Chinese organized crime networks and Mexican cartels are using Canadian ports to trade highly lucrative fish bladders for the precursor chemicals needed to produce fentanyl, according to a memo from the Canada Border Services Agency (CBSA). It said organized criminal networks transport the fish — called totoaba — from the West Coast to China, while the chemical precursors to make toxic drugs are sent through Canadian ports. The report from the CBSA, first obtained by Radio-Canada through a freedom of information request, said Canada is being used as a "transit point" for the illegal product — though the quantity of...