Feed companies are increasingly substituting fishmeal with plant-based ingredients which is recognized to be a more sustainable practice. A multidisciplinary team of researchers studied the trade-offs between marine and terrestrial resources in shrimp feeds. They found that the substitution of fishmeal moved pressure to land-based production systems with environmental repercussions.

The study modeled incremental fishmeal substitution, from 20-30 percent to zero, by plant ingredients such as soybean meal concentrate, rapeseed meal concentrate, pea protein concentrate and corn gluten meal, which are typically included in modern feeds for the two main shrimp species produced globally, whiteleg shrimp (Litopenaeus vannamei) and black tiger shrimp (Penaeus monodon). The team then assessed the impact that this could have on marine and terrestrial resources, such as fish, land, freshwater, nitrogen and phosphorus.

Researchers found that complete substitution of 20-30 percent of fishmeal totals, depending on the species, could lead to an increasing demand for freshwater of up to 63 percent, land of up to 81 percent and phosphorus of up to 83 percent.

Wesley Malcorps from the University of Stirling’s Institute of Aquaculture said that “substituting fishmeal for plant ingredients is considered by many to be environmentally sustainable, as it reduces dependency on finite marine resources. However, this would shift resource demand from the oceans onto the land, potentially adding pressure to the land-based food production systems, which are already under pressure to meet global demand for food, feed, biofuels, and bio-based materials. In turn, this would affect the environment and biodiversity, as well as the availability and prices of crops.”

Malcorps suggested that finding an optimal balance between marine and terrestrial resources in aquafeed, strategically including high quality fishmeal, improving the use of fish by-products and food waste in feeds and investigating the potential for novel ingredients such as microbial biomass, algae and insect meals should be explored.

Read full study here.