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The use of whole fish derived from low trophic-level fisheries (also known as small pelagic species, or reduction fisheries) is often criticised as being inefficient. This paper offers a general view of the production of fishmeal and fish oil by species, country and region. The available edible yield of food produced using this resource under business as usual practices (i.e via fishmeal and fish oil production, aquafeed and aquaculture and a proportion consumed directly as food) against a hypothetical 100% consumption as food (with available by-product going to fishmeal and fish oil manufacture) is calculated using 2019 data. The results indicate that a 588,061 tonnes greater volume of available processed edible aquatic protein (wet weight) is estimated to be produced under business-as-usual practices, amounting to an additional 3.58 billion meals provided per annum. This is based on current conversion factors resulting from the use of fishmeal and fish oil as ingredients in combination with others in the manufacture of aquafeed. The paper discusses the use of this resource as raw material in the production of fishmeal and fish oil. [ABSTRACT FROM AUTHOR]

Commercial farming of Atlantic salmon in Scotland started in 1969 and has since expanded to produce > 179,000 t year − 1 . A government department has published annual statistics and information on the seawater and freshwater sub-sectors of the Scottish salmon farming industry since 1979, and this review collates and discusses metrics covering aspects of production, farm sites and systems, fish performance, socio-economics and environmental pressures. Trends illustrated in this case study of aquaculture development include: initial increases in numbers of farms and companies, followed by decreases due to industry consolidation; increases in average farm size, and productivity of systems and employees; increases in survival, size at age and productivity of fish (yield per smolt, ova per broodstock); reduced dependence on wild stocks for ova. This case study also illustrates the importance of disease management, control of biological processes to overcome natural seasonality (i.e. production of out-of-season smolt), and the international nature of aquaculture. Improvements in fish survival, growth and productivity are attributed to progress in vaccination and health management (including fallowing), husbandry, system design, feed formulation and provision, and introduction of technology and mechanisation. Salmon farming is discussed in relation to the challenging strategy of “sustainable intensification”. Improved growth and survival over a period of increasing rearing unit size, farm size and output and decreasing relative staff input counters the common assumption that intensification compromises animal welfare. The value of capturing time series data on industry wide metrics is illustrated as it enables identification of trends, underperformance and bench-marking, as well as assessment of resource use efficiency, environmental pressures, and ultimately sustainability. Statement of relevance This review is an original collation of a comprehensive set of time series of official statistics on an entire, discrete and regionally important sector of commercial aquaculture. [ABSTRACT FROM AUTHOR]