North Towards the Kaiser: Part Two

We started toward Ikola sometime in the morning four days ago. We first stopped by at the village of Kabwe and then navigated our ship toward Karema at the Ifume river delta. Four hours after our departure we passed Ikola and two hours later we anchored at Mpondogoro. Prior to nightfall we had managed to navigate our ship a little further north to Rwega. There we collected cichlids for a few days before returning south again.

For a long time it was assumed that there was only species of Cyathopharynx, but recently it has become understood that we are dealing with at least two species. It was discovered that both species are able to live in the same habitat at the same locale. However there seems to be some differences with respect to the niche each species seems to prefer. The first species, C. furcifer, can be found in a setting that is characterized by relatively shallow, stagnant water. This usually means inlets with sandy areas rich in sediment. It is also common that these areas contain plentiful aquatic plants. C. furcifer builds sand domes in this habitat with plants and layers of sediment. C. sp "furcifer dark," the second species of the genus, can be found in the same habitat as the previous species. Each species prefers a different type of niche. C. sp "furcifer dark" prefers a setting that consists of stone and rock formations close to the sandy bottom. This transitional zone between rock and sand can be found at a depth ranging from nine to sixty feet. C. sp. "furcifer dark" builds low and wide sand domes on the rocks in this area. Individual fish can be seen grazing on the rocks. This way these fish ingest algae as well as sediment that are present on the rocks. Sometimes you can even see smaller groups of younger individuals feeding on floating algae in the water. A few years ago a variety of C. furcifer called "Johari" was being exported from Kabwe. They were caught in the sandy niche just outside the fishing station a little south of Kabwe. This species has yet not been found at Ikola where C. sp "furcifer dark" is found. Besides these two identified species there is a possibility that more exist. The varieties in the northern part of the lake differ from the two previously mentioned. It is not known whether these populations are the same as one of the two identified species or whether they represent new species. Photo by Mikael Karlsson.

September 14, 1997

Today was a beautifully sunny day. During the first hours of the morning the temperature was nice and warm but later on in the afternoon it became almost dangerously hot. At night, however it got just as cold as it had on previous nights. During the first two hours we collected fish around Rwega. Later, right before lunch as the beans on the stove were getting ready, we pulled up our anchor and started sailing south toward Mpondogoro. The coastline between Rwega and Mpondogoro consists of very steep flat rocks. Cacti and other plants that seem to be specialized in enduring long periods of dry spells grow on these rocks. It is a wild terrain with bushes, cacti, trees and grass that cover this steep area. A large part of the vegetation was in great need of rain. You could see many dried-up plants. However, the rain was not to come until December. There were some small inlets and even a few smaller lagoons here. In these lagoons the water was turquoise, warm, crystal clear and dizzyingly inviting. As we were traveling right before lunch the wind had not yet started to blow and the surface of the water in the lagoons, as well as in the smaller inlets, was like a smooth floor. One could easily see the rocks down on the bottom. We slowed down the boat and enjoyed the beautiful scenery.

Telmatochromis temporalis from Rwega, Ikola. Photo by Mikael Karlsson.

Diving at Mpondogoro

At 1:00 p.m. we arrived in Mpondogoro and stared to prepare lunch. The divers were served a big plate of corn flower and boiled beans. One hour after our arrival I began diving while the rest of the crew was taking their lunch break. We had anchored some sixty feet from the shore. As I was diving over the rocky area I could see Callochromis macrops hover above the sandy bottom ahead. Also present here is Aulonocranus dewindti with its territory in the shape of a sand crater nest. Above the sand there were big schools of Enantiopus melanogenys hurrying by. The rocky habitats north of Ikola are the host of Telmatochrornis temporalis. South of these locales, for example at Cape Mpimbwe the same type of habitat hosts another species such as Telmatochromis burgeoni. T. temporalis can often be seen in shallow water. It probably feeds on fine-threaded algae that can be found in this turbulent rocky niche.

Enantiopus melanogenys from Rwega, Ikola. Photo by Mikael Karlsson.

