Seafood exports in the first half of the year reached US$1.69 billion, a reduction of 11.24 per cent compared to the same period last year, the association said in a recent report.
Exports of frozen shrimp had seen the largest reduction both in terms of volume and value, it added.
In May alone, the country exported about 13,531 tonnes of shrimp worth more than $109.5 million, a reduction of 1.7 per cent in volume and 9.1 per cent in value over the same period last year.
In Bac Lieu province, the country's biggest "shrimp basket", total earnings from seafood export in the first half of the year was just $55.71 million, 31.88 per cent of the annual target.
Luong Le Phuong, deputy minister of Agriculture and Rural Development, said the current economic downturn had reduced shrimp consumption in key markets.
Stricter technical barriers for shrimp import set by China and other importers had also made things more difficult for shrimp exporters, he added.
Truong Dinh Hoe, VASEP general secretary, said along with the fall in seafood consumption, their prices had also fallen in most markets.
He noted that the nation's seafood export markets were also shrinking. Last year, the country's seafood products were shipped to 126 countries and territories, but this had fallen to 120 this year.
In the first six months of the year, the EU still remained the largest importer of Viet Nam's seafood products, followed by Japan, China and the US.
According to the UN Food and Agriculture Organisation (FAO), prices of many seafood items would fall further in the next six months due to plentiful supply.
If the export of seafood products would not improve in the remaining months of the year, the sector would find it hard to achieve the target of $4.5 billion for this year, Phuong said.
He asked seafood enterprises to improve their competitiveness and enhance trade promotion efforts to boost exports in the remaining months of the year.
The total area for shrimp farming in the Cuu Long (Mekong) Delta in the first half of the year has reduced remarkably over the same period last year to around 566,000ha, according to the Aquaculture Department under the Ministry of Agriculture and Rural Development.
Financial difficulties, high prices of shrimp feed, unstable shrimp prices and the high risk of epidemics had discouraged farmers from persisting with shrimp farming, the department said.
This in turn, would put local seafood processing companies and exporters into greater difficulties as they would have insufficient raw material to process for export, it added.