Deep and far sea net cage culture fish school quantity measuring method

The invention discloses a deep and far sea net cage culture fish school quantity measuring method, which comprises the following steps of: integrally scanning a target net cage by using omnidirectional sonar so as to convert into a single-time net cage scanning video; training to obtain a fish school recognition model; obtaining a spatial three-dimensional coordinate of each identified fish in each frame of sonar scanning image of the target single-time net cage scanning video through integral scanning and a fish school identification model; arranging a plurality of water layers; performing density clustering processing on the spatial three-dimensional coordinates of each water layer to obtain a water layer clustering estimated fish quantity of each water layer; obtaining a sufficient number of neural network training data; training to obtain a net cage total fish quantity fitting model; and at the target time, through the steps 3-5 and the net cage total fish quantity fitting model, outputting a net cage tot