When I visited Lembeh in September/October there were flamboyant cuttlefish around in numbers that I have never seen before. On more or less every dive, we saw one or more flamboyants. Blue ring octopus were not as common, but still there was hardly a day when we didn´t see them. This is very much in contrast to the situation now, at least considering adult octopus and cuttlefish. We have seen some, but while still here, they are not nearly close to the densities experienced in September/October. Where did they all go?
Actually, cephalopods, the group that octopus and cuttlefish belong to are quite short-lived. Not only that, they only reproduce once and then die! This pattern of reproduction, where an individual grows for almost all its life, mates and then die, are called semelparity.
Other animals continue living after reproduction and produce other litters some time after. Such a strategy, with multiple reproductive events after the onset of maturity, is called iteroparity.
The answer is that all life histories, that is the allocation of energy over time, consist of trade offs. Food is seldom unlimited, and if it where, time or developmental rate would limit the options available for an animal. The first ting that needs to be realized is that reproduction, having offspring, is expensive. Experiments have time after time verified that reproducing individuals of a lot of different species die earlier than non-reproducing individuals. That is the first trade off, choosing between a long life or offspring. And having no offspring is a fundamental screw up in nature, as your genes get lost for the future, so choosing long life rather than reproduction is not an option for animals looking for success in life.
The second trade off is that costs are related to the effort that is put into reproduction. Everything else equal, the more offspring that is produced, the less survival or future growth rate an individual will experience.
The third important trade off is that an individual need to keep significant amounts of energy reserves in order to survive over long time in the future. Up to around 90% of the energy budget might have to be allocated to future survival if that is the goal. Thus, an individual can produce a vastly higher amount of offspring in one reproductive event if no energy is saved for future survival. Thus, if an individual irrespective of reproduction faces quite high mortality rates, it could obviously be advantageous to “go all in”, reproduce with all the effort you can, and save nothing for a very uncertain future. And that is exactly what cephalopods do, invest all they got in one single “big bang” litter instead of saving themselves for another day.
The cool effect of that here in Lembeh is that there now are quite a number of minute, fully colored flamboyants around. The young flamboyants are really cool, brightly colored and have a lot of attitude.
I started the week diving a lot, but with routine engine servicing (7 engines over 2 days), new restaurant furniture (pics to follow soon) and removing a flower bed and preparing for the final phase of the roof renovation (above the wet camera room) – I am heading into the weekend feeling I haven’t dived enough, even though i have dived more times this week than i did between September 2011 and September 2012!
The diving highlight for me was finding a strange shrimp all by myself and experimenting with lighting on a few critters. The big downer was missing some cool sightings such as the 3 bluerings on this afternoons dive.
Last night I was feeling a little bored and felt that I needed to relieve some urges from deep in my soul. The only cure to that was to go and watch some sex!
Before you all start thinking im losing my mind, I am, of course, talking about Mandarinfish (Synchiropus splendidus). These beautiful little fish are nymphomaniacs, and get it on every-night. They are one of the most frustrating things to photograph and i havent tried to take pictures of Mandarinfish for about 4 years, so i thought it was about time for some stress!
I headed out with Johan and his two guests (Alex and Barbara). I took my own guide, Marnes, so that Alex and Barbara didn’t have to hear my foul language when i missed the shots that i wanted :).
In the end it was quite a nice dive with some success. Only one other boat arrived and they graciously put their guests a little further down the patch from us and i think everyone had a good time 🙂 By the time the other boat left we were just finding some frogfish, Bobtail Squid and cool nudis mating. For more details on the Mandarinfish dive i did a creature feature post on the NAD site. For those of you too lazy to click there, here are some photos below, but there are more on the website:
Well, as Lembeh must be the frogfish capital of the world, and frogfish are some of my favourite critters, I think that frogfish actually merits another blog entry. So here it is.
Frogfish are probably most known for their built in bait, an illicium or “fishing rod” that is topped with the esca, the worm- or shrimplike lure it self. The illicium and esca are formed from the foremost rays of the anterior dorsal fin, and can be moved in different directions in front of the mouth when prey comes close enough.
Frogfish belong to the family Antennariidae in the order Lophiiformes, which among others also include the supercool deep water anglerfish with lures that are shining with light. With a few exceptions, the most notable being the Sargasso frogfish, frogfish are mostly shallow water fish, living among rubble, sea weed, coral heads and other underwater structures that can aid the frogfish in hiding their outline from prey and predators.
In Lembeh strait a number of species are found. I have seen eight or nine species in Lembeh, but there are probably one or two more around.
Frogfish are notoriously hard to determine to species. Many species come in different colors, so color is at best a weak clue to what they are. Colors seem to change with background, making camouflage excellent, but on the other hand not helping very much in species determination.
A combination of habitat, body shape, and, maybe most important, characteristics of the lure can most often be used to at last narrow it down to a couple of likely names. A few, however, such as the hairy frogfish with it´s wormlike lure and the warty frogfish with it´s warty exterior are very characteristic and often easy to name. Others, such as the hispid, the painted and the giant (also called Commersons) frogfish are not to hard to determine if the lure is visible.
Then there are a number of frogfish with lures that are hard to see and quite similar markings that I find pretty hard to determine to species underwater.
And finally, Lembeh is home to at least one undescribed species, which has not been named by scientists yet.
