Tuesday, August 12, 2008

CHERRY BLOSSOM BASSLET

This beautiful photo taken by Toshio Tsubota shows the cherry blossom basslet in its natural habitat off of Osezaki. It typically is not encountered on these reef slopes until you reach a depth of 30 m and is not common until you reach much greater depths.

The cherry blossom basslet (Sacura margaritacea) is a member of the family Serranidae and the subfamily Anthiinae. It is deeper-bodied member of the anthias group and have thread-like filaments that extent from the dorsal and the caudal fins (these are especially elongate in male specimens). It reaches a maximum length of about 15 cm.

The cherry blossom basslet is distributed from southern Japan to south to Taiwan. If you look at its range, you can see that it is found in more northern regions than most of the coral reef fishes we see at the local aquarium stores. I have seen many of these fish on rocky reefs off Osezaki, Japan. Here it is found at depths of 13 to over 50 m on current-prone, rocky reef slopes. It often moves among or above long whip corals or can also be found hanging under overhangs or at the mouth of caves (juveniles are more likely to be found in caves). Adults of this species are often found at depths of 40 m. It tends to occur in shoals, consisting of many females and a single male. It sometimes forms mixed groups with other anthias (e.g., elongate anthias [Pseudanthias elongatus] and the anthias [P. fasciatus]). Like other anthias, S. margaritacea feeds on zooplankton. To catch their prey, these fish move high into the water column to feed. Like other members of the subfamily, they are protogynous hermaphrodites. That is, males result from female sex change. The males are the most dominant individuals in the shoal.

The male cherry blossom basslet is a spectacular fish that is becoming more available in the aquarium trade, although it still commands a high price.

I have reliable information from Japanese aquarist (namely aquarist Hiroyuki Tanaka) and from Kevin Kohen (the fish expert and manager at liveaquaria.com - see link to right) who also has experience with Sacura, that this fish is quite hardy. It is also often seen on display in Japanese public aquariums because of its beautiful appearance, as well as its hardiness.

First thing to consider is temperature of the aquarium. As mentioned above, this fish is typically found at cooler water temperatures. At Osezaki, the summer time temperature at a depth from the surface to about 30 m is from 22 to 26 degrees Celsius. There is a sharp thermocline below 30 m, where water temperature drops to as cold as 16 C in the summer and 11 degrees Celsius in the winter! As far as aquarium temperature is concerned, S. margaritacea should be kept at 18 to 25 degrees Celsius (Japanese aquarists prefer to keep them at the lower end of this range).
All anthias should be fed frequently, as they spend most of their day in the water column picking off zooplanktors. If you find your Sacura is a bit finicky, try feeding it young livebearers (e.g., guppies, mollies) or live ghost shrimp. They will usually take foods like frozen mysid, chopped table shrimp or bite-sized pieces of marine fish flesh. Kevin tells me that a male cherry blossom basslet may become dominant over smaller fish tankmates, occasionally nudging them to assert their position in the hierarchy. But they are rarely so aggressive toward heterospecifics that they cause them harm. It will eat fish that are small enough to swallow whole. Adults should be housed in a tank of at least 135 gallons and may acclimate more readily if kept in a dimly-lit aquarium. Also, avoid placing more than one male in the same tank.

Female cherry blossom basslet. A lovely aquarium fish that does best at lower water temperatures.

This fish commands a high price for two main reasons. First of all, not that many fish are imported from Japan to the US (or any other country for that matter). They are also found at moderate depths and require special handling techniques to help avoid problems with decompression. So, unavailability and the greater time required to capture this fish means more money per fish.

©2008 Scott W. Michael

Saturday, August 9, 2008

A BEAR SHANGRI-LA

Hallo Bay, Katmai National Park.

Scott W. Michael and Janine Cairns-Michael

The great bear quest was conceived on a warm September night in our Nebraska home. A week before, my wife, Janine, and I had been roaming through rain forest on the Olympic Peninsula, Washington. While hiking the mountain trails, I was intrigued with the possibility that we may see black bears (much to my dismay and Janine’s relief, we did not see one). But I had caught the “bear bug.” After our return from this lush national park, I went to the local library and checked out every book they had on the Ursidae (the scientific designation for the family that contains all eight known bear species). One of the books I found was particularly mesmerizing – it was on the brown (grizzly) bears of Katmai National Park, Alaska. I was unfamiliar with this national treasure and the idea of observing these mighty creatures on their turf was very intriguing. Before long, I made the following proclamation to my beloved – “We are going on a trip to Alaska to walk among the grizzly bears.” Janine responded in her now-Americanized Kiwi accent, “Yes Dear, that would be nice.” She was not concerned about my proposal, assuming that like some of my obsessions before it, that it too would pass after a few weeks.

