scholarly journals Ichthyofaunal diversity of the Omo-Turkana basin, East Africa, with specific reference to fish diversity within the limits of Ethiopian waters

Check List ◽  
2017 ◽  
Vol 13 (2) ◽  
pp. 2059 ◽  
Author(s):  
Mulugeta Wakjira ◽  
Abebe Getahun
Keyword(s):  
Native Species ◽  
River System ◽  
Specific Reference ◽  
Fish Diversity ◽  
East African ◽  
Lake Turkana ◽  
Turkana Basin ◽  
Northern Portion ◽  
Omo River ◽  
Annotated Checklist

The freshwaters of the East African nation of Ethiopia are divided into nine main drainage basins. One of these, the Omo-Turkana basin, spans a large part of southwestern Ethiopian highlands and northern Kenya, and consists of the Omo-Gibe (or simply, Omo) River and a northern portion of Lake Turkana. Despite some development activities, including proposed dam construction with potential impacts on ichthyofaunal diversity, the Ethiopian part of the basin generally lacks comprehensive study or full scientific documentation. During the current surveys 31 species were identified from the lower Omo River and Ethiopian part of Lake Turkana, with some new records for the basin. The Omo River system was found to be richer in species while Lake Turkana has a higher abundance. Ichthyofaunal diversity within Ethiopian waters is specifically addressed, and an annotated checklist for native species of the basin is provided.

High prevalence of non-native fish species in a remote region of the Mamberamo River, Indonesia

2020 ◽  
Vol 26 (3) ◽  
pp. 293
Author(s):  
Arif Wibowo ◽  
Dwi Atminarso ◽  
Lee Baumgartner ◽  
Anti Vasemagi
Keyword(s):  
Native Species ◽  
River System ◽  
New Guinea ◽  
Current Status ◽  
Native Fish ◽  
Fish Diversity ◽  
Main River ◽  
Main River Channel ◽  
High Prevalence ◽  
Major River

Indonesian freshwater fish diversity is threatened by human activities such as logging, land clearing, pollution and introduction of non-native species. The latter may pose serious threats to endemic freshwater fauna even in relatively pristine and isolated habitats. One such area, West Papua in the island of New Guinea, is one of the least studied regions in the world and a biodiversity hotspot. The Mamberamo River contains the highest proportion of non-native fish compared to other major river systems in New Guinea. To document this, we conducted a field study to validate and further temporally characterise the fish biodiversity to ascertain its current status. Since the last ichthyological survey 15 years ago, we detected two additional non-native species (Leptobarbus melanopterus and Oreochromis niloticus) that have established in the river system. Moreover, our survey revealed that non-native fish are extremely common in the mid reaches of the Mamberamo River, comprising 74% of total catch, with non-native Barbonymus gonionotus (family Cyprinidae) now established as the dominant species. The biomass of non-native B. gonionotus now exceeds that of all native fish combined in the main river channel. These results highlight the serious threat of invasive species in remote regions that support high levels of endemic biodiversity. Plans for containment, prevention through education programmes, and management are urgently required.

scholarly journals Inventory of the fish fauna from Laranjinha River, Paranapanema River system, Brazil

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Bruno Ambrozio Galindo ◽  
Renata Rúbia Ota ◽  
Thiago Deruza Garcia ◽  
Raul Henrique Cardoso Nascimento ◽  
Willian Massaharu Ohara ◽  
...  
Keyword(s):  
Native Species ◽  
Fish Fauna ◽  
River System ◽  
Abundant Species ◽  
Iucn Red List ◽  
Fish Diversity ◽  
Migratory Species ◽  
Absolute Abundance ◽  
Average Abundance ◽  
Comprehensive Survey

Abstract: This work is the most comprehensive survey of the Laranjinha River´s fishes, a tributary of the Cinzas River, Paranapanema River basin. Throughout its course, there is only a low-height dam, including a transposition system located 98 km from its mouth. The sampling was carried out in nine locations, from the source to the mouth, with six field incursions in each location, using different fishing gear. A total of 11,924 fish were collected, distributed in seven orders, 27 families, and 100 species. The most representative order in the number of species was Siluriformes, followed by Characiformes. As for the families, Loricariidae comprised 21% and Characidae 14% of species richness. Phalloceros harpagos was the species with the highest absolute abundance, representing 11.3% of the total, followed by Hypostomus ancistroides with 9.8%. However, considering the average abundance and frequency of occurrence, Hypostomus ancistroides was the most abundant species, followed by Hypostomus cf. paulinus, Psalidodon aff. paranae and Phalloceros harpagos. Among the collected species, the Apteronotus acidops, Brycon orbygnianus, Brycon nattereri, Crenicichla jupiaensis, and Rhinelepis aspera were classified as endangered on the most recent IUCN Red List. Also, from the total sampled fish, 9.8% are considered non-native species. Among the native species recorded, 10 species are large migratory species, which indicates that the Laranjinha River is a route for spawning and maintenance of species diversity in the middle Paranapanema River. Therefore, the Laranjinha River is a heritage of fish diversity and deserves special attention in its preservation.

