Invasive species are leading to ecosystem changes and socioeconomic deterioration around the globe. In 2018, unknown soft corals were noticed forming a massive ‘blue carpet’ on a shallow reef environment at Todos os Santos Bay, South-west Atlantic. In this study we identified the species, quantified their distribution and abundance as a first step for baseline invasion monitoring, and discussed origin, vector and impacts on native competitors. Coral samples were identified based on morphology and a multilocus DNA barcode, and benthic structure was characterized using digital photoquadrats. Our results revealed two new harmful non-native octocorals in this tropical rocky reef, the ‘blue polyps’ genus Sarcothelia (Xeniidae), native to Hawaii but likely an undescribed cryptic species, and Briareum hamrum (Briareidae), native to the Indian Ocean. Sarcothelia sp. was the dominant taxon in the rocky reef (mean cover 23.66% ± 21.46), exhibiting high coverage as well in the sandy and patch reef habitats (15.83% ± 15.81), however, only three colonies of B. hamrum were found, all outside the sampling area. These octocorals were in physical contact with native benthic organisms, mainly with the most abundant group, but apparently avoid turf algae in sandy and patch reef habitats. We suggest that irresponsible marine aquarium releases likely introduced these species to Brazilian reefs. After identifying the aquarium trade as the main vector of octocoral introductions, we reinforce the importance of inspecting marine species importation and the urgent need to implement a government plan to mitigate invasive species' impacts on the natural reefs of Brazil.

We assessed the distribution, diversity and abundance of corals in Pakistani waters. A total of 29 hard coral species (eight families and 14 genera), one black coral species and eight soft coral species (three families and seven genera) were recorded from 18 dive sites at nine locations along the coastline. Distribution of hard corals was extremely poor at Mubarak Village and Sandspit, and corals were not found at Goth Abdul Rehman, Gadani (Kuchiani) and Buleji. Moderately rich coral communities were recorded at Churna Island and at more exposed sites around Astola Island. By contrast highly diverse hard coral communities, with up to 80% cover, were found only at the northern sheltered side of Astola Island where Favites complanata, Favites pentagona, Coscinaraea monile and Porites nodifera were the most abundant species. Favites complanata was recorded from most dive sites at Astola Island. Porites nodifera and Pocillopora damicornis, and to a lesser extent Porites harrisoni, Leptastrea pruinosa and Psammocora obtusangulata formed large single species stands. No ‘true’ coral reef was found at any dive site; however, the formation of proto-reefs was evident around Astola Island. Soft corals were dominant at most exposed sites, particularly at Ormara (Roadrigues Shoals) and Jiwani. By comparing diversity with other locations in the region, corals distribution and growth appear to be fairly poor in Pakistan.

Fatty acids (FAs) composition of eight zooxanthellate soft corals, Sinularia leptoclados, S. flexibilis, S. aff. deformis, S. lochmodes, S. cf. muralis, S. densa, S. notanda and S. cruciata collected in Van Phong Bay (Vietnam) were studied to identify possible origin of unsaturated FAs. The main FAs were 14:0, 16:0, 7-Me-16:1n-10, 16:1n-7, 16:2n-7, 18:0, 18:1n-9, 18:4n-3, 20:4n-6, 20:5n-3, 22:6n-3, 24:5n-6 and 24:6n-3. On the average, saturated, monounsaturated, and polyunsaturated FAs (PUFAs) contributed 35.6, 6.2 and 54.0% of total coral FAs, respectively. PUFAs of n-6 series predominated in all animals (n-6/n-3 > 1.6). The content of 20:4n-6 varied from 10.2 to 23.8%. The main n-3 PUFA was 18:4n-3 (on the average, 5.4%); the contribution of 20:5n-3 and 22:6n-3, typical PUFAs of marine organisms, was not more than 2.4 and 3.9%, respectively. In Sinularia, PUFAs were produced by endosymbiotic dinoflagellates (zooxanthellae) and the coral host tissue, or obtained with food. Zooxanthellae can be considered as the source of C16 PUFAs and 18:4n-3. The coral host synthesized 18:2n-7, 24:5n-6 and 24:6n-3 acids. The low content of 18:1n-7, saturated odd-chain FAs and saturated methyl-branched FAs indicated a negligible contribution of bacteria to total lipids of Sinularia. A comparison of the levels of diatom and dinoflagellate FA markers in coral and plankton lipids showed eukaryotic microalgae to play a secondary role in feeding of Sinularia. The high level of 20:4n-6 may be considered as an indicator of heterotrophic feeding of Sinularia.