Toward an atlas of Salish Sea biodiversity: the flora and fauna of Galiano Island, British Columbia, Canada. Part I. Marine zoology Author Simon, Andrew D. F. https://orcid.org/0000-0002-5358-8974 Institute for Multidisciplinary Ecological Research in the Salish Sea, Galiano Island, Canada adfsimon@imerss.org Author Adamczyk, Emily M. Institute for Multidisciplinary Ecological Research in the Salish Sea, Galiano Island, Canada & University of British Columbia, Vancouver, Canada Author Basman, Antranig Institute for Multidisciplinary Ecological Research in the Salish Sea, Galiano Island, Canada Author Chu, Jackson W. F. https://orcid.org/0000-0002-7776-9446 University of Victoria, Victoria, Canada Author Gartner, Heidi N. Royal British Columbia Museum, Victoria, Canada Author Fletcher, Karin Port Orchard 98366, Port Orchard, United States of America Author Gibbs, Charles J. Pacific Marine Life Surveys, Port Coquitlam, Canada Author Gibbs, Donna M. Pacific Marine Life Surveys, Port Coquitlam, Canada Author Gilmore, Scott R. 7494 Andrea Cres, Lantzville, Canada Author Harbo, Rick M. Royal British Columbia Museum, Victoria, Canada Author Harris, Leslie H. Natural History Museum of Los Angeles County, Los Angeles, United States of America Author Humphrey, Elaine Institute for Multidisciplinary Ecological Research in the Salish Sea, Galiano Island, Canada & University of Victoria, Victoria, Canada Author Lamb, Andy Pacific Marine Life Surveys, Port Coquitlam, Canada Author Lambert, Philip Royal British Columbia Museum, Victoria, Canada Author McDaniel, Neil McDaniel Photography, Vancouver, Canada Author Scott, Jessica Ocean Wise, Vancouver, Canada Author Starzomski, Brian M. University of Victoria, Victoria, Canada text Biodiversity Data Journal 2022 2022-03-10 10 76050 76050 http://dx.doi.org/10.3897/BDJ.10.e76050 journal article http://dx.doi.org/10.3897/BDJ.10.e76050 1314-2828-10-e76050 440282C625BD5D90A9623563DB6850F5 Porifera Grant, 1836 Notes [ 3 classes: 15 orders: 27 genera: 40 species ] The name ' Porifera ' derives from Modern Latin and means, literally, "bearing pores", referring to the pores that perforate the body wall of these organisms. Porifera are commonly known as sponges and have the simplest body plans of all multicellular animals, with no tissues or organs. Currently there are 9,452 valid species recognised worldwide, including representatives from both fresh and saltwater habitats ( Hooper and van Soest 2002 , Van Soest et al. 2012 , de Voogd et al. 2021 ). Most sponges have a unique internal canal system used for circulating water, which is made of a series of progressively finer filters connected by chambers lined with flagellated cells called choanocytes. The phylum is divided into four classes: Calcarea (calcareous sponges), Demospongiae (demosponges), Hexactinellida (glass sponges) and the Homoscleromorpha (homoscleromorphs) ( Gazave et al. 2011 ). Currently, there are 70 valid species recognised in the Puget Trough/Georgia Basin ecoregion ( de Voogd et al. 2021 ), though many species remain undescribed in this cryptic group. Indeed, we estimate as many as 300 to 400 taxa may be present off the coast of British Columbia (Austin, unpubl. 2017). To date, 40 taxa have been documented locally, with all classes but the homoscleromophs confirmed for Galiano Island. Most sponges are filter feeders that tend to thrive in strong current or wave-swept habitats. In tidal passages along the coast of British Columbia, sponges are often the most conspicuous and abundant sessile invertebrates present (Neil McDaniel, pers. obs.). Given that it is difficult to census the biodiversity found in areas with strong currents, additional species have likely gone undocumented from channels around Galiano Island. The homosceleromoph sponge Oscarella sp., for example, is known to occur in inlets of Vancouver Island and would likely be found in deeper waters around Galiano Island with further search effort. This dataset also includes three undescribed sponge species, which is likely a small percentage of the undescribed species in this region. Indeed, new sponge species are frequently described based on specimens sampled in deeper waters ( Reiswig 2018 ). The glass sponges Aphrocallistes vastus Schulze, 1886 (cloud sponge) (Fig. 4 ) and Heterochone calyx (Schulze, 1886) (fingered goblet sponge) form extensive deep-water reefs or bioherms, globally unique to the coasts of western Canada and the USA ( Dunham et al. 2018 ). Glass sponge reefs contribute to the productivity of benthic ecosystems by forming habitat for diverse communities of invertebrates and fish and also play an important role in water filtration and carbon sequestration ( Dunham et al. 2018 ). A total of 19 reef complexes have been mapped throughout the region, covering an area of ~ 12 km2 ( Dunham et al. 2018 ). The reef off Galiano Island is one of the largest reefs mapped in the region, supporting dense populations of A. vastus and H. calyx and a high diversity of marine animal species ( Chu and Leys 2010 , Chu and Leys 2012 ). Uncertainty regarding sponge diversity primarily results from their cryptic nature, which demands specialised knowledge of their skeletal structures and advanced microscopy techniques to confirm species. Most sponges are characterised by their calcareous or siliceous spicules. The abundance, morphology and arrangement of these spicules, along with the form, texture and colour of the sponge, are used to identify specimens with reference to previously-described species. Austin and Ott ( Kozloff 1996 ) provide keys to 130 intertidal and shallow subtidal species, including ~ 20 calcareous sponges, eight glass sponges and 100 demosponges. Additional regional accounts of Porifera include Lamb and Hanby (2005) , Carlton (2007) , Harbo (2011) , Austin et al. (2013) , Austin et al. (2014) , Jensen et al. (2018) and Ott et al. (2019) . For annotated records of sponges reported for Galiano Island, see supplementary materials (Suppl. material 2).