An old name for herrings. See: Alec Sauce
The OED has; "A herring. Also: a pickle or sauce made from small herrings or anchovies, used by the ancient Romans." and quotes Laurence Andrewe, 'Noble Lyfe Bestes' of 1527; "Alec the heringe is a Fisshe of the see..whan he is fresshe taken he is very delicious to be eten."