Ten months later, Janine and I were on a small skiff that was ferrying us (and a handful of other bear fanatics) from a converted crab boat, dubbed the “MV Kittiwake,” to the sandy shore that fringes portions of Katmai National Park. While I was sure that this was going to be a unique and exciting adventure, I had no idea how profoundly the next six days would impact my life.

A female brown bear in repose watches us as we set-up our photo equipment.

We arrived in Hallo Bay that afternoon on a Cessna floatplane. It was a beautiful, sunny afternoon and a magnificent flight from Kodiak. Rugged mountains, islets and sheltered bays rolled out beneath us as we made our way to the Shelikof Strait. By the time we reached the Strait, we could see the magnificent Aleutian Range and Katmai National Park. Our gracious pilot, Dean Andrews, made a high pass over the sedge flats where we were able to see numerous brown bears sleeping and grazing in the green expanse! After our smooth landing in Hallo Bay, we were immediately whisked by skiff to the “Kittiwake” to meet the rest of the bear-viewing party and prepare for our first bruin encounter. As soon as we were able to get our camera gear ready and our field gear on, we were on our way to the intertidal flats. At this point, my skin was literally tingling!

Not only were we “buzzing” at the possibility of seeing the second largest land carnivore, the setting that surrounded us was truly awe-inspiring. Even Janine (a citizen of New Zealand, one of the most “scenically-gifted” places on earth), was overwhelmed by the vista that spread out before us as we motored to the estuarine sand flat. At this point, it was evident to both of us that this was going to be a very special trip. We reached the drift-wood littered beach and we were immediately aware that the beasts we had come to admire were nearby – there were bear paw prints, of varying size, impressed into the sand.

On our way to the beach, Brad Josephs (bear expert and guide) gave us a briefing on how we should behave in order to both ensure our safety and to have the least amount of impact on the bears. We bunched-up and moved along the shoreline until we reached a tributary that held great promise. Before us, there were two light colored sows (i.e., female) that were standing in the middle of the water way. They were very vigilant, scanning the water’s surface for any turbulence that may indicate the presence of a piscine prize.

An older female dubbed Nana - although she is small, few bears mess with Nana.

We set-up our camera equipment near the water’s edge, leaving enough room for any bear following the meandering stream contour to safely pass in front of us. Within minutes, camera motor drives were whirring as the two bears began running up and down the stream, being provoked into action by ripples generated by a salmonid back or tail.

This was the beginning of the salmon run, when these anadromous “super-fish” smell their way back to their place of “birth” and re-enact the process of procreation that has occurred for millions of years. Soon after releasing their sexual products, the adult fish die, leaving a virtual “scavengers buffet” that is utilized by bears, eagles, gulls, foxes and wolves. During our six day stay, chum salmon (Oncorhynchus keta) were in the process of re-acclimating to a riverine environment. While the salmon were present, they were by no means as easy to come by or catch as they would be later in the season. We were amazed at how much energy the bruins used loping to and fro as they attempted to find and capture the illusive fish.

One thing that seemed obvious from the get-go was that these bears were oblivious to our presence. They continued to move up and down the river and on a couple of occasions plodded along the bank very near to our group. Janine, who prior to arrival in Alaska, had expressed some consternation about how she would respond when she encountered Ursus arctos at close quarters, was not overcome by panic, but overwhelmed by a wave of veneration.

A grizzly bear stampede!

Both bears tired of pursuing their illusive quarry and eventually left the area, so Brad decided we would move further down the stream to see what we could see. We crossed a portion of the sedge meadow, where we saw moose and wolf sign, as well as two medium-sized female “brownies’ (slang for brown bear) grazing on the plenteous sedge, but even more amazing was the sight that greeted us upon rounding the bend. There were eight more brown bears of varying shapes and sizes. Several of the bruins were bounding through the water, while others were sitting or in repose on the bank, seemingly content to observe the frenetic behavior of their kin. Suddenly, five of the beasts were up and running our direction - it was a bruin stampede! The sleuth of bears, apparently in response to a noise or movement observed in the water adjacent to our group, ran past us, coming with 30 feet of our astonished gang. Once again, it was obvious that they could care less about us - they were only interested in the possibility of securing a salmonid meal.

