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Glasseye Snapper

Member Since 11 Oct 2005
Offline Last Active Yesterday, 08:06 AM

#365963 3 Damsels and 1 I don't have a clue

Posted by Glasseye Snapper on 06 October 2015 - 04:25 PM

Things are even a bit more complex. Using DNA sequences it became clear that the species D. albisella from Hawaii, D. strasburgi in the Marquesas match the DNA evidence. D. trimaculatus from the Red Sea and Zanzibar, and presumably the entire (Western) Indian Ocean , forms a distinct clade, more different than the Pacific D. trimaculatus is from the other three Eastern relatives. Some of the D. trimaculatus and D. auripinnis from the Pacific mix together on the phylogenetic tree so they really are very similar despite the different colouration.


One of the phylogeny papers also stated "On the other hand, D. auripinnis coloration patterns (yellow lower body and fins) may either be reflective of recent speciation with little genetic divergence (or lineage sorting), or due to ecological adaptation to turbid waters (Randall & Allen 1977)." They don't explain the turbid waters logic but often fish have a light belly to stand out less against the bright surface when seen from below. If the turbid waters are yellowish then perhaps a yellow colouration of the lower body works better. However, I've never seen noticeable yellow water colouration near reefs except for algal blooms in the shallow lagoons behind a fringe reef. I don't find it very convincing but it is my best guess at this point.



#365862 Unknown Fish from GBR Australia

Posted by Glasseye Snapper on 04 October 2015 - 05:31 PM

Seeing your typical highfin grouper in the second post having both the white saddles and yellow fin margin makes me more confident that the one in the first post is indeed a highfin grouper.


There are several reasons I "know this stuff". Most important is probably that I'm a self-identified fish geek and have been since early childhood. Another is Reef Fishes of the East Indies, a somewhat pricey but priceless three-volume set of books with virtually all known reef fish in the coral triangle and areas west up to and including the Andaman Islands of Thailand. I've also found it to be very accurate unlike many other ID books. Another good, though certainly not error-free or complete resource is fishbase.


Unfortunately I only get to make one dive trip per year, but if I go I tend to make a lot of "slow dives", preferably solo or, better, with a like-minded buddy rather than a group and dive master. On one occasion I made 50 dives on the same house reef in a 3 week trip. I love that because you get a lot of time to really look at all the fish, get a feeling for their behaviours, habitat preferences and subtle differences with time of day, mood, developmental stage, or just intrinsic variability. If you look at them in detail you also get a sense of what aspects tend to be conserved within species and which are variable. That even helps when identifying fish you have never seen before, such as the Pseudocoris yamashiroi.


Finally, I am working on a website to help myself and others in learning about identification, distribution, typical habitat and behaviour. That means I have spend a lot of time looking through all my images. The framework is almost finished and then I will start adding more species. You can have a sneak preview here




When it is ready for prime time I'll announce it here on wetpixel.



#365350 Dragonet

Posted by Glasseye Snapper on 17 September 2015 - 06:57 PM

Several dragonets in my books and on the internet look somewhat similar but I couldn't find any that were clearly like yours. Going through my own images I found an arguably better match from the philippines. Not as pretty as your image but it does the job.




Interestingly, there was a quite similar one in the same area that has a black "moustache", shown below.




Reef Fishes of the East Indies mentions that the black moustache line is characteristic for the male mangrove dragonet which they name Callionymus enneactis. Now it gets complicated. Fishbase has an entry for C. enneactis but show an image from Jack Randall that is a very different dragonet. I'll check with Jack to see what is going on. Reef Fish Identification Tropical Pacific does not have C. enneactis but do show the corresponding image which they name Callionymus parvus (little sand dragonet). Going to Catalog of fishes, it turns out that this is an incorrect synonym, but that C. enneactis is also no longer correct because the genus name has been updated so it is now Paradiplogrammus enneactis. So my suggestion is that you are dealing with the female mangrove dragonet.


Looking forward to what other interesting finds you have hidden in your collection.



