Shallow rocky shoreline, Tanganyika Lake, Ubwari Peninsule, Cape Banza, DRC

_st place in Biotope Aquarium Design Contest 2022

Volume of aquarium: 168 liters

Dimensions of aquarium: 70/50/48 (cm)

List of fishes: Eretmodus marksmithi, Macrobrachium jelskii

List of plants: Equisetum giganteum, weeds

Description of Decorations and Substrate: An illuminated aquarium, designed exclusively to receive the only specimen of the Eretmodus marksmithi found in Brazil. The objective is to offer the best possible conditions to ensure animal welfare.

Approximately 50 kg of stones were used in the assembly. The rocks are kaolinite-rich sandstones that occur along the entire coast of the Ubwari peninsula and also in Brazil. In addition to rocks of different sizes and irregular shapes, the landscaping is completed with sand with a wide granulometric range, which varies from very fine grains to coarse sand (over 10 mm), resulting from the mixture of sands from different beaches in Rio de Janeiro.

A twig of Leucaena leucocephala, a common land plant in the region, and empty shells complete the landscaping.
The assembly is done on different levels that form plans to favor the animal’s natural behavior. Like all gobies, the eretmodus marksmithi prefers to cling to rocks.

It is possible to observe the efficiency of the hardscape to guarantee the behavior of the animal. After placing the fish in the aquarium, the filamentous algae were completely consumed by E. marksmithi. Strong lighting and adequate photoperiod ensure a supply of algae, which are essential for fish feeding. It is possible to notice the marks left by the teeth when scraping the stones.

Description of Equipment: The filtration system consists of a rear integrated/internal sump with a nominal volume of 33 L (70/10/48 cm) divided into four compartments.

The first compartment is for the decanting of suspended solids. The next compartment is filled with a polyester fibers sheet for mechanical filtration. Subsequently, a compartment is filled with sintered ceramic (equivalent to 2 liters) which serves as a surface for the growth of bacterial colonies (nitrobacter, nitrosomes…) to promote biological filtration, oxidation of ammonia (NH3) to nitrite (NO2) and from nitrite to nitrate (NO3). The last compartment works to return water to the aquarium, with the aid of a 2000 L/h motor pump, model SB2000 SarloBetter.

An aquarium heater, EHEIM Thermocontrol 125, has been positioned in the last compartment of the sump to keep the aquarium temperature at 27 °C. In this same compartment, a small air pump is used to ensure the dissolved oxygen saturation level, approximately 8 ppm (27 °C).

LED luminaire (cold white[6000K]/blue/red) and LED floodlight (RGB) with adjustable intensity, were used to simulate (not automated) different lighting conditions, twilight or full sun.

Water Parameters: Water temperature: 27 °C
pH: 9,1
Conductivity: 632 µS/cm
GH: 214 mg/L (~ 12 °dGH)
KH: 374 mg/L (~ 21 °dKH)
Dissolved oxygen: 8 ppm

Additional Info: The fish care starts with choosing the biotope aquarium culture. This aquarium intends to go beyond aesthetic issues and is very concerned with the physicochemical conditions of water. In this way, it promotes the health of the fish.

So that eretmodus marksmithi does not feel alone and fulfills the trophic role, some macrobrachium jelskii were introduced into the aquarium. Due to its morphological similarity and functional redundancy, the shrimp macrobrachium jelskii was inserted to replace the macrobrachium moorei, an endemic species of Tanganyika.

The lighting turns on and off gradually, taking advantage of the intensity adjustment capability of the LED bars. Avoiding abrupt changes in lighting conditions.

The fish is fed once a day and in minimal amounts. NLS AlgaeMax and Dr. Bassleer’s functional foods with vegetable extracts of garlic, açaí, and lapacho tree are used. Weekly pellets are offered soaked, and subsequently dried, in an alcoholic extract of propolis. Propolis is a natural functional additive which, when used at the appropriate dosage, results in better fish health, acting as an immunostimulant, food additive, antimicrobial and therapeutant (De la Cruz-Cervantes et al.).

