A peer-reviewed article by Hutchings and Reynolds (2004) suggests that we should be very pessimistic about the viability of our world fish populations living outside of aquariums and fish farms.
Allee effect, also known as depensation. Heightened extinction risks were highlighted recently when a Canadian population of Atlantic cod (Gadus morhua) was listed as endangered, on the basis of declines as high as 99.9% over 30 years. Unprecedented reductions in abundance and surprisingly low rates of recovery draw attention to scientists' limited understanding of how fish behavior, habitat, ecology, and evolution affect population growth at low abundance. Failure to prevent population collapses, and to take the conservation biology of marine fishes seriously, will ensure that many severely depleted species remain ecological and numerical shadows in the ecosystems that they once dominated.