Without Limits

It was in afternoon and most of the crew was resting after lunch. The Poseidon Explorer was anchored at Mpondogo. Directly north of the village we could see steep cliffs reaching all the way down into the lake. The rocky habitat continued down to a depth of ten meters (thirty feet) where the wide sand areas took over. It was unbelievably bright and enjoyable to dive here. You could see the rocky habitats around you at a visibility of about 4.5 meters (fifteen feet). But since everything you see in the underwater world is, in fact, twenty-five percent closer than it is, the actual visibility was more like eight meters (twenty-four feet). In the water near the small village of Mpondogo just north of Ikola, the diffuse shadows created by rocks and other similar formations in the underwater world could be seen up to 15 meters (forty-five feet) away. Beyond that, a blinding turquoise light dissolved all images of the underwater landscape. A fog of plankton distorted the sharp beams of the afternoon sun. I was in the water with carefully bent knees, my body slightly upright looking down at the bottom three meters (nine feet) in front of me. Young specimens of the ancient fish species of Lake Tanganyika were whirling around the rocks and sand. The water in some areas was very rich in plankton. It seemed like I, too, was floating with the plankton a few meters above the cichlids on the bottom.

Leeches

The water of Lake Tanganyika was completely crystal clear at Mpondogoro, north of Ikola. We were diving in the brightest areas of rocky habitats. Up above, the surface was moving slowly and one could see the reflections of the sunbeams on the bottom. Sharp lines were formed as the sunbeams broke through the surface. Suddenly the peace was interrupted by a strange sensation. I felt something slimy on my upper lip just under the mask. I really didn't understand what was going on and since I couldn't see anything but cichlids hovering around between the rocks, I did nothing at first. Eventually I touched my chin instinctively with my hand and found a beautiful but unpleasant leach. It was not too attached, yet. It just hadn't had enough time to do so. I hadn't shaved lately and maybe that was the reason that the leech was not able to attach himself. But as soon as I pulled him loose from my face he headed for my right hand and attached himself very hard in only a short moment. Since I was holding some equipment with my left hand, my only free hand was the right one. I tried to get rid of the leech by rapidly flailing with my right hand back and forth through the water but the little rascal just sucked on to my hand tighter. I then let go of my equipment and let it float up toward the surface. I tried to pluck it off with my left hand but since it was so slimy I just couldn't get a hold of it. I wrapped it between the fingers of my left hand and made a fist. I then pulled my hands in opposite directions and I finally managed to get him off me. However he immediately started swimming toward me so I started kicking with my fins to get rid of him. After that, I "got out of Dodge."

Tropheus sp. "Kaiser" from Kasalamnjaga, Ikola. Photo by Mikael Karlsson.

Cichlids on the run

All of a sudden this scary feeling came over me. I could see all the fish swim toward me. They were swimming from shallow to deeper water. It was obvious that they were escaping from something because they were swimming as fast as they could. In these big schools one could see all kinds of species of Petrochromis, various Tropheus, Neolamprologus and Julidochromis. More and more fish swam toward me and passed me. As I was trying to think of various reasons why they were escaping, the last fish swam by and it got totally still with no trace of life. Suddenly an otter came swimming by. It went through the water smoothly going after the small cichlids. I was behind a rock on the bottom. The otter didn't see me until he was only two meters (~ six feet) away. It stopped and looked at me scared. I was holding my breath. So was the otter. I didn't move . I just kept still without making any sounds. A few small air bubbles let themselves out from the otter's nostrils and continued up toward the surface. Shortly thereafter I had to exhale and the otter disappeared in the opposite direction as fast as he could go. Almost instantly the fish reappeared at their respective territories.

You regularly see plundering schools of half grown Lamprologus callipterus move through the water. They seemingly eat anything that could be categorized as food. Sediment stirred up from rocks or the sandy bottom triggers a hysterical, almost maniacal, eating behavior. The individuals in the school literally throw themselves over the potential food. Likewise, when small, unprotected schools of fish fry are seen the same kind of food searching mechanism is triggered. L. callipterus tries to eat as many of the young as possible before the fry manage to escape or get rescued by bigger, more aggressive individuals. The smaller L. callipterus then leave the area of plunder aricf continue their raids throughout the area. These schools always consist of males exclusively. The females, who don't grow bigger than just a few inches, can only be found in areas with empty shells. In the areas with empty shells you can also find grown males that are big enough to move the whole shells. In this way they gather large colonies of shells some even with sexually mature females in them. In the open areas of the sandy habitat one can sometimes see several square meters covered with shells gathered by L. callipterus. Photo by Mikael Karlsson.

