April 9, 2019 — A new study by researchers at the University of Stirling’s Institute of Aquaculture concludes that there is an urgent need for a paradigm shift in the definition of sustainable shrimp feed.
The global farmed shrimp industry has an estimated production volume around four million metric tons (MT), and has become one of the biggest consumers of fishmeal in the aquaculture sector. This has put pressure on aquafeed manufacturers to find suitable alternative ingredients that do not affect the health or growth rates of the shrimp.
However, substituting in plant-based alternatives to fishmeal may not be the panacea that ecological campaigners are counting on, according to the recently published research.
“The Sustainability Conundrum of Fishmeal Substitution by Plant Ingredients in Shrimp Feeds,” by Wesley Malcorps, models the effects of decreasing the inclusion of fishmeal in commercial diets.
“As demand for shrimp feed increases, feed manufacturers are shifting towards crop-based ingredients, in a move that is mainly driven by economic incentives. This is evidenced by looking at the relative price of fishmeal compared to common plant ingredients such as soy protein concentrate, cereal, and wheat gluten. Some consider the move to be a sustainable transition, as it reduces the dependency on a finite marine resource,” Malcorps told SeafoodSource. “However, a change in ingredients would shift resource demand from the oceans onto the land and could affect the nutritional value of shrimp.”
His team set out to model incremental fishmeal substitution by plant ingredients in feed for giant tiger prawns (Penaeus monodon) and whiteleg shrimp (Litopenaeus vannamei). The models were used to assess the consequent impact on marine and terrestrial resources such as fish, land, fresh water, nitrogen, and phosphorus.