A photocatalogue of marine invertebrates captured from trawl surveys is now available to download as PDF (no paper copies were made).
http://waves-vagues.dfo-mpo.gc.ca/waves-vagues/search-recherche/display-afficher/352884
http:/ / www.dfo-mpo.gc.ca/ Library/ 352884.pdf

An English-only summary portfolio (small posters) is available on figshare here:
Nozeres, Claude (2014): St. Lawrence marine invertebrates posters. figshare.
http://dx.doi.org/10.6084/m9.figshare.985581

Note: some taxa still require confirmations (especially polychaetes and ascidians).

The main taxonomic reference is the taxonomic catalogue:
Brunel, P., Bosse, L. & Lamarche, G. (1998). Catalogue of the marine invertebrates of the estuary and Gulf of St. Lawrence. Canadian Special Publication of Fisheries and Aquatic Sciences, 126. 405 p.

http://waves-vagues.dfo-mpo.gc.ca/waves-vagues/search-recherche/display-afficher/223686
http://www.dfo-mpo.gc.ca/Library/223686.pdf less ↑