SHANGHAI – Keith Jones takes his family out for a special meal of bighead carp whenever his Chinese in-laws are in town.

At dinner this spring in Aiwanting Restaurant in a trendy Shanghai shopping district, Jones’ in-laws help devour a massive carp head.

Jones, from the United Kingdom, has lived in Shanghai for three years with his Chinese wife and their daughter — long enough to know that the freshness of the cherished carp is of top importance to Chinese diners.

That’s why carp eaters in this southern China city say they would never eat frozen fish from American lakes and rivers, even though scientists say they believe fishing is one of the best short-term solutions for controlling invasive Asian carp as they threaten the Great Lakes.

Big River Fish, a processor in Pearl, Ill., says it has a deal to ship Asian carp to the northern China city of Beijing to serve at high-end restaurants.

But in Shanghai, residents say the only fish they eat frozen is from the ocean. Freshwater fish must be eaten within hours of being killed.

“The company will have no channels to sell them here,” Jones’ mother-in-law, Liu Guilou, said through a translator, referring to Big River Fish.

Bighead carp, called “hua lian” in Mandarin, has been a Chinese delicacy for so much of China’s centuries-old history that many in Shanghai simply say they like to eat it because it’s traditional.

Local supermarkets, small grocers and street-side sellers comply, offering live fish in tanks or in low plastic trays and then butchering them on site.

At a Shanghai Carrefour supermarket, a sign says the fish come from Hongze Lake, China’s fourth-largest lake, about 200 miles northwest of Shanghai. But Gui Jin Yu, who works the Carrefour fish counter, says most of the fish are farmed locally.

Most customers just buy the treasured head of the carp, which commands twice the price of the fish’s bottom half. At about $4.30 for a four-pound fish head — a pricey dinner by Chinese standards — bighead carp also is twice as expensive as other comparable fish.

In a famed but difficult preparation from Hunan province, the fish is steamed in garlicky broth and topped with fresh-cooked red peppers.

The preparation is difficult and time-consuming, so families such as Jones’ often go to local restaurants to eat it on special occasions. It’s the signature dish of the high-end Aiwanting Restaurant, where diners step off an elevator into a lobby dotted with pillar-shaped tanks of huge swimming goldfish.

A small order of Aiwanting’s fish heads and peppers costs 78 yuan — about $12, which would purchase four to eight dishes at most everyday Chinese eateries. (The dish sells for about half that price at a lower-end Shanghai restaurant.) After a 15-minute wait, the Aiwanting wait staff delivers a huge fish head, its two halves still connected, cut off just behind the gills and the side fins. The soft red peppers and their spicy seeds are poured over the top.

Diners dig in with their chopsticks, patiently pulling out tiny bones laced through the white flesh to enjoy the pleasant heat infused by the peppers and broth. The peppers even hide some of the ultra-fishy taste in the gills and the egg-white-like fat around the face.

To an American palate, the taste of those treasured parts evokes memories of dirty water sloshing against a seaside dock.

As is common at Shanghai restaurants, Aiwanting buys carp every morning. It’s killed at the market and eaten later that day.

“We want to keep the freshness and quality,” the manager, Luo Huayong, said through a translator. “It loses its freshness if it’s not eaten the same day.”