Hawaiian Rafting Adventures - Underwater Photo of the Week

Monster In A Kelp Forest

Mon, 6 Feb 2012 00:00:00 GMT

Hi Gang!

This week’s POTW is a shot from my home waters in southern California. It is a picture of a giant sea bass, Stereolepis gigas, a species also commonly referred to as the black sea bass and giant black sea bass. The photograph was created in a kelp forest at San Clemente Island, the southernmost of California’s eight Channel Islands.

There is no doubting the fact that as adults these fish are indeed giants. They are known to grow to a whopping 7.4 feet, and the heaviest known individual tipped the scales at 563.5 pounds. You can just imagine what it might be like to turn around and see one of these monsters looking at you eyeball-to-eyeball. That’s exactly what happened to me when I captured this shot.

I certainly was not expecting to encounter a giant sea bass on that late afternoon dive. In fact, my camera was set up with a 50 mm macro lens. Our boat was anchored outside of the kelp, and I had just entered the forest on my way toward an inside reef when I turned around to make sure that I had not lost my dive buddy.

But instead of seeing my buddy, I saw this huge fish starring at me from only a couple of feet away. It was definitely time to start shooting

In a perfect world I would have had a much wider lens, perhaps my Nikon 17 mm-to-55 mm zoom. But one thing I always try to remind myself of is that you can always wish for another lens when an opportunity is in front of you, but the best thing to do is to make a picture with the lens you have at the time. So I did.

I took a quick light meter reading, set my f/stop and strobe power, and began to shoot. The giant sea bass posed for at least a minute, probably longer. Then the fish turned and disappeared into the kelp forest as silently and quickly as when it first appeared.

Another great diving moment!

I always love seeing giant sea bass because they are such an iconic species in southern California water. In the very early 1900’s giant sea bass were abundant in California, but by the early 1930’s very few were being caught by commercial fishermen. Sadly, their demise was another case of overfishing, a combination of commercial, sport and spear fishing.

Lucky me, I saw my first giant sea bass during a squid run in 1975 the first year I moved to California. I’ll never forget that dive. It was a night dive, and I had never seen a fish the size of a small Volkswagen until one appeared in my face just like the one in the kelp forest. I was new to California, and I thought sightings like that probably occurred on a regular basis. But it was almost 15 years before I saw my second giant sea bass.

In fact, giant sea bass had become so rare that in 1981 the California legislature banned both the commercial and recreational take of the species. It was feared that the protection was a case of too little too late. But there is good news. The giant sea bass population is definitely bouncing back. While their numbers are not what they were during the early part of the last century, the species has definitely rebounded. Today, while sightings are not common, they are far more common than they were fifteen or twenty years ago, and there are some specific dive sites where you have a reasonably good chance of seeing a giant sea bass during certain times of the year.

It just feels good to be able to write a story that looks like it can, and will, have a happy ending!

I hope you enjoy this week’s POTW and the story behind the shot!

See you next week,

Marty

Male California Sheephead At The Eureka Oil Rig

Mon, 30 Jan 2012 00:00:00 GMT

Hi Gang!

This week’s POTW is a second image from my dive on January 2, 2012 on the Eureka oil platform off Long Beach, California. The shot is a picture of a male California sheephead, Semicossyphus pulcher, swimming through part of the rig’s invertebrate encrusted support structure.

The California sheephead is an iconic fish species in the waters of southern and central California waters. A treat for divers and a highly sought after food source by fishermen, California sheephead are generally considered to live in association with the seafloor in relatively shallow, inshore waters of kelp forests and other areas where the substrate is rocky. The oil rigs have become artificial reefs and it is not uncommon for divers to encounter California sheephead on their oil rig dives where all marine life is protected by the no-take staus of the water surrounding the rigs.

California sheephead are members of the wrasse family. Similar to other wrasses, California sheephead undergo three life phases, a juvenile, initial and terminal phase. All California sheephead are hatched as females (juvenile phases) and remain females through both their juvenile and initial phases. Terminal phase California sheephead undergo a sex change and are transformed into males so that breeding females have access to a potential mate.

If not enough males are present in a given area, dominant females will soon develop into males. When California sheephead become males, the fish develop a large bump on their forehead and the previously pink-to-red head and rear of the body turn black. California sheephead have large protruding teeth that are used for crushing and prying open the hard shells of mollusks, crustaceans and echinoderms, including sea urchins that they prey upon.

To clear up a point of potential confusion I want to make it clear that the words sheephead and sheepshead are used to refer to several species of fishes in waters around the world. Not all of those species that are known as some type of sheephead or sheepshead are types of wrasses. The fish in this week’s POTW image is specifically known as the California sheephead.

For several reasons including pollution and fishing pressure, California sheephead populations have seriously declined in recent years. However, the species appears to be on the rebound. In any case, it was a nice feeling not only to see this male, but to see a number of males around the Eureka oil platform.

If you would like any additional information regarding the oil rigs off California coast or the invertebrates in this photograph that have encrusted the structure of the oil rig, check out last week’s POTW. I shared two images from my recent day at the Eureka rig in consecutive POTWs, and I elaborated on the rigs and some of the invertebrates in last week’s piece.

I created this week’s POTW with my Nikon 17-to-55 mm zoom lens set at a focal length of 35 mm. This lens is a great choice for creatures that are the size of a typical lobster to a sea lion. That said, the lens is used behind a dome port in my Subal housing, and when using the set up around a reef I have to be careful not to bash into the substrate, an act that can damage the reef scratch my dome port.

I really enjoy using my 17-to-55 mm lens. The way I often use it is to get as close to my subject as I can so that I can shoot through as little water as possible. Doing that means I shoot through as few suspended particles in the water as possible, and I can get the most vivid colors with my strobes. So, I get close and then ride the zoom control to alter the lens’ angle-of-view to compose my frame.

I hope you enjoy this week’s POTW!

See you next week,

Marty

California Sea Lion At The Eureka Oil Rig

Mon, 23 Jan 2012 00:00:00 GMT

Hi Gang!

In southern California when the stars line up, meaning the weather and water conditions are at their best, the thing to do is to drop whatever else you are doing, load your cameras and get wet. This bit of California diving advice is especially true during the winter months when you can’t count on good conditions. Lucky me, with great conditions in our area that is exactly what I did yesterday to welcome in the New Year. I went diving on the Eureka oil rig out of Long Beach, California with a few friends, and we enjoyed relatively calm seas, some sunshine and very good visibility for winter water in my home waters.

Here’s a bit about the oil rigs: A series of oil rigs stretch along the California coast from the Long Beach (just south of Los Angeles) area to Santa Maria which is just south of Monterey Bay near the middle of the state. Some of the rigs have been decommissioned and some are still operational. A number of the rigs are built in relatively deep water with their support structure being secured on the seafloor as deep as 600 to 700 hundred feet below the surface. The various support pillars and cross beams create a reef-like oasis for all kinds of creatures ranging from tiny invertebrates to fishes, California sea lions and any number of open ocean creatures that swim by at times to take a look. The rigs are no-take zones, and over the years they have become wonderful artificial reefs for divers to explore when conditions are favorable.

