Is it necessary for Dalian to declare to Hong Kong now?

No need. According to official website news from the National Immigration Bureau, since 00: 00 on May 15, 2023, the exit-entry administration department of Dalian police has fully restored the "National General Office" for mainland residents to travel to China, Hong Kong and Macao, implemented the "National General Office" for mainland residents to apply for visiting relatives, working and studying in China, Hong Kong and Macao, and adjusted the validity period of the stay endorsement for mainland students to travel to China, Hong Kong and Macao. We will fully resume personnel exchanges between the Mainland and Hong Kong, Macao and Taiwan, cancel the entry-exit appointment arrangement through the land port between China and Guangdong, and set no quota for customs clearance personnel.