#365234 3 Damsels and 1 I don't have a clue

Posted by Glasseye Snapper on 14 September 2015 - 03:37 PM

I don't know the first damsel. To me it looks like a sweetwater demoiselle (Neopomacentrus aquadulcis) but that is only known from Papua and I don't see another Neopomacentrist that could take its place elsewhere.


Assuming Nr. 2 is the "I don't have a clue", it is a young triggerfish. Not sure exactly know which one. My gut feeling says a Pseudobalistes, e.g. yellowmargin triggerfish but they normally have at least some darker dots, not just golden.


Damsel Nr 2 is a orangefin dascyllus (D. auripinnis)


The last one is not a "third damsel" but a female black-spot angelfish (Genicanthus melanospilos). I have always thought that they try to resemble damselfish and you find them away from reef walls in the open hunting for plankton together with damsels. The male is very different with vertical black stripes.



#365189 Anyone know these fish?

Posted by Glasseye Snapper on 13 September 2015 - 07:00 AM

Here is the damsel after rotating 180 degrees. Looks perfectly normal. Not sure if you inadvertently rotated it yourself or took the image from the top and shooting backwards.


Ocellated spots tend to occur on the dorsal fin or both the dorsal and anal fins at the same time. I can't quickly think on one only having such a spot on the anal fin. But colors can lie, morphology normally does not. Damsels only have one dorsal fin and two fins anal and (paired) ventral fins on the bottom. That tells you the fish was upside-down.





#365156 Anyone know these fish?

Posted by Glasseye Snapper on 11 September 2015 - 05:00 PM

I expect the top one is a dragonet but hard to say which one from this orientation.


The last one is the princess damsel (Pomacentrus vaiuli)


The second I would guess to be initial phase yellowhead wrasse. I've not seen them with such a white dorsal color but the lines behind the eye are typical.


I haven't seen the third one but the shape looks a bit like a whiptail, genus Pentapodus. Try and see if any of them from the Fiji area resemble your fish.



#363349 Red Sea long white shell

Posted by Glasseye Snapper on 18 July 2015 - 07:21 AM

OK, it is indeed a Scaphopod and a member of the Dentalium genus. Scaphopod shells were used by pre-historic cultures in the region (Natufians) for beads and they are also found in burials. They collected them in the Mediterranean and Red Sea, as well as from fossil deposits (Scaphopods have been around for 360My). The Natufian Red Sea shells belonged to the Dentalium reevei species complex. Likely that is what the one in my image is as well (but there are other similarly looking species in the Red Sea).


They live in the sand with the wide opening pointing down and feeding on diatoms and other small sand creatures. The other end has a much smaller opening (smaller than in the image, probably due to damage) and touches the surface of the sand.



#362908 Red Sea "Rhinoceros" blenny

Posted by Glasseye Snapper on 04 July 2015 - 07:04 AM

I just returned from the Red Sea and included three days at Marsa Shagra to see if, four years later, I could still find this fish. I did and, looking a bit better, found about a dozen in the same area. On my first try I didn't find them and when I did I realized I had forgotten how small they are. You have to get close to the rocks and look for match-stick sized heads. What makes it easier is that they often breath very rapidly. Most only stick their head out of the worm hole and I did not see any of them come out to grab plankton particles. A Red Sea fish scientist is interested in describing this species and I may even be involved in the process, possibly including a field trip, which would be very exciting.


Front view



Side view






#357132 Olympus 60mm macro focus distance display.

Posted by Glasseye Snapper on 28 January 2015 - 05:55 PM

At 1:1, closest focus is 7.5 inch but that is measured from the sensor. Subject distance in front of the lens will be about half of that. A bit less again due to the port. This parameter is not intrinsically dependent on sensor size and a 60mm APS-C lens, or a full frame lens if one existed, will have equivalent subject clearance. The reason that a full frame camera appears to lead to more working distance is that people use longer focal lenses to get the same field of view and, for instance, a 100mm macro lens will have greater working distance.



