ADM Publisher Curt Bowen looked at me and grinned as he stood on the stern platform of the "San Juan Diver". Moments later he strode into the cold green water lapping up against the massive stone wall that was towering above us. Pausing only a few moments before descending, he hollered to ADM Videographer, Rusty Farst, to "stop being a pansy-ass" and to jump in. Moments later the three of us slowly descended down the steep wall that continued underwater into the rich, green depths. I could dimly hear the sound of the "San Juan Diver's" engines receding as our charter boat Captain backed his boat away from the drop off to await our return. Completely enshrouded in huge, billowy white and orange plumose anemones, the huge wall seemed to resemble a dense wad of cotton balls interspersed periodically with bright swaths of color. Grinning into my regulator mouthpiece, I watched as both Curt and Rusty had their first experience of Northwest wall diving in the cold waters of Washington's San Juan Islands. As they darted to and fro amongst the anemones, finding creatures that must have seemed alien to them coming from their warm water home in Florida, I could tell that they were having the time of their lives even as the cold gnawed at their bones through their dry suits.
I, however, was searching for something in particular…… something seldom seen even by Northwest divers that would really get these two Floridians to pause and take notice. Using my light, I briefly scanned the side of each rocky ledge that I encountered, hoping that the beam would help me to pinpoint my intended quarry. About 15 minutes into the dive I found what I was seeking and began to position myself to take some shots once Rusty and Curt arrived on the scene.
Rusty arrived first and would have missed my find entirely had I not shined my light directly at it. With a start, he jerked back in surprise, eyes wide in his mask. Within seconds the video professional within him took over and he began to immortalize the scene from various angles, his system lighting up the immediate area like a Hollywood set. I floated behind him or to the side, snapping still photos as Rusty went about his business.
As dense as he can be sometimes, eventually even Curt noticed that his two staffers were paying a LOT of attention to a very specific portion of the wall. With a couple of kicks he approached from the side so as not to disturb Rusty's filming, confusion written all over his face over what we were looking at. I well remember Curt's reaction when it first dawned on him what exactly we had found. He began to ease his faceplate past the anemones and in toward the subject…… then bent almost double backwards with a start as he realized that his face had been within inches of the claws of the largest crab he had ever seen - an unusual find even in the Pacific Northwest – a gigantic Puget Sound King Crab.
For the next 15 minutes or so the two of them examined or filmed the crab from every angle. Once Curt realized how slow the crab was he gently lifted it from its perch on the wall, turning it this way and that so as to see every aspect of it while avoiding the all-too-obvious claws. I could tell that they were literally bursting with questions, but they would have to wait until we were all back on the boat. Later, as we continued the rest of the dive, it occurred to me that I really didn't have very many answers for them regarding this species. I made a vow before I even hit the surface to find out more about this creature.
Puget Sound King Crabs, Lopholithodes mandtii, are members of the Anomura group. One manner in which this particular group of crustaceans can be readily identified is that they have a pair of antennae outside the eyes that they use to recognize and communicate with other individuals within their species. Additionally, members of the Anomura group appear to have only three pairs of walking legs. This is deceptive, however, in that the fourth pair of legs in fact does exist but is usually not readily visible. In the case of L. mandtii, the fourth pair of legs is inside the large carapace shell and will not be visible to divers. For those used to the "usual" appearance of other Pacific Northwest crab species, such as the Dungeness, with four pair of walking legs, Puget Sound King Crabs will look highly unusual – almost "lop-sided" – due to this "missing" pair of legs that are usually so prominent in most other crab species.
Puget Sound King Crabs belong to the Lithodidae family. Millions of years ago this family originally evolved from hermit crabs, (the Paguridae family), and have since been described as "hermit crabs that have abandoned the practice of carrying shells". In fact, the larval stages of Lithodidae appear virtually identical to those of hermit crabs and many aspects of the adult shape bear a resemblance to their hermit crab ancestors. More species of Lithodidae crabs are found in the Northern Pacific than in any other location on Earth, leading many researchers to make the conclusion that the family initially evolved in this cold, vast region.
Like hermit crabs, Lithodidae such as Puget Sound King Crabs are right-handed, the right claw being far larger than the left. The claws of Lopholithodes mandtii are fascinating to examine, each of the two designed for a different and specific function. The left claw is noticeably smaller than the right and appears to be almost spoon-like. It can close tightly without gaps and is used by the crab for tasks involving "finesse" and detail work, such as scraping. The huge right claw, however, is another matter entirely. It is designed for crushing the hard shells of its prey, (the author recently located an adult Puget Sound King Crab in the San Juan Islands of Washington by following the sound of it crushing and crunching large Goose Barnacles!). The right claw has what almost appear to be human molars, both top and bottom, (see close-up photo), that perform the same function that our molars do – crushing and grinding. As a diver, one look is quite enough to convince you that your fingers belong nowhere near this right claw! As I mentioned above, this huge claw is particularly useful in crushing prey items such as barnacles and sea urchins, (which I have also seen being "crunched" apart on another occasion), but apparently Sea Stars are the Puget Sound King Crab's primary food, the giant Sunflower Star, Pycnopodia helianthoides, being a particular culinary favorite.
