Creature Feature: Shame-Faced Crab

The shame-faced crab (aka box crab) gets its name from the way its claws (or chelae) cover its face as if it were trying to hide in shame.  Classified in the genus calappa, what distinguishes these crabs from others is their distinctly bulky carapace (upper portion of the shell) which can reach lengths up to 3.5 inches and widths of nearly 5 inches. The calappa species became labeled box crabs because when threatened these crabs pull their large pincers tight around their bodies, hiding their legs under the canopy of their carapace, forming a well-armored “box”.

The shame-faced crab’s squat, rounded and convex shell may be a rosy or yellowish hue with grooves and/or spots on it. The triangular mouth, as well as its eyes, are generally hidden behind the large forceps of its first pair of walking legs. In some species the impression of shame is further enhanced by large reddish-pink spots on the pincers which make the crab look even further embarrassed. The other pairs of legs are rather skinny since they are rarely used.

The shame-faced crab generally remains in an inactive state, burrowed in the sand, eyes looking upward, waiting for potential prey to come by. It can remain in this position for several days, with only its eyes, antennae and upper carapace protruding from the sand. Its forceps also protrude to form a “breathing cave” behind them, preventing sand from blocking its air passages. On the occasion that it does choose to run, it puts its body completely upright and straightens its legs. To bury its self again, it simply pushes its forceps against the sand like planks which then forces its body backward into its burrow.

This crab’s favorite snacks are oysters, mollusks, snails, and other marine invertebrates. Its specially formed forceps and right pincer are well-adapted to pick its prey apart, and strong enough to crack their shells. There is a large accessory tooth at the base of the moveable finger and a corresponding flat plate on the fixed finger which act like a vice to crack through the shell. The left pincer is relatively longer and sharper and used to extract the gastropod’s body from the broken shell. This guy below in the video doesn't accomplish his task with lightening speed, but watch  as he goes about getting some dinner.

http://www.waza.org/en/zoo/choose-a-species/invertebrates/other-aquatic-invertebrates/calappa-granulata

Chris’ Dive Experiences: Coral Diving In Southern California?

Thousands of Southern California scuba divers travel to Hawaii every year to

Photo Courtesy of Lesley Alstrand

dive on colorful coral reefs in clear water. A few of these divers no doubt know that there are beautiful purple hydrocoral- encrusted reefs teeming with fish right here in SoCal. When this site is caught on the right day, its visibility rivals Hawaii's.  The best part? It is just a short boat ride away.

Farnsworth Bank is a well known set of seamounts off the backside of Catalina Island, California. These seamounts are known for abundant marine life, purple hydrocoral, and great visibility. Farnsworth is equally known for ripping currents and zero visibility.  Due to these ever-changing conditions, getting to dive Farnsworth Bank is special. And catching it on a stellar day will give any diver a set of dives they will always remember.

Photo Courtesy of diver.net

Farnsworth Bank had been on my must dive list since I first got certified. I had been on two previous 3-day liveaboard trips that hit sites in the Southern Channel Islands and had intentions of diving the site, but conditions on both of those trips never allowed it. I awoke on the second day of my third trip to excitement from fellow divers. We were anchored at Farnsworth Bank. You couldn’t have asked for better surface conditions with no wind and the ocean laying as flat as a lake.

After a thorough dive site breifing, no one wasted time gearing up and jumping in. As we descended down the anchor line, we were greeted with equally good conditions underwater. Beautiful blue water with zero current and easily 80 feet of visibility. In these great conditions it took no time to see our target below us. As we looked down we could see a set of plant-encrusted seamounts surrounded with abundant fish life.

We dropped down to 100 feet and started working our way around and up the seamount, enjoying the contrast of the bright purple hydrocroal alongside the yellow and green of the kelp; the red, brown, and gold of the Gorgonians; all with a back drop of the cobalt blue of the Pacific Ocean. The life on these seamounts was supercharged from Seastars and Urchins to a variety of colorful Nudibranchs surrounded by Garibaldi, Rockfish, and Lingcod.