This week’s POTW is an image of a California sea lion swimming over the end of a pipe on the Eureka oil platform that is encrusted with a dense carpet of colorful corynactis anemones and white metridium anemones. Corynatic anemones are sometimes referred to as strawberry anemones due to the brilliant red hues of some specimens, but these corallimorphs (close relatives of anemones) occur in many hues. Metridium anemones, the white anemones in the photograph, are sometimes called plumose anemones.

It is quite common to encounter California sea lions around the rigs. They can easily haul out of the water on some of the structure that is above the water line, and there is plenty of food available for them in the water around the platform.

I created this week’s POTW with a Tokina 10-to-17 mm zoom lens in a Subal housing. At 10 mm the lens is a fisheye with a field-of-view of 180 degrees. For this photograph I had the lens set to 10 mm so I could get close to the encrusted pipe and still capture the wide, colorful foreground. Even with the great conditions and a slightly upward shooting angle I was using an f/stop of f/4. Even when we consider the conditions to be really good, southern California waters can be a bit dark and green, and that is why I used such a wide open aperture. Using an f/stop of f/4 and being very close to my foreground meant I needed to use a low power setting on my Ikelite DS-161 strobes.

I hope you enjoy this week’s POTW! I am going to share another image from my first dives in 2012 in next week’s POTW.

See you next week, and my best wishes for a Happy 2012 To All of You!

Marty

Manta Silhouette

Mon, 16 Jan 2012 00:00:00 GMT

Hi Gang!

This week’s POTW is yet another image from my recent trip with Captain Steve and friends to Mexico’s Revillagigedo Islands aboard the liveabord dive boat, the Rocio del Mar. The shot is a silhouette of a pair of manta rays captured at a well-publicized dive site named The Boiler at San Benedicto Island. San Benedicto is the northernmost of the four islands in the group.

While it cannot be guaranteed, The Boiler has a reputation for providing some wonderful manta ray encounters over the years, and it certainly did not disappoint during our trip. During one dive I had seven mantas in my field of view at one time, and I suspect there were others swimming close by. We dived The Boiler on both the first and last days of our trip, and while diving there divers in our group also saw bottlenose dolphins, whitetip reef sharks, a small group of scalloped hammerheads, and a tiger shark. Not too shabby!

However, as is most often the case, the feature attraction on our trip was the manta rays.

When creating silhouettes I shout in the manual mode so that I can set my f/stop, shutter speed and ISO exactly the way I want to.

One of the keys to creating a silhouette is that you absolutely need to see distinct contrast between your subject and the background that borders the subject. In this case, I needed to see the contrast between the manta that is blocking the sun ball and the surrounding water. A strong upward shooting angle will often helps you find that contrast.

Once you see the contrast the next key is to properly expose the background. Do that and your silhouetted subject will appear dark against the properly exposed background, and you will have a silhouette. When taking your light meter reading you want to be sure to take it on the water around the ray, not on the body of the ray or on the sun. In this case I took my light meter reading on a band of blue water right next to the ray that I wanted to be the same hue and brightness in my image that it looked to my eyes when I was in the water. I always use the spot-metering mode when taking a light meter reading for a silhouette so that I can be sure my light meter is aimed exactly where I want it to be.

But contrast and a properly exposed background are not all that is required to do the trick. Your subject needs to have an interesting shape. Hard to beat a manta ray for a marine animal with an interesting shape.

Use a fast shutter speed to help “freeze” the action, and you are more likely to get a razor sharp image with crisp lines that separate your subject from its background. In this case I used a shutter speed of 1/350^th of a second.

No doubt about it, with a lot of mantas in relatively shallow water, great visibility, and a sunny day, I had a lot going for me. So, after I had created several nice silhouettes with a single manta ray in the frame, I decided to get creative and see if I could manage to compose a silhouette with a second animal in the frame. Given the conditions of the day I was able to get several opportunities where I thought I could compose a frame I would like, but I only had one pass that was as nice as the one that appears as this weeks POTW.

I hope you enjoy the shot!

See you next week,

Marty

Captain Steve Films A Bottlenose Dolphin

Mon, 9 Jan 2012 00:00:00 GMT

Hi Gang!

In late November of last year I used an image of a diver swimming with a bottlenose dolphin that I captured during a trip to Mexico’s Revillagigedo Islands. The picture was taken at a site called Cabo Pearce at Socorro Island. In that POTW piece I mentioned that while in my experience close encounters over a prolonged period with pods of wild bottlenose dolphins are generally considered to be unusual events, at one time they were fairly common at Cabo Pearce.

Well, it happened again. I can’t say for certain that it was with the same animals, but during my recent trip with Captain Steve and friends aboard the Rocio del Mar a group of bottlenose dolphins approached us during several dives at Cabo Pearce. On the first dive one of the dolphins swam up to Steve and stopped only a foot or so behind his head. At least, that is what I was told. I was not with the Captain at the time. I felt like the tale might have been exaggerated somewhat, but I couldn’t be sure. Apparently, Steve didn’t see the dolphins until they were swimming away, and he didn’t really know what had happened until some other divers told him about it once he was back onboard.

Skip ahead to our next dive. This time I was with Captain Steve, and after about 20 minutes I turned to look at the Captain and I watched one bottlenose dolphin swim right up to the back of Steve’s head and stop literally a foot or so from Steve’s head. Steve had no idea a dolphin was right behind him, and neither did several other divers that were swimming in very close proximity to the Captain as they were all engrossed in trying to photograph some manta rays.

I am not sure why I was looking back at Steve at the time, but I was. After a few seconds another diver swam up to Captain Steve, tapped him on the shoulder and pointed at the dolphin. Within a few seconds Captain Steve started to record the action as several dolphins swam amongst our group of divers.

The cameraman in the bottom right hand corner of this week’s POTW is Captain Steve with his video system capturing the action.

I was using my Tokina 10-to-17 zoom lens at the time and had the lens set to 10 mm. In other words, the lens was “seeing” a 180-degree field of view. In short, I was using a fisheye lens and was able to fill a large portion of my frame with the dolphin. That is because the dolphin was only three feet or so in front of me. What a great moment, and a great dive!

The POTW I shared last November was shot in much deeper water, but this time I was only a few feet from the surface so I had a lot of sunlight to work with. The visibility was not at its best, but it was certainly good enough. The bottom line is that I couldn’t have asked for a much better photo opp, and neither could Captain Steve.

I hope you enjoy this week’s POTW!

See you next week with another image from our Revillagigedo trip,

Marty

Whitetips Piled Up Like Cordwood

Mon, 2 Jan 2012 00:00:00 GMT

Hi Gang!

I have just returned home from a trip to Mexico’s Revillagigedo Islands with Captain Steve aboard the liveaboard dive boat Rocio del Mar, and no doubt about it, we had a blast! Great diving with a Noah’s Ark of big animals including more manta rays than we could keep track of, bottlenose dolphins, and at least eight species of sharks.

