Wide variety of fish species. It always includes this intertidal zone and is sometimes used to mean the same as the intertidal zone. Though, the meaning of "littoral zone" can be overall well beyond the intertidal zone. The littoral zone is the same as a sea, lake or river that is close to the shore. In coastal environments the littoral zone extends from the high water mark, which is very rare inundated, to shoreline areas that are permanently submerged.