Malaysian authorities have detected parasites in a shipment of canned sardine weighing over 16 tonnes imported from China via Singapore, Malaysian media reported. Malaysian Quarantine and Inspection Services Department (Maqis) said that samples taken from the batch were...
That article neither supports nor denies your claim: it just says parasites have evolved resistance to what was previously used against them.
The major issue there is with the anti parasite treatment: that is what is killing herring.
Parasites do not magically appear from nowhere. They are species which have co-evolved with their hosts for millennium. These fish parasites are extremely common across the entire ocean. Farms just provide a place for large groups of fish to get infected.
All of which is to say that parasites in fish are common in wild fish which are never near farms.
Then you didnt read it.
Fact is that open water fish farms devastate wild stocks.