(Repeats fixing typo in seventh para)
By Philip O'Connor
RECIFE, Brazil, June 12 (Reuters) - Soccer fans visiting Recife for the World Cup may be unaware that the city is not just famous for football - it is also one of the most dangerous places in the world to swim due to the risk of shark attacks.
Supporters strolling on the sandy beaches of the city, which will host five World Cup matches, are being met by a forest of warning signs in English and Portuguese, and newly-built watchtowers where lifeguards keep a close eye on bathers.
The Boa Viagem beach suffers a high number of shark attacks and an above-average number of fatalities, and local authorities are keen to avoid any incidents with unsuspecting soccer fans during the World Cup.
"In the 20 kilometres of beach we have in the state of Pernambuco, we have an atypical concentration of sharks, above the world average," local lifeguard captain Helder Silva told Reuters in an interview at one of the many watchtowers along the shore.
"Across these 20 kilometres of coastline we've had 59 incidents over 21 years, which is considered above the world average for attacks."
The waters off the coast of the capital of the Pernambuco region are mainly populated by bull and tiger sharks, which Silva says are attracted by the jetsam emptied into the sea by two local rivers.
In July of 2013 an 18-year-old Brazilian tourist from Sao Paulo, Bruna Gobbi, died after she was bitten on the leg by a shark at the Boa Viagem beach.
"Tourists often are not aware of the problem with sharks here, nor do they know the prevention measures. So we've needed to reinforce our efforts," Silva said.
"The World Cup is going to happen during the rainy season here, which is the period of greater risk of shark attack.
"We've nearly doubled our number of watch towers, which was part of the planning to receive the World Cup, and we've doubled our personnel to cater for the demand of the World Cup."
As his colleagues intently study video monitors showing the situation on the strand, Silva said a campaign to make visitors aware of the dangers of swimming at the city's beaches was well underway, and seemed to be paying off.
"This year, we've not registered any attacks. Last year we had two, one here on Boa Viagem beach and another on Praias dos Corais in the neighboring town."
Silva demonstrated a device used by lifeguards called a Sharkshield, which uses an electronic pulse to repel sharks, before offering soccer fans and swimmers some simpler tips.
"To avoid a shark attack, avoid swimming in the ocean in unprotected areas or open shore. Here on our coast we have protected areas inside natural reefs, so it's recommended that if you swim, to do it in these areas at low tide," he said.
"Don't swim alone. Stay in groups and don't spend too much time in the water. Don't go in the water if you're bleeding, as it attracts sharks."
But high up the beach, sunbathing American soccer fan Quinn Gemperline told Reuters that he was not too worried about the prospect of a shark attack.
"If you swim past the reef wall maybe you should be a little worried, but this side of the reef I think you should be fine. I haven't seen any sharks but I have seen a lot of the signs," he said.
"Every year there are fewer shark attacks than people who die from vending machine accidents, so I am not too worried."
(Editing by Ed Osmond)