Photo Courtesy of Scott Gietler

The group slowly circled the pinnacle working their way up to shallower waters. At one point, as I was waiting for Lesley and Willey to finish up with pictures of a Rockfish, I backed off the site a touch into open water. This vantage point gave me a complete picture of what we were lucky enough to be diving on this exact day and time. I  looked down at the pair of photographers communicating with each other just a touch below me on a wall and I was speechless at the sight of the typical color palette of a southern California kelp dive mixed with some colors you may expect only to find off an island in the middle of the tropics. I looked up, taking in the sight of the sun dancing on the surface 65 feet above us pushing rays of sunlight through the water, when a flash out of the corner of my eye caught my attention. I turned to see a large Bat Ray swimming over the top of the seamount, with the sunlight bouncing off the tips of its pectoral fins as it swam. This vision solidified just how beautiful Southern California diving can be.

This dive will always be burned in my memory. The explosion of life and color that can be found right here in our backyard which yields experiences that would rival any tropical dive destination. Get out there and dive these special sites. It may take many times, but one day you'll be the one that was at the right place at the right time!

Photo Courtesy of Lesley Alstrand

Join The Dive Shack August 2-4 for a chance at diving Farnsworth Bank and other great sites around the southern Channel Islands.
http://www.gotodiveshack.com/pdf/SCIcharter.pdf

Creature Feature: Narwhal (Monodon monoceros)

While those of us in the Northern Hemisphere are now into the frigid winter season, what better topic to write about than that of a special, you might even say mythical, Arctic creature, the Narwhal. These unusual creatures are what legends are made of and the source of its horn has been the topic of a few tales.

The Inuit legend of the Narwhal
A wicked woman lived with her daughter and her son, who was born blind. As the son got older, his sight improved, even though the mother tried to convince him of his helpless state. One day a polar bear came near the house and the mother told the son to aim a bow and arrow at the bear through the window covered with seal skin and strike him down. The boy pulled back the arrow and the mother took aim from him. The arrow struck the heart of the bear and although the boy could hear the groans of the dying bear, the mother laughed scornfully at him, saying that he had missed the bear. That night the mother and the daughter had fresh polar bear meat while the mother cooked dog meat for the son. Later the boy's sister told her brother that his shot was successful and secretly gave him meat.

Time passed and an old man came to the house for a visit. Before he left, he told the young girl how she could help her brother regain his sight. In the spring, he told them to watch for a red-throated loon who would swim trustingly toward them. Once the loon was close enough, the blind brother should wrap his arms around the loon's neck and the loon would take him to the bottom of the lake. Once they came up, his sight would return. The loon told the young man not to tell about his regained sight until later in the summer when he would send a pod of belugas to their campsite.

When summer came and the ice began to break, the belugas began to move. On one occasion, a pod was closer to land than usual. The young man grabbed his harpoon and told his sister to accompany him to help him aim. They went to the shoreline and the mother, seeing the son with a harpoon, became concerned and followed them. Once she was close to them, the son gave the end of the line from the harpoon to his mother, asking her to tie it around her waist to hold the harpooned animal. The concerned mother told her daughter to make sure he was after a small animal as she was tied to the harpoon. The son instead aimed for the largest whale and harpooned him. The mother was cast into the sea. As she submerged she spiraled around the line, with her long hair twisting into a long lance. This is how the narwhal came to be.

In medieval times, Europeans believed the narwhal tusk was the horn from the legendary unicorn and it came with all the unicorn's magical powers. Believed to cure poisoning and melancholia, Vikings and other northern traders sold the horns for more than their weight in gold.

The name narwhal comes from the old Norse word "nar" which means corpse, referencing the blue-grayish, mottled pigmentation like that of a drowned sailor (calves are actually born brown, with no spots). The scientific name, Monodon monoceros, is a Greek derivative meaning "one-tooth one-horn" or "one-toothed unicorn". The narwhal, or narwhale as it is also known, is a medium-sized, toothed whale that lives year-round in the Canadian Arctic and Greenlandic waters, and whose closest relative is the beluga whale.

This fascinating horn is actually a very long tooth. All narwhals are born with 2 teeth in their upper jaw. After the first year of life, the male narwhal's left tooth grows outward in a counterclockwise spiral. The tooth can grow upwards of 7 to 10 feet long. The function of the tooth is not exactly known. It has been suggested it might be used as a display of dominance during rivalry or courtship, it may aid in obtaining food, or even be used to amplify sonar pulses emitted by the narwhal, but it has not been shown to be used as a weapon. "Tusking" is a behavior displayed by males when they rub their tusks against one another, possibly to determine dominance within the group.