This week’s POTW is a shot of a group of whitetip reef sharks, Triaenodon obesus, that were piled up like cordwood in a small cave at Roca Partida Island. I had made several trips to Roca Partida over the years, and I was aware of one cave where I had previously seen groups of whitetip reef sharks at rest. But on this trip we found at least seven of these holes within only a few yards on each other, and all of them were filled with whitetips.

As their name implies, whitetip reef sharks can be easily recognized by the prominent white colored markings on the tips of their fins and tail. Whitetip reef sharks typically occur in and around reef communities throughout the tropical waters of the Indo-Pacific region, including the Red Sea. They typically occur in association with reef communities from the intertidal zone to 130 feet. A typical adult attains a length of four to six feet.

Unlike many other widely known and more highly publicized sharks such as tiger sharks and bull sharks that have thick, muscular, powerful looking bodies, the otherwise gray-to-brown bodies of whitetips are rather slender and supple. Their design and flexibility enable whitetips to get into the cracks, crevices and ledges in reefs where other larger, less flexible species cannot go.

Whitetip reef sharks are characterized as sleepy and sluggish during the day as they tend to rest on the bottom or cruise in a rather leisurely fashion. Unlike many shark species, whitetips do not have to swim 24 hours a day in order to respire as they are able to move water across their gills even when they are at rest.

Given the right opportunity during the day whitetip reef sharks will certainly spring into action in order to feed. At night, they “come alive” and undergo an obvious “personality” change. Under the cover of darkness, whitetips transform themselves into active hunters, working either individually or in groups as they explore holes, caves, cracks and crevices in search of prey. The “name of the game” seems to be “look into enough places and eventually you will flush out enough potential prey to fill your belly.” Stomach content analyses demonstrate that a variety of small fishes, crustaceans and octopuses are favorite prey items.

The slender body design and sand paper-like skin of whitetip reef sharks makes them very adept at digging or slamming their into small crevices to gain access to a midnight snack. The skin of sharks is composed of small, tough, miniaturized teeth known as dermal denticles, or “skin teeth,” teeth, as opposed to the scales present in most bony fishes. Since these sharks tend to hunt around coral reefs, this slender-body, tough skin design proves to be an example of Mother Nature at her best as whitetip reef sharks can quickly and aggressively maneuver around, in, over and through the tight confines of a typical coral reef when hunting without harming themselves.

After their nightly forays whitetips often return to the exact same ledge or crevice where they spend their days. Sometimes the same shark returns to the same location for many weeks or even months on end. Both during the day and at night, whitetips are often observed to gather together and move in loosely organized, but highly competitive packs.

I created this week’s POTW with my Nikon 17-to-55 mm zoom lens mounted on a Nikon D300 camera. The camera was inside of a Subal housing. I lit the scene with a pair of new Ikelite DS-161 strobes.

The biggest challenge was that I was working in an area that was fairly surgy, and it was a challenge to get as close to the sharks as I wanted to without getting pushed into them by the surge. I made sure to set my controls before I moved in for my shot, and when I got into position I shot a series of shots and then backed up. After that I backed up, checked my shots, made adjustments and tried it all again.

This week’s POTW is one of my better efforts. I hope you enjoy it!

See you next week,

Marty

A Sapsucking Slug: What A Name For Such A Beauty!

Mon, 26 Dec 2011 00:00:00 GMT

Hi Gang!

This week's POTW is a shot of a relatively small, stunningly gorgeous reef creature that has a common name that belies its appearance. The animal is commonly referred to as a "black and gold sapsucking slug". Maybe its just me, but to me this name simply does not convey the beauty of Mother Nature's handiwork in this case. In fact, the name sounds kind of off-putting to me. But I think this slug is a real stunner!

The black and gold sapsucking slug, Cyerce nigricans, is a type of opistobranch mollusk that is commonly mistaken as a nudibranch. The sapsucking slug is very closely related to nudibranchs, but opistobranchs and nudibranchs are described in different sub-classes, Opistobranchia and Nudibranchia respectively. As is the case with many opistobranchs, this sapsucking slug lacks the external shell found in many other of it's close mollusk relatives including scallops, snails, mussels and oysters. However, some other sapsucking slugs do have very small external shells, while still others are equipped with internal shells.

The black and gold sapsucking slug occurs in the Indo-Pacific region, and is most common from Fiji to Guam. This week's POTW is from Fiji.

Sapsucking slugs are quite common in many reef communities, but they often go overlooked by sport divers because of their diminutive size and the facts that many species lack the attractive colors and striking features displayed by the black and gold sapsucking slug. The black and gold sapsucking slug attains a maximum length of only a couple of inches, but that still makes it considerably larger than many of it's closest relatives as many are less than 1 cm long.

As it's common name suggests, the black and gold sapsucking slug feeds on various types of seaweeds by sucking their sap. This slug is equipped with a very distinctive, rasping tongue-like organ known as a radula. The radula of a black and gold sapsucking slug has a single row of very sharp, knife-like teeth that are used one tooth at a time. A single tooth is used to penetrate the seaweed cell, and then the content of the cell, the sap, is sucked out with a powerful pump-like tube.

Most sapsucking slugs feed on types of green seaweeds with each species of slug selectively feeding on some preferred species of green seaweeds. That said, it is worth noting that that some sacoglossans prey upon the eggs of other slugs.

In some instances the slug retains parts of the seaweed known as chloroplasts that contain chlorophyll without damaging them. Amazingly, these chloroplasts continue to conduct photosynthesis inside of the slug, a natural thief that has essentially stolen the chloroplasts from the seaweed. The slug benefits by using some of the by-products of the photosynthesis as food for itself. Mother Nature is truly an amazing lady!

In addition to this very clever adaptation some sapsucking slugs can exude a noxious secretion that repels potential predators. And that is still not the entire bag of tricks as some species can raise and flare the projections on their skin known as cerata to help frighten away potential predators.

I captured this week's POTW with a Nikon 60 mm lens mounted on a Nikon D300 camera that, in turn, was inside of a Subal housing that was set up with a flat port. I used a pair of Ikelite DS 160 strobes to light the shot. Two tricky parts of photographing slugs and nudibranchs in the size range of the black and gold sapsucking slug are (1) finding a complimentary background that helps the subject standout in the frame and (2) finding a shooting angle in which the antennae and other body parts don't "get lost" in the background by blending in. With such spectacularly colored subjects it can sometimes be a challenge to remember how easy it is to waste a great photographic opportunity by failing to be extra careful to keep the background and your shooting angle in the forefront of your thoughts when composing your shot.

I hope you enjoy his week's POTW!

See you next week,

Marty

P.S. I am currently on the plane with Captain Steve as we are just beginning our trip to Mexico's Revillagigedo archipelago. I look forward to sharing a few images from our adventure in upcoming POTWs.

Cortez Damselfish

Mon, 19 Dec 2011 00:00:00 GMT

Hi Gang!

