Morphological and genetic analysis of Gracilaria sp. cultured in ponds and coastal waters

Abstract

Seaweeds of the genus Gracilaria are an important aquaculture commodity, commonly cultured in brackish water ponds as well as in coastal waters. In South Sulawesi, Indonesia, the Gracilaria acultured in ponds has been named G. verrucosa, while Gracilaria cultured in coastal waters has been named G. gigas. Morphologically, these two types of Gracilaria do look different. Detailed examination shows that they appear to have similarities. This study aimed to examine whether these two types of Gracilaria are different species or not. The study used morphological characters and COI mitochondrial gene barcoding to assess the Gracilaria types cultured in ponds and coastal waters. Samples were collected from Ujung Baji Village in Takalar Regency, the main seaweed producing region in South Sulawesi Province, Indonesia. The results indicate that both Gracilaria types have similar genetic characteristics as well as shared morphological characters. Based on these analyses, it is considered that both Gracilaria types cultivated may be strains of the same species.

Seaweed in Indonesia: farming, utilization and research

“…After detailed study of morphology and molecular DNA analysis the latter authors concluded that G. verrucosa, G. gigas and G. changii are one species. Morphological differences observed are probably caused by different culture conditions; plants growing freely in shallow ponds develop a different shape than the same plants growing in the open sea while being tied to lines (Arbit et al, 2019). (2021) noted the difference between official production data on one side and informed industry consensus that estimate the total annual dried seaweed production at 300,000 to 360,000 tons (Neish, 2021) or 365,000 tons (Anggadiredja, 2021) on the other side.…”

“…Besides from G. verrucosa, which is a cosmopolite found in five continents including Asia and Indonesia (Algaebase, www.algaebase.org), information whether the other Gracilaria species are endemic or were introduced to Indonesia could not be found. It should be noted that there is considerable controversy over the taxonomy of the genus Gracilaria and related genera (Arbit et al, 2019). After detailed study of morphology and molecular DNA analysis the latter authors concluded that G. verrucosa, G. gigas and G. changii are one species.…”

The Evolution Road of Seaweed Aquaculture: Cultivation Technologies and the Industry 4.0

“…Gracilaria spp. are one of the main producers of agar due to their fast growth and large agar content [ 170 ], being responsible for 80% of the global production of this phycocolloid [ 1 ].…”

Seaweed Aquaculture in Indonesia Contributes to Social and Economic Aspects of Livelihoods and Community Wellbeing

“…Most Gracilaria culture is undertaken in brackishwater ponds, usually in polyculture with milkfish (Chanos chanos), shrimp or other euryhaline species [42][43][44][45]. There is some culture of Gracilaria using long-line techniques in shallow coastal waters of Takalar Regency, South Sulawesi [46]. Gracilaria cultured in ponds produces agar of a lower gel strength than wild collected seaweed, and reportedly lower than maricultured seaweed, and thus brings prices toward the bottom range for food agar [40].…”