A system for grading aquatic organisms, the system comprising: a process line having: concentration control means configured to control a concentration of the organisms in water; a grading unit coupled to an output of the concentration control means, the grading unit comprising at least: a pump; and a grader having chambers each with an adjustable slit; and a counter at an end of the process line, the counter being configured to count organisms; flow measurement means at the counter, configured to measure fluid flow speed; two or more receptacles at the end of the process line, the receptacles for receiving aquatic organisms from the grader; and a central control system, wherein the counter and the flow measurement means are configured to send information to the central control system on a performance of the grading process, and wherein the central control system is configured to compare the information to data stored in a database and send feedback signals to adjust settings of each individual component of the grading unit (4, 5), including adjusting based on the feedback signals a speed of the pump and a slit setting of the grader, during the grading process to optimize the grading process. a process line having: concentration control means configured to control a concentration of the organisms in water; a grading unit coupled to an output of the concentration control means, the grading unit comprising at least: a pump; and a grader having chambers each with an adjustable slit; and a counter at an end of the process line, the counter being configured to count organisms; flow measurement means at the counter, configured to measure fluid flow speed; two or more receptacles at the end of the process line, the receptacles for receiving aquatic organisms from the grader; and concentration control means configured to control a concentration of the organisms in water; a grading unit coupled to an output of the concentration control means, the grading unit comprising at least: a pump; and a grader having chambers each with an adjustable slit; and a pump; and a grader having chambers each with an adjustable slit; and a counter at an end of the process line, the counter being configured to count organisms; flow measurement means at the counter, configured to measure fluid flow speed; two or more receptacles at the end of the process line, the receptacles for receiving aquatic organisms from the grader; and a central control system, wherein the counter and the flow measurement means are configured to send information to the central control system on a performance of the grading process, and wherein the central control system is configured to compare the information to data stored in a database and send feedback signals to adjust settings of each individual component of the grading unit (4, 5), including adjusting based on the feedback signals a speed of the pump and a slit setting of the grader, during the grading process to optimize the grading process. wherein the counter and the flow measurement means are configured to send information to the central control system on a performance of the grading process, and wherein the central control system is configured to compare the information to data stored in a database and send feedback signals to adjust settings of each individual component of the grading unit (4, 5), including adjusting based on the feedback signals a speed of the pump and a slit setting of the grader, during the grading process to optimize the grading process.