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Posts Tagged ‘Goby’

Spot The Difference

These two Shrimpgobies are very similar, and if you aren’t paying much attention you will dismiss them as being the same.

These are two of my favourite critters, and i consider them a connoisseur’s choice when people make their wishlist for Lembeh.  They are very hard to shoot until you hit Zen mode and all the wildlife starts ignoring you, add to that once you scare them you have to wait 5 minutes minimum for them to come out of their hole again – it can eat up your divetime quite quickly.

The big give away between the two is the dorsal fin, and you will also notice that thier behaviour is a little different – the Yellownose has a cool way of displaying to show it’s territory.

Yellownose Shrimp Goby

Yellownose Shrimp Goby

Black-Ray Shrimpgoby

Black-Ray Shrimpgoby

 

The Asshole Fish and his friends.

Purple Coral Crab, room-mate of Mr Assholefish

The Purple Coral Crab, (Trapezia serenei).

The last few days I have been spending several hours diving in the same place freezing my ass off looking for this stupid fish, that I have named the asshole fish.  The asshole fish lives in Seriatopora Corals from 1m to 10m depth and I hate him.
He gets his name because he has some kind of attention deficit disorder and he cant sit still.  Everytime you get him in focus he moves to a slightly different position where he ends up with a piece of the beautiful coral getting in the way of an important detail, so then you have to wait for him to come back to that spot again – or try repositioning the camera to get him in his new location.  Or as inevitably happens you decide not to reposition and wait.  And wait.  Keep waiting. Notice that he’s in a great position so its worth moving.  You move to the other side of the coral.  He promptly moves back to where you were.  Asshole fish.

You go back to your original place and decide to wait for him to move around his mini territory, hopefully returning to his sitting place that is sharply in focus whilst you’re just waiting

Mr Assholefish and Mrs Assholefisch.  Laughing from the other side of the coral.
The Redhead Coral Goby cannot sit still and is very annoying to photograph.

for him to pop in, you make a deal with him in your head ‘just come here little fishy, i’ll get the shot i want and i’ll leave you alone, we’ll all be happy then,  pleaaaaaasssssseeeee‘  Of course he jumps back into the prime position you want him in, but just for long enough to seemingly laugh… then go off again chasing his mate.   Yes there are two asshole fish in one piece of coral.  It’s taken you 30mins to realise this.

So now you have Mr Assholefish and Mrs Assholefisch (she’s German) sitting in the other side of the piece of coral, laughing at you.  You hold your nerve and wait. maybe pee a little to alleviate the boredom.

As your mind wanders you start to notice the other denziens that share the coral with Mr Assholefish and Mrs Assholefisch. There are the beautiful Coral Crabs (Trapezia sp.) which occasionally pinch Mr Asshole fish when he gets too close.  They also protect the corals from Crown of Thorns Starfish, such is their commensal relationship.  There also seemed to be some kind of snapping shrimp, who also didn’t like Mr Assholefish and Mrs Assholefisch.

As your eyes begin to strain through the viewfinder,  you look up to observe the coral as a whole – you notice 4 or 5 pairs of orange eyes looking at you.  The Assholefish family have babies.  Baby Assholefish are generally bullied by the adult fish if they go anywhere near the safety provided by the centre of the coral, so they are forced to live out on the tips, where it is coincidentally easier to take pictures.  But do not forget they are assholefish and it is in their DNA to be, well, assholefish.

Baby Assholefish!
Juvenile Redhead Coral Gobies choosing to look away at the exact moment you pull the trigger.

These juveniles will dart back and forth and generally infuriate you, this time because they are too small for he 100mm prime, but if you put the dioptre on there then you are too close and you scare them away. Grrrr!

So, if you want to see the assholefish and friends they are on most divesites, but please be careful with the corals – choose a coral head that has been damaged in the past and has a ‘window’ to the inside. Just in case you are staying elsewhere, the Assholefish normally goes by the name: Redhead Coral Goby (Page 325 in the Reef Fish ID book).

