Spatiotemporal dynamics and resource use efficiency in mariculture production: A case study in Southeastern China

The rapid expansion of marine aquaculture poses a big challenge for sustainable development. More efficient production strategies are necessary to ensure a sustainable mariculture sector, yet the potential of feasible production gains without further environmental impacts is largely unknown. This work took one of the biggest mariculture centers in China to analyze the spatiotemporal dynamics of mariculture products in 2003, 2010, and 2016, explore potential factors associated with resource use efficiency, and quantify the potential of these factors to increase regional production. The mariculture sector had a rapid expansion in 2003–2010 and accelerated product diversification in 2010–2016, with overall annual growth rates of 4.6%, 24.9%, 14.6%, 20.4%, 24.7%, and 8.7% in finfish (Larimichthys crocea and others), sea cucumber (Apostichopus japonicus), abalone (Haliotis spp.), laminaria (Laminaria japonica), gracilaria (Gracilaria spp.), and porphyra (Porphyra spp.) production, respectively. Resource use impacts were dominated by finfish production (over 90% of the total), but recent increases were mostly due to the farming of other products. Our study also identified several demographic (household size), socioeconomic (income per capita), technical (farming density, feed usage, and energy usage), and environmental (distance between farms and total nitrogen concentration) variables that were correlated with resource use efficiency. Simulations based on regression models suggested that changes in these factors could increase fish and seaweed production by at least 3%–18% and 2%–23%, respectively, without increasing resource use levels. Sustainable intensification of local mariculture systems could be achieved by enhancing the access to more efficient technology and financial capital, increasing the willingness of engagement in the sector, facilitating the transaction of sea use rights, reducing the amount of nutrient released in coastal areas, and including the heterogeneous effects of farm distances and water quality in marine spatial planning. Our results highlight the existing opportunities in policymaking for more sustainable food production systems and the management of coastal ecosystems in mariculture-dominated seascapes.