ed , ▁because ▁the ▁Portuguese ▁fish ing ▁tradition ▁in ▁the ▁North ▁Atlantic ▁developed ▁before ▁the ▁in vention ▁of ▁re fr iger ation — there fore ▁it ▁needs ▁to ▁be ▁so aked ▁in ▁water ▁or ▁sometimes ▁milk ▁before ▁cook ing . ▁The ▁simpler ▁fish ▁d ishes ▁are ▁often ▁flav oured ▁with ▁vir gin ▁o live ▁oil ▁and ▁white ▁wine ▁vin eg ar . ▁ ▁Portugal ▁has ▁been ▁fish ing ▁and ▁trad ing ▁cod ▁since ▁the ▁ 1 5 th ▁century , ▁and ▁this ▁cod ▁trade ▁accounts ▁for ▁its ▁w ides p read ▁use ▁in ▁the ▁cu is ine . ▁Other ▁popular ▁sea fo ods ▁includes ▁fresh ▁s ard ines ▁( es pecially ▁as ▁s ardin has ▁ass adas ), ▁oct opus , ▁squ id , ▁c utt le fish , ▁c rab s , ▁sh rim p ▁and ▁pra wn s , ▁lo b ster , ▁sp iny ▁lo b ster , ▁and ▁many ▁other ▁cr ust ace ans , ▁such ▁as ▁bar n acles , ▁ha ke , ▁horse ▁m acker el ▁( sc ad ), ▁lamp rey , ▁sea ▁bass , ▁sc abb ard ▁( es pecially ▁in ▁Made ira ), ▁and ▁a ▁great ▁variety ▁of ▁other ▁fish ▁and ▁shell fish , ▁as ▁well ▁as ▁m oll us cs , ▁such ▁as ▁cl ams , ▁muss els , ▁o yst ers , ▁per iw ink les , ▁and ▁scal lo ps . ▁Cal de ir ada ▁is ▁a ▁ste w ▁consisting ▁of ▁a ▁variety ▁of ▁fish ▁and ▁shell fish ▁with ▁pot atoes