We present the results of integrating the fisheries sector into an existing computable partial-equilibrium global model of agriculture, livestock, bioenergy, forestry, and land use. The model is constructed by reconciling publicly available global datasets from the FAO as well as the literature. The model of the fish sector represents capture and aquaculture at the country level. Capture is further differentiated at the level of FAO Major Fishing Areas, while aquaculture differentiates between subsistence systems and systems fed commercially formulated aquaculture feeds. Seafood is split into 10 commodity groups. International trade is bilateral and the model differentiates between food, feed, and other uses of fish. Using projected changes in population and income, future demand for seafood is estimated to exceed 250 million tons in 2050. Future supply from capture fisheries is expected to be determined by fishery policies and to remain limited, and the remainder of the demand shall be satisfied from aquaculture. The aquaculture production systems of the 10 commodity groups are characterized using varying feed ratios and varying feed composition of fish meal, fish oil, soybean meal, rapeseed meal, maize, wheat, and groundnut meal. We estimate that the aquaculture sector will require an additional 120 million tons of terrestrial feed products in 2050. Due to the relatively high efficiency of the aquaculture sector, this translates into relatively minor land-use effects, namely an additional 12 million hectares of cropland in 2050.