Some individuals would therefore not have been caught, since no baited hooks would have been available to trap them, leading to an underestimate of fish stocks in the past.
The commercial fishing industry is expanding and many people rely on it for their livelihoods, but environmentalists say there are more commercial fishermen and women than the world needs.
The warming of the waters also means that there is distribution in fish pieces, and communities that depend on fish for livelihood that will impact upon the livelihoods.