Watching two manatees in our condo complex boat channel this morning, my wife and I were startled by a large fish that partly surfaced near the sea wall, its prominent dorsal fin slicing through the calm water. I initially mistook it for a dolphin but it never surfaced to breathe and disappeared with no further sightings.
While its identity remains uncertain, I suspect it might have been a bull shark, a species that favors shallow coastal waters, bays and brackish river mouths. Found across the globe, these sharks are able to live in both saltwater and freshwater habitats and have been found far upstream from the ocean (near the junction of the Ohio and Mississippi Rivers in North America, for example). Adults average 7-9 feet in length and generally weigh 300-400 pounds; however, much larger specimens have been encountered. Breeding occurs in brackish waters, in late summer or fall, and females (which are larger than males) give birth to 4-12 free swimming young after a gestation period of almost a year.
Named for both their stocky build and aggressive behavior, bull sharks feed on a wide variety of aquatic animals, including fish, crabs, rays, sea turtles, small sharks, wading birds and aquatic mammals; they, in turn, may be victims of humans, larger sharks or saltwater crocodiles. Since they favor shallow waters (and since they are especially aggressive), bull sharks likely account for more human shark bites than any other species.
