"As a result, anything that is edible is targeted, and anything threatening like alligators are killed."
The people simply ignored laws against killing species which they depended on for food.
"It's all very well for us to sit back in New Zealand and say, look at what we bad humans are doing to the natural environment, we need to stop them doing it.
"But when you are there, staying with a little community of 30 people all related to each other, all just trying to get by day to day, and they kill an endangered turtle in front of you and eat it, and they talk about the manatees [sea cows] they have eaten, it's very hard to be critical."
But Dr Orams believes the world cannot stand by and let species become extinct. He said sea cows numbered "in the low thousands", and some Amazon species such as the giant otter were down to a few hundred.
Eco-tourism could be a solution, he said, because it would give local people an income that would allow them to buy other foods. That income would depend on preserving natural species.
"If people are prepared to go and spend money to see them, that provides an immediate incentive to preserve them.
"The fact that [Blakexpeditions] were there and spending a lot of money because we were interested in seeing some of the wildlife helped some of the local people develop a sense of pride in their jaguars, their Macaw parrots, manatees and giant otters."
The Brazilians did not eat the otters. But people competed with them for the edible fish in the river.
Dr Orams, a former New Zealand Olympic yachtsman, is a part-time member of Team New Zealand and was a friend of Sir Peter.
He said Sir Peter's role in Blakexpeditions was irreplaceable, because no one else combined his yachting experience, narrating skills and corporate fundraising ability.
Dr Orams has recommended that these roles should now be shared among several people.
"I still see Blakexpeditions as a vehicle with huge potential, and now I feel compelled to try and help Peter's vision become a reality," he said.
"Things are hard because Peter isn't here any more. But just because he has gone doesn't mean his dream has."
Dr Orams and two Auckland University whale researchers, Rochelle Constantine and Merel Dalebout, will speak at the National Maritime Museum on Princes Wharf at 7pm on Tuesday. Admission is $10.
Seaweek 2002
Costal Marine Research Group
Peter Blake, 1948-2001
nzherald.co.nz/environment