Narwhals travel in pods of 4 (keeping to generally smaller groups under the winter ice cap)  up to 20 in the summer, feeding on fish, shrimp and squid. In winter, they eat benthic critters (flat fish) as deep as 4900 ft (1500 m) under the arctic ice. They are the deepest diving mammals. Their dives can last anywhere from 7 to 25 minutes. Sometimes these groups fall victim to the shifting ice pack, get trapped and are hunted by Inuit, polar bears, orcas, or walruses. In the summer they congregate in larger groups, in shallower ice-free waters.

Narwhals are very vocal creatures, making clicks, squeals and whistles to communicate and/or navigate.

Paul Nicklen/National Geographic/Getty Images

Fast Facts
Type:  Mammal
Diet:  Carnivore
Size:  13 to 20 ft
         (4 to 6.1m)
Weight:  3,500 lbs 
             (1,600 kg)
At Birth: 5 ft; 175 lbs
Max Life Span:  50 yrs

[1] http://en.wikipedia.org/wiki/Narwhal
[2] http://www.enchantedlearning.com/subjects/whales/species/Narwhal.shtml
[3] http://animals.nationalgeographic.com/animals/mammals/narwhal/
[4] http://www.narwhal.org/IntuitLegend.html

Be a Hero with a "Save-A-Dive Kit"

Ever been all set to go for a dive and at the last minute your buddy realizes he’s forgotten something, or worse, some piece of your equipment has broken, and you had to call the dive? Wasn’t that just the worst? Or even worse, what if this happened to you on your trip-of-a-lifetime in that exotic destination you had always dreamed of diving?

Recently, on a SoCal live-aboard trip I led for a weekend of diving, we had many different equipment issues pop up that could have ended diving for several people on board.  If it were a local beach dive, that might not have been such a big deal, but being stuck sitting on the boat all weekend while everyone else is diving really isn’t all that much fun. And for me, it is not an option at all.

When I pay to go on a trip to get several dives in (especially in a new location), I want to make sure I am prepared for any unexpected events, such as gear malfunctions.  So I would like to talk a bit about some of those unexpected events and what you, as a well-prepared diver, can do to save the dive.

We all know scuba is a pretty gear intensive sport, so there could be a number of things that might go wrong that you can be prepared for.  Let’s start with some of the easy fixes with basic equipment: masks, fins, mouthpieces, snorkels and streamlining clips.  Having a spare strap or two for masks and fins is always a great idea.  Extra snorkel keepers are also a good thing to have around, as well as spare gear clips for streamlining (including retractors).  For those divers who have a tendency to bite down harder on their mouthpiece than they need to, having an extra one for yourself or a dive buddy can come in handy.  It’s always nice to make sure everyone has their equipment streamlined.  Spare clips for your’s or your buddy’s hoses are an easy thing to carry extra of.  Remember it might be you that has to use your buddy’s octo.  Do you really want it dragging around in the sand because he forgot his clip?  Another simple piece of gear that is great to have on hand is a box of spare o-rings.


Now let’s move on to something that takes a little bit more thought: BCD’s and dive computers.  Even though we take care of our gear, once in a great while something is bound to break.  The bcd has many areas of concern, such as buckles, straps and weight pouches.  Of those, the one that poses the most common problem is the weight pouches.  They generally do not break, but they do fall out on occasion for different reasons.  If you lose one, there is no safe way to do the dive without proper weighting.  Having a spare pouch (or if you’re “old school”, a spare weight belt) or two will come in handy.  And if you have changed out your original bcd tank strap for maybe a quick release type, you might just want to keep the old one in your dive bag just in case.

Now to what I think is the biggest issue that might end your dive: the dive computer.  Atomic and Suunto make great computers, but remember they are just that, an electronic device.  The main reason any computer might fail is often the battery.  Make sure you check the battery status before you go on your dive, and always have a replacement battery available.  If you can’t replace the battery yourself, you might have a tech nearby that knows how to do it for you.  And while I am on the subject of batteries, make sure you have a spare one for the transmitter to your air-integrated computer.  Another great idea is to have a completely separate computer.  Yes, you should be diving with two computers on your body, just in case.  If one of your computers fails during your dive, you are still able to continue on because you you’re your backup computer.  I really don’t know too many professional divers who dive with just one dive computer.  It just makes sense to have redundancy when it comes to such important equipment. 

