Are there more fish and sea life in marine reserves?

Yes, there are certainly more fish and marine life in marine reserves, although this can only be said about the affected species that the marine reserve is protecting that would otherwise be fished.  Unaffected species would be the same inside and outside the marine reserve.  It is important to note that when comparing the number of species inside and outside of the reserve that the numbers are greater inside not only because they aren't being fished, but because the area outside the reserve is being fished more in order to compensate for the lost area. Regardless, the fish and other marine life in marine protected areas (MPA’s) are more plentiful and they also tend to be bigger because they live longer.