As the bears past, a couple stopped and adopted a bipedal stance in order to better spy any stirring at the water’s surface. A large female past by with a yearly youngster in tow. She was the only bear that may have been agitated by our presence because as she past she engaged in a threatening vocalization known as jaw-popping (a unique utterance that is made by knocking the teeth together). It was impossible to tell if our group elicited this behavior or if it was the activity of the other bears around her. (We came to find out she was a rather nervous mother that would often jaw-pop if other bruins moved past.) The female and her offspring eventually moved down the bank a short distance and plopped down with their backs towards us. We watched these bears for some time before they disbanded and moved off. It was time to make our way back to the boat.
Snaggle-tooth looks more like a big shaggy cow, as he grazes on sedge, than a predatory bruin.

We took a different course back to the “Kittiwake,” opting to transverse the luxuriant sedge meadow. While in route, Brad spotted one of his old buddies – a huge male that had been appropriately dubbed “Snaggle-tooth.” This battle-scarred old warrior was once one of the dominant males in this area. His jaw has been broken during "mouth-to-mouth" combat and as a result his right canine tooth protruded from his mandible. As we approached, Brad informed us that he was a very “human-habituated” bear and even though he was approaching 1,000 pounds and had been at the top of the pecking order during his prime, “Snaggle-tooth” had never caused problems with any of Brad’s bear-viewers. We sat and watched this gentle-giant as he jerked mouthfuls of sedge from the earth and masticated it like a big, shaggy cow. What an impressive beast he was! Although not universally known to the general public, brown bears feed heavily on plant matter. Along the southwestern Alaskan coast, sedge grass, as well as a miscellany of other botanical species, make up an important food item in the diet of U. arctos.

A little further along the edge of the sedge meadow we encountered another massive old boar named “Flop-ear.” Steve Stringham, a bear expert that had come to greet and briefly joined our group, suggested that he was probably over 25 years of age and that he once instilled trepidation into the other male bruins that fished this bay. His immense frame was not as well-muscled as the younger males that now ruled the Hallo region. He was scarred and even sported a relatively fresh wound on his left flank. Later during our stay, we were happy to see both “Flop-ear” and “Snaggle-tooth” catch a number of fish. Hopefully, they were able to put on enough fat to see them through another winter dormancy.

Flop-ear was once a dominant boar in the region, but now he no longer elicits trepidation in the younger males that are in their prime.

John Rogers, the skipper and owner of Katmai Coastal Bear Tours, met us with the skiff to ferry us back to the "Kittiwake." I had spoken with John a number of times during the 10 months prior to this day and he assured me that I would be blown away by the trip. I could tell he was waiting for a response when we returned to the skiff, but we were gob-smacked! Janine and I were overwhelmed with what we had experienced in our first several hours of being bear voyeurs and did not know how to express our amazement in words. (After several minutes looking at him and shaking my head in disbelief, I simply grabbed his hand and began uttering “Wow” over and over.)

These were our first hours exploring Hallo Bay. There were to be many more amazing days of bear-viewing in Hallo, as well as Kukak, Kuliak and Kaflia Bays. Throughout our stay, I was impressed with Brad Josephs and his wildlife-viewing philosophy. He went to extreme lengths to ensure that our presence did not deleteriously impact the bruins. As a couple interested in the welfare of the animals we are taking photos of, we try to consider the impact our behavior has on our photographic subjects. With Brad and Katmai Coastal Bear Tours, I never felt as though I was “crossing-the-line” when it came to the well-being of the bears.

As I mentioned above, this trip really did change our lives. Upon returning home, I began gathering up as much literature on bear biology as I could find and I am currently trying to figure out a way that I can spend more time in the field photographing and studying these amazing mammals. Janine no longer suffers from “bear-phobia.” Her fear of bears has been replaced with a healthy respect and she is looking forward to upcoming bruin encounters in Alaska, Canada and the lower 48 states. But more than anything, we have both been overwhelmed by the magnificence that is Ursus arctos. We now feel that we must be advocates for the bear and teach others just how important and special these creatures are and how wanting the North American wilderness would be without them.

For more on bear-viewing in Katmai go to www.katmaibears.com!

©2008 Scott W. Michael

Friday, August 8, 2008

OFTEN OVERLOOKED NANO-REEF FISHES

The tailspot blenny is a wonderful aquarium resident that can be housed in a nano-reef. This individual was photographed in West Papua, where it is quite common.

Here is a wonderful little fish that has only been making its way into the aquarium trade for approximately 5 years. It is the tailspot blenny (Ecsenius stigmatura) (a.k.a. tailspot comical blenny). If you do not own one of these fish, shame on you! It is a fascinating fish to watch, is attractive, and tends to get along with its tankmates.

The tailspot blenny is easily recognized by the black spot at the base of the caudal fin, that is trimmed in white. There is also a black patch on the mid-belly and an orange rim around the eye and a blue line under the eye. This diminutive little fish (it reaches around 5 cm in total length) is a resident of West Papua, the Moluccas and the Philippines (the individuals in the aquarium trade come from Cebu). It is found on reef faces and fore-reef slopes at depths of 2 to 30 m. It is typically a solitary species, although it is sometimes found in small groups.