So to make sure you have a worry free dive, you should carry with you what we call a “Save-A-Dive Kit”.  This will help to make sure you, or your buddy, can still make the dive no matter where you are, beach or boat.  Unfortunately, we cannot fix everything in the field, but for 99 percent of the issues that may come up, we can.  It doesn't have to be anything fancy. Just make sure your kit has the spare items that will keep you from calling your dive.  If you have any questions about what to put into your kit, talk to your instructor or go to your local dive shop.  If you are one of those people who don’t think it is necessary to have a kit, I have a question for you.  Why do we carry a spare tire in our vehicles?  How often does a tire go out on us?  Better safe than sorry – right?  One last thing, the kit does not have to be just for your dive gear.  Don’t forget about your underwater camera. 

Creature Feature: Blanket Octopus

Referred to by some as the "Caped Crusader" or the "Batman" of the underwater world, the blanket octopus is a strangely beautiful creature. This fascinating cephalopod was given the common name of blanket octopus because of its flowing webbing connected between its dorsal and dorsolateral arms, resembling a large blanket, as displayed by this adult female. As you can see in this photo, its remaining arms are much shorter and lack webbing.

These octopi are classified in the pelagic cephalopod genus tremoctopus. They are further broken down into four species Gelatinous Blanket Octopus (tremoctopus gelatus), Palmate Octopus (tremoctopus gracilis), Common Blanket Octopus or Violet Blanket Octopus (tremoctopus violaceus), and Tremoctopus Robsoni. Sightings of these elusive creatures are rare, but they are known to have been found in the subtropical and tropical waters of the Mediterranean Sea and the Atlantic Ocean, and along the northern coast of Australia,  preferring surface to mid-water depths.

This cephalopod does not use ink to defend against predators as other octopi do. Instead, it uses its blanket to intimidate predators with its size. It has also been observed to display another defense mechanism. These particular octopi are immune to the deadly sting of the Portuguese Man 'o War jelly. The males and young females who lack the enormous blanket instead rip off the poisonous tentacles of a man 'o war and use them as a weapon against their would-be attacker.

The Blanket Octopus is an extreme example of sexual dimorphism. This term refers to the differences between the size and various physical characteristics of the male and female in the same species. "Imagine if your spouse was 40,000 times heavier and a hundred times larger than you. This is reality for the male blanket octopus..." [1] A male may grow up to approximately an inch in length, whereas an adult female can reach a length of 6.5 feet. The males have a specifically modified third tentacle which it fills with sperm. During mating the male rips of this tentacle, presents it to the female, then drifts away to die. The female then stores this tentacle inside a large internal body cavity until she is ready to lay up to 100,000 tiny eggs. Interestingly enough, females have been found with multiple tentacles stored in this cavity. When the female is ready to fertilize her eggs, she will pull out this stored tentacle and squeeze it "like a tube of toothpaste" over the eggs which she will then carry at the base of her dorsal arm until they hatch.

Below is a short, albeit cheezy, video showing the fascinating beauty of a female unfurling her blanket.

This second video shows another octopus calmly cruising the depths. Watch closely around 1:40 where it appears one of her banners disconnects. I could find no explanation for this, but she appears to continue on unfazed.

To see a picture of a male blanket octopus go to :

http://www.selfishgene.org/Tom/Papers/MDNetal_NZJFMR02.pdf [2]

[1] Pickrell, John (Aug. 12, 2003)."Walnut-Size" Male Octopus Seen Alive for First Time. National Geographic News.

[2] Norman, M.D.; Paul, D.; Finn, J.; and Tregenza, T. (2002). First encounter with a live male blanket octopus: the world's most sexually size-dimorphic large animal. New Zealand Journal of Marine and Freshwater Research 36: 733-736.

The Undersea World of Jacques Cousteau

The creative juices have seemed to slow down for my fellow contributors lately so rather than just writing another Creature Feature, I have been thinking long and hard about what to write that you all might find interesting. When I write my blogs it is always because it is a subject I want to know more about myself. I research it and then I like to share what I find with you.

So what to write about this week? Well, why not write about one of the great innovators of SCUBA, Mr. Jacques Cousteau. For us over 40 folks, the name is pretty familiar, but for the younger generations, maybe not so much. Being a child of the 60's, I remember sitting in front of the TV with our dinners on our TV trays watching such great shows with my family as the forever bubbly Lawrence Welk Show, Laugh In, Hee Haw, The Wonderful World of Disney, Mutual of Omaha's Wild Kingdom, and of course, The Undersea World of Jacques Cousteau.

