High tuna and shrimp prices have eaten into third-quarter profits at seafood giant Thai Union Frozen Products.

The company today (1 November) booked net profit of THB817m (US$27.4m) for the three months to the end of September, down almost 19.7% on a year earlier.

Thai Union, which struck a deal in July to buy John West owner MWBrands, said “escalating” raw-material prices had “inevitably affected margins”.

The group said tuna prices had been “relatively volatile”, while the price of shrimp had jumped 20-30%.

Thai Union posted a 3% increase in sales to THB17.43bn. In US dollars, sales were up 11% but the strengthening of the Thai baht had weighed on sales.

In the first nine months of 2010, net profit fell 4% to THB2.63bn. Sales dipped 1.8% to THB50.86bn.