Bioeconomic analysis of the environmental impact of a marine fish farm Miguel Rabass  o, Juan M. Hern  andez * Institute of Tourism and Sustainable Economic Development (TIDES), University of Las Palmas de Gran Canaria, Spain article info Article history: Received 16 December 2013 Received in revised form 27 January 2015 Accepted 22 April 2015 Available online 25 May 2015 Keywords: Bioeconomic model Environmental impact Managerial practice Impact indicator Settled matter Spain abstract The evaluation of the environmental impact of aquaculture installations is nowadays a common social demand in many countries. The usual scientific approach to this question has been to assess the outcome from an ecological perspective, focussing on the effects produced on benthos or the water column and interactions with marine flora and fauna. In this paper, a bioeconomic model is developed to extend this traditional approach, to determine both the amount of total settled matter, its dispersion on the ocean floor and impacts on the marine ecosystem, while also taking into account other social considerations such as discounted net profits and investment returns. The model was applied to the case of off-shore gilthead seabream production in a coastal area of the Canary Isles archipelago, where the tidal current is predominant. Cage emissions and the degree of degradation of seagrass meadows on the seabed were taken as ecological impact indicators, while the net present value (NPV) for a specific time period was used as an economic indicator. By analysing the simulation results obtained by the bioeconomic model, we were able to determine the combination of production volume and harvest quantity which yields the greatest economic efficiency for different levels of degraded area. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction In the last decades, the world aquaculture production has greatly increased, diversified, intensified and advanced technically. In particular, from a modest 0.6 million tons in 1950, the annual production has reached 79 million tons in 2010, excluding plants and non-alimentary products, and although it has slowed in the last years, it maintains a healthy annual growth rate of 6% (FAO, 2012). It is expected that its contribution to economy and society will in- crease in the future. This spectacular growth of aquaculture has aroused controversy related to negative impacts of this activity on the environment, and its sustainability has been questioned (Read et al., 2001). Fish farming produces emissions (feed waste, faeces, medicines and pesticides) which originate undesirable effects on wildlife pop- ulations, such as the transmission of diseases through the ingestion of contaminants or escaped fish, in addition to other negative ef- fects on the ecosystem (Read and Fernandes, 2003). Other types of social impacts are generated by the installation, such as the visual impact made on areas with high landscape value. But, of all the environmental outcomes of the development of aquaculture, the one that has caused most controversy is that of the enrichment in organic matter, as reflected in the proliferation of studies con- cerning this issue (Cho and Bureau, 2001; Islam, 2005; Olsen et al., 2008; Hall, 2011; Byron and Costa-Pierce, 2013). The accumulated organic matter stimulates overproduction of bacteria, who trans- form the composition, structure and functions of sediments. Some of the effects are: decay on the oxygen concentration, increase of oxygen demand, perturbations on the common cycles of nutrients, provoking changes in the biomass and diversity of marine species. Concerned by the environmental effects of aquaculture in- stallations, some institutions and researchers have developed in- dicators for environmental management in certain areas (Fezzardi et al., 2013) and recommended the implementation of Best Man- agement Practices for the production of specific species and culture system (Boyd, 2003; MacMillan et al., 2003; Collins et al., 2007). The objective of these practices is to achieve environmental respectful productions, which are availed by official certifications and eco-labels. * Corresponding author. Institute of Tourism and Sustainable Economic Devel- opment (TIDES), University of Las Palmas de Gran Canaria, 35017 C/ Saulo Tor on s/n, Las Palmas, Spain. E-mail addresses: miguelrabasso@hotmail.com (M. Rabass o), juan.hernandez@ ulpgc.es (J.M. Hern andez). Contents lists available at ScienceDirect Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman http://dx.doi.org/10.1016/j.jenvman.2015.04.034 0301-4797/© 2015 Elsevier Ltd. All rights reserved. Journal of Environmental Management 158 (2015) 24e35