Born June 11, 1910, Jacques Cousteau entered the École Navale (the French Naval Academy) in 1930 and graduated as a gunnery officer. Unfortunately (however fortunate for us) a car accident cut short his dreams of a a career in naval aviation, so during his time of rehabilitation from this accident he turned his interests to what lay under the sea. 

In 1936 Cousteau began his diving career with a pair of Fernez underwater goggles. (As a little side note, Maurice Fernez was a pioneer in the field of underwater breathing apparati. He was elemental in the transition from the tethered diving helmet of the 19th century to the invention of the self contained equipment of the 20th century.) The actual self contained underwater breathing apparatus (SCUBA) used by Jacques Cousteau in the 40's was invented by Commander Yves le Prieur in 1926. Dissatisfied with the length of time this unit allowed him to stay under water, Cousteau improved the design by adding a demand regulator invented by Émile Gagnan in 1942. In 1943 Cousteau tried out the first prototype aqua-lung which finally made extended underwater exploration possible and opened the door to the open-circuit scuba technology we use today. With that Cousteau embarked on a long career of ocean exploration and underwater film-making.

In the late 1940's, he took part on a small team assigned to explore the Roman wreck of Mahdia (Tunisia). It was the first underwater archaeology operation using autonomous diving, opening the way for scientific underwater archaeology. In 1950 Cousteau founded the French Oceanographic Campaigns and leased a ship called Calypso which he had refitted as a mobile laboratory for field research and the principal vessel for his diving and filming. For his 1956 film "Silent World", Cousteau, assisted by Jean Mollard, constructed the experimental underwater vehicle SP-350, the "diving saucer", which was able to transport the researcher to depths of 1150 feet. In 1965 Cousteau repeated his success with 2 more experimental vehicles which could now reach depths of 1640 feet.

To recite Jacques Cousteau's numerous achievements and accolades would take longer than this blog's depth. Suffice it to say, Cousteau influenced abundant changes in the perception of our oceans. Cousteau believed in sharing his scientific concepts with the world and regularly referred to himself as an "oceanographic technician". The legacy of his life's work includes more than 120 television documentaries, over 50 books, and an environmental protection foundation with an astounding membership of over 300,000 (http://cousteau.org/).

Jacques-Yves Cousteau died unexpectedly in Paris on June 25, 1997, at the age of 87. To this day, he is one of the most famous undersea explorers of the 20th century. If I have piqued your interest in this passionate visionary of the underwater world, you might find one of these other websites interesting:

http://www.biography.com/people/jacques-cousteau-9259496

http://news.nationalgeographic.com/news/2010/06/100611-jacques-cousteau-100th-anniversary-birthday-legacy-google/

Creature Feature: Rosy-lipped Batfish (Ogcocephalus porrectus)

By request, today I present you with the rosy-lipped batfish (scientific name: ogcocephalus porrectus). Found in the waters of Cocos Island off the coast of Costa Rica, this odd looking fish looks like it is ready for its "maybe it's Maybelline" close-up for smear-proof lipstick, but it definitely needs a shave.

This bottom-dwelling fish can be found at depths ranging from 90 to 450 feet. Seen from above, it has been said to resemble more of a "frog fish roadkill" than a bat. Full-grown it is about the size of your open hand, nearly flat on top, and spreads its pectoral fins out to its sides. A slow and clumsy character, the rosy-lipped batfish uses its pectoral and pelvic fins like legs to crawl on the ocean floor rather than swim. Ichthyologist and batfish expert John McCosker says they prefer to “sit upright, like old tail-dragging airplanes.”

It has a leathery skin that feels like sand paper and large spiny knobs covering its back. To add to its bizarre appearance, this fish has a unicorn-like horn protruding from its head. According to McCosker, this rostrum (a Latin word meaning "beak") is "firm - sort of like chicken gristle, and it protects a thin, retractable appendage that the batfish deploys to lure small edible fishes".

Ogcocephalus corniger is found in the waters of the southeastern
United States and the eastern Gulf of Mexico. 

Rosy-lipped batfish are voracious, carnivorous eaters who prefer a diet consisting mainly of small fish, shrimps, mollusks and crabs. An interesting x-ray of a close relative to the rosy-lipped batfish shows just what they enjoy eating. Another close relative is the red-lipped batfish, also called the Galapagos batfish (Ogcocephalus darwini), so aptly named for its choice of residence.

Why this drag-queen-looking fish looks like it does, I don't know if anyone really knows. I didn't find any answers in my research. But does the rosy-lipped batfish remind you of anyone in your family?