The tailspot blenny is a wonderful fish! It exhibits and interesting color pattern, including orange and blue eye liners, and spends more time in the water swimming about than many other blennies. It can be housed in a nano-reef as small as 15 gallons. Provide plenty of hiding places, preferably small holes that it can back into, in the live rock. You can use a ¼ to ½ inch drill bit to create some of these in the rock. Feed meaty and herbivore foods at least twice a day.

Ecsenius stigmatura is very neighborly. It rarely bothers fish tankmates, including other smaller blennies. If it has been in a tank for a while, it will assert its dominance over newly introduced members of the same genus (especially in a smaller tank). It is more likely to be picked on by dottybacks, more aggressive damsels, and hawkfishes. You can keep more than one in a tank of 75 gallons or larger (a known heterosexual pair can even be housed in a smaller tank, but sexing them is difficult). It rarely bothers clams or corals.

The tailspot blenny spends almost an equal amount of time resting in its favorite hiding hole and swimming about the aquarium looking for food. It does not appear to be a big algae eater, like some others in the family. It may leap out of an open aquarium.

©2008 Scott W. Michael

Thursday, August 7, 2008

EARTH-EATING – GEOPHAGY IN BROWN BEARS

Grizzly bears intentionally ingest earth, which may serve several different functions.

In a famous quote about the food habits of the grizzly, naturalist John Muir states that these bears “eat everything but granite.” It turns out that Muir’s statement is not quite right, as while they have not been documented to eat rocks, they will eat earth! Some of the soil found in grizzly scat is not doubt ingested unintentionally along with their normal foods, like roots and ground squirrels. But grizzlies also intentionally eat soil and river sediment.

There are a few anecdotal accounts of brown bears diving down in the river ways in which they fish to take mouthfuls of mud from the river bottom. It has been suggested that they do this to clean their alimentary tracts of internal parasites. At Katmai National Park, we found brown bear scat that was comprised of fine sediment. The fecal material also contained numerous worms (I cannot be sure of the identification of the parasites involved, but they looked like a type of nematode).

In Yellowstone National Park, Mattson et al. (1999a) found 12 sites where grizzlies consume soil and found earth in some scat samples. These areas were free of vegetation due to thermal activity. Geophagy was most common between March and May and again from August to October – these correspond to times when ungulate and mushroom eating was also common. The researchers concluded the soil consumption may have several functions. Like ungulates, grizzlies may eat earth to detoxify secondary compounds present in the foliage they consume and to supplement their diet with potassium. In the areas where grizzlies ingested soil, the earth has very high in potassium, magnesium and sulphur. The authors also suggest that that by consuming these soils, the bears may prevent diarrhea by helping to get rid of some parasites and bacteria in the alimentary tract.

References:

Mattson, D.J., G.I. Green and R. Swalley. 1999. Geophagy by Yellowstone grizzly bears.
Ursus 11:109-116.

Tuesday, August 5, 2008

BROWN BEAR FISHING BEHAVIOR: PREY SELECTION

A big brown bear with a big salmon. There is more to the fishing behavior of Ursus arctos than meets the eye! Photo by Scott W. Michael.

“In small backwaters where the fish collect in shoals and where the fins of the fish are visible while they move against the current. The bears either enter the water attempting to drive the fish into the shallows, or stand in the water, lowering the head to the surface while waiting for the fish and catching it rapidly with the paws.... The catching of fish is easier in spawning places with calm water, where the fish are less cautious and strong. When the fish are numerous the bear eats mainly the head and part of the back, when fish are scarce, they are eaten completely. The stomach of a large bear may contain 20 kg of fish. However, plants and berries are always found together with fish.”
Yu. V Averin (1948) describing the feeding behavior of the Russian brown bears in the Kronoki reserve (in Stroganov 1969)

As far back as 1889, bear-watchers reported that bears selectively ate parts but not all the salmon they caught. A. M. Nikol’skii (in Stroganov 1969) stated that when fish are abundant, Russian brown bears eat only the head and roe of the salmon, leaving the body. When the fish are scarce, they consume their entire catch. Yu Averin, in the 1948 quote above, also reported on this phenomenon.

