That anecdote doesn't pass the smell test. The article says "the 1860's". Quoth wikipedia: «The last convict ship to be sent from England, the St. Vincent, arrived in 1853». Another source[1] states that the worst death rate of the fleet was 33%, far below the 60% in your source.
Makes for a great story/example though! Which I guess is how these anecdotes propagate.
I read the same story in The Fatal Shore [1] which to my knowledge is a very well researched/factual book on early convict history (though I don't recall the success rate being initially as low as 40%, it was low though).
Makes for a great story/example though! Which I guess is how these anecdotes propagate.
[1] http://www.historyaustralia.org.au/ifhaa/ships/2ndfleet.htm