Aquaculture and Fisheries Interactions: Implications for the Global Supply of Fish

Aquaculture, or more generally fish farming, and fisheries interact in several different ways. First, many types of fish farming require fish products as inputs, mostly for feeding purposes. Second, farmed fish and wild fish products compete in fish markets with consequences for both the industry and, of course, consumers. Third, fish farming generates various types of polluting agents that may affect wild fish stocks and their habitat. Several other interactions exist. This paper is primarily concerned with the implications of the first of these interactions, namely the input relationships, for the overall supply of fish products in the future. To the extent that the fish farming industry demands wild fish products such as fish meal, fish oil, etc. as inputs, the price of these products is increased compared to what would otherwise be the case and, as a result, the price of fish landings. This encourages increased demand from the fish farming industry may – especially given the ecosystem context of most fisheries – lead to long-term fluctuations, instability and even chaotic behavior of wild fish supply. A formal model describing the above considerations is constructed. Possible schedules of global supply of fish products are calculated given various assumptions about (i) fisheries management, (ii) wild fish requirements of the fish farming industry, and (iii) technological progress in fish farming. The impact of expanding global fish farming on the wild fish industry and global supply of fish products is assessed.