From Out of the Past - Part IX

            A casual glance at the chart (in the previous posting) and you may notice two trends.  One, over a million horseshoe crabs per year for over a half century were harvested from Delaware Bay for use as fertilizer.  I’m no mathematician, but that seems like a lot of Limulus pulled from the waters of the Bay.  Or, we can look at it this way.  If we assume that a average adult horseshoe crab is approximately twelve inches wide and up to two feet in length (including its tail), then 1,000,000 horseshoe crabs (laid side by side and end to end) would spread out over an area of approximately 45.91 acres.  That’s roughly the size of 35.32 professional football fields, 95.35 Madison Square Gardens, or 851.42 average American homes (considerably larger than your local subdivision).  You must admit, that’s a lot of Limulus laying around and smelling up the place.
          Second, you’ll also note that there was a substantial decline in the number of horseshoe crabs harvested from the waters of the Delaware Bay from roughly the middle of the 19th century to the end of the 20th century.  This was due to a combination of factors including the development of, and competition with, alternative fertilizer sources; the very pungent and malodorous smells that would emanate from the factories (and the lands surrounding those factories) as the result of dying, dead, or decaying horseshoe crab bodies; the encroachment of human populations (and the subsequent building of homes for that burgeoning human population) along this prime stretch of real estate, and a potential decline in the availability of Limulus in the Bay.  Also significant was the fact that it took more men, time, and gear to harvest the same amount of horseshoe crabs in the 1900s as it did in the 1800s.
          It also seems safe to assume that there was a significant decline in the need for horseshoe crabs as fertilizer.  However, there wasn’t necessarily a significant decline in the need for horseshoe crabs.