It was me and my brother Charlie
Two bigger shavers you ne'er did see
Were spearing eels in the month of April
And starving slaves out on Scatterie


What does the last line mean?

I know that a number of slaves managed to find freedom in Nova Scotia.
However, ex slaves in Canada found it very hard to survive.
Taken literally the song suggests that Charlie and his brother actively starved slaves.
Surely this is unlikely.

Perhaps it just means that there were slaves who were starving on Scatterie.

Or perhaps the word 'slaves' means something else in this context.

Any ideas?