In just a couple of days I will be picking Captain Steve up at the San Diego airport, and along with another mutual friend, Steve Ando, we will be heading to Mexico’s Revillagigedo Islands on the liveaboard dive boat Rocio Del Mar. This will be my third trip on the Rocio in the past 16 months. The other two were trips to the Midriff Island in Mexico’s Sea of Cortez. Diving in the Midriffs is a lot different than diving at the Revillagigedo Islands. The water at the Revillagigedo Islands (aka Socorros) should be considerably warmer than at the Midriffs, and the vis should be in the 60 to 100 foot plus range. At least that is what we are hoping for. As for the diving at the Revillagigedo Islands, it is centered around trying to find big animals like whale sharks and schools of scalloped hammerheads.

In any case, the boat will be the same, so tonight I was looking through my images from my previous Rocio Del Mar trips, and I decided that this shot of an intermediate phase Cortez damselfish, Stegastes rectifraenum, would make a good choice for this week’s POTW. As its common name suggests the Cortez damselfish is a member of the family Pomacentridae, the family that contains all 321 species of the world’s damselfishes. This little guy was only a couple inches long, and when full-grown will be less than four inches in lenght, but despite its diminutive size an intermediate stage Cortez damselfish makes a big impression. The adults are a dull brownish hue with only faint blue markings that are not always evident. Kind of blah compared to the stunning colors of the juveniles and intermediate stage fish.

Cortez damselfish are typically encountered in the eastern Pacific and Sea of Cortez in relatively shallow, rocky reef communities. They are active swimmers that are neither the most wary nor most cooperative of fishes when it comes to trying to take their picture. They are constantly on the move, but never swim too far, and seem to at least sometimes be a little bit curious about divers and cameras. Cortez damsels are an omnivorous species that feed on a wide variety of food sources. Studies specimens have lived for as long as 11 years.

The key to my photographic success was to be quick with my camera system when I had a chance to compose an interesting frame without moving so fast that I frightened the fish causing it to alter its pose or swim away. It was a case of trying to be quick without getting in such a hurry that I scared the fish.

I composed my frame as quickly as I could when the opportunity for this shot presented itself, and then focused on the eye as fast as I could as I almost always try to do when photographing any creature that has at least one eye in my shot. I banged off a series of three frames before the fish moved. This shot represents my best effort, and I hope you enjoy it! I should mention that I spent quite a bit more time working with this Cortez damselfish. I had several chances to bang off a series of a few shots. It is kind of a be quick, compose, focus and shoot, and then work with the fish again until I could bang off a few more shots. Repeat, and then repeat some more.

The Revillagigedo Islands are mostly about big animal encounters, so I doubt we will spend much, if any, time looking for creatures as small as Cortez damselfish. But you never know. I look forward to my trip with Captain Steve, and to providing a report in my POTW column when we return.

See you next week,

Marty

Ulua On The Prowl

Mon, 12 Dec 2011 00:00:00 GMT

Hi Gang!

This week’s POTW is a shot of a fish that is known to Hawaiians as an ulua (uh-lew-uh). Some people refer to the fish as a giant trevally. Ichthyologists know the species as Caranx ignobilis. To further complicate the matter, the ulua is also commonly referred to as the giant kingfish, barrier trevally and lowly trevally. Of course, having so many common names is exactly why specialists use taxonomic names. Those names are “official,” and every species has only one name consisting of its genus and species. Using the taxonomic name helps specialists avoid confusion.

I am going to refer to the fish by its Hawaiian name, ulua, because I created this week’s POTW in Hawaiian waters.

The ulua is one of 140 species described in the jack family, Carangidae, a name derived from the Caribe language for jacks. Occurring in the Atlantic, Pacific, and Indian Oceans, jacks are chiefly marine fishes that as adults are only seen on rare occasions in brackish waters.

Like other jacks, the ulua lives in the water column. Adults are usually encountered in lagoons or on the seaward side of reefs. Juveniles commonly inhabit estuarine waters, and other low salinity areas including some turbid rivers and coastal lakes that are accessible from the ocean.

As adults these fast moving fishes are primarily nocturnal predators that feed upon a variety of crustaceans, mollusks and bony fishes. Ulua are known to hunt individually as well as in schools. They are also known to accompany other animals including monk seals and sharks that might scare prey that the ulua can pick off while the prey is disoriented.

The ulua is a large member of the jack family. According to the data on fishbase,org, the heaviest ulua weighed in at a whopping 176 pounds, and the longest specimen was over 5.5 feet long. That explains why many people refer to the species as the giant trevally.

The primary reason that I chose this image for this week’s POTW is that the ulua is highly regarded as a game fish by many serious spear and sport fishermen. This is especially true in Hawaiian waters. Although ulua are sometimes curious about divers, I have found that freediving usually provides the best way to get close to them. Unfortunately, ulua populations are thought to be declining in Hawaiian waters.

I created this week’s POTW with Nikon 17-to-55 mm zoom lens with the focal length set to 28 mm. The lens was mounted on a Nikon D300 that was placed in a Subal housing. Because I was freediving at the time I decided to use a single strobe for reduced drag. I used one Ikelite DS 160 strobe to light the shot.

I hope you enjoyed learning a little about the ulua and seeing this week’s POTW!

See you next week,

Marty

Humpback Season Has Arrived!

Mon, 5 Dec 2011 00:00:00 GMT

Hi Gang!

So I am talking with Captain Steve on the phone a few days ago and he tells me that the first humpbacks of the winter have arrived in Maui. Instantly I am both jealous and ecstatic. Jealous because I am not in Maui right now, and ecstatic because I will be going to visit the Captain and his gang this winter while whale season is in full swing. Whale watching in Maui is about as good as life gets for me!

I suppose it is obvious that because I am not in Maui right now that this week’s POTW of a breaching humpback whale is from a previous trip. In fact I created this image during Whale Week 2011 this past February. Whale Week is a special event every February run by the Captain and some whale specialists in an effort to help whale experts gather information about the population dynamics of Hawaii’s humpbacks. All of us that are involved do our best to photograph the underside of the tails of as many whales as we can because the tail photographs enable the experts to identify individual whales. In essence, the tail photos serve as “whale fingerprints”.

Sometimes during Whale Week we don’t do as much diving as we otherwise would, but that’s the good news because less diving means that the whale watching is good.

While the main objective is to photograph the underside of the tails of the humpbacks we also get to enjoy and photograph a lot of other surface activity. This activity includes spy hopping, pec slapping, tail lobbing, breaching, and other forms of play, competition and frolicking etc. No doubt about it, humpbacks put on quite a show at the surface, and it is something that I just can’t get enough of.

As is the case for a lot of observers, for me breaching is a highlight of the surface shows. You never know when or where a humpback is going to breach, but in many instances a whale breaches several times in succession. This means that if you miss the first one you have a very good chance to catch the next one, and the one after that, and the one after that etc. Breaching is a common sight off Maui during the winter months, and like so many people I have seen humpbacks breach hundreds of times. No doubt about it, I get a huge charge out of it every time, and I think I always will.

