Abstract
back to Publications Austin, W.C., Conway, K.W., Barrie, J.V. & Krautter, M . (2007): Growth and morphology of a reef-forming glass sponge, Aphrocallistes vastus (Hexactinellida), and implications for recovery from widespread trawl damage.
Growth and morphology of a reef-forming glass sponge, Aphrocallistes vastus (Hexactinellida), and implications for recovery from widespread trawl damage
Abstract: Living hexactinellid reefs, known only from the western Canadian shelf, are being damaged by dredging and trawling. Recovery of damaged or destroyed hexactinellid reefs depend on many interrelated factors including sponge larval settlement and survival, sponge growth rates and the balance between suspended sediment trapping by the sponges and smothering by sedimentation. In this paper we present our work on one species found on the reefs, Aphrocallistes vastus, Schulze 1887, measuring growth rates (approximately 300 cm2 yr-1), the sizes of larger sponges (up to 3.4 m long x 1.1 m high x 0.5 m wide), indicators of successful recruitment (low based on occurrence of only one small individual in study site), and the form sponges can take under various environmental conditions. A. vastus sponges are very fragile and one was observed to die after breaking in two. Broken sponges have been observed on trawled reefs.