Building a Glass Sponge Reef

• Main Authors: Keenan Guillas, Amanda Kahn, Nathan Grant, Stephanie Archer, Anya Dunham, Sally Leys
• Other Authors: Sally Leys, Amanda Kahn, Nathan Grant, Stephanie Archer, Anya Dunham
• Format: Other/Unknown Material
• Language: English
• Published: 2019
• Subjects: glass sponge reef; Porifera; recruitment; larvae; settlement; biodiversity; northwest Pacific; Hecate Strait; Pacific; Queen Charlotte; Alaska; Glass sponges
• Online Access: https://era.library.ualberta.ca/items/e63d1504-8875-4d7e-98ae-cb4f1a6b74a9; https://doi.org/10.7939/R3RF5KX9J

ABSTRACT Glass sponge reefs are endemic to the continental shelf waters of British Columbia and Alaska where they form complex three-dimensional habitats used by a variety of commercially important fish and invertebrate species. The Hecate Strait and Queen Charlotte Sound Glass Sponge Reefs Marine Protected Area (HSQCS-MPA) was designated in February 2017 to protect 2410 km2 of reef habitat. Efforts to establish baseline information regarding reef-associated taxa in the new MPA have documented the diversity of megafauna in detail, but little is understood of the cryptic epifauna inhabiting hidden crevices within the reefs, and even less is understood of larval recruitment, the key reproductive process maintaining long-term reef health and stability. We collected specimens of a reef-building glass sponge Farrea occa from the HSQCS-MPA and described the diversity of their epifauna. Four hundred eighty-nine organisms from six phyla were documented, including seventy-two sponges from three classes. We found several glass sponges: known juvenile reef-builders (two Aphrocallistes vastus and two Heterochone calyx); the lyssacine sponge Leucopsacus scoliodocus, previously known in Canadian waters only from Jervis Inlet; and an unidentified dictyonine sponge previously unknown to waters of British Columbia. Also present were the carnivorous sponge Lycopodina occidentalis, 11 Desmacella austini, and a calcareous sponge. The growth stages we observed suggest multiple settlement events by glass sponge larvae between February and early March. Of the 489 invertebrates, 454 were attached to dead sponge skeleton despite live tissue being much more available as substrate. This study highlights trends in recruitment at sponge reefs, explores factors that may affect larval settlement, describes new sponge associations, and provides the first description of the range of macrofauna found on glass sponges, acting as a baseline for continued monitoring of the MPA.