I captured this POTW breach with a Nikon 70-to-200 mm zoom lens and a 1.7 telextender mounted on a Nikon D 300 camera. This breach was the third in a series of three breaches. I suppose I could go on and on trying to describe what it is like to see a 50-foot long humpback launch itself out of the water with water flying everywhere as the whale spins around as it crashes and splashes its way back to the surface. But my words will never do the scene justice. So, I am going to stop here and share one of my photographs from a breach that I enjoyed last year.

I hope you enjoy this week’s POTW!

See you next week,

Marty

Silky Shark

Mon, 28 Nov 2011 00:00:00 GMT

Hi Gang!

In just a few days I will be heading to Mexico's Revillagigedos Islands (aka the Socorros) with Captain Steve and friends for a week of big animal diving in a truly wonderful wilderness area on the liveaboard dive boat Rocio Del Mar. I have been lucky enough to have dived the islands several times over the course of my career, so in preparation for our upcoming trip I was able to review some images from previous trips to help me "get my head in the photographic game" before we go. During that image review process I came across this image of a silky shark, Carcharhinus falciformis, that I created on a previous trip, and I thought it would make a good POTW for this week.

While I know that I should never count on seeing a silky shark on any given dive at the Revillagigedos, an encounter certainly doesn't surprise me. Silky sharks occur in much of the world’s subtropical waters, and in the eastern Pacific they are commonly seen in near southern Baja at the Revillagigedo Islands where they tend to inhabit continental shelves and shelves, slopes and reefs around offshore islands.

Silky sharks are very capable predators that chase down tunas and other fast swimming fishes. They also prey upon a variety of squids and pelagic crabs. Large silky sharks will attain proportions of 10 feet in length and weigh more than 760 pounds. Big fish!

Water conditions are often favorable for photographing sharks and other big animals at the Revillagigedos, but that doesn't mean you can get as close to the sharks as you would like to. However, luck was on my side during this encounter and getting close didn't prove to be very difficult with this particular animal on this day as I was lucky enough to get several close passes.

What did surprise me- in a pleasant way- was the fact that because the shark repeatedly swam at, and then up and over me, I enjoyed the opportunity to shoot a number of vertical images. A lot of big animals, especially a variety of sharks, don't often lend themselves to vertical frames, but this animal was a very cooperative poser. Lucky me!

I created the image with a Nikon 17-to-55 mm zoom lens mounted on a Nikon D2x in a Subal housing. I used a pair of Ikelite DS 125’s to light the shot. I used the shutter priority mode and was careful not to use too much strobe as it is easy to blow out, or grossly overexpose, whitish body parts on sharks and other open ocean animals that are countershaded, meaning they are dark on the top of their body and whitish below,

I hope you enjoy this week's POTW!

See you next week,

Marty

Diver With A Bottlenose Dolphin

Mon, 21 Nov 2011 00:00:00 GMT

Hi Gang!

In a couple weeks I am headed back to big animal country. I am off to Mexico's Revillagigedo archipelago with Captain Steve and a couple of other good friends on the live aboard Rocio Del Mar in pursuit of Mr. Big. There are four main islands in the Revillagigedo group. The largest is Socorro, and the collectively speaking the islands are often referred to as the Socorros because the gringo tongue routinely butchers the word Revillagigedo.

The islands are between 220 and 400 miles south of Land's End, a noted landmark in Cabo San Lucas at the southern tip of Mexico's Baja peninsula. It will take us roughly 24 hours by boat to reach these remote islands, but having dived there on a number of occasions I can assure you that a bit of a long boat ride is a small price to pay for the chance to dive with the likes of whale sharks, scalloped hammerheads, manta rays and who knows what else. On past dives at the tiny island of Roca Partida I've seen an amazing seven species of sharks and two species of tunas on a single dive!

In preparation for our upcoming trip I recently spent some time reviewing images from past trips. During that process I found an image that I think makes a great shot for this week's POTW. It is a photograph of a scuba diver swimming with a bottlenose dolphin. I captured the moment at San Benedicto Island three years ago.

Speaking in general terms, wild dolphins tend to be rather wary around divers, especially noisy, bubble-making scuba divers. While there are noted exceptions such as the pods of Atlantic spotted dolphins that inhabit the Little Bahama Bank in the northwest Bahamas and Hawaii's spinner dolphins, in most cases we feel lucky to get as much as a glimpse of dolphins underwater. Certainly in my experience this has been the case with pods of bottlenose dolphins, but for unknown reasons the pods of bottlenose dolphins in the Socorros frequently investigate their diving counterparts, and sometimes the encounters last for an entire dive. Once again, I don't think anyone knows exactly why these dolphins seem so curious about us, but I am certainly grateful that this is often the case.

I made this week's POTW with a Nikon 17-to-55 mm zoom lens mounted on a Nikon D2x camera. The focal length was set to 23 mm. I have usually enjoyed very good weather and water conditions at the Revillagigedos, but at the time I created this photograph it was very cloudy. As a result of the prevailing weather conditions I had to shoot with my aperture wide open to properly expose the background while using a shutter speed of 1/250th of a second so I could do my best to "freeze the action" of the fast moving dolphin. Even then, I needed to bring up, or lighten, the background with image manipulation software. I don't think I could have created this image back in the days when film was king. So, chalk one up to digital technology!

I hope you enjoy this week's POTW, and I hope Captain Steve and our other buddies get to enjoy a similar experience.

See you next week

Marty

A Giant Among Frogfish

Mon, 14 Nov 2011 00:00:00 GMT

Hi Gang!

Let’s go back to Maui for this week’s POTW. It’s a profile photograph of the face of a giant frogfish, Antennarius commerson, that I captured on a dive with Captain Steve on the backside of the island of Lanai. The species is also commonly referred to as Commerson’s frogfish.

Frogfishes are often referred to as anglerfishes by fishermen in reference to the lure-like appendage connected to the first ray of their dorsal fin that is used to attract unsuspecting prey to within striking range. Worldwide there are approximately 300 species of anglerfishes. %0 of these species are known as some type of frogfish. The family Antennariidae contains the most species of frogfishes.

On the whole, frogfishes are a rare find, but they appreciated by any observant diver who comes across them. Masters of camouflage, frogfishes adapt to look almost exactly like the surrounding environment, and as a result are extremely difficult to spot when resting. At rest a frogfish often looks like a sponge, branches of corals or large clumps of encrusting algae, and some species actually cultivate bits of algae that grow on their bodies to help them in the art of camouflage. Their color ranges from off white to vivid hues of oranges, yellows, reds and greens. Some fish are solid, others mottled and others spotted depending upon the look of their surroundings and their “mood of the moment.” Their globular, somewhat humorous looking bodies are highlighted their small and upturned mouths giving these fish a face that “only their mother could love.”

