FAQ
A contribution of The Cephalopod Page
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Hi Jim,
I have some questions - maybe you have some answers. I realize that you don't get paid for this, and I don't expect something for nothing so, let me begin by offering up a trade: some info for my services as a dive guide. If you ever make it to Maui, I'll be very happy to take you out on a shore dive to find our favorite friends (or any other critters you may be interested in). I have over 6,000 dives here in Maui waters as an instructor and guide, so maybe I could be of service to you. I've been finding and "catching" octopus here for many years. Often looking over my shoulder to find one looking back at me! I have lots of stories I could tell but I'll save them for your visit.... My questions are: How long does it take for an octopus to regenerate its supply of ink after it has seemingly "exhausted" its supply. I remember reading that they are born with it, but I haven't been able to find info on how long it takes to regenerate it. The small ones we catch squirt out so much ink compared to the larger ones, and their attempts to flee are very vigorous and rapid. It seems that as they get larger in size, they are less likely to "panic", and squirt out less ink - or is it just a function of size, age, and ink "supply", and not one of behavior? I've heard of studies showing that octopuses that squirted ink had a shorter life span than those that didn't. Something about the stress level required to produce that behavior. Also, there is the question of how much of a vulnerable situation are they in by not having their ink as a defense against predators. Many dive operators are adopting platforms of "no negative impact" on marine life. Yet to see one relaxed, perched on my arm, while divers caress it is always very heartwarming. It is a gift and a great learning experience to the divers. I believe that experiencing and understanding of our sea creatures will help preserve our seas - but at what cost to the octopus? An answer to my ink questions will help. Thank you, Rene Umberger |
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| Rene,
I have had the pleasure of going to Hawaii twice and while I unfortunately don't have any upcoming plans to go again, I'll certainly look you up if I do! You are asking some interesting questions and I'm not aware of the answer to many of them. There is a finite amount of ink and it is stored in the ink sac which is connected to the end of the digestive system. The animals can control how much ink comes out and probably how it comes out (i.e. a decoy the size of the animal or a big cloud). I'm not aware of any studies on how fast they can recharge their ink supply. Our cuttlefish seem to make new ink quickly. I have heard of collectors purposely stressing animals so that they expel all their ink so that they don't ink and foul their water during shipping. An inking cephalopod is stressed and is trying to flee from something. Stress can't be a good thing. However, I've never heard that octopuses that don't ink live longer, much less found any scientific evidence to back that up. You are right though, inking is one of their last line of tricks to avoid predation and an octopus without this trick is more vulnerable. There are differences in behavior between younger and older octopuses although I don't know of anyone who has looked at inking. I'm not sure why the larger octopuses that you observe don't ink as much - perhaps though experience, they know that you are not a threat? Perhaps they have developed their other tricks more (color, texture, etc) and are less reliant on ink. Perhaps there are a lot more predators after the smaller cephalopods. Almost any fish would eat a baby octopus. It seems to me that the size of the ink sac decreases relative to body size as the animal grows although I've never measured this. You are correct that octopuses are born with a fully functional ink sac. The ink sac is easy to see in well developed eggs. Bathypolypus arcticus, the deep-sea octopus that I am currently studying, does not have an ink sac and this is typical of deep-sea octopuses. I also agree that education is the best weapon we have for protecting our environment and the creatures that live in it. That is one of the reasons I decided on creating The Cephalopod Page (TCP). If you are able to get an octopus to sit on your arm and it doesn't ink then I don't think that there is any harm unless octopuses are often hunted by humans for food in the area (which is common in some areas of Hawaii). If the animal inks or turns red or white it clearly isn't comfortable. You could also "make friends" with an octopus that is in a regularly visited dive site by offering it food (a crab) or just observing it every time you visit. Hopefully it would come out to greet you after a while and you could then try to see if it would open a corked jar. No doubt such a demonstration would leave a lasing impression with the divers you lead. BTW do you get the small little octopuses in shallow water in Maui? - sometimes they are called crescent octopuses. Although they are fairly common and you can find them in 3 feet of water, they are undescribed! I'd be interested in your stories. Dr. James B. Wood (ceph@is.dal.ca) Dalhousie University |