The lure of the frogfish indicates that frogfish are specializing on fish as prey. With a few exceptions, fish is exactly what frogfish eat. When a small fish comes close to the frogfish, the lure is waved in an enticing way in front of the mouth of the frogfish. The prey fish will often be conned into believing that it is the luckiest day in its life, which most often is the last feeling the prey fish will have. When the prey comes close enough, the frogfish extends its enormous mouth, inhaling a lot of water and a small, and highly likely very surprised, fish. The mouth movement of the frogfish is so quick that scientists have problems explaining how that speed is even possible.
The teeth of frogfish are very pointed and directed backwards towards the interior of the mouth. Thus, anything caught by a frogfish will have a really hard time escaping, while the direction of the teeth will allow the frogfish to move the prey inside the mouth. Frogfish are extremely elastic, being able to swallow prey as large as themselves.
Frogfish have three ways of moving. First, like most fish, they can swim through the water column using their caudal fin. They can also use a water jet by expelling water through the small gill openings behind the pelvic fins. Finally, frogfish can more or less gallop over sandy bottoms, in a rather ungraceful running motion resembling what a cross between a sea lion, a football and a horse would look like in full speed.
So, now I am of running an ecology/photo course in the Red sea. Those of you that follow this series will probably have the next entry available in a couple of weeks.
Update 1. In the blog on cephalopods I mentioned that we still had a couple of species to be seen. Not so now, we saw an algae octopus yesterday and on this morning’s first dive, not one but two hairy octopus were found. I guess that´s it for the cephalopods! Maybe not if we get really picky about the number of bluering species in the area, but as even experts seem to have quite some trouble defining that, we will just leave it at bluering for now.
Update 2. In the blog on seahorses and relatives, there was a blaring omission. No pictures of the pygmy seahorse itself, the Hippocampus bargibanti. No such omission now, here is a bargibanti from today. Interestingly enough, I have a distinct feeling that there are way more bargibanti in the area now than a couple of years go when I first came here.
Update 3. The seahorse blog did not have a picture of a pregnant ghost pipefish. Here is a pregnant female with the extended pelvic fins holding the eggs.
Update 4. There was some discussion here at NAD on whether frogfish lack gills, lack gill covers or neither. Frogfish have gills, have no proper gill covers but exhale the water exchanging gasses over their gills through a little hole at the base of their front “feet” (“arms”, “legs”?). The holes can be used as water jets, propelling the frogfish along quite like a cephalopod.
Talking about frogfish, there will soon be a new batch of small hairy frogfish around. A couple of hairy frogfish, where the female is very full of eggs, seems to be having a cozy day in the strait today, spending some quality time together. The couple will probably heat up the action tonight, so look out for a floating egg masses in the strait tomorrow. Judging by the size of the female, it will be a big one!
Frogfishes! Always fun to see and wherever they are found often the stars of the local diving critters. Lembeh delivers frogfish in so many shapes, sizes, and colours, that you could spend a week or more just checking out the varieties here in the strait. Well, maybe not shapes as most are more or less shaped like a hybrid of a ball and a fish, with the expected agility of such a creature! The last two days, we have seen painted, spotfin, giant, warty, hispid and striated frogfish and the striated has shown both it´s shorthaired and longhaired version.
So what are frogfish? All frogfish are small to medium sized sit and wait predators, that tend to find a more or less species-specific spot where their specific camouflage can be used. As an example giant and painted frogfish are most often found in or next to sponges, where the frogfish blends in in an amazing way with the colour and texture of the sponge. Another example is the hairy frogfish, which most often will be found right next to small colonies of corals with long tentacles on their polyps, giving a surprisingly efficient illusion of the frogfish being part of the coral colony.
Making the illusion even more thorough, frogfish do not have gill covers like most other fish, but expels the water flushing over their gills through small holes at the base of the pectoral fins. Thus no moving gill covers will alert any predator or prey that there is a rather tasty or dangerous, depending on perspective, frogfish just in front of you.
Frogfish, or anglerfish, which is their proper name, use their famous fishing rod called an illicium that is tipped with a lure, a so-called esca. The lure is waved in front of the mouth of the frogfish and, as the frogfish itself blends in with whatever it is sitting on or next to, passing fish cannot believe their luck when they see such a tasty morsel being available. The passing fish will approach and try to catch the lure, but will soon find itself in the stomach of the frogfish. In contrast to the sluggish and otherwise slow life style of frogfish, they actually are able to perform one of the quickest movements in the animal kingdom. The extension of the mouth and subsequent inhalation of water is over in milliseconds, often giving an illusion of pure magic when one observes a small fish in front of a frogfish suddenly just not there any more!
This afternoon’s dive will partly be spent in search of the elusive Randall´s frogfish. This small species is very cryptic, spending most of it´s time in rubble or clumps of dead sea weed. It is really hard to find, so luckily we can have a try tomorrow again. And the day after! The good thing about looking for almost impossible stuff here in the strait is that you will see so much cool other stuff while trying, so it is highly likely that we more or less will forget whatever it was we started out with looking for!
Most fishes look cuter when they are juvenile – and this goes specially for frogfishes. So of course we were quite happy, when we found 2 tiny baby painted frogfishes on a dive this week. When they just hatched, they can be found as tiny little blobs in the sand. They are about 3-4 mm long. On this picture you can see one of the baby Frogfishes next to the tip of my pointing stick. We hope there are some more of them and that we will find them soon … as long as they are still small and cute 😉