2016 SoE Marine Chapter - State and Trends - Deepwater corals and sponges (30 m – 250 m)

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "The state and trends of quality of habitats and communities – Deepwater corals and sponges (30 m – 250 m)". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record.

DESCRIPTION OF ECOLOGICAL HABITAT/COMMUNITY FOR EXPERT ASSESSMENT
Corals and sponges are habitat-forming biota that often enhance benthic biodiversity in deep shelf waters by providing complex structural living spaces for a large number of other species from a variety of taxa (Pitcher et al. 2007a, Buhl-Mortensen et al. 2010, Fromont et al. 2012). Most species of corals and sponges need stable substrata for larva to settle and attachment of adult colonies, thus they are usually not associated with mobile or soft-sediment habitats. While corals are often thought of as being associated with tropical waters, coral species are found throughout Australia’s shelf waters and can make up a significant component of the cold-water assemblage. Coldwater corals include stony corals (Scleractinia), black corals (Antipatharia), and octocorals (Alcyonacea)
. 
Our knowledge of these taxa in Australian waters below typical diving depths stems mainly from a few broad-scale biodiversity surveys covering the Gulf of Carpentaria (Long et al. 1995; Harris et al. 2007; Bustamante et al. 2011), Great Barrier Reef shelf (Pitcher et al. 2007a), Torres Strait (Pitcher et al. 2007b), Pilbara (Pitcher et al. 2016b), southern south-east, north-west, and western south –west regions, and the Lord Howe/ Norfolk ridge area (McEnnulty et al. 2011, Williams et al. 2011, Dunstan et al. 2012). Both corals and sponges were found to be highly diverse with many undescribed species, as well as many ‘unknown’ (sensuHooper et al. 2013) species (McEnnulty et al. 2011, Fromont et al. 2012, Alderslade et al. 2014). For example, sponges in the GBR were the most diverse group with the highest levels of rarity (Pitcher et al. 2007a) and some of the most abundant sponges discovered were new species (Sutcliffe et al. 2010). In addition, species turn-over between samples was extremely high for both taxa (Schlacher et al. 2007, Fromont et al. 2012, Alderslade et al. 2014). The sponge fauna of NSW shelf waters was reviewed in order to improve our understanding in east coast subtropical and temperate waters (Davis et al. 2010).
Recently (2008 onwards), IMOS has funded an AUV program that allows repeat photographic surveys to document the cross-shelf distribution of reef associated benthic invertebrate assemblages at a broad set of latitudinally spaced nodes along Australia’s eastern and western coastlines. This program, if continued, will allow long-term monitoring of the state and trend of deep shelf reef sponges and corals at a fixed set of sites and feed into future SoE assessments. While species identifications are not always possible from such imagery, a national identification framework has been established for consistently annotating this imagery to the finest scale possible (CATAMI refs), and initial analysis (e.g. Perkins et al. 2015) demonstrates patterns similar to the biodiversity surveys above, with high diversity and high species turnover between locations samples (e.g. Monk et al., in press). 
Both sponges and corals are frequently used as indicators of benthic ‘vulnerable marine ecosystems’ (VME) in conservation planning (FAO 2008, Tracey et al. 2008, Williams et al. 2015). 
The ability of sponges to filter large volumes of water makes them a critical link between the benthos and the overlaying water column (WAMSI 2016), and recent studies of productivity on shallow coral reefs suggest that filter feeding by sponges may account for up to 90% of the trophic coupling between pelagic and benthic ecosystems (ref). Such coupling is equally likely on deeper reefs and temperate latitudes as well. The species-level identification of deepwater sponges has not been standardised across Australian collections at this stage; however, this may be possible in the future through SpongeMaps, an online collaboration tool for sponge taxonomists (Hooper et al. 2013; Hall &amp; Hooper 2014). 
DATA STREAM(S) USED IN EXPERT ASSESSMENT
This assessment is based on data from several Marine National Facility Surveys (available via CSIRO Data Trawler http://www.cmar.csiro.au/data/trawler/). Links to specific data sets are provided in the "On-line resources" section of this record.
• Voyage of Discovery north-west (SS05/2007)
• Voyage of Discovery south-west (SS07/2005 &amp; SS10/2005)
• Tasmanian seamounts surveys (SS01/1999, SS02/2006 &amp; SS02/2007, SS01/2008 &amp; TT01/2008)
• Habitat and population assessment of giant crabs (2003 - 2005) 
• Gulf of Carpentaria survey : beam trawl megabenthos (SS03/1990)
• Mapping &amp; Characterisation of Biotic &amp; Physical Attributes of the Torres Strait (Epibenthic Sled)
• Great Barrier Reef Seabed Biodiversity Project  (Epibenthic Sled)

2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]
• 2016 •
Assessment grade: Good
Assessment trend: Improving
Confidence grade: Limited evidence or limited consensus
Confidence trend: Limited evidence or limited consensus
Comparability: Grade and trend are somewhat comparable to the 2011 assessment
• 2011 •
Assessment grade: Good
Assessment trend: Stable
Confidence grade: Limited evidence or limited consensus
Confidence trend: Limited evidence or limited consensus

CHANGES SINCE 2011 SOE ASSESSMENT
Evidence for the good 2011 grade for the Temperate East Region is unclear and it is suggested that this previous grade for the East Region was incorrect based on new information on trawl footprints in the 5 marine regions.

Tags: biogenic habitat, coral, deepwater invertebrates, expert assessment, sponge
Organization: Australian Ocean Data Network