While finding a Frogfish for the first time is certainly challenging, many specimens can often be found for days, or even months, on end as they remain in almost the exact same spot in the exact same position. And if they are not there as expected, often they can be relocated within a few inches or a few feet of their original location. Once a frogfish seems certain that it has been discovered they tend to turn and face away from intruding divers rather than swim away.

While they are awkward swimmers, frogfishes are superbly adept ambush predators. When on the hunt they remain almost perfectly still as they extend the “lure” that is connected to the almost invisible first ray of their dorsal fin and wiggle it about to attract their prey of small fishes. This lure typically consists of a lumpy globule on the end of a nearly invisible fishing-pole like ray. Where a human fishermen is somewhat blinded at the surface of the water, frogfishes have the ability to direct the lure towards their prey and following the action with their eyes. They also manipulate the lure to appear life-like and with the already remarkably similar resemblance to animals such as worms, crustaceans and fishes, the illusion is complete and the ploy often results in a successful baiting.

Scientists have video taped the lightening speed at the moment of attack when the frogfish lunges at and engulfs its prey. The action takes place much to fast for human eyes to follow. As it makes its move a frogfish opens its suddenly enormous mouth as wide as it can as quickly as it can creating a pressure differential in the surrounding water. The near vacuum helps the fish suck in the surrounding water and the prey in an incredibly fast act. This feeding technique is known as “gape and suck,” and all the action occurs in less than one-hundredth of a second! If lost, the lure can be regenerated, but the process is not a fast one.

Frogfishes would win very few races in the world of fishes as their stocky bodies are propelled by a stumpy tail. Frogfishes also move by using jets of water squirted from their mouths. In addition, their pectoral and pelvic fins have evolved into “flattened hands” that they use to prop themselves when the fishes rest and to assist them when they “walk” across the sea floor. When moving across the bottom frogfishes alternate the forward movement of their pectoral fins in a tetrapod-like walk or they can move both pectorals forward at the same time, using the fins like humans use crutches to propel themselves sluggishly forward. In addition, the highly modified pelvic and pectoral fins are capable of grasping the surrounding substrate. This adaptation helps frogfishes hold still as they attempt to ambush their prey.

Giant frogfish occur in the Indo-Pacific, Eastern Pacific, Red Sea and the waters of South Africa all the way to Panama, and of, course, in the Hawaiian Islands. As its common name suggests, giant frogfish are bigger than most other frogfishes. Full-grown adults can reach a length of 15 inches. Giant frogfish are bottom dwellers that are usually found in lagoons and in reef communities.

This week’s POTW was created with a Nikon D2x camera and a 105 mm lens. I used a pair of Ikelite DS 125’ strobes to light the shot.

I hope you enjoy this week’s POTW!

See you next week,

Marty

A Gray Whale Opens Wide

Mon, 7 Nov 2011 00:00:00 GMT

Hi Gang!

It’s fall, and depending on how far north one is on the west coast of North America, that means it is either California gray whale season, or it is about to be. Of all the marine creatures that occur in the waters along the west coast of North America, few, if any, have captured the hearts and minds of the public to the degree that California gray whales have.

In recognition of how much California gray whales mean to so many people I have chosen a topside image of the open mouth of a gray whale as this week’s POTW. The shot was captured in Mexico’s San Ignacio Lagoon, one of a series of lagoons and bays on the Pacific side of the Baja peninsula that the whales visit at the southbound end of their annual 10,000 mile-long migration from the waters of the Bering and Chukchi Seas to the north where the whales feed during summer in the Northern Hemisphere.

Along with species such as blue, humpback, sei, fin, northern and southern right, Bryde’s, and minke whales, California gray whales are one of eleven species of baleen whales. Baleen whales are toothless, and feed primarily on plankton and myriad species of small bony fished that they strain from the water. When feeding, baleen whales swim open-mouthed through dense concentrations of their prey or scoop their prey in shovel-like fashion off of the sea floor in areas where the bottom is soft. The baleen bears some resemblance to a synthetic fiber, and a mouthful of baleen looks like some sort of natural toothbrush. The sheets of baleen hang from the upper jaw.

When California gray whales feed they gorge themselves on a variety of small crustaceans and worms found in bottom sediment. When feeding, a gray whale dives to the bottom, rolls onto its side and takes bottom sediment and water into its mouth. Then the whale closes its mouth causing the water and sediment to get expelled through the overlapping series of baleen plates. The baleen traps the food near the tongue, and the food is then swallowed.

When gray whales are in the lagoons and bays in Baja it is not unusual for the whales to approach boats of admiring tourists. That is exactly what happened to me when I created this week’s POTW. A pair of whales approached our boat, and actually rubbed up against the hull. One of the whales raised its head above the surface and opened its mouth exposing the baleen plates.

I had a Nikon 12-to-24 mm lens mounted on a Nikon D300 in anticipation that I might get a few shots of a whale that was close to our boat, but I did not expect to see an animal open its mouth only a few feet from the boat. My camera was set to shoot as many as eight frames a second. I was able to compose a nice frame using a focal length of 24 mm, and I captured several usable images before the whale closed its mouth. This week’s POTW is the one that I consider to be the best photograph in that series.

I hope you enjoy this week’s POTW!

See you next week,

Marty

Diver With A Green Turtle

Mon, 31 Oct 2011 00:00:00 GMT

Hi Gang!

It’s back to Maui and a dive with Captain Steve for this week’s POTW. The photograph is a shot of David Fleetham, a Maui resident and a very good friend of mine, checking out a green sea turtle on a dive off the island of Lanai that we made with the Captain.

Worlwide there are seven or eight species of sea turtles, depending upon whether or not the single species of green turtle should be divided into two species, one in the Pacific and one in the Atlantic.

The green turtle, Chelonia mydas, is probably the best known of all the world’s sea turtles due to its value as a food source and the amount of research that has been conducted on this species. Green turtles are named for the green color of their body fat, not the color of their shell as is commonly thought. The average size of the carapace of an adult is between 36 and 43 inches, and animals in this size range typically weigh between 200 and 300 pounds. However, green turtles are known to weigh as much as 700 pounds. The carapace of an animal of this size is approximately 5 feet long.

Unlike most sea turtles, green sea turtles are herbivores. The chief components of their diet are a variety of algae and sea grasses.

Sea turtles are air-breathing reptiles that inhabit tropical and

sub-tropical seas around the world. Their shells consist of an upper part known as the carapace, and a lower section known as the plastron. With the exception of leatherback turtles (Dermochelys coriacea), the number and arrangement of scutes is often used to differentiate between the species. An interesting difference between the various species of sea turtles and their land dwelling counterparts is that sea turtles are incapable of retracting their head and limbs inside their shell.

Land dwelling ancestors of modern day sea turtles first appeared on earth approximately 200 million years ago. Between 50 and 100 million years later these land dwellers expanded their habitat to include the open sea. The only other major groups of modern-day marine going reptiles are the marine iguanas that live only in the Galapagos Islands off the coast of Ecuador, saltwater crocodiles, sea snakes and sea kraits (very close relatives of the sea snakes).

