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