Brain Suckers!

Following up to Bent’s enthusiasm for all things parasitic, i saw a parasitic copepod on a goby today at Nudi Falls, this one was on a soft coral so was in a nice position to shoot near to the sand.

Parasitic Copepod on Goby

A Parasitic Copepod sucking the brain juice from an unsuspecting Goby – note the size of the lump on the head!

Once I took a photo or two I noticed a pulsation in the body of the Copepod which looked like a peristaltic action to take fluids (food / brain juice / magical powers) from the host. I managed to get some video of it so you can take a look below:

The Gobies had a patch of eggs, so the presence of the parasite is not detrimental enough to prevent procreation, but it stall is a pretty gruesome way to live your life! Lembeh seems to be full or parasites these days, so when you are visiting keep checking for more smaller things on the smaller thing that is living on the bigger thing.

 

 

Commensal Bryaninops gobies

For some reason certain animals are on the “cool” list that everyone wants to see and photograph and others are placed on the “not so cool” list and get ignored by most divers and photographers. Scarcity and cuteness seems to be two important factors determining the popularity of an animal. Despite not really ticking either the scarce or the cute box, due to their interesting life style the gobies of the genus Bryaninops have a long time been on my favourite list, and I more or less never pass a wire coral without checking it out for a goby or two.

Goby on wire coral

Few other divers seem to find them very interesting, so I mostly get to have the wire corals and the gobies more or less for myself. This time in Lembeh, Paulus, my excellent guide, knowing about my interest in parasites, in the beginning of my stay showed me a couple of Bryaninops with the characteristic copepod parasites that many of these gobies carry, with the gobies living on other animals that I did not normally associate the gobies with.

Goby with a heavy load of copepod parasites on sponge

During the weeks I stayed, I found gobies on a lot of different sedentary animals, more or less always colour matching the animal the goby associate with.

Goby on soft coral

The Bryaninops gobies are found as commensals on different coral groups as well as sponges, sea squirts, sea stars and even on Halimeda algae.

Goby on Halimeda algae

The pelvic fins of the gobies are more or less adapted to be a disc capable of sucking the goby to its host during currents.

Goby on sea star

They never move far from their host, and can often be seen moving quickly around on the surface of the host, feeding on small zooplankton drifting by in the current.

Goby on tube sponge

Being commensal means that the interaction between two animals are neutral for one of the, in this case the host. The other partner, in this case the goby, of the interaction receives some benefit of being in a commensal relationship. There is no doubt that commensal gobies receive benefits by living on their hosts. The gobies settle as small larvae on their hosts and change colour to match the host during ontogeny.

Goby on soft coral

Obviously such a colour match leads to some kind of concealment for the goby which otherwise has no protection against predators. When detected the gobies also use their hosts as hiding place, moving quickly to the other side of the host.

It is, however, not really clear that the hosts are unaffected by the interaction. At least one of the species, the common and wide spread wire coral goby Bryaninops yongei, lays their eggs on a patch of the wire coral where the gobies have cleared the coral from living polyps. Thus, at least in this case, it is unlikely that the coral is not negatively affected, and the relationship then should rather be classified as a parasitic interaction. On the other hand the goby might protect the coral from coralivores, thus mitigating the cost of the lost polyps somewhat.

Goby tending eggs (the black spots beside the goby) on soft coral

Many new species of those gobies are now being recorded by goby experts from different parts of the world. The diversity of commensal gobies in Lembeh is probably quite high judging by the number of different gobies of slightly different shapes I saw on a number of different hosts during my two week stay, and I would not be surprised if there was one or two undescribed species among them. It will require a goby specialist to really understand what species are present here in Lembeh, so at least I, not that much into goby taxonomy, will have to enjoy the active and often quite beautiful fish without really knowing what specific species it is. On the other hand, with many other groups of high diversity in Lembeh, that happens quite often here, so one just have to get used to it!

