Temperature-dependent development in the larvae of the pearl oyster Pinctada fucata

The pearl oyster, Pinctada fucata , is a bivalve mollusk known for its economic and ecological value. Pearl farming once thrived in Hong Kong, but has largely disappeared since the 1970s. With its historical and cultural significance, both the government authorities and local fishers are exploring ways to revitalise this industry. To support this objective, this study investigates the effects of temperature on the ontogenetic development of P. fucata to inform the development of culture techniques suited to Hong Kong’s conditions. Larval cultures were conducted in a laboratory setting using the temperature range observed during the summer months and the spawning period of pearl oysters. Two constant temperature treatments were used, representing low (23 °C) and high (28 °C) temperature treatments. Larvae reared at 23 °C exhibited delayed development, poor growth, and substantial mortality by day 21, with only 1.6 ± 0.2% of larvae remaining. In contrast, larvae reared at 28 °C had significantly higher survival by day 21, with 5.5 ± 1.3% of larvae remaining, showed better growth, and settled as spat. Temperature plays a well-established role in enhancing larval development in various invertebrates, and our study indicates that a rearing temperature of 28 °C is suitable for the culture of P. fucata . Hong Kong’s coastal waters experience considerable temperature fluctuations, and this variability may present challenges for pearl oyster culture. To achieve successful farming and ensure the long-term sustainability of pearl oyster cultivation in Hong Kong, the use of temperature-controlled hatcheries are recommended to help maintain optimal culture conditions.