Overall efficiency of the system is extremely low currently, thanks to a low concentration of those photon-catching structures, but individually they capture about 40 percent of the light's energy, meaning a higher concentration could make for very hearty soup indeed.
First make the Japanese soup stock, or dashi: In a 4-quart saucepan, combine 3 quarts of water, the kelp, and bonito flakes and place over medium-low heat.
By contrast, humans kill around 100 million sharks every year - a number that has ballooned in recent years because of the enormous demand for shark fins to make shark fin soup.
