Non-PRO English to Spanish Science Fisheries Tuna handling

Hi, I am translating a manual on how to handle tuna in a purse seiner and I have found this term.

"Vessels could not preserve fish for more than 30 days, and often large portions of catches were rejected for canning"

I have two ideas and I would like your help here:

a) the catches aren't good enough for canning (or anything else)
b) The catches are good just for canning, not for anything else.

Thanks in advance