Probabably Bryaninops yongei

Symbiosis and commensalism

On my day job part of my time is used to teach ecology for undergraduates in biology. Maybe not such a surprise, many of the best examples of interactions between species that I use in my teaching come from marine ecosystems. This is especially true when dealing with symbiosis theory.

Symbiosis means “together living”, and describes animals or plants living together with a tight relationship with each other. It is reserved for animals or plants of different species, but the exact definition is under some discussion. I will use it in its general sense, including obligate (the different species need each other) and facultative (at least one species affects the other species, but the interaction is not essential for either). Used in this sense, symbiosis includes commensalism, mutualism and parasitism. Today´s entry will be on the least exciting of the three, commensalistic interactions.

Emperor shrimp feed on the bypassing substrate and do not harm their sea cucumber host, gaining protection by living on the unpalatable sea cucumber.

Commensalism describes the relationship between two organisms where one organism benefits without affecting the other. Many such examples are found in marine environments. One likely example is the small porcelain crabs residing on soft corals. The porcelain crabs get a perch to sit on and protection among the arms of the soft coral, while the soft coral is unaffected.

Porcelain crab on Dendronephtya soft coral

Another example would be the gobies that live on many other animals in the sea, often changing colour to closely resembling their host. It is likely that the host in most circumstances are rather unaffected by the gobies seeking shelter.

Commensal goby

Commensal goby

The gobies and the porcelain crabs exemplify commensalistic interactions where one species lives on the other species, which is a true symbiosis. They are probably also more or less obligate, as predators quickly would kill both gobies and porcelain crabs without the shelter of the hosts . Commensalism doesn´t have to include symbiosis. This was clear when we were in a slight current on Hairball, watching a box crab rip a smaller crab to pieces. Box crabs are messy feeders, so a lot of the bits and pieces of the crab were swept down current out of reach of the box crab. However, it was not just lost, as a couple of big flounders quickly placed themselves behind the crab and ate the morsels coming with the current, benefitting the flounders without harming the box crab.

Box crab with waiting flounder

Finally, one part of the pair can already be dead when the commensalistic interaction takes place. Hermit crabs, having to find shelter for their soft anterior parts, need empty shells in order to hide the unprotected part of their body. Different snails provide these shell after the snails are dead, which means that the hermit crabs are benefitted by the presence of snails, while snails are unaffected by hermit crabs.

Hermit crabs fighting over shells

World’s cutest Goby

Blackfin Coral Goby

This is – what i believe – the world’s cutest Goby: The Panda Goby (Blackfin Coral Goby / Paragobiodon lacunicolus). This shy little fish grows to maximum 3cm in size and lives exclusively in Pocillopora damicornis hard corals. His sandy coloured body, with dark fins and his orange head in combination with his face expression make him so attractive to most Goby lovers. But the Panda Goby is not only a cutie … it is also very difficult and frustrating to photograph it: It is hiding deep inside the coral branches – which makes it difficult to light. Plus it is constantly changing position. The key is to watch it for a while and figure out, which branches and spots within the coral it preferrs … and then wait for your shot. It might cost you a whole dive though …

Mating Notodoris with Hitchhiker and Parasite

Mating Notodoris with Goby and parasite

On a recent dive this week we went to Pulau Putus on the northern end of the Lembeh Strait – a dive around a little island that offers spectacular hard corals, a wall and very good critter life. This is also where we found these mating Notodoris minor. As they are not the most common nudibranch i was already excited enough to see two of them together. But the topping on the ice was the little goby with a parasite sitting on the left one of them. So i had a good lough first and then took some shots (without disturbing the 3 of them … 4 actually if you count the parasite).
Notodoris are a rather big growing nudibranch that can reach 10 cm in size. They lay yellow eggs and are day active. They are usually seen on coral dive sites rather than on muck sites.