a rather unusual computation, but gives another example of quantities of calories available from animal sources. what a veritable feast! 68 billion kilojoules is about 15 billion calories, of which about 10 billion would be from fat... The ovarian energy content of whole ovaries was used to estimate the energy from herring spawn added to Prince William Sound beaches from 1988 to 1995. Since 1989, when there was a massive oil spill, the annual amount of energy added to the Prince William Sound ecosystem by herring eggs has decreased from 68 x 1,000,000,000 kJ to 10 x 1,000,000,000 kJ in 1995. http://www.uaf.edu/seagrant/Pubs_Videos/pubs/RP-97-04.html