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.
After leaving Lembeh in October I honestly thought that it would be about a year until I could visit again. I had quite a number of trips elsewhere planned and also a lot of stuff to do on my day job. After spending the rest of the fall with doing paperwork, and an extremely early winter onset at my home in Sweden, combined with a record amount of snow, it became clear that I had to get some diving in before planned. So here I am back in Lembeh again, more than happy to be blogging about the stuff we see and take pictures of during the next couple of weeks. I know I am most likely preaching to the choir here, but it was pretty obvious already yesterday five minutes after my arrival that 28 degrees Celcius and sun so strong that you actually would benefit from sunglasses beats the climate around the polar circle by just an incredible amount on the life quality scale.
What are the differences then from October? Well, some are resort based. Simon and his staff have fixed a really nice bar on the second floor with a great view over the strait. The boats were already fixed in October, but now there are new, quick and very well planned boats here. The guides are the same, which I am very happy with. The former chairs, which probably were made of concrete, iron scraps and lead, have been replaced (some would say that that is a bad thing, breaking a long tradition, but then again other people seem to want to be able to actually move their chairs). Compared to my last visit, being the low season now, there are very few people here. Having visited Lembeh during more or less during all seasons, I really wonder why there is a low season, as the diving has been very good whenever I have ben here.
The diving is not the same though, different animals seem to be common at different times. And that takes us to the differences under water. Most of the seasonal differences here seem more to be a question of differences in densities of animals rather than differences in what species can be found here. The flamboyant cuttlefish, which were common to the point of being not very interesting in October, have left their marks with eggs in most of the empty coconuts on the sands.
Flamboyants are still around, but not as many as then, which makes sense, as flamboyant and their relatives die soon after mating. The same goes for blue rings that are tending their eggs now, but are not seen in the same more or less ridiculous densities as in October. I would be surprised if there are as many frogfish around as on my last visit. But, that said, I am pretty sure that something else will be much more common now. Apparently there are quite a number of Harlequin shrimp here now, and they are always fun to watch.
After some days of diving here, I will get back to you with what else is common now. Wire coral shrimps were very common today at least, as you can see from today`s shots!
It seems to me, that we see a lot of Phyllodensium Nudibranchs at the moment. We encountered 4 different Types only yesterday – and 3 Solar Powered Nudibranchs (Phyllodensium longicirrum) on a single dive at “Tanjung Kubur”. The one you can see on this picture was a smaller one. As i was preparing for the shot, i realised, that there was a little fish hiding between the Cerata (tentacles) of the Nudibranch. It turned out to be a little Wrasse seeking shelter within the “arms” of the Solar Powered Nudi. This shot was taken in a brief moment, when the Wrasse came out of its solar powered home.
Even though we also saw a Blue Ringed Octopus, 2 Ambon Scorpionfishes, a Flamboyant Cuttlefish, Hairy Shrimps and other cool Critters on this dive at, the little Wrasse hiding in the Nudibranch was still my personal favourite of this Dive.
We were 6 Divers and had Johan, Stenley and Marnez as Guides with us.
Invertebrates are in general stupid animals. Mussels, snails, and most other members of the mollusk group would certainly score pretty low on any scale of creative brightness, but their life style on the other hand does not require a brilliant mind. The only exception is the cephalopods, translated from greek as headfoot, such as the squid, cuttlefish and octopus. The cephalopods are highly adaptable animals, making creative use of their environment when hiding and hunting prey. Cephalopods are bright animals, with some of the octopus being significantly smarter than even some vertebrates. An octopus ability to learn mazes is in the range of that of a rat (which is good at learning mazes!), and octopus learn to open glass jars with screw on lids very quickly and do remember how for a long time. One of the octopus, the coconut octopus, is the only invertebrate currently being classed as being able to use tools. Coconut octopus live on sand flats and would be very easy prey for medium-sized and larger fish when the octopus is up and moving around in search of prey. Coconut octopus solve this problem by placing different objects such as empty shells or coconut husks on certain places in their territory, and use those objects to hide in when in danger.
During the week I have been here in Lembeh, we have during just a couple of days seen flamboyant cuttlefish, coconut octopus, reef squid, broadclub cuttlefish, pygmy cuttlefish, wunderpus, bobtail squid, starry night octopus, blue ringed octopus (at least 5!), mototi octopus, algae octopus, mimic octopus as well as reef octopus. It seems that we only got one left on the list now, the hairy octopus, which seems to be very seasonal, and not here now. (See update here.)
