Taiwan's Kuomintang in general and President Ma Ying-jeou in particular have long been the pet aversion of southern Taiwan's rural population. The formula is simple: The farther away from Taipei, the less do people want to hear about the KMT's China-friendly course and closer cross-strait cooperation.

Now, however, the KMT thinks it might have found a holy grail to sway public opinion in the opposition strongholds, albeit an unlikely one. It's not some giant infrastructure project, neither is it the development of yet another industrial park. It is the farming of the grouper, a fish that enjoys increasing popularity on China's newly affluent dinner tables.

Hong Kong, where they are known as garoupa, and China are grouper-hungry. Taiwan's government wants the island's south to satisfy the demand. Taiwan was the first country in the world to develop hatchery and breeding techniques for so-called king groupers. They are raised in ponds, one of Taiwan's farm items to be given zero tariff treatment in the China-Taiwan economic cooperation framework agreement (ECFA). There is currently a 13 percent tariff on live animals.

Since China's market is worth up to US$3.1 billion annually, Taiwan's southern Pingtung and Kaohsiung counties, with the approval of the government in Taipei have been experiencing a boom that resembles a gold rush: farmers, fishermen and factory workers alike are scrambling to cash in by setting up fish farms. Some analysts expect annual grouper revenues to triple or more.

Yet, what is meant to be an invitation to southerners to have a piece of the lucrative cross-strait trade cake comes along with weighty repercussions for the environment. Taiwan's aquaculture industry has long been blamed for land subsidence caused by the pumping of groundwater.

In particular, since the 1990s Taiwan has been facing massive land subsidence in coastal areas, and in many rural regions the figures are dramatic. Parts of Dacheng Township in Changhua County has sunk as much as 1.6 meters, while Taisi in Yunlin County, Dongshih in Chiayi County, Hunei in Kaohsiung County and Jiadong in Pingtung County have experienced subsidence of 30, 40, 62 and 38 cm, respectively.

Government agencies in Taipei dismiss the objections. The grouper is a saltwater fish, they say, and as such it has nothing to do with land subsidence. But matters are not that simple, and Ma's attempt to win hearts and minds in the south is likely to bring along plenty of environmental issues.

"Although the Fisheries Agency promotes saltwater fish aquaculture, it does cause land subsidence, because groundwater is still needed to adjust pond water salinity," said Peter Lin Sun, an associate professor of aquaculture at Taiwan's National Pingtyung University of Science and Technology. "You can find severe land subsidence caused by clusters of grouper ponds, too."

Apart from threatening infrastructure and putting rail traffic safety in jeopardy, sunken areas are more likely to be devastated by flooding brought by typhoons that frequently hit the island, critics say.

Fish farming isn't the only culprit that draws fresh water. Agriculture, factories and private wells pump, too. But the KMT's ambitious plan to turn Taiwan into the world's largest grouper producer could tip the balance, environmentalists say, especially since saltwater aquaculture comes along with yet another nasty feature, which is soil salinization.

"It is absolutely necessary to set up buffer zones between saltwater fish farms and agriculture land, but the Fisheries Agency fails to do so," says Sun, who made it his mission to take on wrong government policies which in his eyes could turn fertile farmland into deserts. "Agriculture and saltwater aquaculture have to be separated by fresh water channels since otherwise the seepage of the pond water will salinize the land."

It's not only through leaks in ponds that salt could eventually make its way into the soil, it's typhoons as well. The recent typhoon Fanapi, for instance, severely damaged 344 hectares of fish breeding ponds in Kaohsiung and Pingtung County.

Fish farming – whether freshwater or saltwater – can lead to a vicious cycle: the use of groundwater leads to land subsidence, which in turn causes coastal land to be flooded with seawater during typhoons; seawater not only renders agricultural land useless for a few years, it also erodes steel bars in reinforced concrete, consequently destroying bridges and buildings, and shortening the lifespan of the very dykes that were meant to keep the seawater in the ocean where it belongs.

There's yet another factor hushed up in the government's praise for grouper farms. That the water that fills the grouper ponds was taken from the ocean doesn't mean that the effluent discharge will go back there. The key factor for economically successful aquaculture is the control of water quality, especially in high stocking density. Fish excretion is high in ammonia, nitrites and nitrates, and any uneaten feed quickly leads to the fouling of water. Therefore, saltwater in the breeding ponds not only has to be replaced constantly but also must be regarded as a pollutant. Organic nitrogen, phosphate as well as aggressive chemicals that are used in the ponds are likely to trickle away somewhere in the environment.

Over the last year, the price of quality grouper has increased 56 percent. In accordance with the KMT's cross-strait policy, which led to the thawing of once- hostile China-Taiwan relations, live grouper can now be transported to 11 harbors in China's Fujian Province, right across the Taiwan Strait.

Politically, the promotion of grouper farming seems a quick fix for the KMT. In the important mayoral elections in Taiwan's five big cities to be held in November, in which 60 percent of Taiwan's electorate will be eligible to cast ballots, the KMT's southern candidates lie hopelessly behind.

Residents of the rural south – male - age group 40 to 60: this is the very clientele the KMT in the past hadn't even bothered much trying to woo. Yet, it's exactly members of this target group who have always been vowing never to make business with China that are now keen cashing in on the grouper craze.

Whether this will eventually profit the KMT remains to be seen. But just as Taiwan's aquaculture experts raise environmental questions over grouper farming, the island's political observers see little benefit. Wang Yeh-lih, chairman of the Department of Political Science of National Taiwan University, told Asia Sentinel: "Although the grouper boom is to help the KMT, it won't be anything more than marginal. It just has the symbolic meaning that Taiwan's agricultural products have more opportunities after ECFA."