Selection of cutting machine on removing fouling organisms on abalone shellfish and technological parameter optimization

Abstract: Abalone is a main commercial shellfish in China. Fouling organisms such as Hydroides, Balanus and Ostrea plicatula are harmful for shellfish cultivation. It's common to see lots of fouling organisms adhering on abalone shellfish in Fujian cultivation areas. Fouling organisms will increase the burden and make activities and feeding of abalone hard. The breathing holes are blocked by fouling organisms, which is another danger and may cause abalone suffocation. In this study removal technology was researched to keep the growth of abalone well. We know electric machines such as milling machine, electric motor saw and grinding machine have a certain value in use and the method could be used on removing fouling organisms. In order to verify the optimal machine and improve the removal process, the research focused on the impacts of removal method by machine and its parameters. Survival rate was one of the most important indices for the evaluation of removal processing, and removal speed was the other. The quality of removed shellfish of abalone needed to be judged by sensory evaluation. The comprehensive point was based on shellfish integrity, fouling organisms remained and abalone vitality. Hand held milling machine, electric motor saw and grinding machine were tested separately to remove the fouling organisms. The effects of different machines on removal speed and survival rate were compared, and the effects of different machines on sensory evaluation standard of abalone were analyzed simultaneously to select the optimal machine on removal. Then, the selected machine was tested to make follow-up testing. Different rotary files with the diameter of 6 mm (cylindrical round head, conical round head and conical tip) and different rotating speeds (17 000, 20 000, 23 000, 26 000 and 30 000 r/min) were tested respectively to get the optimal parameters. The results indicated that the optimal machine is hand held milling machine because it could provide stable performance of removal and keep a high survival rate. Although the fouling organisms were removed quickly and thoroughly by grinding machine, the survival rate of abalone was declined significantly after removing. The removal speeds of electric motor saw and hand held milling machine were very close. The score of fouling organisms remained increased significantly because the fouling organisms in the shellfish ditch were removed completely by milling machine with conical round head file. When the milling machine rotating speed was at 20 000-30 000 r/min, the removal speed increased significantly. The temperature of abalone was on the rise when the rotating speed was higher than 23 000 r/min, but the abalone vitality declined quickly with the increasing of the temperature of abalone. Through the test of using the optimal machine to remove fouling organisms, the optimal combination of the parameters above was obtained, which are using hand held milling machine with 6 mm diameter conical round head file, and its rotating speed is 20 000 r/min. Under this condition, the removal speed is 72.69 fouling organisms per minute, the survival rate is 98.87%, and the score of shellfish integrity, fouling organisms remained and abalone vitality is respectively 9.85, 9.72 and 9.81. The study provides reference for application of removal technology of fouling organisms on abalone shellfish.