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CHAPTER 1 high consumer biomass supported by comparati vely low primary producer biomass). But in eutrophic systems, the consumers relied mostly on HUFA availability, and oft en HUFA limitati on resulted in algal blooms. The study showed that opti mal levels of both HUFA as well as phosphorous (stoichiometry) at the plant-animal interface are crucial for shaping the food web pyramid and HUFA conservati on through the food web. Figure 2. Picture f rom van de Waal et al., (2009). Primary producers show a wide range of C:P rati os. Consumer animals like zooplankton or fi sh show a narrow-fi xed range due to homeostasis. According to the stoichiometry hypothesis, a possible mismatch and trophic decoupling might be expected when C:N:P rati os become too far apart between food and consumer. 1.2. Formulati on of the problem 1.2.1 Challenges in aquaculture World aquaculture producti on conti nues to be the fastest growing animal-food producing sector with an immense increase from 32.4 to 66.6 million MT in the period 2000-2012. Aquaculture products are an important source of animal protein and HUFA, which are crucial for human health. The producti on from capture fi sheries reached its maximum potenti al in most main fi shing areas and further increases in seafood supply need to come from aquaculture. To meet the growing demand for fi sh-food products with an increasing world populati on to 10.5 billion people in 2050 (an increase of 36 % compared to 2019 and constant birth rates), aquaculture producti on needs to grow to 150 million ton by 2050. To do so, the aquaculture sector needs to intensify, bringing along serious challenges regarding sustainable growth. In aquaculture, more than 80% of fi sh and 98% of shrimp are produced in ponds (FAO 2014). Over the last decades, pond producti on intensifi ed. This This chapter has been submitted for publication to "Aquaculture Nutrition" as: