2/15/16 - 5pm report
Migration started late this year
Blacktip sharks were weeks late for their winter migration to Florida, but now that they've arrived, they've pretty much taken over.
Like Monarch butterflies or your grandparents, blacktip sharks love heading south for the winter. But this year the sharks didn’t show up for their Florida migration on time. Florida Atlantic University biologist Dr. Stephen Kajiura studies the blacktips and their migration patterns down the Atlantic Coast. He shot this video after waiting weeks for the blacktips to make an appearance. The sharks will typically first arrive in mid-January, but the waters off the coast of Palm Beach were empty until the end of the month. But now that they’re here, the blacktip sharks are congregating in huge numbers. Dr. Kajiura estimated more than 10,000 of the sharks are swimming just off the coast of Palm Beach, Florida. And we really mean just off the coast. “The interesting thing is these sharks are right up against the shoreline. You could stand on the shore and toss a pebble and hit a shark, they’re that close,” Dr. Kajiura said. So what’s up with the bizarre behavior from the sharks? Part of the reason could be 2016’s particularly strong El Nino. The phenomenon's effects can be felt across the globe, changing the behaviors of sharks and other marine animals including sea snakes, sea lions and seals. Warming ocean temperatures could also play a role. If waters farther north are staying warmer for longer, then there's less reason for the blacktips to leave on time. But just in case you’re afraid the influx of sharks might spoil your Palm Beach vacation, Dr. Kajiura said the blacktip sharks are relatively harmless. He said, “For the most part, these sharks are really skittish, so when you get in the water, they're going to scatter and go away." This video includes clips from Tony Isaacson / CC by 3.0 , Florida Atlantic University , Palm Beach Daily News and Seth Setiadha / CC by 3.0 .
Dr. Stephen Kajiura is a professor of biological sciences at Florida Atlantic University.
For the past several years, he's been tracking the migration patterns of blacktip sharks.
This year, he said they came to south Florida much later than usual.
Dr. Kajiura said the sharks typically come to south Florida in mid-January.
This year, he said they came much closer to February.
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"We've had an unusually warm winter, and as a result it may be the water was sufficiently warm where they were so there may not have been motivation to move south to warmer waters," Dr. Kajiura said.
He added that the blacktip sharks normally go back up north at the end of March, but this year the late migration south may push back that date.
Blacktip sharks usually get up to six feet in length and are very skittish, Dr. Kajiura said.
"The blacktips in general, if you jump in the water, they're going to take off. So the chances of being bitten are pretty small," he said.
This year, the FAU scientist said that many of the blacktips are hanging out off the coast of Palm Beach County.
"I fly from Miami, all the way up to Jupiter. The vast majority of sharks are found from Palm Beach to the Jupiter Inlet area. We don't find many south of there, at least we haven't so far," he said.
It's not clear why they're congregating in that area, but Kajiura said it may be because of the habitat found off the coast.
"You have some more exposed rock on the sea floor in the Palm Beach area and further north and you often see the sharks sheltering in those rocky areas," he said.
Dr. Kajiura said that sharks typically mate up north before coming south. He adds that of the 32 sharks tagged so far, all of them have been males.
He said the pregnant female sharks may not have wanted to travel as far.
The goal is to tag a total of sixty sharks. Dr. Kajiura performs aerial surveys once a week, then tags sharks from a boat weekly as well.
He hopes to one day connect the tagged sharks to social media sites so people at home can track their travels as well.