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Methods are described for the determination of age from otoliths of the kob (Argyrosomus hololepidotus) and the spotted grunter (Pomadasys commersonni.) Growth curves provide estimates of length for age, while use of length/weight relationships enable estimates of weight for age to be made. These are discussed in relation to the age composition of estuarine populations, age at sexual maturity and years of greatest weight increment. [ABSTRACT FROM PUBLISHER]

The species composition of soft corals of the families Tubiporidae, Alcyoniidae, Nephtheidae, and Xeniidae is presented for the Dahlak Archipelago (15-16ºS) in the southern Red Sea in Eritrean waters. A comprehensive collection was made during several field trips (1993-2002) to various sites in this archipelago. Some unexamined specimens obtained during the Israeli South Red Sea expeditions (1962 and 1965) to the region were also included in the study. A systematic list of soft corals is presented, comprising 28 species based on the material and previous literature. The list includes five genera (Rhytisma, Sinularia, Paralemnalia, Scleronephthya, and Heteroxenia) and sixteen species recorded for the first time in the southern Red Sea. Seven of these species belong to the genus Sinularia and three to Ovabunda. All the species found belong to the Indo-Pacific faunistic province and have been previously recorded elsewhere in the Red Sea. A distinct north to south latitudinal diversity attenuation of soft corals at both the species and generic levels is evident in the Red Sea. This pattern can be at least partially attributed to differences in environmental conditions between the two extremities of the Red Sea, such as surface temperature, salinity, nutrient concentrations, and turbidity. The biogeographic setting of the southern Red Sea reefs, the gateway to the Indian Ocean, makes them a stimulating target for future research on soft corals. Such studies will contribute to our knowledge on the status of the reefs in this region and will include a temporal scale to provide feedback on reef health for conservation purposes. [ABSTRACT FROM AUTHOR]

Recent surveys conducted on Reunion Island coral reefs revealed an atypical manifestation of black band disease on the main framework building coral, Porites lutea. This BBD manifestation (PorBBD) presented a thick lighter-colored band, which preceded the typical BBD lesion. Whilst BBD aetiology has been intensively described worldwide, it remains unclear if corals with apparently similar lesions across coral reefs are affected by the same pathogens. Therefore, a multidisciplinary approach involving field surveys, gross lesion monitoring, histopathology and 454-pyrosequencing was employed to provide the first comprehensive characterization of this particular manifestation. Surveys conducted within two geomorphological zones over two consecutive summers and winters showed spatial and seasonal patterns consistent with those found for typical BBD. Genetic analyses suggested an uncharacteristically high level of Vibrio spp. bacterial infection within PorBBD. However, microscopic analysis revealed high densities of cyanobacteria, penetrating the compromised tissue as well as the presence of basophilic bodies resembling bacterial aggregates in the living tissue, adjacent to the bacterial mat. Additionally, classical BBD-associated cyanobacterial strains, genetically related to Pseudoscillatoria coralii and Roseofilum reptotaenium were identified and isolated and the presence of sulfate-reducers or sulfide-oxidizers such as Desulfovibrio and Arcobacter, previously shown to be associated with anoxic microenvironment within typical BBD was also observed, confirming that PorBBD is a manifestation of classical BBD.

Coral diseases have caused a substantial decline in the biodiversity and abundance of reef-building corals. To date, more than 30 distinct diseases of scleractinian corals have been reported, which cause progressive tissue loss and/or affect coral growth, reproductive capacity, recruitment, species diversity and the abundance of reef-associated organisms. While coral disease research has increased over the last 4 decades, very little is known about coral diseases in the Western Indian Ocean. Surveys conducted at multiple sites in Reunion, South Africa and Mayotte between August 2010 and June 2012 revealed the presence of 6 main coral diseases: black band disease (BBD), white syndrome (WS), pink line syndrome (PLS), growth anomalies (GA), skeleton eroding band (SEB) and Porites white patch syndrome (PWPS). Overall, disease prevalence was higher in Reunion (7.5 ± 2.2%; mean ± SE) compared to South Africa (3.9 ± 0.8%) and Mayotte (2.7 ± 0.3%). Across locations, Acropora and Porites were the genera most susceptible to disease. Spatial variability was detected in both Reunion and South Africa, with BBD and WS more prevalent on shallow than deep reefs. There was also evidence of seasonality in 2 diseases: the prevalence of BBD and WS was higher in summer than winter. This was the first study to investigate the ecology of coral diseases, providing both qualitative and quantitative data, on Western Indian Ocean reefs, and surveys should be expanded to confirm these patterns.