weird. was it heavy bodied or slender?
heres some pics of different sharks.
soupfin (from california, just north of LJ)
black tip
small dusky, they look about the same all through their life and are common to california
and bull
they can all be found in socal and can have black on their fins. the others you might encounter are salmon sharks, great whites (they come in small packages too, saw a 4fter in oceanside harbor), sevengills, oceanic white tips, tigers and hammers.