the near future. and costs of farming seafood have become increasingly clear. BACKGROUND Social and Environmental Benefits Trends in Aquaculture Production Aquaculture development has numerous social Descriptions of the characteristics and trends and environmental benefits. For example, it can in global aquaculture production can be found play a vital role in ensuring access to afford- in recent reports by the United Nations Food able seafood and in generating income from and Agriculture Organization (3) and Bostock the sale of seafood in both developed countries et al. (5) and are based on data from 2008. Most and developing countries (12–14). As of 2008, aquaculture takes place in freshwater systems in 10.8 million people relied on aquaculture as a developing countries. Sixty percent of all aqua- source of income and livelihood, with 94% of culture by tonnage is produced in freshwater, them in Asia, and the value of global aquacul- 32.3% is in seawater, and 7.7% is in brackish ture harvests was estimated at approximately water. Most (88%) aquaculture is produced in US$98.4 billion (3). Asia, including 62% in China. Aquaculture can also provide ecosystem Freshwater aquaculture is composed pri- services, such as wastewater treatment (15), marily of finfish (54.7% of all aquaculture bioremediation (16), and habitat structure (17, production by tonnage), most of which are 18). Aquaculture operations can help to rebuild carp species (71% of freshwater production by depleted wild populations through stock tonnage) that are farmed in China. Freshwater enhancement (19) and spat dispersal (20), and fish are raised in ponds, lakes, canals, cages, scientific research conducted for aquaculture and tanks that range from extensive operations can have spillover benefits for fisheries and with few inputs, low stocking densities, and marine sciences (21). Because aquaculture can little control over production to intensive pro- be done under highly controlled conditions, duction systems with comprehensive inputs, aquaculture products can be guaranteed to high stocking densities, and complete control contain fewer contaminants and other health over all aspects of production. risks than wild seafood (22). Marine and brackish aquaculture is composed primarily of mollusks (24.9% of all aquaculture production by tonnage including shell Environmental, Resource, weight), finfish (9.7%), and crustaceans (9.5%) and Social Problems (3). Organisms are cultured in coastal ponds, Although aquaculture has the potential to feed tanks, cages, and rafts (5), and operations are millions of people, some types of aquacul- Annu. Rev. Environ. Resourc. 2012.37:247-276. Downloaded from www.annualreviews.org mostly intensive systems, except for mollusks ture production may severely degrade aquatic by Stanford University - Main Campus Lane Medical Library on 11/15/12. For personal use only. and seaweed aquaculture, which require few ecosystems, pose health risks to consumers, re- inputs (6, 7). duce incomes and employment in the capture Although extensive production is currently fisheries sector, and diminish food resources dominated by small- to medium-scale enter- for poor populations. The negative environ- prises with few employees and a relatively mental impacts of freshwater and marine aqua- small market share, production by intensive culture have been reviewed extensively (e.g., operations is increasing rapidly, and consolida- 23–27). Major environmental problems include tion can be seen throughout the supply chain pollution of nearby aquatic and benthic ecosys- of many internationally traded aquaculture tems with excrement and metabolites, uneaten products (5, 8, 9). Commercial aquaculture is feed, herbicides, antibiotics, and other chemi- still a nascent industry relative to other food cals

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