Water care is a fundamental requirement of this project. The Degens et al. and Tiercelin et al. works guided the physicochemical conditions in which water must be maintained. The cations Na+, K+, Mg2+, Ca2+ and the anions Cl- (chloride), SO4– (sulfate) and the carbonates (CO3– and HCO3-) were considered the macroelements, and the main values of the concentrations were reproduced in the aquarium. Appropriate amounts of sodium bicarbonate, sodium carbonate, magnesium chloride hexahydrate, calcium chloride dihydrate and anhydrous potassium sulfate were measured and solubilized in tap water. Dosing each of the chemical elements was the way to guarantee the concentrations found in nature, as industrialized products are unable to reproduce the elementary ratios, especially if we refer to the Ca and Mg ions, responsible for the hardness of the water. GH values hide the exact concentrations of these elements and may represent different summations of Ca and Mg concentrations. Controlling the Na+/K+ ratio promotes sperm motility, favoring reproduction within the system (Morita et al.).

50 L of water of system is changed every two weeks. The partial water change is made with water previously treated with conditioners, added with salts and in thermal balance with the aquarium, so that there are no considerable oscillations.

Aquarium video:

Description of the Area Surrounding the Biotope: Cape Banza (4°04’88.9″S 29°24’23.9″E) is located in the far north of the Ubwari Peninsula, in the northern basin of Lake Tanganyika, in East Africa, Democratic Republic of Congo. The Ubwari peninsula is delineated by two geological faults. Is one of the regions with the lowest anthropogenic impact on the entire coast of Lake Tanganyika. With very low population density (0.5 people/km2; DRC 1988), there are no roads. Watersheds are small, limiting sediment discharge.

Since the discovery of sub-lacustrine hydrothermal fields at Cape Banza, along the western arm of the East African Rift, in the late 1980s, the region has suffered from the ecological threat of hydrocarbon exploration. Currently, the Ubwari Peninsula region is involved in armed clashes. Photographic records and videos are extremely rare. By choosing this region, I hope I can help with awareness and preservation.

Description of the Underwater Landscape of the Biotope: Cabo Banza is characterized by a rocky coastline, typically made of sandstone, which extends downhill to an average depth of 4 meters and the intercalated bottom of rocks and sand in the shallow regions.

Description of the Habitat Parameters: The limited discharge of sediments in the region reflects in a water of very low turbidity, favoring the growth of benthic algae (Alin et al). Ideal place for the occurrence of herbivorous fish, such as eretmodus marksmithi.

List of Fishes and Invertebrates Occurring in the Nature Biotope: list of animals based on articles ACTA ICHTHYOLOGICA ET PISCATORIA (2011) 41 (3): 201–214 and CONSERVATION BIOLOGY (1999) 13 (5) : 1017-1033.

