Have discovered one other work that might (or might not) shed a bit of light on this obscure matter.,

Coe, Sophie, 1994. _America's First Cuisines_. Austin: University of Texas Press.

This is in the bibliography of

Davidson, Alan, 1999 (2nd edn 2006). _Oxford Companion to Food, The_. Oxford: OUP

and is referred to from the article on 'Maya food', which merely states that 'there is also evidence of trade in conserved fish' and doesn't go into further detail.