- The development of the Sargassum glaucescens seedling production technique
In the past four years, we investigated the S. sphagnum in Penghu waters. The reproductive sori matured in July, and the zygotes releasement peaked between July 4th and July 15th. The seedlings reached sporophyte stage at the end of October, and go through a period of dormancy until the end of January. The seedlings kept growing from February to mid-June(In the natural environment they would grow until late July).The investigation was suspended during COVID-19 pandemic period, thus the adult stage couldn’t be observed. Although the seedling production skill for S. sargassum is well-developed now, but the proliferation of seaweeds is an obstacle to overcome. The introduction of juvenile algivorous conch, e. g., Tectus pyramis and Laevistrombus canarium, into the cultivation environment would effectively minimize the impact.
- The application of macroalgae cultivation system – the revitalization of an abandoned fishing port
The macroalgae cultivation system was deployed in a abandoned fishing port. The system covered 50 % of the surface area of the fishing port and improve the habitat in 65 days. It was observed that a large number of Siganus fuscescens fry aggregated and foraged in the system. After the reduction of algal coverage as a result of grazing, the fish fingerlings moved out of the area when they reached about 15 cm.
- The development seabed cultivation system
The seabed cultivation system could provide macroalgae seedlings for farming, thus reduce the dependency on the natural colony. We’re now able to cultivate two species of macroalgae on seabed. S. hemiphyllum var. chinense: a batch of seedlings cultivated for 170 days were planted in Hongluo sea area in November 11th, 2020. The blades were easily grazed by Euplica scripta at the start, but the biomass grew fast in December and reached about 200 cm in length on April 1st. The reproductive sori were mature on April 22nd and produced zygotes ready to be collected. S. sphagnum: a batch of late stage seedlings cultivated for 94 days were planted in Hongluo sea area in October 27th, 2020. The seedlings reached sporophyte stage on November 13th, and entered dormant state until February. The algal structure reached about 60 cm by the last third of June, while the adult stage left unobserved due to the COVID-19 pandemic after June.