Skip to main content
SLU publication database (SLUpub)

Report2014

Modeling the effects of locally sourced fish feed ingredients on net phosphorus loading to the Baltic Sea

Vrede, Tobias; Lindholm, Teresa; Futter, Martyn; Markensten, Hampus

Abstract

Phosphorus and nitrogen release from open cage fish farms is an environmental problem that may result in eutrophication. This concern needs to be addressed if aquaculture is to expand in the Baltic Sea area. All of the nutrients released from the fish farm come from the feed used in fish production. Currently, the vast majority of the nutrients are imported to the Baltic Sea in the form of raw ingredients used in feeds. In order to achieve a more sustainable industry, from the eutrophication point of view, it is thus important to develop more environmentally sound feeds. In order to reduce the import of nutrients, and to close nutrient cycles within the sea, the inclusion of Baltic Sea sourced ingredients in fish feeds could be a solution. Here we present a simple steady state model of phosphorus (P) fluxes in aquaculture in the Baltic Sea. By replacing half of the fishmeal used in the feed with Baltic Sea sourced fishmeal the net P loading can be reduced by 65% if the fish production remains constant, or alternatively, the fish production could be more than doubled while still meeting a target of a 20% P loading reduction. A zero net P load to the Baltic Sea can be achieved if a wider variety of raw ingredients sourced from the Baltic Sea are included. We also present other scenarios to illustrate the gains of using an increased amount of Baltic Sea sourced nutrients in fish feeds. Due to the probable increase in price for fish feeds if more local ingredients are used, incentives that favor an increased utiliza-tion of Baltic Sea sourced nutrients need to be put in place. Increased nutrient recirculation, potentially even a closed nutrient loop within the industry, would improve many aspects of the sustainability of fish farming, as well as show the dedication of Baltic Sea aquaculture to act in an environmentally responsible manner while developing to fulfil the increased demand for local high quality fish. In conclusion, the model presented here gives results that are relevant and of great value for strategic management purposes, and form a basis for discussions and decision making. The model output is qualitatively sound and gives a good understanding of potential net P loading in different scenarios, although the exact numbers should be interpreted with great care.

Published in

Reports of Aquabest projects
2014, number: 9/2014
ISBN: 978-952-303-084-8
Publisher: Finnish Game and Fisheries Research Institute