Fisheries Research Institute Promotes Multi-stage Aquaculture for Hard Clams, Survival Rate Increased by Over 10%

Central News Agency

(CNA Correspondent Wang Shu-fen, Taipei, 22nd) Facing the impact of extreme weather on aquaculture, the Fisheries Research Institute (FRI) of the Ministry of Agriculture is promoting a multi-stage aquaculture method for hard clams. Empirical results from demonstration farms in Yunlin last year showed that the survival rate can be increased by more than 10%, and it will be promoted to major hard clam producing areas in Changhua and Chiayi this year.

The Ministry of Agriculture issued a press release today introducing the FRI's new multi-stage hard clam aquaculture model, which effectively reduces environmental risks by adjusting stocking sizes and shortening the cultivation period.

The FRI stated that empirical results from guided demonstration farms in the Yunlin area showed the hard clam survival rate increased by over 10%, with an average net profit of NT$1.23 million, providing a new business model for the traditional hard clam aquaculture industry that balances efficiency and risk management.

The FRI explained that the mortality rate in hard clam aquaculture has risen in recent years. Field data analysis found this is closely related to the deterioration of water and bottom sediment quality in aquaculture ponds, particularly evident during periods of high temperatures and frequent rainfall. To reduce losses caused by extreme weather, the FRI proposed the 'multi-stage aquaculture' technology, aiming to have hard clams grow to market size and be harvested before the pond environment deteriorates.

Currently, regular hard clam farmers can choose to stock seeds ranging from tiny (about 1,200 to 1,500 per catty) to 500 per catty, raising them to market size. The 'multi-stage aquaculture' model adds an intermediate stage: raising the 500-per-catty seeds to 200-300 per catty before transferring them to the final grow-out ponds for market size.

The FRI noted that stocking larger-sized seeds can shorten the time needed to reach market size, reducing clam mortality caused by climate-induced organic matter accumulation at the bottom during the late stages of cultivation, thereby increasing the survival rate and harvest yield.

Last year, the FRI promoted this new model to 4 demonstration farms in Yunlin. During the demonstration period, they faced climate challenges such as rapid temperature rises in April and May, plum rains, and Typhoon Danas. Ultimately, the survival rate still reached over 60%, an improvement of about 10% compared to the 50% of typical models, adding about NT$150,000 in revenue per hectare for farmers. After deducting production costs, the demonstration farms had an average net profit of NT$1.23 million, showing significant economic benefits from the multi-stage model.

Additionally, the FRI found that because the cultivation period is shortened to 6 months, farmers can flexibly adjust from the traditional one harvest per year to 'two harvests per year.' This not only improves land utilization efficiency and total output value but also allows farmers to avoid climate risks in specific seasons, greatly enhancing business stability.

The FRI stated that due to the good demonstration results, they will further promote it this year to major hard clam producing areas like Changhua, Chiayi, and Yunlin. In the future, they will continue technical guidance and demonstration promotions to help farmers improve production efficiency and business stability, strengthening the hard clam industry's resilience to climate change, and substantially increasing farmers' incomes.