Invertebrate · Stinging · Hard corals

Yellow Scroll Coral

Turbinaria reniformis Bernard, 1896

syn. Turbinaria disparata, Turbinaria lichenoides, Turbinaria reptans, Turbinaria veluta

3 mCITES IILeast Concern

1078

Turbinaria reniformis, commonly referred to as yellow scroll coral, belongs to the Dendrophylliidae family and is a colonial stony coral. It is native to the Indo-Pacific region and has been classified as "vulnerable" by the International Union for Conservation of Nature.

Turbinaria reniformis is characterized by its flat, plate-like structure or shallow chalices, occasionally forming tiers. The corallites, which are the skeletal cups that house the polyps, are widely spaced and located solely on the upper surface of the plates. These corallites have a diameter of 1.5 to 2 mm and possess thick walls, either sinking into the coenosteum (skeletal tissue) or appearing conical in shape. The coral exhibits a distinct rim devoid of corallites and typically displays a yellowish-green hue.

The geographical range of Turbinaria reniformis spans an extensive area, encompassing the 🌊 Red Sea, 🌊 Gulf of Aden, 🌊 Indian Ocean, central Indo-Pacific, northern 🇦🇺 Australia, southern 🇯🇵 Japan, South China Sea, and various island groups in the West and Central Pacific.

Turbinaria reniformis is a zooxanthellate coral, forming a symbiotic relationship with unicellular dinoflagellates called zooxanthellae. These photosynthetic organisms provide nutrients and energy to the coral, necessitating the coral's preference for relatively shallow, well-lit marine environments. However, under conditions of thermal stress, the coral may expel the zooxanthellae, resulting in bleaching and eventual mortality. Studies have shown that when the surrounding seawater is moderately enriched with nitrogen, the coral exhibits greater resilience to thermal stress and is able to retain its zooxanthellae.

Turbinaria reniformis is gonochoristic, meaning that colonies are either male or female. Breeding occurs synchronously, with all colonies in a given area releasing gametes into the sea approximately one week after the occurrence of a full moon in November.

Why it's threatened

Residential & commercial development

Housing & urban areas · Commercial & industrial areas · Tourism & recreation areas

Transportation & service corridors

Shipping lanes

Biological resource use

Intentional use: (subsistence/small scale) [harvest] · Unintentional effects: (subsistence/small scale) [harvest] · Motivation Unknown/Unrecorded

Human intrusions & disturbance

Recreational activities

Invasive species, genes & disease

Unspecified species

Pollution

Type Unknown/Unrecorded · Soil erosion, sedimentation · Ozone

Climate change & severe weather

Temperature extremes · Storms & flooding

This family is known to have relatively low bleaching vulnerability (Marshall and Baird 2000, Thompson and Dolman 2010), and is considered apozooxanthellate. It also has low vulnerability to COTS predation (Keesing 2021).

The collection of this species for the aquarium trade may lead to overharvest and localised reductions in abundance, especially for populations of naturally rare species (Bruckner and Borneman 2006). However, the wild collection of corals is highly selective and considered low impact in the long-term relative to other activities such as coral mining and dynamite fishing (Green and Shirley 1999, Pratchett et al. 2020).

In general, the major threat to corals is global climate change, in particular, temperature extremes leading to bleaching and increased susceptibility to disease, increased severity of ENSO events and storms, and ocean acidification.

Coral disease has emerged as a serious threat to coral reefs worldwide with increases in numbers of diseases, coral species affected, and geographic extent (Ward et al. 2004, Sutherland et al. 2004, Sokolow et al. 2009). Outbreaks of coral diseases have damaged coral reefs worldwide with the most widespread, virulent, and longest running coral disease outbreak currently occurring on the Florida Reef Tract and throughout the Caribbean. The disease, stony coral tissue loss disease, has been ongoing since 2014 (Precht et al. 2016) and has devastated affected reefs along Florida (Walton et al. 2018, Williams et al. 2021) and throughout the Caribbean (Alvarez-Filip et al. 2019, Kramer et al. 2019). Numerous disease outbreaks have also occurred in the Indo-Pacific (Willis et al. 2004, Aeby et al. 2011; 2016), Indian Ocean (Raj et al. 2016) and Persian Gulf (Howells et al. 2020). Escalating anthropogenic stressors combined with the threats associated with global climate change of increases in coral disease, frequency and duration of coral bleaching and ocean acidification place coral reefs in the Indo-Pacific at high risk of collapse.

Localized threats to corals include fisheries, human development (industry, settlement, tourism, and transportation), changes in native species dynamics (competitors, predators, pathogens and parasites), invasive species (competitors, predators, pathogens and parasites), dynamite fishing, chemical fishing, pollution from agriculture and industry, domestic pollution, sedimentation, and human recreation and tourism activities. The severity of these combined threats to the global population of each individual species is not known.

Threat classification from the IUCN Red List.