Abstract: A device for grading aquatic organisms is disclosed. The device includes a pump, a grader, two or more receptacles for receiving aquatic organisms from the grader, a counter, and a control system. The grader comprises a rotating barrel with a plurality of chambers, a bottom part of each of the plurality of chambers having an adjustable slit. The control system is designed to adjust at least one of a rotation rate of the grader or a slit setting of the grader based on information from the counter.

Abstract: The invention relates to a device, a system and a method for grading live aquatic organisms in fluid into batches by using a central control system (7) that controls the grading process in a continuous manner resulting in optimisation of the grading process, said control system (7) optimizing individual grading components, namely concentration control (3) of fish, pump (4) speed and grader (5) settings, based on a software and a database (8) containing pre-set counting data.

Abstract: A method, a device and a fish-farm for controlling the concentration of living organisms in fluid in order to facilitate the handling of the organisms such as grading and counting. The apparatus comprises a first in-feed channel for a flow of living organisms, a second in-feed channel for a flow of fluid, a chamber containing a lever for regulating the flows from the first and the second in-feed channels through the chamber, an outlet, a computer, and a sensor. The sensor is positioned in the first in-feed channel for detecting the density of living organism in the flow, and the computer continuously and automatically regulates the ratio of flows from the first and the second in-feed channels through the chamber and towards the outlet by the lever in response to the density of living organisms in the flows determined by the sensor.

Abstract: The invention comprises a system and an optical device (1) to facilitate the counting of objects, e.g. fish and other organisms living in freshwater or sea, especially when using large-scale equipment in fish-fanning. The system makes it possible to diminish the distance between the recording camera and the objects to be counted.