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Graphical abstract Highlights • Diversification of the Opecoelidae appears driven by intermediate host switches. • A new genus and subfamily are suggested for the only lineage of trematodes known to infect corals. • Trematodiasis in corals is likely caused by a complex of many species. • Four new opecoelid species from butterflyfishes in French Polynesia are described. Abstract Podocotyloides stenometra Pritchard, 1966 (Digenea: Opecoelidae) is the only trematode known to infect anthozoan corals. It causes disease in coral polyps of the genus Porites Link (Scleractinia: Poritidae) and its life-cycle depends on ingestion of these polyps by butterflyfishes (Perciformes: Chaetodontidae). This species has been reported throughout the Indo-Pacific, from the Seychelles to the Galápagos, but no study has investigated whether multiple species are involved. Here, we recollect P. stenometra from its type-host and type-locality, in Hawaiian waters, and describe four new species from examination of 768 butterflyfishes from French Polynesia. On the basis of morphology, phylogeny and life-history, we propose Polypipapiliotrema Martin, Cutmore & Cribb n. gen. and the Polypipapiliotrematinae Martin, Cutmore & Cribb n. subf., for P. stenometra (Pritchard) n. comb., P. citerovarium Martin, Cutmore & Cribb n. sp., P. hadrometra Martin, Cutmore & Cribb n. sp., P. heniochi Martin, Cutmore & Cribb n. sp., and P. ovatheculum Martin, Cutmore & Cribb n. sp. Given the diversity uncovered here and the ubiquity, abundance and diversity of butterflyfishes on coral reefs, we predict that Polypipapiliotrema will prove to comprise a rich complex of species causing disease in corals across the Indo-Pacific. The unique life-cycle of these taxa is consistent with phylogenetic distinction of the group and provides evidence for a broader basis of diversification among the family. We argue that life-cycle specialisation, in terms of adoption of disparate second intermediate host groups, has been a key driver of the diversification and richness of the Opecoelidae, the largest of all trematode families and the group most frequently encountered in coral reef fishes. [ABSTRACT FROM AUTHOR]

Abstract: In this study, coral recruitment was measured on a kilometer-wide scale over two years on shallow (5–6m depth) fringing reefs in St. John, US Virgin Islands, with the objective of determining the extent to which variation in recruitment was affected by biophysical coupling involving temperature and flow. Coral recruitment was measured using settlement tiles deployed at 10 sites along 10km of shore. The tiles were first deployed in August 2006, and thereafter replaced every ≈6months to sample from either August to January, or January to August over 2years. Seawater temperature was recorded at the 10 sites using logging thermistors, and flow was quantified using drogues. Overall, corals recruited at a rate equivalent to 76 corals m−2 6months−1, and were represented mostly by poritids (43% of recruits), agaricids (29%), faviids (17%) and siderastreids (7%). Although the density of recruits differed among sites in a pattern that varied among periods and years, there was a consistent trend for mean density to decline from ≈4 corals tile−1 at eastern sites, to ≤1 coral tile−1 at western sites. One aspect of seawater temperature – the daily range – differed among sites and was greater at western compared to eastern sites, and while it was related inversely to recruitment over one of the sampling periods, it was equivocal as a physical process affecting recruitment. Instead, our results are consistent with biophysical coupling involving patch depletion and downstream filtering, whereby patches of coral larvae are delivered to the south shore of St. John and depleted of larvae through settlement as the water progresses westward. [ABSTRACT FROM AUTHOR]

Abstract: Coral reefs in Jakarta Bay have been subjected to scientific studies since the 1920s. Also from that time on biological collections were made. The reefs in the Jakarta Bay have been under long-term natural and anthropogenic stress. With the biological collections and historical documents the coral species richness in Jakarta Bay around 1920 was reconstructed. New data from this bay and the adjacent offshore Thousand Islands archipelago were obtained during a 2005 research expedition. A comparison of the coral assemblages between 1920 and 2005 reveals a clear decline in species numbers. The most prominent results include the near-shore disappearance of species belonging to the families Acroporidae, Milleporidae, and to a lesser extent Poritidae. The overall coral species composition of the reefs has changed considerably, which is partly reflected in a strong decline in coral species richness. About half the number of species recorded in 1920 was found again in 2005. [ABSTRACT FROM AUTHOR]

The sliding and overturning of unconsolidated rubble by hydrodynamic forcing is expected to cause physical damage to settled coral recruits and asexual fragments by scouring and smothering. Yet, few empirical studies have tested the relationship between rubble mobilisation frequency and the survival and growth of these corals. Here, we tested the response of small coral fragments to varying levels of experimental scouring and smothering, proxies for rubble mobilisation impacts, on two coral species with distinct functional traits; Porites rus (robust, encrusting) and Pocillopora verrucosa (sensitive, branching). This study investigated: 1) how coral fragment survival was affected by inversion on rubble or sand substratum over ~2 w (i.e. smothering); and 2) how the survival, growth and tissue properties of fragments were affected by rubble being overturned (i.e. experiencing scouring or abrasion) at different frequencies over ~10 w. Smothering substratum had a profound influence on the probability of fragment survival. For both species, survival was <2% after 5 d when inverted on sand, whereas nearly all survived when inverted on rubble. Following scouring, most P. rus fragments survived over the ~10-w period irrespective of scour frequency. However, P. verrucosa showed high mortality (45% loss) across all treatments, likely influenced by initial handling and fragmentation. For P. rus , increasing scour frequency caused sublethal effects of significantly reduced tissue growth and pigmentation, and increased partial mortality. These findings indicate that small fragments – and potentially recruits – are unlikely to successfully recruit in frequently-mobilised rubble beds regardless of their functional morphotype, but may persist in rubble beds in lower-energy environments. This provides valuable insight into the limitations on coral recovery in rubble beds, which could inform reef recovery programs considering substratum stabilisation. Combined with an understanding of a reef's hydrodynamic environment, this research can assist managers in prioritising damaged reefs for active interventions. Unlabelled Image • Rubble movement affects coral fragments via smothering and scouring. • Fragments rapidly die after being overturned onto sand, but not onto rubble. • Increasing scour frequency reduced pigmentation and increased partial mortality. • Recruitment is likely lowered in frequently-mobilised rubble beds. [ABSTRACT FROM AUTHOR]