Fig. 2.  Two post-reproductive and moribund male Humboldt squids Dosidicus gigas in Baja California being collected as food for captive green turtles (usually thought of as being seagrass-eaters)

Fig. 1.  Giant squid Onykia robusta caught in a trawl net off the coast of Vancouver Island, British Columbia

For reasons of large body size, fast-moving predatory activities, large beak, relatively large brain, and an eye structure similar to that of humans, cephalopods rank among the most interesting of all marine invertebrates.  A considerable mythology has developed around them. The first authentic photos of a living giant squid Architeuthis were obtained only in 2005, and there are reports of other large deep sea-inhabiting squid species.  Only two octopus species are commonly encountered on the northern parts of the west coast of North America, the giant octopus¹ Enteroctopus dofleini and the smaller Octopus rubescens.  Two other species², Octopus bimaculoides and O. bimaculatus, occur only in southern California and Baja California. Their distributions overlap but not a lot is known of their ecological relationships. A deep-water octopus species Octopus californicus was discovered over a Century ago, but its habits are little known.   Several species of squids inhabit, or regularly visit or wash up on, west-coast shores, including the shallow-water Rossia pacifica, the oceanic squid Doryteuthis (Loligo) opalescens, and the deep-dwelling giant squid Onykia robusta(Fig. 1).  An increasingly common visitor to west-coast shores, including British Columbia and southern Alaska in summer and early autumn, is the feisty Humboldt squid Dosidicus gigas³ (Fig. 2), which likely follows incursions of warm-water northwards.  Modest fisheries for giant octopuses Enteroctopus dofleini exists in Alaska (landings of about 200 metric tonnes annually) and Queen Charlotte Islands, British Columbia. Capture of squids Doryteuthis opalescens represents the largest fishery in California, with over 100,000 metric tonnes being harvested annually.

NOTE¹ how “giant” is Enteroctopus dofleini? Specimens up to 40kg are commonly caught. The largest individual recorded anecdotally from northern British Columbia weighed in at 270kg with a tentacle spread of 9.7m (High, 1976)

NOTE² how related are the west-coast species? This is investigated for the four species mentioned here, with the addition of a deep-water Californian species Octopus californicus, by researchers at Simon Fraser University, BC.  DNA-sequencing suggests that O. bimaculoides and O. bimaculatus form their own clade, separate from a clade containing Enteroctopus dolfleini and O. californicus.   Octopus rubescens is separate from the others, but possibly more closely aligned with the southern California group (Sosa et al ,1995) 

NOTE³ up to a decade ago sightings of Humboldt squids were mostly restricted to Mexico and southern California.  However, since summer 2009 they have been seen on the west coast of Vancouver Island, BC and also in Alaskan waters.  Researchers at the Department of Fisheries, B.C. have recently attached telemetry devices to specimens caught off Vancouver Island, so further information on their movements may be forthcoming