The correct answer is - declined.
The Aswan Dam is a dam that is very often a topic of discussion, as it is both very useful and very damaging, so it has a lot of supporters and lot of critics.
This dam, when it comes to the marine life in the Nile River, has been very damaging. The reason for that is that the dam stops the free movement of the species, be it for food or for mating, they can not pass through it. Also, the water is more static, and that lead to bigger temperature of it, as well as more evaporation, which changed the environment in which the marine life was evolved to exist in. The free flow of nutrients in the water is also largely stopped. All of that has led to a big decline in the marine life in the Nile River and its delta.