On proper coral reefs only a couple of cephalopods can be found. The much larger diversity of cephalopods here in Lembeh is due to the mosaic of habitats that can be found. Mototi and blue-ringed octopus, as an example, prefer to live in rubble. Mimic octopus live in sand, while bobtails and flamboyants live in siltier conditions. Wunderpus prefers a mixture of sand and rubble, while most squid and cuttlefish, being more or less living in the water column, are found over different bottoms.
More or less everyone seems to be well aware of the powerful toxin used as a defense by blue-ringed octopus. Less known is that most, if not all, octopus have toxins in their saliva that are injected when the octopus bites something or someone. Mototi seem to be in the range of the blue-ringed, while most other octopus seem to be less dangerous, but great care should be taken not to be bitten by any octopus. Some of the cuttlefish, such as the flamboyant cuttlefish are poisonous enough to quickly kill any predator brave enough to ignore the flamboyants flashing of warning colours, deterring most predators from even trying.
Most cephalopods have the ability to change colour and skin texture very rapidly, thus being able to melt in in the environment while moving around. The many pygmy cuttlefish we see here now are prime examples of that feature. They look like sponges, sand, coral and even crinoids.
Juveniles of broadclub cuttlefish like to hang around soft corals and change colour and to some extent skin structure to resemble the coral colony.
No molluscs tomorrow, the nudis will have to wait a day or two. It is highly likely that the sea horses and their relaitves will be the subject for tomorrows entry, but, as always, something could get in the way during the mornings dives.
As a colorful contrast to the black or grey sands in Lembeh strait, nudibranchs of different sizes, shapes and colors are plentiful here. The vivid colors of many of the nudibranchs such as those of the Risbeckia are clear messages to predators that the nudibranchs are very nasty food items, filled with poison from the cnidarian prey of the nudibranchs.
It makes a lot of sense to announce the danger of eating the nudibranchs, as they get no help from the poison once ingested, despite killing of the predator in the process. The clear colors send a powerful message to would be predators that it is not worth even trying, letting both prey and predators take care of their own business without being harmed. These kinds of signals, where bright colors give a message of a horrible fate to a predator-to-be are called aposematic signals.
Some of the other very venomous animals, such as the flamboyant cuttlefish, the mototi octopus as well as the blue-ringed octopus that we currently see every day here in the strait are perfectly sized prey for may of the carnivorous fish feeding in the sands. However, given that these cephalopods themselves try to catch fish, a constant aposematic signal would complicate life for the blue-ring and the flamboyant scaring of the prey. The solution is to turn the aposematism on when threatened and turn it of again when the danger leaves, as shown here by a mototi octopus.
Thus, both flamboyant cuttlefish and blue-ring octopus are at the same time both among the most camouflaged and the brightest colored animals here in the strait, vividly demonstrated by the flamboyant cuttlefish flashing strong colored circles or waves of vivid colors when agitated and blending in with the rubble in an amazing way whenever left in peace.
The Flamboyant Cuttlefish (Metasepia pfefferi) is a member of the cuttlefish family – but a very untypical one. Unlike other cuttlefish it is not shy at all but displays it’s poppy colour signals to communicate the potential danger of the poison in his flesh to potential predators. This makes it really easy to observe and photograph the flamboyant cuttlefish. Another difference from other cuttlefishes is the fact that the flamboyant cuttlefish does not swim but rather “walks” on the sandy bottom using its mantle flaps and arms.
The smaller male fertilizes the eggs of the bigger female, that then lays them under objects like coconutshells, broken bottles etc. The eggs are round and the little cuttlefish often can be already seen inside the eggs. The hatchlings immediately display the typical colour after hatching and start hunting. The Flamboyant Cuttlefish is an excellent hunter that – like all cuttlefish – catches their prey with its feeding tentacles.
Best place to see Flamboyant Cutllefish in Lembeh Strait: Flamboyant Cuttlefish can be found on all Muckdive Sites in Lembeh. Eggs can be also found troughout the season as they reproduce year round.
Phototipps: 100mm or 60mm are both ok as the Flamboyant Cuttlefish is not shy – for photographing hunting scenes the 60mm is better though.
It’s “Baby Time” in Lembeh … or at least this it how seemes. This morning we bumped into a lot of juvenile critters on both dives. We saw juvenile frogfish (that fit on your thumbnail), various tiny juvenile nudibranchs (that would fit under your thumbnail;) ), several baby cuttlefish (also flamboyant cuttlefish), a tiny juvenile robust ghost pipefish and a baby pinnate batfish. And even besides that … we just kept going from one critter/photo subject to the next for 75 minutes on each dive.
The diving is really good these days and very rich in critters: very uncommon for january … but we will not complain 😉