I don't think we can answer this question just like that. The question should be formulated a bit differently:
WHAT is in danger from the effects of overfishing?
Well, in the end of the "effect-spectrum" we are in danger, since we also eat fish. But the most affected species are the ones that form the aquatic ecosystems. Such as fish. Examples:
1 - Many of the fish we eat, feed on sea-weed. If there aren't enough fish to eat the growing population of sea-weed, many fish die of intoxication.
2 - We don't have almost any fish restrictions in a way, because we can eat basically all of them. Therefore, many fish (which are also being eaten) find themselves in a lack of food.
3 - Many times, we concentrate on a specific species, which is a main cause of the extinction of species.
Hope it helped,
BioTeacher101