Rich marine flora and fauna, fish habitats and traditional knowledge of fishermen community of each coastal region are planned to be identified and recorded as part of the initiative.
A 20 km coastal stretch between Valiyathura and nearby Puthukurichy has already been completed in the first phase.
The procedure to map another 50 km stretch between Thiruvananthapuram and Kollam began here today, a top official said.
"With the support of local fishermen forums, we are trying to record all possible underwater ecosystems and fish habitats," he said.
In the initial phase, around 50 ecologically sensitive natural coral reefs and habitat of various rare underwater marine species had been identified in Valiyathura-Puthukurichy stretch, he said.
The Board would also record all traditional fishing techniques, fishing gear and hooks used, he said.