Amazon river creature "torments" kayaker

[Maxmars]

A little put off by the second-hand poster of this piece, I offer it for your consideration.

The setting: A kayaking enthusiast on the Amazon river was alarmed when he experienced a turbulent interaction with a barely seen creature large enough threaten his small craft.  

[Video: https://youtu.be/GNrEQyL35uM]

The text accompanying this video shows that as the kayak was disturbed and presumably shoved or pushed, other similar splashes were occuring many yards away, simultaneously.  I thought I saw a fin, or something like it, in one of the frames.

How the poster decided to invoke "Occams' Razor" to declare it a likely Mapinguari sighting eludes me... unless he has no idea what Occam's Razor is.

[NeoAstra]

I thought Picarucu at first but, Amazonian manatee pod maybe?
YT comments seem to think so...
The first one that goes under the boat looks like it has considerable algae growth on it. 
I know I wouldn't want to be caught by whatever it is. 

[pianopraze]

Looks like dolphins feeding… and a couple random other creatures floating by feeding also.

different dolphins, but similar techniques:

[Video: https://www.youtube.com/watch?v=bzfqPQm-ThU]

[worldstarcountry]

I live in Florida and like our Amazonian friends south of us we get both dolphins and manatees. Appearance wise they most certainly fit the bill of manatees. You can compare them to any youtube video of manatees at the Big Bend power Plant cooling tower discharge channel. An entire nature center has been built around this channel because of all the cool stuff that shows up during the cold days.

I have not seen a group of manatees ever act like that, but then again I never seen a pod get disturbed. For all we know this was the alpha male and his sudden reaction simply triggered the others out of some defensive flight response.

As far as the video with the dolphins, if I am not mistaken I saw that on BBC Life and those dolphins only do that behavior down in Florida Bay. But I may be mistaken, it is just from memory. I should pop in the blu ray and find out. 

[Maxmars]

...

I find it more likely to be manatees, or some cousin.  The paddle-like flipper seems to bear that out... but I might still be wrong.

The dolphin behavior in the video has been recorded elsewhere... I can't find it now, but I know it isn't exclusive to dolphins of the Florida region... but still, maybe I'm mistaken.

[pianopraze]

I think it’s several things going on at once.

probababy a big run of fish. There are several animals species going after them at once.

In this example: seals, larger fish, sharks, whales, birds, etc… all going after a run of smaller fish.  I think we are seeing Amazon equivalent and kayaker was in the middle of it:

[Video: https://www.youtube.com/watch?v=6zOarcL1BSc]

[SchrödingersRat]

A little put off by the second-hand poster of this piece, I offer it for your consideration.

The setting: A kayaking enthusiast on the Amazon river was alarmed when he experienced a turbulent interaction with a barely seen creature large enough threaten his small craft.  

[Video: https://youtu.be/GNrEQyL35uM]

The text accompanying this video shows that as the kayak was disturbed and presumably shoved or pushed, other similar splashes were occuring many yards away, simultaneously.  I thought I saw a fin, or something like it, in one of the frames.

How the poster decided to invoke "Occams' Razor" to declare it a likely Mapinguari sighting eludes me... unless he has no idea what Occam's Razor is.

[Image: https://en.wikipedia.org/wiki/File:Mapin...Brazil.jpg]

A woman I went to high school with and remained friends with over the years is the Director/Curator of primates at the Bronx Zoo.  Prior to that, she was the director of Mammals there.  I asked her to look at the footage and she said "There's no way that's a manatee".  She's not sure what it is, but she said the splashing at a distance near the end of the video was interesting and more indicative of a reptile or school of fish than a mammal.

[Maxmars]

A woman I went to high school with and remained friends with over the years is the Director/Curator of primates at the Bronx Zoo.  Prior to that, she was the director of Mammals there.  I asked her to look at the footage and she said "There's no way that's a manatee".  She's not sure what it is, but she said the splashing at a distance near the end of the video was interesting and more indicative of a reptile or school of fish than a mammal.

Very cool.  I am surprised because I thought the 'flipper-like' or perhaps 'fin' rolling out of the water, that was my best guess.  Of course I defer to experienced experts... so now the question resurfaces ( pun) ... what was it?