Most salmonids are anadromous. That is, they hatch in freshwater, move into the sea, and return to the freshwater streams where they hatched to spawn themselves. While it varies from one species to the next, in many parts of Alaska, three different species of salmon spawn during the months of July through early October. The salmon enter their spawning grounds and typically live in freshwater for 5 to 25 days (depending on the species and location) until they die of senescence. Many die before this time as a result of bear predation. In one study, of 1,933 salmon tagged by researchers as they entered three different Alaskan streams, 64 % of the tagged fish were killed by bears, 33 % died of senescence, and 2.6 % died from other causes (like stranding on the beach or were killed by other predators).

When a salmon makes its way into freshwater, it stops feeding and expends incredible amounts of energy on reproduction and the act of swimming upstream – as a result, from this point forward the nutrient value of a fish will drop as they burn stored fat and protein. Researchers Hendry and Berg (1999) found that the total energy content of a salmon drops from 40 to 50 % and the lipid content plummets as much as 80 to 95 % from the time the fish enter a stream and the time when they die of senescence. It would make sense then that brown bears would attempt to capture and consume those fish that have spent less time in Alaska’s streams and that the fish that the bears find least attractive would be those that are reproductively spent and in the process of dying.

But how could a bear determine the nutrient value of a fish (e.g., how long it had been in freshwater)? In some salmon species there are very overt signs of senescence. For example, male red or sock-eye salmon (Oncorhynchus nerka) develop hooked jaws during the spawning period. Salmonid energy stores are depleted and the immune system begins to suffer, as a result of stress and malnutrition, the skin becomes discolored and patches of fungus appear. The longer a salmon is in freshwater engaging in the spawning process, it picks-up more wounds on the body from fighting and frayed fins as a result of nest digging. So, it maybe that these outward signs of a salmon’s physical condition (potential energy content) could be used by grizzlies to help select the most valuable prey.

Researchers have examined if brown bears target those fish that have been in freshwater for a shorter period of time (“younger” fish) and thus have greater nutrient content. They found that in streams where bears can easily capture salmon that they do select younger salmon. In one such stream, the bruins fed most heavily on fish that have been in the stream for three days or less, while they totally ignored fish that had been in freshwater for over 12 days. However, in streams that were wider, had deep pools and/or lots of structure (e.g., sunken limbs and overhanging banks) brown bears fed more on “older” fish (individuals that have been in the stream for over 12 days). In these streams, the salmon that have recently entered freshwater are more energetic and better able to elude the bears, while “older” fish that have expended lots of energy and are “on their last fin” are easier to catch. While the “younger” fish may have more nutrients, the bears will expend more time and energy to catch them. Therefore, in these streams, going after the less elusive, but less nutrient-rich fish, is a better strategy.

Other factors that will impact brown bear foraging strategies are the density of fishes in a particular stream and the weather. When the streams are chock-a-block with amorous fish, the bears can be more selective, while if the fish are few and far between, they cannot afford to be as particular. Likewise, if the streams are breaking their banks and the water is turbid as a result of excessive rain, bears are not as selective. It is get what you can, when you can! There are also individual bears that apparently develop a taste for rotting salmon carcasses. Bledsoe (1987) tells of a bear named “Zubin” at McNeil Falls that would leave a good fishing spot to go scavenge for dead fish.

Food handling in brown bears sometimes changes as the fishing season goes on. At first, the bears will consume the entire salmon, but as the season goes on, on if it has been a good salmon run, the bruins become more selective, restricting their feeding efforts to the more nutritious bits. They peel off the skin, they nibble out the brains, and tear open the abdomen to gain access to the roe. It is not uncommon to see a grizzly step on a fish, causing a stream of orange, nutritious eggs to spew forth. The bears use their tongue to lap-up the eggs.

References:

Bledsoe, T. 1987. Brown Bear Summer: Life Among Alaska's Giants. New York, New York, E P Dutton. 249 Pp.

Hendry, A. P. and O.K. Berg. 1999. Secondary sexual characters, energy use, senescence, and the cost of reproduction in sockeye salmon. Can. J. Zool. 77:1663-1675.

Quinn, T.P., S.M. Gende, G.T. Ruggerone, and D.E. Rogers. 2003. Density-dependent predation by brown bears (Ursus arctos) on sockeye salmon (Oncorhynchus nerka). Can. J. Aquat. Sci. 60:553-562.

©2008 Scott W. Michael

FOOD HABITS OF PHYLLOGNATHIA CERATOPHTHALMA

Everyone knows the harlequin shrimp (Hymenocera elegans or H. pictus). It is one of the most ornate invertebrates on the planet and has the somewhat ghoulish habit of slowly eating sea stars. But do you know about the harlequin’s kin, Phyllognathia ceratophthalma (both shrimps are in the family Hymenoceridae).

