[1] Geol Survey Canada, Nat Resources Canada, Inst Ocean Sci, Sidney, BC V8L 4B2, Canada
[2] Geol Survey Canada, Bedford Inst Oceanog, Nat Resources Canada, Dartmouth, NS B2Y 4A2, Canada
[3] Geosci Australia, Canberra, ACT 2601, Australia
[4] Moss Landing Marine Labs, Ctr Habitat Studies, Moss Landing, CA 95039 USA
[5] British Geol Survey, Edinburgh EH9 3LA, Midlothian, Scotland
[6] Pelagica Ltd, Lochwinnoch PA12 4BS, Renfrew, Scotland