From a list of the most dangerous sites in the world for shark attacks. Recife, Brazil:
The trouble started in the 1980s, when Porto Suape was constructed to the south of Recife. The construction sealed off two freshwater estuaries, which had served as the birthing waters for many bull sharks. When the estuaries were closed, the sharks went to the next estuary, which happens to discharge right into Recife's waters. A nearby channel used by surfers became these sharks' new feeding grounds. The sharks may have been driven even closer to Recife's shore by a slaughterhouse, which was disposing of blood in nearby tributaries.
Yeah, swimming at a beach that's next to both a shark birthing area and a slaughterhouse that dumps blood into the ocean seems like a bad idea.
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