Complex sentence: Each board initially consisted of five members, later increased to seven, and they were responsible for the management, control, improvement, development and maintenance of the facilities at these ports, and empowered to levy wharfage dues.
Split into simpler sentences: Each board initially consisted of five members, later increased to seven. They were responsible for the management, control, improvement, development and maintenance of the facilities at these ports, and empowered to levy wharfage dues.