By Katie Gerstle |
In honour of Octo-ber (see what we did there?), let’s take a minute to appreciate just how cool these invertebrates truly are.
Above: A giant Pacific octopus, from seatoskyscuba.com.
Here are a few facts that you may not have known about one of the most elusive creatures that we’re always on the lookout for during a dive; in these waters around British Columbia, the most common 8-legged sight is the giant Pacific octopus, Enteroctopus dofleini.
First and foremost… The original and grammatically correct plural of octopus is in fact “octopuses”, not “octopi”. The use of an “-i” suffix was likely born under the presumption that octopus comes from a Latin root. In fact, it is from a Greek word, whose plural is “octopodes”. The word may have come to the English language via scientific Latin, but it was never a native Latin word.
The giant Pacific octopus is a highly sedentary creature; it spends approximately 94% of a 24-hour day staying still and hiding, often seeking shelter in kelp beds or in their rock dens.
Females lay an average of approximately 106,800 eggs at a time.
As the largest octopus in the world, they weigh 22 - 44lbs (10 - 20kg) at maturity, but have been recorded to reach a maximum weight of 110lbs (50kg). The largest recorded arm span was 30ft/9m when the limbs were fully extended!
Octopuses are known to be the most intelligent group of invertebrates. They possess both short-term and long-term memory, can learn through conditioning, have the capacity to play, possess personalities, and use their highly-adapted visual memory center to differentiate between abstract shapes and even individual humans.
Four separate accounts of a giant Pacific octopus exhibiting rare, violent behaviour towards divers was documented in the waters around Washington State and Vancouver Island, BC. These behaviours are yet to be explained.
They are the most abundant species of octopuses found along the Pacific continental shelf, from Korea to Alaska and as far south as California, and are therefore a common form of bycatch in trawl, longline, and pot fisheries.
Anderson, R. C., & Mather, J. A. (2007). The packaging problem: Bivalve prey selection and prey entry techniques of the octopus Enteroctopus dofleini. Journal of Comparative Psychology, 121(3), 300.
Anderson, R. C., Mather, J. A., Monette, M. Q., & Zimsen, S. R. (2010). Octopuses (Enteroctopus dofleini) recognize individual humans. Journal of Applied Animal Welfare Science, 13(3), 261-272.
Conrath, C. L., & Conners, M. E. (2014). Aspects of the reproductive biology of the North Pacific giant octopus (Enteroctopus dofleini) in the Gulf of Alaska. Fishery Bulletin, 112(4).
Harbo, R. M. (1999). Whelks to whales: Coastal marine life of the Pacific Northwest. Harbour Publishing Company: Madeira Park, BC.
Scheel, D., & Bisson, L. (2012). Movement patterns of giant Pacific octopuses, Enteroctopus dofleini (Wülker, 1910). Journal of Experimental Marine Biology and Ecology, 416, 21-31.