A collection device 6 for collecting sludge such as sunken particulate waste and sunken farm organisms such as dead fish from an aquaculture cultivation unit 1 positioned in a body of water. The collection device 6 comprises a collection head 10 at the bottom of the cultivation unit 1 for collection of sunken sludge and sunken farmed organisms. The collection head 10 comprises a funnel formed top plate 20 wherein the sunken sludge and organisms are collected in or in vicinity to the lowest point of the funnel. A first removal system (40, Fig 6) for sunken sludge, having a first inlet (42, Fig 7) for sludge and small particles at the lowest point of the funnel formed top plate 20. The first inlet 42 being provided with a retaining system 45 for holding back farmed organisms and in that the first removal system further comprises a first pumping system for removal of said sunken sludge from the first inlet 42. A second removal system 60 for sunken farmed organisms accumulated on the top plate 20 and a second pumping system for removal of the sunken organisms from the top plate 20.The present invention relates to a waste collection and removal system from a sea-based aquaculture cage. In particular, it is disclosed a device and a method suitable to collect different types of waste such as sludge and dead fish from the bottom of an aquaculture unit in an effective way, allowing an improved and more effective use of the waste afterwards.
