Warming, crops, and insect pests: Crop responses to climate warming suggest that yields will decrease as growing-season temperatures increase. Deutsch et al. show that this effect may be exacerbated by insect pests (see the Perspective by Riegler). Insects already consume 5 to 20% of major grain crops. The authors' models show that for the three most important grain crops—wheat, rice, and maize—yield lost to insects will increase by 10 to 25% per degree Celsius of warming, hitting hardest in the temperate zone. These findings provide an estimate of further potential climate impacts on global food supply and a benchmark for future regional and field-specific studies of crop-pest-climate interactions. Science , this issue p. 916 ; see also p. 846

Aquaculture's pressure on forage fisheries remains hotly contested. This article reviews trends in fishmeal and fish oil use in industrial aquafeeds, showing reduced inclusion rates but greater total use associated with increased aquaculture production and demand for fish high in long-chain omega-3 oils. The ratio of wild fisheries inputs to farmed fish output has fallen to 0.63 for the aquaculture sector as a whole but remains as high as 5.0 for Atlantic salmon. Various plant- and animal-based alternatives are now used or available for industrial aquafeeds, depending on relative prices and consumer acceptance, and the outlook for single-cell organisms to replace fish oil is promising. With appropriate economic and regulatory incentives, the transition toward alternative feedstuffs could accelerate, paving the way for a consensus that aquaculture is aiding the ocean, not depleting it.

Liu, J., V. Hull, M. Batistella, R. DeFries, T. Dietz, F. Fu, T. W. Hertel, R. C. Izaurralde, E. F. Lambin, S. Li, L. A. Martinelli, W. J. McConnell, E. F. Moran, R. Naylor, Z. Ouyang, K. R. Polenske, A. Reenberg, G. de Miranda Rocha, C. S. Simmons, P. H. Verburg, P. M. Vitousek, F. Zhang, and C. Zhu. 2013. Framing sustainability in a telecoupled world. Ecology and Society 18(2): 26. https://doi.org/10.5751/ES-05873-180226

China is the world's largest producer, consumer, processor, and exporter of finfish and shellfish (defined here as “fish”), and its fish imports are steadily rising (1–3). China produces more than one-third of the global fish supply, largely from its ever-expanding aquaculture sector, as most of its domestic fisheries are overexploited (3–6). Aquaculture accounts for ∼72% of its reported domestic fish production, and China alone contributes >60% of global aquaculture volume and roughly half of global aquaculture value (1, 3).

Aquaculture is a fast-growing segment of the world food economy and a leading vector of aquatic invasive species in the United States and abroad. Surprisingly, little national or international oversight exists even for deliberate introductions of exotic species in aquaculture. The authors of this Policy Forum propose a policy agenda on exotic introductions as aquaculture expands that includes scientific risk assessment for all nonnative introductions and single-agency oversight for the prevention, containment, and monitoring of ecologically harmful species.