I think that the answer has to do with
the fact that each sentence represents two words that start with the same letter.
Jeff's company advanced slowly, aware of the presence a rare crocodile species on the long river. (edited)
Jeff is referring to Jeff Bezos, whose company is Amazon, a long river. American crocodiles (although black caimans are found more regionally) are a rare crocodile species found by that river. So we still have two As...
Jackson had his wallet in hand and was admiring some foreign banknotes. "This Japanese currency, I say! Check out the golden colour!"
This could be talking about yellow yen. Although this was the first clue I thought I found, I don't understand the reference to Jackson though...maybe Andrew Jackson, on the American $20; or Michael Jackson, who sang the song "Money"...?
Nobody seemed interested. At the moment they were more focused on observing the organizational behaviour of some carnivorous fish in the ship's wake.
This could be the psychology of the piranhas. I think this is one of the correct clues...
The Zairian jungles were filled with exciting lifeforms.
This could be the critters or creatures in the Congo. (Exciting trivia, the Rumble in the Jungle happened in Zaire's capital, Kinshasa, between George Foreman and Muhammad Ali!) I think this is something with the Congo, if not creatures...
At any rate, another word for romantic love could be
Adoration, which means that the man could have been talking about adoration of Abigail? Or another girl's name that starts with A?