This odd shrimp, which is known in the aquarium trade as the Bongo bumblebee shrimp or the spiny tiger shrimp, is rarely seen in the wild or in the aquarium trade. I have only seen three of these shrimp during years of diving in locations where they are known to occur (the Western Pacific from Okinawa south to Queensland, Australia). This is because it is very small, reaching a maximum length of around 2.5 cm, and very cryptic. Like Hymenocera, it also does not appear to be a very common creature. Because of these factors, very little else is known about this shrimp species.

In steps Kevin Kohen, livestock manager of www.liveaquaria.com. Kevin is one of the most knowledgeable guys in this industry and has been a great help to me (he has assisted my efforts so much that I dedicated REEF FISHES Volume 5 to him and two other labrid lovers). He is not only astute, but he is still hardcore crazy about fishes and inverts, even after decades of being in the hobby. If he has access to something unusual, it is just as likely to go in one of his office tanks (if he has room) as onto the website for sale.

Kevin has been keeping specimens of P. ceratophthalma for several months now and has observed some very interesting things about its natural history. Up until now, data on the feeding habits of this little crustacean were not available. It has been assumed that they are echinoderm-eaters only because of their relationship with Hymenocera, but I have not found any direct observations of their food habits published in the literature. Thanks to Kevin, we now know that they eat asteroid sea stars as well as ophuroids! Don’t believe me, check out Kevin’s video at the link below.

Kevin's Bongo Bumblebee shrimp video (click here)

Here is what Kevin reports on his captive P. ceratophthalma:

“Well it turns out that this little guy loves to kill and eat mini white brittle sea stars. They are now going after tiny blue Asterina sea stars as well and are using their claws to pry them over from a flat bottomed specimen container. The behavior of the crustacean is very similar to Hymenocera elegans. It seems to use its two front spike like maxillipeds to constantly pierce the sea star until it surrenders, then starts consuming the brittle legs and all.”

If you have had any experience with this shrimp I would be eager to hear your stories!

Sunday, August 3, 2008

WARTY FROGFISH SLIDESHOW

video

©2008 Scott W. Michael

FLASHING A FLASHER

Probably the most difficult fish to photograph during its courtship display, the blue flasher wrasse (Paracheilinus cyaneus). Photo by Scott W. Michael.

Sorry folks. One more wrasse entry and then I will talk about another group of fishes. You have to realize I am still glowing in the aftermath of Volume 5, which is about 380 pages of wrasses. So, here goes another labrid topic…..

I was recently flipping through a book by Michael Aw when the name “Roger Steene” jumped off the page. Roger and I are good friends and I am always curious to see what people write about him, as he is truly a one-of-a-kind character (if you have ever been with Roger in the field, than you know what I mean!)! I started at the beginning of the paragraph that contained the Steene moniker and read on. This section of Michael’s book was talking about challenging photo subjects. He was quoting Roger, who has long said that the most difficult fish species to photograph are the flasher wrasses (genus Paracheilinus). Michael took up Roger’s challenge and presented the results at the top of the page – there was a good photo of a McCosker’s flasher (Paracheilinus mccoskeri) .

I love flasher wrasses and have been trying to take photos of them in the field for over a decade now. I have been somewhat successful after spending hours attempting to snap shots of Paracheilinus in full “flash” (definition: when fish has all fish spread and its colors flashing). Much of this is simply being lucky, but I have also learned a few techniques that I thought I would share.

One a recent trip to West Papua (the Raja Ampat Islands) as a guest of Max Ammer and Sorido Bay Resort, I had the opportunity to once again hone my flasher photography skills. Roger and I found a small group of blue flasher wrasse (Paracheilinus cyaneus) on the fringing house reef. I hate to tell you this Michael, but even within the genus, there are some species that are more difficult to shoot than others. The Paracheilinus in Michael’s book is one of the easier flashers to photograph. Roger, Gerry Allen and myself, all agree that the blue flasher and a newly described species from Triton Bay, West Papua (Paracheilinus nursalim), are the most demanding fishes to nail. This has to do with their behavior. Some flashers will hesitate momentarily when in full flash, so if you are ready, it is possible to get stellar shots with relatively little effort. But the blue flasher is not that kind of “cat!” It is always dashing about, dashing through the water like a kite in a hurricane!

Here is how I was able to get some good shots of P. cyaneus:

Reconnoiter Flasher Habitat . You will need to be prepared to scuttle around the seafloor like a nervous fiddler crab. Fortunately, flashers are most often found on rubble slopes so you don’t have to be as concerned about fins and hands damaging coral colonies. Before I go into flasher photo mode I scour the area for scorpionfish (at least big, none cryptic varieties) as it is very easy to accidentally get stung when you are moving with your eye pressed up to the viewfinder. Most of the flasher’s activities are usually limited to a relatively small area so it is possible to survey the location before getting into hunting mode. So get the lay of the land before you begin stalking your quarry.

