First records of illegal harvesting and trading of black corals (Antipatharia) in Madagascar

Black corals (Cnidaria: Antipatharia) have been used all around the world for a long time, whether as money or for medicinal purposes and jewellery manufacturing. Except in Hawaii where these fisheries are well known, black coral harvests are usually made without any control or any management. This is the case in many tropical islands and particularly in Madagascar, where the illegal trade is continually expanding. Since 2011, an illegal traffic of black corals has been occurring in the main cities of the southern and coastal regions of Ambovombe and Tolagnaro. In 2014 and 2015, hundreds of kilograms of black coral skeletons and a lot of diving material were seized by the authorities in the Anosy and Androy regions. Despite this and the continual harvesting of these natural resources, there has been no study of the excessive exploitation in this region. This paper is the first to talk about this new threat and to analyse and discuss the benefits of these fisheries. The first seizures and the efforts carried out on the island to stop the trade are explained. This paper highlights the urgency of studying these corals before making an appropriate conservation and management plan

Widest geographic distribution of a shallow and mesophotic antipatharian coral (Anthozoa: Hexacorallia): Antipathes grandis VERRILL, 1928 – confirmed by morphometric and molecular analyses

We provide the first record of the shallow and mesophotic ( 200 m depth) benthic taxa have such wide geographic distributions

Assessing trophic relationships between shallow-water black corals (Antipatharia) and their symbionts using stable isotopes

Shallow-water antipatharians host many symbiotic species, which spend their adult life with their host and/or use them to have access to food. Here we determine the trophic relationships between four common macrosymbionts observed on/in Cirripathes anguina, Cirrhipathes densiflora and Stichopathes maldivensis in SW Madagascar. These include the myzostomid Eenymeenymyzostoma nigrocorallium, the gobiid fish Bryaninops yongei, and two palaemonid shrimps, Pontonides unciger and Periclimenes sp. The first is an endosymbiont living in the digestive tract, while the others are ectosymbionts. The analyses show that most likely (i) none of the symbionts uses the host as a main food source, (ii) nocturnal plankton represents a main part of the diet of antipatharians while the symbionts feed preferentially on diurnal plankton, (iii) the myzostomid has the narrowest trophic niche, (iv) the two shrimps have distinct trophic niches and feed at lower trophic level than do the other symbionts. Concerning the myzostomids, they had the same δ13C values but had significantly higher δ15N values than the hosts. TEFs (Trophic Enrichment Factors) recorded were Δ13C = 0.28 ± 0.25 ‰ and Δ15N = 0.51 ± 0.37 ‰, but these were not high enough to explain a predator-prey relationship. These worms rely on the coral diet but may also ingest host fluids explaining the slight enrichment in heavier nitrogen isotopes. On the other hand, the ectosymbionts use the coral as a pathway to have access to food from the midwater: they feed from the water passing nearby the black corals, but a kleptoparasitic behaviour cannot be excluded

ITS1 variation among Stichopathes cf. maldivensis (Hexacorallia: Antipatharia) whip black corals unveils conspecificity and population connectivity at local and global scales across the Indo-Pacific

Due to the dearth of molecular markers variable enough to distinguish species of black corals, species delimitation in Antipatharia is still mainly based on morphological traits. One of the few markers available, the internal transcribed spacer (ITS) region located in ribosomal DNA, has already been used several times to infer phylogenetic relationships among antipatharians. However, this region was never considered in population-scale studies of shallow-water black corals till now. Here, we sampled two phenotypic variants of 41 specimens of the shallow-water antipatharian Stichopathes cf. maldivensis along the SW of Madagascar. The sampling area represents 200 km of shore and encompasses the runoffs of three rivers. We used direct sequencing to determine the main ITS1 types present in the genomes of the collected specimens and retrieved sequences from GenBank for Indonesian specimens. Then, we constructed a haploweb to visualize possible species boundaries using the criterion of mutual allelic exclusivity. With this method, we confirm that the previously described phenotypic variants belong to a single species that apparently extends from Indonesia to Madagascar. Likewise, the three rivers that pour freshwater in southwestern Madagascar do not appear to act as a barrier for the larval dispersal of this species. This study highlights the usefulness of ITS markers within antipatharians at both species and population levels.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Shallow-water black corals (Cnidaria: Anthozoa: Hexacorallia: Antipatharia) from SW Madagascar

Terrana, Lucas, Bo, Marzia, Opresko, Dennis M., Eeckhaut, Igor (2020): Shallow-water black corals (Cnidaria: Anthozoa: Hexacorallia: Antipatharia) from SW Madagascar. Zootaxa 4826 (1): 1-62, DOI: https://doi.org/10.11646/zootaxa.4826.1.

