Fisheries in upheaval : the role of environmental changes, aquaculture and community

The contribution of marine capture fisheries to global food security and the development of many coastal communities around the world is evident. Since the late 1980s, however, fishing communities have globally experienced structural changes in fish production due to the quiescent periods of capture fisheries and the significant capacity growth in aquaculture. This global trend is not attributable to a single driver but related to the complex interaction of many factors, both internal and external to the fisheries system including: environmental fluctuations, marine ecosystems, management institutions, socio-cultural characteristics of fishing communities and seafood markets at both global and local levels. Despite the significant implications of socio-environmental factors on fish production, the root causes of changes in these factors are often beyond the control of an individual fishing operator and indeed fishery managers. Understanding the process and implications of the transition in fish production induced by various socio-environmental changes is necessary to ensure sustainable fish production and enhanced adaptive capacity of fishing communities. This thesis explores how environmental changes, including long-term environmental fluctuations and local weather conditions, influence fish production, and how structural changes at community level, such as the increase in aquaculture and aging fishers, affect the economic wellbeing of fishing communities. These objectives are addressed in the three essays presented in this dissertation. The first essay examines the effectiveness of alternative fishery management approaches for small pelagic fisheries, the target species of which experiences cyclic stock collapse due to multi-decadal environmental fluctuations. In this first essay, an age-structured bioeconomic model is developed to explore possible trade-offs between the fishery’s overall profits and the intertemporal distribution of fishery profits; these trade-offs are further related to the possibility and extent of stock collapse driven by cyclic environmental fluctuations. The second essay evaluates the community-level transition process in fish production between coastal fisheries and aquaculture and provides an understanding of how the connectedness of neighbouring fishing communities influences the transition between the two economic activities. In this essay, a panel data set of 1,922 fishing communities is constructed based on the Census of Fisheries in Japan. A spatial panel regression model is used to examine whether, and to what extent, coastal fisheries and aquaculture act as a substitute at the community level, and whether there are spillover effects of changes in a community’s production mix on neighbouring communities. The third essay undertakes an empirical analysis of the impact of local environmental and socio-economic factors on the productivity of a small-scale fishery. Using an instrumental variable approach, day-to-day variation in sea surface temperature, cross-sectional differences in market accessibility and age of individual fishers are explored to measure the own-price elasticity of demand. The estimated demand parameters are used to evaluate how fishing revenue and consumer surplus within the fishery are affected by the local socio-environmental conditions. The results in this dissertation highlight the importance of considering socio-environmental changes at multiple scales in time and space in order to sustain fishery productivity and to keep the economic wellbeing of fishing communities viable. The bioeconomic model of a small pelagic fishery developed in the thesis shows that the effects of multi-decadal environmental fluctuations on the fishery are heightened by the cumulative impact of fishing. Although restricting fishing reduces a fishery’s overall profits, it smooths the intertemporal distribution of profits, resulting in greater intergenerational equity. Additionally, community-level analysis provides evidence of substitution effects between capture fisheries and aquaculture in Japanese fishing communities. The results show that an increase in a community’s aquaculture intensity is likely to occur in concert with a decrease in the number of coastal fishing entities within the community. The results also show that changes in a community’s production mix are not solely determined within the community per se but also depend on the production mix of neighbouring fishing communities. Finally, the thesis finds that increasing sea surface temperature and aging workforce in a small-scale fishery increase fish supply in a local market, and there are positive net effects of these socio-environmental changes on fishing revenue and consumer surplus within the fishery