#354389 60mm VS 100mm DOF

Posted by Glasseye Snapper on 16 November 2014 - 01:00 PM

So Bart, would I have to assume in your scenario that the 105mm would allow me the same depth of field as the 60mm should I choose to move further away from the subject thus forcing me to seriously crop my image to achieve the same affect as the 60mm (final image magnification for presentation)? Just trying to decide if I need to include the 60mm in my arsenal of lenses.


You would not need to crop at all. Once you move back with your 105mm to get the same magnification as the 60mm the images will be the same size. Interceptor121 has a lot of good other comments on field of view and background. Like CamelToad if I had to choose between my canon 100mm and 60mm I would keep the 100mm. And like Bill I am now using m43 with the 60mm which happens to sit right in between the 60mm and 100mm when used on APS-C.


I think for most people the two dominant reasons to prefer the 60mm over 100mm is that the former is more versatile because it gives more leeway to get images of larger critters as well as the small stuff without having to back off too much. The other is for people who dive in peasoup and want to get as close as possible. The 100mm advantages are when you want a bit more working distance for lighting or to not scare your subject. I almost exclusively shoot fish for which the latter is important. If my passion was nudibranch I would probably keep the 60mm. A secondary advantage is for those using wet diopters. They give more bang for the buck on longer lenses.



#354161 Threatening to violate copyright. At least they're upfront about it!

Posted by Glasseye Snapper on 08 November 2014 - 07:38 AM

You have been entirely reasonable and remarkably patient. I suggest you yourself let the ABC guy print your huge perfect files just the way she wanted them and put them on the wall in his shop for $750 each. When she sees them she will come running back and gladly pay your asking price plus postage :)



#354016 Any ideas what this little fish might be?

Posted by Glasseye Snapper on 03 November 2014 - 06:59 PM

I also think it is a juvenile Black-banded demoiselle. In Anilao I always found them on muck sites, not on reefs. The top image shows older individuals with little yellow. The bottom, for same dive, a young one with the yellow.







#353052 F'n Stop - big rookie mistake

Posted by Glasseye Snapper on 28 September 2014 - 04:41 PM

In my experience the only reliable way to remember all the little things that need to be taken care of is to actually take an image when the camera setup is complete, including flash. It doesn't help you remember to put a diopter on a lens that needs one in a dome but takes care of most other mishaps. Of course the problem then becomes to remember to take that test shot. Oh, it also helps to not put your wetsuit on backwards. Been there done that  :)



#349846 Sydney Scorpionfish - an unexpected discovery...

Posted by Glasseye Snapper on 04 July 2014 - 05:07 PM

Thanks for sharing. I just send out images to researchers in Hawaii and Russia for species where they only had preserved museum species to look at. Diving is a lot of fun but we are actually making very valuable observations, even though we may not realize it.



#349768 Flash flooded or?

Posted by Glasseye Snapper on 02 July 2014 - 05:26 PM

I had a similar case with a Sea&Sea 110a strobe last May. In my case I had been down for close to an hour and had been taking pictures normally until at some point the strobe started to malfunction. Looking at the strobe there was dark stuff oozing out of the top cap and I could see the blue o-ring popped out of the groove. I aborted the dive (solo shore dive so that was easy). Upon opening the battery cap it was clear that the strobe was flooded. One of the batteries was damaged at the nipple end, as far as I remember the others looked nasty or maybe just dirty but without structural damage. I cleaned out the battery compartment immediately with fresh water followed by a soak in cleaning vinegar. Finally another rinse with water and then drying in front of the air conditioner. To my surprise and relieve the strobe functioned just fine for the remainder of the trip.


I wasn't sure if the strobe flooded first leading to battery damage or vice versa. I assumed it was operator error but have found the lid closing system of the 110a to be rather fool-proof. In addition, if it was flooding first then why did it not happen earlier. From the discussion here it appears that it may actually have been the battery that was at fault. I was using Imedion powerex 2400mAh and a MAHA powerex smart charger. They are supposed to be good and the problem did not reappear so I hope it was just an unlucky but one-time event.