Characteristics of the infestation of Seriatopora corals by the coral gall crab Hapalocarcinus marsupialis Stimpson, 1859 on the great reef of toliara, Madagascar

peer reviewedThis study describes the association between the obligatory symbiont coral gall crab Hapalocarcinus marsupialis and its stony coral hosts Seriatopora sp .within the Great Reef of Toliara in Madagascar and attempts to dis- cuss their symbiotic status through comparison with previous studies. These corals are inhabited by crabs living in galls that can be categorised in four distinct morphological stages, where the first one corresponds to a small bud and the last one represents a completely closed gall surrounding the crab inside. Within the reef, 563 colonies of Seriatopora species were observed by scuba-diving at ten different stations: 37.8 % of them were infested by H. marsupialis , with a total of 763 galls, and with a majority of stage 4 galls. Galls are monopolised by females that can have different morphologies. Females store the sperm in two spermathecae and are fertilised when their morphology and size are similar to males and the gall is not closed. Histological observations coupled with scanning electronic microscopy analyses show that closed galls are made of an external living tissue, a mid skeletal layer and an internal living tissue. The internal living tissue includes polyps similar to the external tissue, some of them being sex- ually mature. Nitrogen and carbon isotopic signatures confirmed that these crabs are filter-feeders and do not feed on their host. This association perfectly highlights the difficul- ties to define the symbiotic status of a symbiont if one con- siders inflexible the three categories of symbiosis commonly defined.DÉVELOPPEMENT DE POLYAQUACULTURES DANS LES VILLAGES CÔTIERS DU SUD-OUEST ET DU NORD DE MADAGASCA

Previously unlisted scleractinian species recorded from the Great Reef of Toliara, southwest Madagascar

The scleractinian biodiversity of Madagascar is mainly known from one study performed in the Bay of Toliara (SW of Madagascar) in the 1970s. In the present study, this biodiversity was re-investigated 40 years later, at 2 sites previously considered as atypical, but now subject to high anthropogenic pressures. Results showed lower species diversity compared to the previous study, and to similar sites in the Indian Ocean region, but most of the well-rep- resented genera were recorded. The occurrence of previously unrecorded species suggests that the scleractinian communities are changing, in addition to declining. The findings of the present study constitute a baseline of scle- ractinian structure studies, focused on diversity change. Further investigations on this reef must consider these changes, and management measures must be adapted to ensure greater efficiency

Investigating densities of Symbiodiniaceae in two species of Antipatharians (black corals) from Madagascar

peer reviewedHere, we report the first methodological approach to investigate the presence and estimate density of Symbiodiniaceae cells in corals of the order Antipatharia subclass Hexacorallia, known as black corals. Antipatharians are understudied ecosystem engineers of shallow (200 m) reefs. They provide habitat to a vast number of marine fauna, enhancing and supporting coral reefs biodiversity globally. Nonetheless, little biological and ecological information exists on antipatharians, including the extent at which global change disturbances are threatening these corals. The assumption that they were exempted from threats related to climate change was challenged by findings of high density of dinoflagellates within three antipatharian colonies. Further methodical studies were necessary to investigate the regularity of these findings. An integrated design combining microscopy and molecular techniques was used to investigate the presence and estimate density of Symbiodiniaceae cells within two antipatharians species - Cupressopathes abies and Stichopathes maldivensis - from shallow and mesophotic reefs of SW Madagascar. Symbiodiniaceae-like cells were found within the two species from both shallow and mesophotic reefs, although the overall cell density was very low (0-4 cell mm-3). These findings suggest that high abundance of Symbiodiniaceae is not characteristic of antipatharians, which has relevant implications considering climate change associated disruptions in other corals. However, the high densities of dinoflagellates found in antipatharian colonies exposed to higher light irradiance in other studies should be further examined