Another Leech

I had been diving uninterrupted from 2 p.m. until 4 p.m. During that time I had consumed a little less than 3,000 liters of oxygen. I had been in relatively shallow water during the entire dive - no more than 10 meters (30 feet). However, the water temperature was only 24°C (75°F) so I had become very cold. Water conducts heat away from the body twenty times faster than air. Even if you dive with your wet suit on you will start to feel cold after about an hour. I was standing in half a meter of water and began taking my belt and my oxygen tubes off. I then realized that a leech had attached himself to the inside of my belt. It fell into the water and I could see how it was trying to swim toward a crease in my wet suit. Before it had a chance to attach himself I jumped out of the water onto the side of the boat as the little leech remained in the water. It was still sunny and rather hot on board the ship but the afternoon breeze had been rejuvenated. I was shivering with cold as I was taking off my wet suit but only a couple of minutes in the hot sun was enough to warm me up again.

Only in a rocky habitat mixed with sand can you find Neolamprologus tretocephalus. You can often see individuals hovering motionless just above the bottom. N. tretocephalus is often encountered in deeper and murkier water. Their fins are almost fluorescent neon blue and can be detected several meters away. You hardly ever see any individuals feeding. Maybe that is because N. tretocephalus, as well as Neolamprologus toae which lives in the same habitat, feed at night. Very often you find N. tretocephalus motionlessly hovering just above the bottom in a vigilante fashion. It used to be assumed that N. tretocephalus and Neolamprologus sexfasciatus occupied similar niches in different habitats. However, since it has been discovered that both these species occur together in the same habitats it is likely that they have different living habits and dwell in different niches. Photo by Mikael Karlsson.

Eating fish

At five a clock on Sunday afternoon all divers came to the side of the boat. At that point I had been on board for about an hour getting warmed up, among other things. During this time I had also been able to conclude that the fish we collected earlier were doing well. Now there was time for sorting and identification. A few Labeo cylindricus had been caught in the divers' nets. These were placed in a water tank with other special items. While sorting we noticed that some large Lobochilotes labiatus had been caught. These were given to the cook on board. Other fish that were a little too big for our collection needs were 75 centimeters (a couple of foot and a half) long Boulengerochromis microlepis. Even a couple of Oreochromis ended up being worked on by the fish cleaner and the chef.

Diving Women

We were not the only ones collecting fish in the area north of Ikola. As we were anchored at Mponodogoro we could see five women from the village catching fish pretty much the same way we were. However, they were not equipped with masks, fins or small collecting nets but were carrying a rather big net. They didn't catch a whole lot. The women were dressed in Kangas - thin shawls wrapped around their bodies. As they were diving and swimming in the turbulent water the shawls came loose and became almost totally unwrapped.

Xenotilapia spiloptera

Several varieties of Xenotilapia spiloptera have developed in the rocky habitats. They are often seen in transitional zones between sand and rock or in the deeper sediment rich zone where they almost always move around in pairs. Individuals of this species have characteristic bright glowing purple spots on their bodies. These spots seem to be present in every population. Both males and females brood their offspring. As far as this is concerned, it has been established that there are always at least two individuals present under rocks or other protected areas within the habitat; never a lone brooding individual but always a male and a female. Most of the time you only see one of those individuals with eggs in its mouth. The partner awaits faithfully a few inches away.

Lobochilotes labiatus

Sometimes one can see large individuals of Lobochilotes labiatus. Some individuals almost forty centimeters (sixteen inches) long have been collected. Small individuals are often seen alone in the shallow part of the rocky habitat whereas the bigger individuals dwell in pairs in transitional zones. You never see L. labiatus chasing young fish, particularly in cases where parental adults are protecting them. Their food consists of invertebrates that live in cracks in rocks. Larger individuals can even catch crabs and snails.

Neolamprologus sexfasciatus from Mponodogoro, Ikola. Photo by Mikael Karlsson.

Southward at dawn

When the fish from the night shift had been counted it was concluded that all fish on the collection list had been caught. After that we started to try to figure out where we should anchor our ship over night. It was decided that we travel down to the inlet at Kobogo and anchor there. It was 7:30 p.m. by the time we reached Kobogo. The sun had just set behind the mountains in what used to be Zaïre, now the Congo Republic. Some fishermen sailed by in their small boats in the evening breeze with a red glare in their sails. After that we had a bite to eat before it was time to go to bed. At 4:00 a.m. we changed water and pulled up the anchor and started our journey home as the sun was rising. We continued southward and at 10:00 a.m. our boat sailed into the small port near the collecting station. The collection trip to Ikola was now concluded.