Over the course of evolutionary time, the flippers of sea turtles have been modified for swimming rather than crawling as is their case with terrestrial dwelling tortoises. While the long and powerful fore flippers provide thrust, the rear flippers provide stability and directional control, similar to the rudder on a boat. In contrast to their often slow and lethargic cruises around reefs, Sea turtles are capable of rapid bursts of speed. In fact, several species have been clocked in excess of 20 miles per hour.

I created this week’s POTW image with a Nikon 17-to-55 mm lens with the focal length set to 17 mm. When using a lens with a relatively wide angle of view the best thing to do underwater is usually to get as close as possible to your foreground subject so that you shoot through as little water column as possible. The less water you shoot through the sharper your images and the richer your colors. And yes, this is true even in the extremely clear Hawaiian waters.

I hope you enjoy this week’s POTW!

See you next week,

Marty

Caribbean Reef Squid

Mon, 24 Oct 2011 00:00:00 GMT

Hi Gang!

This week’s POTW is an image of a Caribbean reef squid, Sepioteuthis sepioidea, that was captured during a dive at the Blue Heron Bridge in West Palm Beach, Florida. The area is highly recommended dive site that is easily beach dived. The Caribbean reef squid is also known by the common name of Atlantic oval squid.

Like their close relatives the octopods, cuttlefishes and nautiluses, squids are cephalopod mollusks. The term Cephalopod is derived from the Greek for “head” and “foot.” The “head and foot” reference is made in acknowledgement of the two most prominent characteristics of cephalopods, the enlarged head and the foot that has been modified into sucker-bearing arms that are used for mobility, ensnaring prey and manipulation.

The arms of cephalopods are covered with one or more rows of suckers. Each sucker contains small hooks or other adhesive structures that are used for ensnaring prey. While octopods have eight arms, squids and cuttlefishes have eight arms and two tentacular-clubbed arms making a total of ten appendages. Nautiluses have as many as 90 arms.

In addition to the use of sucker-covered arms for immobilizing prey, most Cephalopods possess a hard parrot-like beak. The beaks of most species contain an immobilizing toxin that is released into the body of the prey once it has been bitten.

Worldwide there are approximately 300 described species of marine animals that are commonly referred to as some type of squid, and many specialists feel very confident that many more species are yet to be discovered. All squids live in saltwater.

While they are sometimes solitary, Caribbean reef squid are often encountered in small gatherings that number a dozen or so. Sometimes the animals appear rather bland, but at other times they use specialized cells in their skin known as chromatophores to produce vivid hues and iridescent spots. They are believed to use their colors as a means of intraspecies communication, possibly to confuse prey, and to warn potential predators to steer clear. That said, a wide variety of fishes including sharks, jacks, tunas, billfishes, and many reef species as well as whales and dolphins are known to prey on Caribbean reef squid.

The color-changing ability of Caribbean reef squid makes it impractical to rely on color to identify the species in the water. Caribbean reef squid are, however, the most commonly encountered species of squid in the waters of Florida, the Bahamas and Caribbean. Adults are typically in the neighborhood of 10 inches long.

From a photographic standpoint, squids are challenging subjects for underwater photographers despite the fact that they are sometimes easy to get close to. Properly exposing them is the issue. The body is easy, but many species have a rather large whitish eye that often gets grossly over exposed when lit by a strobe. This is true even when the rest of the body is properly exposed. The strobe light often “blows out” the eyes causing a ruinous distraction in the image.

Knowing this eye exposure issue to be a problem from past experience, and because I was in about six feet of water, I chose to turn my strobes off when I created this image. Because I was in such shallow water I was able to capture the rich colors in the squid and avoid over exposing the eyes while using sunlight alone to expose the shot.

Had I been just a little deeper the colors would have gone a bit flat. I might have been able to “punch up” the colors in Photoshop, but in this case I did not need to.

I used a Nikon 60 mm lens behind a flat port on a Nikon D 300 in a Subal housing to create this image.

I hope you enjoy this week’s POTW!

See you next week,

Marty

Catfish School

Mon, 17 Oct 2011 00:00:00 GMT

Hi Gang!

This week’s POTW is an image of a school of striped catfish, Plotosus lineatus. The species is also commonly referred to as striped eel catfish, and this is the name used in the popular fish data base web site, fishbase.org.

Striped catfish are encountered on a reasonably regular basis throughout many regions of the Indo-Pacific, Red Sea, Korea, Japan, Micronesia and East Africa. With as many as several hundred individuals, the schools consist of juveniles. Adults tend to be solitary, or they gather in smaller schools. The schools vary in size from a basketball to a scuba diver. Juveniles are usually 2 to 4 inches long, and adults reach a maximum length of close to 10 inches.

The striped catfish is the only species of catfish that occurs in coral reef communities. Like other catfishes, the striped catfish is equipped with chemosensory barbells, the whisker-like appendages below their mouth. These sensory organs help striped catfish feel and taste the cues that might lead them to their prey.

The schools appear to roll, or flow, across the sea floor as the fish search for a wide variety of small crustaceans, mollusks and worms as well as some fishes.

While I have never heard of anyone being harmed by these fish, there is no question that they possess a highly venomous first dorsal spine and in all of the spines of their pectoral fins.

From a photographic perspective the schools of striped catfish pose an interesting challenge mostly because the schools are in constant motion. This means you have to be quick to select a point of focus and compose an interesting frame. In addition, when using a macro lens we usually have to work with a comparatively narrow depth-of-field. So the idea is to trip the shutter when the school is somewhat flattened on the side that is approaching you. This will give you an opportunity to capture the image when a large percentage of the fish that are visible in your frame fall within the bounds of your depth-of-field.

In the case of this week’s POTW I used a 60 mm lens. Knowing that I wanted to maximize my depth-of-field I turned my Ikelite DS-160 strobes up to the full power setting, and as a result I was able to close my aperture down to f/25. Such a small aperture provides good depth-of-field even when focusing on a subject that is close to the lens.

Another challenge when photographing the schools of striped catfish is trying to move backwards to get in front of and stay in front of the school without bashing into the reef behind you. If you are lucky you will encounter a school as it moves over a sand flat, but that is not always the case. In most instances you will want to be especially carefully not to stir up the sea floor as you move because the area you stir up might end up in your next photograph. Neutral buoyancy and keeping your head on a swivel is usually required in order to enjoy some photographic success.

I hope you enjoy this week’s POTW!

See you next week,

Marty

Manta Ray At A Cleaning Station

Mon, 10 Oct 2011 00:00:00 GMT

Hi Gang!

This week’s POTW image is a follow up to another photograph of a manta ray that I shared a few weeks ago. This week’s shot was captured at the same cleaning station in Yap as the previous POTW image, but in this week’s POTW you can see that the mouth-open manta is actually at a cleaning station. In fact, if you look carefully you can see a cleaner wrasse at work providing its cleaning services inside of the manta’s cavernous maw.

