Prawn sludge can become a category 2 subproduct. EU commision incorporates aquaculture sludge into sub-product regulations…

https://www.mispeces.com/noticias/La-Comision-Europea-incorporara-los-efluentes-de-acuicultura-dentro-del-reglamento-de-subproductos/#.YovY0FPRYu9