Madagascar field trip
September 2025
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3/9-2025
4/9-2025
The Dusky Sleeper Goby (Eleotris fusca) is a widespread species that can be found in Marine, brackish, and freshwater. This specimen was found in Faraony river.
Faraony river in Fitovinany region (Site 2). This species seems to be abundant in several rivers we surveyed in Madagascar.
We found a few rocks with plants which looked like clubmosses perhaps a species of ground pine (Lycopodium sp.). This plant was home to several species of shrimps.
The specimen belongs to the Caridina nilotica complex.
Another species found here is Caridina natalensis
6/9-2025
This large river is home to many endemic species.
The Madagascar Scale Prawn (Macrobrachium lepidactylus) is an important food item for many fish species. This specimen was caught in Mananjary river near Betampona and Tsiatosika.
A close-up of the rostrum of Madagascar Scale Prawn (Macrobrachium lepidactylus).
The Mananjary river at the location of capture.
This freshwater snail (Gastropoda) was found at the same location. This could be Neritina pulligera.
We only found this species of gastropod at this location. Neritina pulligera i widely distributed from Eastern Australia through South East Asia to Madagascar and Africa.
The Varuna crab (Varuna litterata) seem to be common in this river. The native range of this species is covers most of the Indo-Pacific and the Pacific Ocean. It can be found in freshwater, brackish, and saltwater.
7/9-2025
The Madagascar Scale Prawn (Macrobrachium lepidactylus) is the largest shrimp species we came across during this fieldtrip. This specimen was 12 cm SL
The Eastern Madagascar Cichlid (Paretroplus polyactis) still seems to be an abundant species in many rivers on the East coast of Madagascar. This is an adult specimen caught in a small stream near the village Maroaomby (-21.026228,48.247550). The species is endemic to the region.
Here we also found the Madagascar Flagtail (Kuhlia sauvagii). An endemic species found in fresh and brackish water on the East side of the island.
The Madagascar round herring (Sauvagella madagascariensis) is a sensitive species also found on this location. This too is an endemic species found only on the East Coast of Madagascar.
The High-finned Madagascar cichlid (Ptychochromis grandidieri) still seem to be present in great numbers at the sites we visited. This juvenile specimen was caught at the same location.
A fully grown specimen of High-finned Madagascar cichlid (Ptychochromis grandidieri) from aquaria looks like this. Foto: by Johnny Jensen.
This freshwater goby resembles Awaous macrorhynchus which is now considered a synonym of Awaous aeneofuscus.
This specimen seem to fit the description of Awaous macrorhynchus better than Awaous aeneofuscus in my opinion.
The fused pelvic fin form a suckerlike grip as an adaptation to strong currents. Awaous macrorhynchus/Awaous aeneofuscus is well adapted to life in a fast flowing river.
The habitat at this location.
12/9-2025
A Small clearwater stream at one of the higher elevations.
| PM | Site 1 | Site 2 | Site 3 | Site 4 | Site 5 | Site 6 | Site 7 |
Unit |
| Temp. | 25.1 | 26.4 | 25.6 | 26.3 | 25.8 | C | ||
| pH | 8.0 | 8.5 | 7.8 | 7.9 | 8.1 | pH | ||
| µS | 77 | 31 | 33 | 73 | 32 | µS/cm | ||
| KH | 2.13 | 1.16 | 1.28 | 2.10 | 1.19 | °dKH | ||
| Cl | 6.06 | 4.37 | 3.98 | 5.71 | 4.42 | mg/l | ||
| Na | 10.85 | 8.24 | 8.30 | 10.68 | 8.37 | mg/l | ||
| Mg | 4.56 | 4.56 | 4.56 | 4.56 | 4.56 | mg/l | ||
| S | 0.22 | 0.22 | 0.22 | 0.22 | 0.22 | mg/l | ||
| Ca | 2.65 | 0.90 | 1.26 | 2.78 | 0.94 | mg/l | ||
| K | 4.56 | 4.56 | 4.56 | 4.56 | 4.56 | mg/l | ||
| Br | 2.07 | 1.96 | 2.06 | 1.98 | 1.86 | mg/l | ||
| Sr | 0.01 | 0.01 | 0.01 | 0.03 | 0.01 | mg/l | ||
| B | - | - | - | - | - | mg/l | ||
| F | - | - | - | - | - | mg/l | ||
| Li | 4.68 | 4.70 | 4.69 | 4.82 | 4.76 | μg/l | ||
| Si | 9871 | 5168 | 6435 | 11000 | 5564 | μg/l | ||
| Ba | 4.40 | 11.76 | 11.32 | 21.53 | 10.66 | μg/l | ||
| Mo | - | - | - | - | - | μg/l | ||
| Ni | - | - | - | - | - | μg/l | ||
| Mn | 2.17 | - | 2.55 | - | - | μg/l | ||
| As | - | - | - | - | - | μg/l | ||
| Be | - | - | - | - | - | μg/l | ||
| Cr | - | - | - | - | - | μg/l | ||
| Co | - | - | - | - | - | μg/l | ||
| Fe | 576.4 | 55.02 | 210.0 | 65.75 | 91.36 | μg/l | ||
| Cu | - | - | - | - | - | μg/l | ||
| Se | - | - | - | - | - | μg/l | ||
| Ag | 17.52 | 2.07 | 21.39 | 4.57 | 5.20 | μg/l | ||
| V | - | - | - | - | - | μg/l | ||
| Zn | - | - | - | 3.67 | - | μg/l | ||
| Sn | - | - | - | - | - | μg/l | ||
| NO3 | - | - | - | - | - | mg/l | ||
| P | - | - | - | - | - | μg/l | ||
| PO4 | - | - | - | - | - | mg/l | ||
| Al | - | 35.19 | - | 100.0 | 69.62 | μg/l | ||
| Sb | - | - | - | - | - | μg/l | ||
| Bi | - | - | - | - | - | μg/l | ||
| Pb | - | - | - | - | - | μg/l | ||
| Cd | - | - | - | - | - | μg/l | ||
| La | - | - | - | - | - | μg/l | ||
| Tl | - | - | - | - | - | μg/l | ||
| Ti | 8.89 | - | 10.75 | 3.09 | 2.81 | μg/l | ||
| W | - | - | - | - | - | μg/l | ||
| Hg | - | - | - | - | - | μg/l |
Water parameters from the locations sites 1-7.
Site 1
Small stream -21,026257,48247711
Site 2
Faraony river in Fitovinany region
4/9-25 kl 10-14
Site 3
Mananjary river in Vatovavy region
Site 4
Fotobonitra river
9/9-25 kl 13:25
Site 5
Namorona river in Vatovavy region
10/9-25 kl 13:10
Site 6
River running into Fariky Karana not far from the village Mahela.
8/9-25 kl 12:46
20°58'07.9"S 48°25'49.5"E
Site 7
A special thanks to:
Den Blå Planet, National Aquarium Denmark
Tsilavina Ravelomanana (Ichthyologist at the University of Antananarivo) MG
Fetra Andriambelomanana (Ichthyologist at the University of Antananarivo) MG
Dr. Thomas Juhasz (Aquatic Veterinary Researcher at the Hungarian University of Agriculture and Life Sciences, Department of Aquaculture) H
Claus Christensen (Aquatic plants) DK