Fishes:
Altolamprologus compressiceps (Boulenger, 1898), Cichlidae: <2% of population at site
Aulonocranus dewindti (Boulenger, 1899), Cichlidae: <2% of population at site
Chalinochromis brichardi (Poll, 1974), Cichlidae: <2% of population at site
Chrysichthys brachynema (Boulenger, 1900), Claroteidae: <2% of population at site
Cyathopharynx furcifer (Boulenger, 1898), Cichlidae: <2% of population at site
Cyphotilapia frontosa (Boulenger, 1906), Cichlidae: <2% of population at site
Cyprichromis microlepidotus (Poll, 1956), Cichlidae: 5–10% of population
Eretmodus marksmithi (Burgess, 2012), Cichlidae: <2% of population at site
Julidochromis marlieri (Poll, 1956), Cichlidae: <2% of population at site
Julidochromis transcriptus (Matthes, 1959), Cichlidae: <2% of population at site
Lamprichthys tanganicanus (Boulenger, 1898), Poeciliidae: <2% of population at site
Lamprologus callipterus (Boulenger, 1906), Cichlidae: <2% of population at site
Lamprologus lemairii (Boulenger, 1899), Cichlidae: <2% of population at site
Lepidiolamprologus attenuatus (Steindachner, 1909), Cichlidae: <2% of population at site
Lepidiolamprologus cunningtoni (Boulenger, 1906), Cichlidae: <2% of population at site
Lepidiolamprologus elongatus (Boulenger, 1898), Cichlidae: <2% of population at site
Lepidiolamprologus profundicola (Poll, 1949), Cichlidae: <2% of population at site
Limnotilapia dardennii (Boulenger, 1899), Cichlidae: <2% of population at site
Lobochilotes labiatus (Boulenger, 1898), Cichlidae: <2% of population at site
Mastacembelus ellipsifer (Boulenger, 1899), Mastacembelidae: <2% of population at site
Mastacembelus moorii (Boulenger, 1898), Mastacembelidae: 10% of population
Neolamprologus calliurus (Boulenger, 1906), Cichlidae: <2% of population at site
Neolamprologus fasciatus (Boulenger, 1898), Cichlidae: <2% of population at site
Neolamprologus furcifer (Boulenger, 1898), Cichlidae: 2–5% of population
Neolamprologus leleupi (Poll, 1956), Cichlidae: 2–5% of population
Neolamprologus mondabu (Boulenger, 1906), Cichlidae: 2–5% of population
Neolamprologus savoryi (Poll, 1949), Cichlidae: 2–5% of population
Neolamprologus toae (Poll, 1949), Cichlidae: 2–5% of population
Neolamprologus tretocephalus (Boulenger, 1899), Cichlidae: <2% of population at site each
Ophthalmotilapia nasuta (Poll & Matthes, 1962), Cichlidae: <2% of population at sit
Ophthalmotilapia ventralis (Boulenger, 1898), Cichlidae: <2% of population at site
Paracyprichromis brieni (Poll, 1981), Cichlidae: 2–5% of population
Paracyprichromis nigripinnis (Boulenger, 1901), Cichlidae: <2% of population at site
Perissodus microlepis (Boulenger, 1898), Cichlidae: <2% of population at site
Petrochromis ephippium (Brichard, 1989), Cichlidae: <2% of population at site
Petrochromis famula (Matthes & Trewavas, 1960), Cichlidae: <2% of population at site
Petrochromis fasciolatus (Boulenger, 1914), Cichlidae: <2% of population at site
Petrochromis orthognathus (Matthes, 1959), Cichlidae: <2% of population at site
Plecodus straeleni (Poll, 1948), Cichlidae: <2% of population at site
Pseudosimochromis curvifrons (Poll, 1942), Cichlidae: <2% of population at site
Pseudosimochromis marginatus (Poll, 1956), Cichlidae: <2% of population at site
Spathodus marlieri (Poll, 1950), Cichlidae: <2% of population at site
Synodontis dhonti (Boulenger, 1917), Mochokidae: <2% of population at site
Synodontis multipunctatus (Boulenger, 1898), Mochokidae: <2% of population at site
Synodontis petricola (Matthes, 1959), Mochokidae: 10% of population
Telmatochromis dhonti (Boulenger, 1919), Cichlidae: <2% of population at site
Telmatochromis temporalis (Boulenger, 1898), Cichlidae: 5–10% of population
Tropheus moorii (Boulenger, 1898), Cichlidae: <2% of population at site
Xenotilapia flavipinnis (Poll, 1985), Cichlidae: <2% of population at site
Xenotilapia leptura (Boulenger, 1901), Cichlidae: <2% of population at site
Xenotilapia sima (Boulenger, 1899), Cichlidae: <2% of population at site
Xenotilapia tenuidentata (Poll, 1951), Cichlidae: 2–5% of population

