In Qingdao, mackerel is also known as "daddy's fish". The girl's boyfriend has to bring two mackerel to the girl's house for the first time. In the spring of every year, when the local Spanish mackerel are on the market, the son-in-law has to bring at least two of them to pay a visit to the old Taishan, and of course, the more Spanish mackerel you bring, the better. So, when the fresh mackerel is on the market, it is the time for the fish seller to pull out the wallet of his son-in-law in Qingdao.

Why is Spanish mackerel called "father's fish"? Why is fresh Spanish mackerel given to the in-laws? There is a legend in the island city folklore.

According to Shazhikou fishermen, a long time ago, a child called Xiaowu, parents died, an old man in the same village to adopt him, he grew up, in order to repay the kindness of his adoptive father, morning and evening to work, daytime fishing, very hard work, so the old man will be his only daughter promised to him as his wife.

One spring, it is the fishing season, father-in-law suddenly fell ill, would like a fresh fish to eat, but the heavens are not good, a few days of storms, can not go out to sea. Seeing that his father-in-law was getting sicker and sicker, Wu braved the storm and went out to sea. The daughter said to her father: "Dad, you wait a little longer, Xiaowu for you to go fishing, will be back in a while."

When Xiao Wu finally caught a Spanish mackerel in the wind and waves, and hurried home, his father-in-law had already died.

From then on, every spring, the couple would buy a fresh mackerel and offer it to the old man's grave.

In this way, it has become a custom for Qingdao people to send mackerel to their father-in-law and mother-in-law in the spring every year, and it has been passed down from year to year.