How many shipyards are there in Zhoushan?

I am from Zhoushan, and there are many shipyards in Zhoushan, including Shenjiamen, Dinghai, Daishan, Qushan, Putuo, Liuheng, and Daju. N many. How is it possible that there are only more than 20 companies? Nanyang Shipyard Shipyard Zhenghe Shipyard Dafang Shipyard Dinghai District Ligang Xingzhou Ship Repairing Factory Zhejiang Hongzhou Shipbuilding Co., Ltd. Zhoushan Ligang Shipbuilding Co., Ltd. Zhoushan Jinzhou Shipyard Dinghai Panzhi Shipyard Zhoushan Haichen Shipbuilding Engineering Co., Ltd. Company Zhoushan Chint Shipbuilding Industry Co., Ltd. Yangfan Group Shenjiamen Jiangwan Shipyard, Zhoushan Shipyard, Ant Island East Coast Shipbuilding Co., Ltd., Wuzhou Shipyard Zhejiang Kailing Shipyard Yancang Shipyard, Maozhi Shipyard, Qianlan Shipyard, Sanjiang Shipyard, Changzhi Shipyard Yihai Shipyard Zhoushan Xinya Shipbuilding Co., Ltd. Zhejiang Ouhua Shipbuilding Wanbang Yongyue Shipyard Putuo Longshan Shipyard Luomen Hengyu Shipyard COSCO Zhoushan Ship Repair Base Zhoushan Putuo Dongpeng Shipbuilding Co., Ltd. Zhoushan Yuanye Shipbuilding Co., Ltd. Zhoushan, Zhejiang Jinhaiwan Shipyard, South Korea's Hanjin Shipping and Qingdao Shunhe Shipping cooperated with Xiushan Tsuneishi Group Daishan County Haizhou Shipbuilding Co., Ltd. .