Primarily a deep-water animal, the Puget Sound King Crab prefers to dwell in rocky habitat in areas of strong current. Areas such as the San Juan Islands, the Strait of Juan de Fuca, and the rocky coasts of Washington and British Columbia fit this need perfectly and in these locations the giant crabs can commonly be found and photographed by those divers with an understanding of what to look for. They can often be found clinging to vertical walls or perched on top of small ledges, similar to those ledges favored by bottom fishes such as Cabezon or Red Irish Lord. Just imagine the type of places where your housecat would like to "hang out" at home, (on top of the refrigerator, on bookshelves, on top of the couch, etc.), and you have a pretty good concept of what a typical Puget Sound King Crab "hang out" location might be like – except underwater!
The colors of a Puget Sound King Crab are stunning – there's virtually no other word for it. As juveniles they are monochromatic – a solid bright orange that at first thought would seem to make them easy to spot. However, many invertebrate animals in the Pacific Northwest are the same brilliant orange - sponges, anemones, cup corals, tunicates and gorgonians, to name a few – so being orange is actually a fairly decent means of hiding while being in plain sight! Often a direct beam from a diver's light is the only means of spotting one of these beautiful creatures. Juveniles also have several "cone-like" peaks on their carapace that appear quite remarkable and significantly fade with the onset of adulthood. Once a juvenile reaches approximately 2 inches or more across the carapace they will begin to assume the color scheme of an adult crab - a gorgeous array of yellows, oranges, reds, purples and blues. Between molts silt and brownish algae will collect on the shell, assisting in masking the rainbow of colors until struck by the gleam of a diver's light. Divers wanting to find these huge and colorful crabs can usually do so by searching ledges, rocky wall faces and the tops of boulders with their dive lights. Such artificial light will almost seem to make them to "leap out" at you, as the crabs will blend in completely with their surroundings without it. Even when actively searching for them, the moment of discovery can often come as a complete surprise - the giant crab almost seeming to appear right before your eyes as if it were part of a magician's trick, not bad for a crab whose carapace can be as much as 12 inches across!
Puget Sound King Crabs are migratory, moving from deep water (100 FSW +) to shallow water (30 – 50 FSW) and then returning to deeper water again during the year. This migratory cycle begins in early winter as the crabs move up from the depths as part of their molting and mating cycles. This is usually regarded as the best time of year for divers to find them due to the fact that during this time frame they are within recreational depths. As with most crabs, Lopholithodes mandtii can mate only after the female has molted. In the days and weeks prior to molting it is not uncommon to find clusters of these crabs perched on top of boulders or on larger ledges, the clusters often being a female on the verge of molting with several males waiting for the "blessed event" and hoping to get lucky! It thus pays for a diver finding one crab to scan his or her light around, as there will generally be more within the immediate vicinity.
When a Puget Sound King Crab molts it will shed everything right down to the tiniest hair on the smallest tip of its exoskeleton. Molts will look almost exactly like living crabs and are often mistaken for such. If a diver is fortunate enough to find a new molt, a quick glance around will often reveal the living crab nearby and all decked out in its new finery. Again, if the molt happens to be a female, several males will also probably be in the immediate vicinity. Few things in nature are as beautiful as a Puget Sound King Crab immediately after molting – fluorescent orange, red and yellow bedazzled with spots of glowing blue sapphire – and I will ever cherish the memory of the first one that I ever saw as a new diver over two decades ago in the San Juan Islands.
Shortly after mating the females will once again depart for deeper water, usually in the month of May or early June. Male crabs and juveniles will continue to remain in shallower waters and will ultimately molt during the summer months. Eventually they, too, will head for deeper waters in the early autumn. The females will then carry up to 186,000 eggs for a full year, with hatching of the eggs occurring over a 12 to 14 day period the following spring. The larvae will then spend about 2 months in the plankton before settling to the bottom, where they will spend the remainder of their lives. Relatively little is known regarding the life span of the Puget Sound King Crab, although the assumption is that they are extremely long-lived as maturity is only reached after 7 years or more.
Since so little is known about this species and it is so rarely sighted, accurate population estimates quite simply do not exist. This lack of information, coupled with the extremely long time span necessary to reach maturity, led the Washington Department of Fish and Wildlife to classify Puget Sound King Crab as a fully protected species several years ago. Because Lopholithodes mandtii is not a commercially valuable species funding has not proven to be readily available for thorough studies of this animal and very little more than what I have cited above is currently known regarding it. Perhaps in the future new opportunities will become available for further study of this remarkable, and incredibly beautiful, animal. Until then, I will continue to happily spend my time in the islands scanning walls and rocky ledges with my lights and camera…….always ready for another chance meeting with the "King of the Emerald Sea".
The author wishes to extend his thanks to Dr. Gregory C. Jensen of the University of Washington School of Fisheries for his kind assistance in providing information for this article. Gratitude is also due to Jeff Christiansen of the Seattle Aquarium for his time spent answering my endless questions and for exchanging tall tales with me of searching ledges in the San Juans. Much of what is good in the above article is because of these two gentlemen and their willingness to help.