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

Brief description

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 (>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 SPECIES/HABITAT/COMMUNITY FOR EXPERT ASSESSMENT Corals and sponges are habitat-forming biota that often enhance benthic biodiversity in the deepsea by providing complex structural living spaces for a large number of species from a variety of taxa (Buhl-Mortensen et al. 2010, Fromont et al. 2012). Most species of deepwater (often termed ‘coldwater’) corals and sponges need stable substrata for larva to settle and attachment of adult colonies, thus they are usually associated with hard-bottom habitats. Our knowledge of these taxa in Australian waters stems mainly from extensive deepsea biodiversity surveys covering the 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) (Table 1). In addition, a variety of corals were photographed in situ and collected during a survey of the Perth Canyon lead by researcheers from the University of Western Australia on board the RV Falkor (http://archiveschmidtocean.org/story/show/3888). Both taxa 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). 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). Coldwater corals include stony corals (Scleractinia), black corals (Antipatharia), and octocorals (Alcyonacea). Some stony corals form extensive reefs in the deep sea, particularly on seamounts (e.g. see Seamount SER); a single species, Solenosmilia variabilis, is the dominant reef-builder in temperate Australian waters. Studies of the reef on the southern Tasmanian seamounts showed that Solenosmilia has been in the area for at least 47,000 years (Fallon et al. 2014). Deepwater corals are frequently used as indicators of benthic ‘vulnerable marine ecosystems’ (VME) in deep-sea conservation planning (FAO 2008, Tracey et al. 2008, Williams et al. 2015). Althaus et al. (submitted) show that representation of deepwater octocoral species (>80 m) in Australia’s reserves is equitable to spatial coverage by reserves, but there is low species overlap in- and outside reserves. The ability of sponge to filter large volumes of water makes them a critical link between the benthos and the overlaying water column (WAMSI 2016). Deepwater sponges include demosponges, calcareous and glass sponges. 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 & Hooper 2014). The broadest regional analysis of deep-water sponges is presented by Fromont et al. (2012) who found that, off WA, the richness and abundance of demosponges and Calcera were negatively associated with decreasing latitude and increasing depth, and hexactinellids positively Fromont et al. (2012). DATA STREAM(S) USED IN EXPERT ASSESSMENT This assessment is based on data derived from Marine National Facility Surveys described in MarLIN (http://www.marine.csiro.au/marlin/search.html) and accessible through the 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 & SS10/2005) • Tasmanian seamounts surveys (SS01/1999, SS02/2006 & SS02/2007, SS01/2008 & TT01/2008) • Habitat and population assessment of giant crabs (2003 - 2005) • NORFANZ survey of Lord Howe Rise and Norfolk Ridge (TAN0308 - NORFANZ) ---------------------------------------- 2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2016 • Assessment grade: Poor-Good Assessment trend: Stable 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 Not clear how the assessment in 2011 was done.

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Statement: QUALITY OF DATA USED IN THE ASSESSMENT Good, analyses of data peer reviewed.

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Purpose
To describe the state and trends in deepwater corals and sponges (>250 m) for use in the Marine chapter of the 2016 State of the Environment report.