How rare is the Carolina hammerhead?

Answer 1

It's pretty rare it was first found by an ichthyologist named Joe Quattro on November 7, 2013 in South Carolina, U.S.A. This specie of shark, has in fact long eluded discovery apparently because it is virtually indistinguishable from the common scalloped hammerhead sharks.

The rarity of the Carolina hammerhead shark, or, Sphyrna gilberti, is said to underscore the fragility of shark diversity in the face of relentless human predation. The female hammerhead birth their young at the ocean-side fringes of the estuary in South Carolina, the pups normally remaining there for about a year before they grow and thereafter they move out into the ocean to complete their life cycle at sea.

Quattro and his team also discovered that the scalloped hammerheads, or Sphyrna lewini, which they were collecting had 2 different genetic signatures in both their mitochondrial and nuclear genomes.