Its north - to - south length is 300 km and its average width is 9 km ; ( not apparently true ) the average depth is 100 m .
Depth reaches a maximum of 400 m in the north - western part .
Its north - to - south length is 300 km and its average width is 9 km ; ( not apparently true ) the average depth is 100 m , although it reaches a maximum of 400 m in the north - western part .