Crustacean:
Allocypria aberrans, Cyclocyprididae: <2% of population at site each
Allocypria claviformis, Cyclocyprididae: <2% of population at site each
Allocypria humilis, Cyclocyprididae: <2% of population at site each
Archaeocyprideis tuberculata, Cytherideidae: <2% of population at site
Candonopsis depressa, Candonidae: <2% of population at site
Cypridopsis obliquata, Cyprididae: <2% of population at site each
Cypridopsis serrata, Cyprididae: <2% of population at site each
Gomphocythere alata, Limnocytheridae: 5–10% of population
Gomphocythere cristata, Limnocytheridae: 10% of population
Mecynocypria deflexa, Cyclocyprididae: <2% of population at site each
Mecynocypria emaciata, Cyclocyprididae: <2% of population at site each
Mecynocypria opaca, Cyclocyprididae: <2% of population at site each
Mecynocypria cf. conoidea, Cyclocyprididae: <2% of population at site each
Mecynocypria subangulata, Cyclocyprididae: 10% of population
Romecytheridea ampla, Cytherideidae: 5–10% of population each
Romecytheridea tenuisculpta, Cytherideidae: 5–10% of population each
Tanganyikacypridopsis acanthodes, Cyprididae: <2% of population at site each
Tanganyikacypridopsis calcarata, Cyprididae: <2% of population at site each
Tanganyikacypridopsis depressa, Cyprididae: <2% of population at site each
Tanganyikacythere burtonensis, Cytherideidae: 10% of population
Bridouxia giraudi, Thiaridae: 2–5% of population
Bridouxia Ponsonbyi, Thiaridae: <2% of population at site
Bridouxia sp., Thiaridae: 5–10% of population
Caelatura burtoni, Unionidae: 2–5% of population
Lavigeria grandis, Thiaridae: 2–5% of population
Lavigeria cf. nassa “fine ribbed”, Thiaridae: 5–10% of population
Lavigeria cf. nassa “small fine”, Thiaridae: <2% of population at site
Lavigeria cf. paucicostata “coarse ribbed”, Thiaridae: <2% of population at site
Lavigeria cf. paucicostata “sand lav”, Thiaridae: 5–10% of population
Lavigeria cf. paucicostata “spiny”, Thiaridae: 10% of population
Mutela spekei, Mutelidae:<2% of population at site
Mysorelloides multisulcata, Thiaridae: <2% of population at site
Paramelania damoni form: crassigranulata, Thiaridae: <2% of population at site
Paramelania damoni form: imperialis, Thiaridae: 10% of population
Spekia sp. “coheni”, Thiaridae: 2–5% of population
Stanleya neritinoides, Thiaridae: <2% of population at site
Stormsia minima, Thiaridae: <2% of population at site
Syrnolopsis minuta, Thiaridae: <2% of population at site

List of Plants Found in the Nature Biotope: Azolla filiculoides (Azollaceae)
Ceratophyllum demersum (Ceratophyllaceae)
Cyperus papyrus (Cyperaceae)
Eichhornia crassipes (Pontederiaceae)
Hydrilla verticillate (Hydrocharitaceae)
Lemna spp. (Lemnaceae)
Phragmites australis (Poaceae)
Pistia stratiotes (Araceae)
Potamogeton spp. (Potamogetonaceae)
Salvinia molesta (Salviniaceae)
Typha capensis (Typhaceae)
Typha domingensis (Typhaceae)
Vallisneria spiralis (Hydrocharitaceae)
Vossia cuspidata (Poaceae)

Threats to the Ecology of the Biotope: The main threat is oil exploration. Since the discovery of sub-lacustrine hydrothermal fields at Cape Banza, along the western arm of the East African Rift, in the late 1980s, the region has suffered from the ecological threat of hydrocarbon exploration. Currently, the Ubwari Peninsula region is involved in armed clashes. Photographic records and videos are extremely rare. By choosing this region, I hope I can help with awareness and preservation.

The aquarium was designed exclusively to receive the only specimen of the Eretmodus marksmithi found in Brazil. The objective is to offer the best possible conditions to ensure animal welfare.

Sources of Information:
ACTA ICHTHYOLOGICA ET PISCATORIA (2011) 41(3). p.201-214 – a recent inventory of the fishes of the north-western and central western coast of lake tanganyika (Democratic Republic Congo) by Maarten Van Steenberge, et al. (http://hdl.handle.net/1854/LU-5697728)

APPLIED GEOCHEMISTRY 15 (2000) 355–368 – Hydrothermal petroleum from lacustrine sedimentary organic matter in the East African Rift by Bernd R.T.Simoneit, Tarek A.T.Aboul-Kassim, J.J.Tiercelin. (https://doi.org/10.1016/S0883-2927(99)00044-X)

BASIN RESEARCH (1997) 9, 107–132 – New palaeogeographic and lake-level reconstructions of Lake Tanganyika: implications for tectonic, climatic and biological evolution in a rift lake by A. S. Cohen, K.-E. Lezzar, J.-J. Tiercelin, M. Soreghan. (https://doi.org/10.1046/j.1365-2117.1997.00038.x)

