The shift of phosphorus transfers in global fisheries and aquaculture
Yuanyuan Huang, Phillipe Ciais, Daniel S. Goll, Jordi Sardans, Josep Peñuelas, Fabio Cresto-Aleina, Haicheng Zhang
Abstract
Abstract Global fish production (capture and aquaculture) has increased quickly, which has altered global flows of phosphorus (P). Here we show that in 2016, $$2.04_{1.59}^{3.09}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>2.0</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>1.59</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>3.09</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> Tg P yr −1 (mean and interquartile range) was applied in aquaculture to increase fish production; while $$1.10_{1.04}^{1.14}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>1.1</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>1.04</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>1.14</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> Tg P yr −1 was removed from aquatic systems by fish harvesting. Between 1950 and 1986, P from fish production went from aquatic towards the land-human systems. This landward P peaked at 0.54 Tg P yr −1 , representing a large but overlooked P flux that might benefit land activities under P scarcity. After 1986, the landward P flux decreased significantly, and became negative around 2004, meaning that humans spend more P to produce fish than harvest P in fish capture. An idealized pathway to return to the balanced anthropogenic P flow would require the mean phosphorus use efficiency (the ratio of harvested to input P) of aquaculture to be increased from a current value of 20% to at least 48% by 2050 — a big challenge.