WWW.WAS.ORG • WORLD AQUACULTURE • DECEMBER 2016 47 Aquaculture in Indonesian lakes and reservoirs has increased greatly in the last three decades, with emphasis on cage culture of carp and tilapia, but also new species like pangasius and pacu. In recent years, however, mass fish kills in cages have been observed with increased frequency and intensity and these have been reported in the Indonesian press. Indonesian government agencies at national and provincial levels have therefore become interested in properly managing existing aquaculture and planning for future development. Indonesia has ambitious plans to greatly increase the number of reservoirs across the country and different agencies at the national level have differing opinions about whether aquaculture should be included in the new reservoirs. Perhaps the best known method for planning and managing aquaculture is calculation of Aquaculture Carrying Capacity (ACC), a measure of the ability of a “system” to assimilate aquaculture activities. The word system is in quotation marks because different ACC’s can be calculated differently depending on the system under consideration. Traditional ACC calculations have usually been done at the farm level, to calculate Production Carrying Capacity (PCC) for managing risk to the aquaculture farm itself. In recent years, increasing attention has been given to calculation of Ecological Carrying Capacity (ECC) for protection of the whole ecosystem (usually some common water body like a lake, bay, etc). Finally, consideration of the human social system leads to calculation of Social Carrying Capacity (SCC) for protection of the public interest. PCC is often calculated with some combination of benthic deposition models and pelagic water quality models. ECC relies on more complex ecosystem models, such as those based on food webs. This so-called ecosystem approach to aquaculture (FAO 2010) has its origins squarely in environmental science. Effective integration of SCC with its qualitative and quantitative dimensions remains an ongoing challenge and one that this project set out to address through its inter-disciplinary practitioner mix. Just how far the quantitative modeling approach applied in estimations of PCC and ECC can usefully be applied to economic and (especially) social issues for effective decision-support outcomes is contested. ECC must also incorporate understanding of the fundamentally subjective views and priorities of various stakeholders, Aquaculture Carrying Capacity in Indonesia Lakes and Reservoirs David A. Bengtson, Francis J. Murray, M. Mukhlis Kamal and Desyana Cut power differentials and relative ability to influence change in formal and informal governance settings. The role of informal governance takes on particular importance in the weak formal regulatory settings typical of many developing countries and was thus a key focus of our work in Indonesia. One of us (DAB) visited Indonesia in 2012-2013 to meet with stakeholders and discuss the ACC concept. A funding opportunity soon became available through the Global Innovation Initiative (GII), supported by the governments of the United States and United Kingdom. This program was based on collaborations of US and UK universities with at least one counterpart university in Brazil, China, India or Indonesia. Our collaboration included the University of Rhode Island (URI) in the USA and the University of Stirling (UoS) in the UK, along with Bogor Agricultural University (Institut Pertanian Bogor - IPB) and Surya University (SU) in Indonesia. We proposed to use existing data and to obtain additional data as necessary to calculate ACC’s for a spectrum of Indonesian lakes and reservoirs in a biophysical, social and economic context. In particular, we wanted to model the impacts of some alternative aquaculture practices and mitigation measures on ACC. The GII program has as a major goal providing opportunities for US and UK graduate students to gain international experience in solving problems of global significance. In our case, the students focused on the GII priority area of Agriculture, Food Security and Water. Our interdisciplinary team recognized that social and natural sciences, along with extension and outreach, are necessary to build the sustainability “three-legged stool” based on environmental, economic and social factors. We therefore gathered information for natural sciences and modeling, and also conducted structured interviews with stakeholders to assess existing aquaculture practices, markets, and fish farmers’ attitudes. A common way to calculate ACC in fresh water is by massbalance modeling of phosphorus (P), as described by Beveridge (1996) based on the Dillon and Rigler (1974) model of nutrient loading, lake water retention time and response in terms of nutrient concentration and chlorophyll. This approach is appropriate for Indonesia because it does not require large amounts of ecosystem (CONTINUED ON PAGE 48) The research group meeting at Bogor Agricultural University, June 2014.
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