BITUMENS IN ORE DEPOSITS. Special Publication of the Society for Geology Applied to Mineral Deposits, vol 9. Springer, Berlin, Heidelberg. – Hydrocarbons, Sulphides, and Carbonate Deposits Related to Sublacustrine Hydrothermal Seeps in the North Tanganyika Trough, East African Rift by J. -J. TiercelinJ. BoulègueB. R. T. Simoneit. (https://doi.org/10.1007/978-3-642-85806-2_7)

Congo Research Group. February 2019 – The CNPSC Rebellion, Social Marginalization and State Complicity in South Kivu by Congo Research Group. (http://congoresearchgroup.org/wp-content/uploads/2019/02/The-CNPSC-Rebellion-Feb-26.pdf)

CONSERVATION BIOLOGY 13(5), 1017–1033, 1999 – Effects of Landscape Disturbance on Animal Communities in Lake Tanganyika, East Africa by Simone R. Alin, et al. (https://doi.org/10.1046/j.1523-1739.1999.96476.x)

GEOLOGY (1989) 17 (11): 1053–1056 – Discovery of sublacustrine hydrothermal activity and associated massive sulfides and hydrocarbons in the north Tanganyika trough, East African Rift by Jean-Jacques Tiercelin; Catherine Thouin; Tchibangu Kalala; André Mondeguer. (https://doi.org/10.1130/0091-7613(1989)017%3C1053:DOSHAA%3E2.3.CO;2)

GEOLOGY (1993) 21 (6): 499–502 – Hydrothermal vents in Lake Tanganyika, East African, Rift system by Jean-Jacques Tiercelin; et al. (https://doi.org/10.1130/0091-7613(1993)021%3C0499:HVILTE%3E2.3.CO;2)

HYDROBIOLOGIA (2000) 436: 59–71, Diatom assemblages in surface sediments along the east coast of Lake Tanganyika by C. Cocquyt & D. Schram. (https://rdcu.be/cphrF)

IUCN (2012). Guide to some invasive plants affecting Lake Tanganyika. Nairobi, Kenya: IUCN ISI and Lake Tanganyika Authority. 64p – Guide to some invasive plants affecting Lake Tanganyika by Esther Abonyo and Geoffrey Howard. (https://portals.iucn.org/library/sites/library/files/documents/2012-048.pdf)

J. EXP. ZOOL. 313A:169–177, 2010 – Sperm Motility Adaptation to Ion-Differing Aquatic Environments in the Tanganyikan Cichlid, Astatotilapia burtoni by Masaya Morita, Satoshi Awata, Tetsumi Takahashi, Akihiro Takemura, And Masanori Kohda. (https://doi.org/10.1002/jez.587)

J. ICHTHYOL. 42(1): 39-43, 1995 – Neolamprologus longicaudatus, a New Cichlid Fish from the Zairean Coast of Lake Tanganyika by Kazuhiro Nakaya and Masta Mukwaya Gashagaza. (https://doi.org/10.11369/jji1950.42.39)

JOURNAL OF GREAT LAKES RESEARCH 46 (2020) 1067–1078 – The taxonomic diversity of the cichlid fish fauna of ancient Lake Tanganyika, East Africa by Fabrizia Ronco, Heinz H. Büscher, Adrian Indermaur, Walter Salzburger. (https://doi.org/10.1016/j.jglr.2019.05.009)

NATURWISSENSCHAFTEN, 1971 – Lake Tanganyika: Water Chemistry, Sediments, Geological Structure by T. Degens, Richard P. Von Herzeix And How-Kin Wong. (https://link.springer.com/content/pdf/10.1007/BF00602986.pdf)

REVIEWS IN FISHERIES SCIENCE & AQUACULTURE 2018, VOL. 26, NO. 3, 337–349 – Propolis in Aquaculture: A Review of Its Potential by Jesús Alberto de la Cruz-Cervantes, et al. (https://doi.org/10.1080/23308249.2018.1424798)

tanganyika.si (http://tanganyika.si/Locations/slides/Cape%20Banza.html)

Tech monde Brésil (https://engworld.mondoblog.org/2016/11/24/potentiel-petrolier-bassin-de-lac-tanganyika/)

malawicichlids.com (https://malawicichlids.com/mw01011.htm)