Go flasher stalking in the late afternoon. Timing is everything! Male flashing tends to reach its apex at dusk, when these fishes spawn. Males begin courting females around an hour before the sun goes down, although less frequent flashing may occur at any time of the day.

Observe before attempting to photograph. If you watch the fish long enough, they normally have a fairly consistent routine. They may dash down to one section of rubble where some females are hanging out and flash at them for several minutes. Then they may leave this area and dash to another location where potential mates lurk near rubble recesses. It is often best to wait in one location (where there are females) and wait for the male to come soaring through.

Pre-focus and “swim the fish into focus.” Forget about using auto focus! The fish moves too quickly and the light levels are often too low to use it effectively. Instead, pre-focus the camera on something that is similar in size to the male flasher. It may be a piece of rubble or coral. Pretend that this non-moving object is the flasher wrasse and preset the focus so that the fish fills the appropriate amount of frame. (The more fish in the frame, the more difficult the shot will be to get.) I try and fill at least ½ the length of the frame with the fish, but you can back off if you want too (it is easier to shot them from a slightly greater distance). When the fish frenetically parades past, find him in the viewfinder and begin to follow his movements through the lens. When he comes into focus, quickly squeeze off a shot. The key is to keep following him with the camera and keep firing away anytime he appears to be in focus. The more shots you take, the more likelihood that you will get a real winner.

While it may sound difficult (and it is!), the more you practice it, the more likely you are to have real success. Roger and I were both very confident that we had nailed the fish you see above (we both use film so we had to wait and see our results when we got home). You can just tell when everything is right – at least when the fish and the focus are spot on. Exposure and potential flashback (back scatter) is another matter. Roger always underexposes his flasher shots by about ½ stop (using exposure compensation) to prevent possible overexposure by the flashes TTL. I don’t, but instead always shoot at smaller apertures (usually just at the limit of the TTL capacity). Of course, not only does more light to the film plan mean more likelihood of overexposing the subject, it also means more backscatter in the picture.

©2008 Scott W. Michael

Friday, August 1, 2008

CLAM-DIGGING BROWN BEARS

A female brown bear nimbly uses her large claws to separate the valves of a razor clam and get to the juicy morsels within. See slide show below for more on this bear. Photo by Scott W. Michael.

When it comes to food, brown bears are very opportunistic. As discussed in past posts, they are also very intelligent. Consequently, they’re always looking for new food sources that they can exploit. Along the coast of Alaska, brown bears congregate in salt marshes in spring and early summer. They feed on sedges, grasses and forbs as they wait for migrating salmon to arrive in nearby estuaries. Some bears move out of the marshes and sedge flats and feed on animals that inhabit shore habitats. Along the Katmai coast, there are large tides that expose an expansive intertidal flat that is exposed for three to five hours a day. Certain bears utilize this habitat, hunting for mussels, isopods, barnacles, marine worms (polychaetes and peanut worms) and small intertidal fishes (blennies and sand lances). While it may seem that burrowing clams would be impervious to brown bear attack, there are some bruins that have learned how to locate, capture and handle these infaunal mollusks.

The intertidal zone along the Katmai coast is home to a handful of clam species. The four species that are known to be eaten by brown bears are the soft-shelled clam (Mya arenaria), the razor clam (Siliqua patula), Nuttall’s cockle (Clinodcardium nuttallii) and the Alaska surf clam (Spisula polynyma). These mollusks spend most of their lives below the sand surface, taking in fresh seawater and planktonic food through tube like siphons. The siphons extends from the clam up to the sand surface. (Those species with a shorter siphon remain near the sand surface in order to respire and feed, while those with a longer siphon can burrow to greater depths.) Many of the burrowing clams are adapted to living in the intertidal zone. When the tide goes out, they remain buried in their wet, sandy sanctuary and await the rising tide to bring back life giving oxygen and food.

Clam-hunting Techniques

At low tide along the Katmai coast, you may see an individual brown bear, or a bruin family (sow a cubs), slowly meandering across the tidal flat with nose skimming the sand surface. Somehow the bears detect the buried clams (possibly by using their keen olfactory senses). When they do, the ursid will stop and begin digging at a leisurely pace. The mollusk-hunting bear will lean on one front paw and use the other as a shovel. It will methodically lift the substrate from the hole and push it back behind the excavation. If the clam is deeper in the sand, the bear might lean on its elbow, laying its head on the foreleg, in order to thrust the digging paw deeper into the substrate. When it reaches the bivalve, it will extract it by lifting it out with its claws/paw or by shoving its head into the hole and grasping the clam in its jaws. Troyer (2005) reports that like fishing, bears vary in their clam-digging prowess. Some bears are very effective “clamers,” while others are inept. If a bear’s digging activity never or rarely results in positive reinforcement, they give up this activity after a time. Troyer also notes that when it comes to clam-digging, some bears are exclusively “right-pawed,” while others only use their left paw.

