From a global perspective, sustainability is a topic of much importance. The UN Sustainable Development Goals (SDGs) were set by the 193 member states of the United Nations in 2015 with a timeline to achieve the goals by 2030. Sustainability in the aquaculture value chain begins with the raw materials used in the feed. Raw materials represent the cornerstone for fish health and growth, and therefore ultimately for the fish farming success.
Historically, the base raw materials for aquaculture feeds have been fishmeal and fish oil, which is sourced from small forage fish, such as anchovies, sardines and capelin. Every year about 19 million tons of wild fish – some 20% of the total quantity caught around the world – are rendered in to fish meal and fish oil. Increasing use of forage fish is unsustainable and, because an additional 37.4 million tons of aquafeeds will be required by 2025, alternative protein sources are needed (Hua K et al. ,2019).
The total production of aquafeeds for all aquaculture species is projected to increase by 75% from 49.7 million tons in 2015 to 87.1 million tons in 2025 (Hua K et al., 2019). Analysts predict that the increased demand of aquaculture for fish meal and fish oil will outstrip the supply of small forage fish, by 2037.
Consistent with available evidences from a range of research trials, plant proteins can replace fish meal either in part or completely when certain dietary recommended conditions are respected. This is relatively well accepted for omnivorous species but less so for carnivorous fish despite solid research results for specific species (Kaushik et al., 2004, Dani, 2018; Kotzamanis et al., 2020, Zapata, 2021). As soy ingredients become an increasingly significant ingredient, it is only natural to focus on sustainability and reducing environmental impact. Soy crops are often connected to environmental issues such as deforestation and other unwanted Land Use Change (LUC) issues. Retailers, NGO’s and consumers in Europe are increasingly concerned that this conversion leads to CO2 emissions, land degradation and biodiversity loss.
The LCA (Life Cycle Assessment) method was used to evaluate the environmental impact of a soybeans throughout their entire life cycle. The method assesses every stage of the production, processing and use of soy, from raw material, packaging and transport to retail, consumption and waste-processing. This work was carried out by Blonk consultancy (The Netherlands) for USSEC.
Results showed that the carbon foot print (in kg CO2-eq/kg product) - without taking the estimated LUC (Land Use Change) into consideration - averaged 0.37, 0.34 and 0.46 kg CO2-eq/kg soybeans for the USA, Argentina and Brazil respectively. For all three countries cultivation accounted for more than 50 % of the CO2-eq. production but there were major differences among the three countries in the effect of transport and processing with Brazil having a much larger impact of transport. Including LUC in the calculations resulted in pronounced differences in carbon foot prints with averages of 0.39, 5.56 and 5.75 kg CO2-eq/kg soybeans for the USA, Argentina and Brazil, respectively. This clearly emphasized the importance of the cultivation methods and the differences among the three major regions in managing natural resources in the production and marketing of soybeans. The U.S. system being characterized by a rotational production in which land conservation plays a major role, and where the use of cropland has decreased by an average of more than 600,000 ha/year over the past 35 years. Over the same period, in the USA, forest land has increased by 2.1 million ha while this has decreased in South American countries.
These data support clearly the potential of soy protein as a sustainable alternative to other protein sources used in aqua production. Replacement of classical protein sources such as fish meal or animal proteins, but also a wide range of plant protein, can be accomplished through the use of responsible and sustainable soy protein. Of course, this requires the establishment of official organization supervising and certifying the sustainability of soy production. Such mechanisms are in place for US soy production, but need to be developed for soybeans of other origin.
References:
Blonk Consultancy 2021. Environmental foot printing & Life Cycle Assessment. https://blonksustainability.nl/consulting/footprinting-and-lca
Dani.D., 2018 A review on replacing fish meal in aqua feeds using plant protein sources. International Journal of Fisheries and Aquatic Species. Tamil Nadu Dr. J. Jayalalithaa Fisheries University. IJFAS www.fisheriesjournal.com
van Diepen, 2020. Proceedings from U.S. Soy Global Trade Exchange and Specialty Grains Conference, August 2020. https://ussoy.org/u-s-soy-the-sustainability-solution/#_ftnref1
Hua, K., J. M. Cobcroft, A. Cole, K. Condon, D. R. Jerry, A. Mangott, C. Praeger, M. J. Vucko, C. Zeng, K. Zenger, J. M. Strugnell 2019. The Future of aquatic protein: Implications for protein sources in aquaculture diets. One Earth 1, DOI; 10.1016/j.oneear.2019.10.018
Kaushik, S. J., Covès, D., Dutto, G. & Blanc, D. Almost total replacement of fish meal by plant protein sources in the diet of a marine teleost, the European seabass, Dicentrarchus labrax. Aquaculture 230, 391–404 (2004)
Kotzamanis, Y., T. Tsironi, A. Brezas, K. Grigorakis, V. Ilia, I. Vatsos, N. Romano, J. van Eys and V. Kumar. 2020. High taurine supplementation in plant protein_based diets improves growth and organoleptic characteristics of European seabass (Dicentrarchus labrax). Scientific Reports 10:12294. https://doi.org/10.1038/s41598-020-69014-x
United Nation Foundation, Sustainable Development Goals (SDGs), 2015. https://unfoundation.org/
Zapata D.B., 2021. Total or partial replacement of fishmeal with soybean meal in the diet of the Pacific fat sleeper Dormitator latifrons juveniles. Lat. Am. J. Aquat. Res. vol.49 no.1 Valparaíso mar. 2021. http://dx.doi.org/10.3856/vol49-issue1-fulltext-2564