At this particular cleaning station the mantas often gather throughout the day in order to get cleaned by a variety of cleaner fishes. Of course, there is no guarantee that a ray will be there when you make your dive, or that the animal will be posing mouth-open for some cleaning at any given time. Sometimes the mantas don’t show up at all; sometimes they make a quick pass over the top of the reef as they glide through the cleaning station; but at other times they stop, open wide and really take advantage of the cleaning services.

As a photographer there are a couple of major challenges to deal with even when the rays are receiving the full treatment. First, it is not cool to swim on top of the reef to try to get close to the rays while they are getting cleaned because if this happens repeatedly the rays are likely to find another site where they can get cleaned. Second, while it can be a great show to watch if a ray that is getting cleaned is 15 or 20 feet away, you are going to end up with a disappointing picture no matter how clear the water is because you will be shooting through too much water.

The bottom line is that I needed some good luck and a lot of factors to fall into place in order to capture this image. I needed a ray that was getting cleaned not only to approach the area where I was “camped out” to watch the show, but to be facing me. So, no doubt I got lucky!

Of course, I made at least 12 dives on the cleaning station before that happened. Time in the water is one way to help yourself get lucky.

However, I had chosen to use a 10-to-17 mm fisheye lens on that dive thinking that I would shoot close up portraits as the rays swam near me after they had been cleaned. Had I known that would have such a good go at a cleaning shot I would have selected a lens with a narrower angle-of-view such as a Nikon 12-to-24 mm zoom lens or even a 17-to-55 mm zoom.

Okay, so things weren’t perfect, but they were certainly good enough. In the end, because I was using such a wide lens I had to crop the image a little in order to help the manta fill a pleasing percentage of my frame. I try to avoid cropping when I can, but the ability to do so while still producing strong images is one of the major advantages of modern day cameras with high megapixel sensors.

I lit the scene with a pair of strobes, and I was careful to take a good light meter reading on the bluish water in the background so that I could properly expose the water as well as the ray. Accomplishing this goal helps the ray standout in the shot and provides a more pleasing background.

I hope you enjoy this week’s POTW!

See you next week,

Marty

Perfect Housemates

Mon, 3 Oct 2011 00:00:00 GMT

Hi Gang!

I am a sucker for shrimp gobies and the snapping shrimps they associate with. I just can’t pass them up. To me, shrimp gobies and their partner shrimp are like garibaldi in southern California. I have photographed them dozens of times before, but whenever I come across them I stop and shoot some more. I suppose this week’s POTW is simply additional proof.

This week’s POTW is an image of a pair of banded shrimp gobies, Cryptocentrus cinctus, with a partner shrimp. As is the case with the POTW images from the past two weeks, this week’s shot was created in Yap, an island state in the Federated States of Micronesia.

The banded shrimp goby experiences two color phases. In one the fish is a much darker blend of brown and dark blue hues. In the phase I photographed the fish is mostly a greenish yellow.

The relationship between the shrimp gobies and the shrimp works as follows: The shrimp digs and maintains the burrow that is shared by both the shrimp goby and the shrimp. In many cases there is only a single fish and a single shrimp that live together. The fastidious shrimp is a tireless worker and would easily win a Good Housekeeping Award. The shrimp has very poor vision, thus it is vulnerable to potential predators.

While they do not help to maintain their shared home the shrimp gobies are ever vigilant, and they keep a sharp eye out for potential trouble. Whenever a shrimp is out of the burrow as they often are when they are clearing debris from their home, the shrimp keep in contact with the fish by using their antennae as they keep at least one feeler in physical contact with the fish. When alarmed, the goby uses the movement of its tail to signal that danger is present, and then both the goby and the shrimp speedily retreat into the safety of their burrow.

To date, no one knows exactly how this relationship first began.

I captured this week’s POTW image with a Nikon 105 mm lens mounted on a Nikon D300 camera. The key to my success was being patient. The burrow was in less than 15 feet of water and I found it at the beginning of my dive. So time was not an issue. What I needed was the right pose, and for that I had to wait. I had plenty of chances to shoot with one goby and no shrimp, a single goby and a shrimp, and with a pair of shrimp gobies peering out of their burrow. But I had to bide my time to get an opportunity with both gobies on guard and a visible shrimp at work outside of the burrow.

I don’t think of myself as an overly patient person, but there is no doubt that photographing wildlife will bet that quality into you, at least at times. There is simply no way to make wild animals do exactly what you want them to on cue.

I hope you enjoy this week’s POTW!

See you next week,

Marty

Gray Reef Shark

Mon, 26 Sep 2011 00:00:00 GMT

Hi Gang!

This week’s POTW is another shot from the Micronesian island state of Yap where I am one serving as one of the photo pros at an event called Manta Fest. Appropriately named, the Manta Fest celebration and photo competition is being held in conjunction with Yap Divers at Bill Acker’s Manta Ray Bay hotel. As I mentioned in last week’s POTW column one of Yap’s more highly acclaimed dives is a shark dive that features gray reef and blacktip reef sharks. It was on our first shark dive of the trip that I captured this photograph of a gray reef shark.

The scientific name for gray reef sharks is Carcharhinus amblyrhynchos. This taxonomic name is derived from the Greek words meaning, “sharp-nosed shark with blunt snout.” Strong black lines on the edge of their dorsal fins also characterize gray reef sharks, and these markings provide a good, but not perfect, feature when identifying the species underwater.

Gray reefs are among the most common sharks in many Indo-Pacific coral reef communities, and in many places they are considered to be an iconic species that represents all of the marine creatures in healthy South Pacific reef communities.

Gray reef sharks are often observed in reef channels and on reef faces, especially in areas where currents are common. The dive in Yap is conducted in an ideal setting at a depth of 40 to 55 feet on the edge of a current swept wall. Rather territorial by nature, the average home range of gray reef sharks is believed to be only one and one-half square miles, so Yap’s shark dive provides a highly predictable chance to get some shark photos.

Gray reef sharks are equipped with numerous triangular-shaped teeth with very fine serrations. The serrations are useful for slicing, cutting, ripping and chewing small fishes that these sharks prey upon. Documented prey fish include butterflyfishes, coronetfishes, needlefishes, soldierfishes and surgeonfishes as well as moray eels. Gray reefs are also known to feed upon some crustaceans and cephalopods.

This week’s POTW was created with a Nikon 17-to-55 mm zoom, my favorite lens for photographing “medium-sized” sharks. Adult gray reef sharks attain an average length of four to five feet, and the variable focal length of the 17-to-55 mm zoom makes for an ideal choice for helping to fill a photographic frame with an animal of that size. I used a pair of Ikelite DS 160 strobes to light the scene.

I worked at getting down low so that I could have a reasonably strong upward shooting angle. The upward angle allowed me to frame the shark against a background of blue water, and that, in turn, helps the shark stand out in my shot. Had I shot at a more level angle the animal would probably have blended in to the dark reef in the background. You might not realize it from this shot, but it happened to be overcast when we made our dive so I needed to do whatever I could to help make the animal easy to see in my shot.

I hope you enjoy this week’s POTW!

See you next week,

Marty