In a study conducted on Katmai bears, it was found that the average harvest rate for clamming bears was 0.69 ± 0.46 clams per minute (Smith et al. 2004). The percentage of excavations that yielded clams was 63%. When it comes to the number of clams ingested, Troyer (2005) reported seeing individual brown bears dig up as many as 50 to 100 clams in one cycle of the ebb-tide. In one four hour period, I watched a female with cubs dig between 180 to 200 holes (it was impossible to determine how many clams the bear ate during this period).

Once they extract the mollusk from its subterranean refuge, the bear has to get to the meat that is housed within the clam’s calcareous armor. In the case of the soft-shelled and razor clams, the valves (which are the two parts that make-up the shell) are not that hard. A bear’s clam-handling technique can vary from one individual to the next. After pulling a clam from the substrate, some bears nimbly use the claws to pull the valves apart (see slide show below). Some bears place the bivalve on the beach and then stomp on it or roll it under their massive paw. This results in the valves breaking apart, which enables the bruin to extract the meat with their lips and tongue. In the case of soft-shell clams, the bear may take the entire bivalve into its mouth and masticate it. This resulted in their swallowing a considerable amount of shell material as well as the clam flesh (along the Katmai coast it is not unusual to see scat that contains clam shell fragments).

Clams Eaten

Katmai Brown bears do not feed on the various clams species in equal numbers. Smith et al. (2004) found that 77% of the time bears dug-up soft-shelled clams (Mya arenaria), 18% of the time they pulled out razor clams (Siliqua patula) and 2% of the time they excavated other clam species (namely Nuttall’s cockle [Clinodcardium nuttallii] and the Alaska surf clam [Spisula polynyma]). Clam species selection is thought to be more a function of species availability rather than preferences related to a species nutritional value. For example, the bears apparently feed more on the soft-shelled clams because they are found closer to shore and thus are available to foraging bears for longer period of time. There is not a difference in the bear’s harvest rate or success rate between soft-shelled and razor clams, even though the razor clam have what appeared to be a more effective anti-predation strategy – that is, when disturbed they pull themselves deeper into the substrate.

Who Digs Clams?

When it comes to a proclivity to dig clams, there are differences between the sexes. Smith et al. (2004) reported that of 233 clamming bouts observed, less than 1% of the clam-diggers were adult males, 44% were females with cubs and 55% were single bears of undetermined sex. How does the overall population of bears in this area compare with those observed clamming? The researchers found that of 16,738 bear (or bear family groups) encounters (over two years), 13% were large adult males, 8% were females with cubs-of-the-year (spring cubs), 17% were females with dependent young and 62% were single bears. It is obvious that females with cubs are overrepresented on the intertidal flats (44% of total population vs. 25% of bears observed clamming), while adult males are greatly underrepresented (13% vs. 1%). During focal sampling of bears working the intertidal zone (that is, where they followed individual bears and recorded their behavior), large adult males spent 0.1% of their time clamming, while females with dependent young invested 4.7% of their time digging mollusks (the single unsexed bears spent 1.4% of their time). The conclusion: females with young cubs most often feed on clams on the intertidal flats.

Benefits to Clam-digging

So what are the benefits for the bruins that dig clams? First of all, clams are a good source of digestible protein. Those brown bears that supplement their diets with these nutritional mollusks, are able to spend much less time munching on vegetation in order to meet their springtime energy requirements. Smith et al. (2004) predicted that a 160-kg brown bear that consumed razor clams for two hours a day could cut down total foraging time by 27% (compared to bears that only consumed vegetation). There is another advantage for clam-digging females that have cubs in tow. Because adult males are rarely seen on the intertidal flats, females with dependent young can forage in this habitat without exposing their offspring to potentially dangerous males. Less time spent feeding and less dangerous for young ones – a definite twofold advantage to hunting clams.

References

Smith, T.S. and S.T. Partridge. 2004. Dynamics of intertidal foraging by coastal brown bears in southwestern Alaska. Jour. Wildlife Manag. 68(20):233-240.

Troyer, W. Into Brown Bear Country. Univ. Alaska Press, Fairbanks, 130 Pp.
Copyright (2008) Scott W. Michael
The slide show below documents the clamming behavior of a female brown bear, with three spring cubs (the latter are not seen in the slideshow).

video