Rock varnish record of the African Humid Period in the Lake Turkana basin of East Africa

The Holocene ◽  
2021 ◽  
pp. 095968362110116
Author(s):  
Tanzhuo Liu ◽  
Christopher J Lepre ◽  
Sidney R Hemming ◽  
Wallace S Broecker
Keyword(s):  
East Africa ◽  
Lake Level ◽  
Drainage System ◽  
Early Holocene ◽  
Lake Turkana ◽  
Moisture Condition ◽  
Turkana Basin ◽  
Rock Varnish ◽  
Geomorphic Features ◽  
Humid Period

Rock varnish is a manganiferous dark coating accreted on subaerially exposed rocks in drylands. It often contains a layered microstratigraphy that records past wetness variations. Varnish samples from latest Pleistocene and Holocene geomorphic features in the Lake Turkana basin, East Africa display a regionally replicable microstratigraphy record of Holocene millennial-scale wetness variability and a broad interval of wetter conditions during the African Humid Period (AHP). Three major wet pulses in the varnish record occurred during the generally wet interval of the early Holocene (11.5–8.5 ka) when the lake attained its maximum high stand (MHS) at 455–460 m. A >23 m drop from the MHS occurred between 8.5 and 8 ka. Subsequently two additional wet pulses occurred during the early to middle Holocene (8–5 ka) when the lake occupied its secondary high stand at 445 m. Collectively, these five wet phases represent an extended wet interval coincident with the AHP in the region. One moderate wet phase occurred during the subsequent climatic transition from the humid to arid regime (5–4.3 ka) after the lake level dropped rapidly from 445 m to <405 m. Five minor wet phases took place during the overall arid period of the late Holocene (4.3–0 ka) when the lake level oscillated below 405 m. These findings indicate that the AHP terminated rapidly around 5 ka in the Turkana basin in terms of lake level drop, but the regional shift in relative humidity from the AHP mode to its present-day condition lagged for about 700 years until 4.3 ka, hinting at a gradual phasing out in terms of moisture condition. These findings further suggest that Lake Turkana overflowed intermittently into the Nile drainage system through its topographic sill at 455–460 m during the early Holocene and has become a closed-basin lake thereafter for the past 8 ky.

Pliocene archaeological occurrences in the Lake Turkana basin

1994 ◽  
Vol 27 (1-3) ◽  
pp. 159-171 ◽  
Author(s):  
Mzalendo Kibunjia
Keyword(s):  
Lake Turkana ◽  
Turkana Basin

scholarly journals Stepwise drying of Lake Turkana at the end of the African Humid Period: an example of forced regression modulated by solar activity?

2016 ◽  
Author(s):  
Alexis Nutz ◽  
Mathieu Schuster
Keyword(s):  
Solar Activity ◽  
Lake Level ◽  
Controlling Factors ◽  
Lake Turkana ◽  
Turkana Basin ◽  
Orbital Precession ◽  
Forced Regression ◽  
Humid Period

Abstract. Although timing of the termination of the African Humid Period (AHP) is relatively well-established now, modes and controlling factors are still being determined. Here, through a geomorphological approach, we characterize the evolution of the final regression of Lake Turkana at the end of the African Humid Period. We show that lake level fall during this period was not constant, yet rather stepwise consisted of five periods marked by rapid rates of lake level fall separated by periods of lower rates of lake level fall. Even the overall regressive trend is associated with regional decreased precipitations due to reduced insolation controlled by orbital precession, we discuss the origin of the five periods of accelerated rates of lake level fall. Finally, we propose that accelerations are associated with periods marked by solar activity minima that locally resulted in the repeated westward displacement of the Congo Air Boundary (CAB), thereby reducing rainfall across the Lake Turkana basin.

scholarly journals Molecular assessment of native fish diversity in UNESCO heritage site, Tasik Raban, using DNA barcoding

2021 ◽  
Vol 4 ◽  
Author(s):  
Ramizah Abdull Rahman ◽  
Nurul Fizatul Nabilah Osman ◽  
Adibah Abu Bakar ◽  
Syazwan Saidin ◽  
Intan Faraha Abdul Ghani ◽  
...  
Keyword(s):  
Native Species ◽  
Dna Barcode ◽  
Diversity Management ◽  
Freshwater Fishes ◽  
Animal Protein ◽  
Fish Diversity ◽  
Freshwater Species ◽  
Heritage Site ◽  
Online Databases ◽  
The World

Freshwater species are the most threatened group to be assessed to date by the IUCN. Freshwater fish has enormous importance as animal protein supplies for human, and it is estimated that 6% of the world annual animal protein supplies come from freshwater fishes. Barcoding projects have been initiated all over the world and the field is constantly growing. In Malaysia however, the field has not been deeply investigated and not many barcoding projects have been undertaken especially for freshwater fishes. The aim of our study is to support the progress of DNA barcode project, especially for inland reservoirs like Tasik Raban, Perak. A Standard methodology using Cytochrome c oxidase subunit 1 (COI) marker was developed to ensure native fishes are barcoded taxonomically and molecularly and ready to be accessed through online databases. Such public references can help increase awareness on local fish diversity management. Information on taxonomy and molecular characterization can be used to plan further conservation programmed especially for depleted, unrecognized, and cryptic native species.

n-Paraffins in the sediments and in situ fossils of the Lake Turkana Basin, Kenya

1982 ◽  
Vol 46 (9) ◽  
pp. 1505-1511 ◽  
Author(s):  
Paul I. Abell ◽  
Marshall J. Margolis
Keyword(s):  
Lake Turkana ◽  
Turkana Basin

How dry was the LGM? A Biosphere-Hydrosphere modelling approach for the paleo-lake Chew Bahir and Omo-River catchment in southern Ethiopia

2021 ◽  
Author(s):  
Markus L. Fischer ◽  
Felix Bachofer ◽  
Martin H. Trauth ◽  
Annett Junginger
Keyword(s):  
Land Cover ◽  
Environmental Data ◽  
Boosted Regression Trees ◽  
Lapse Rate ◽  
Southern Ethiopia ◽  
Lake Turkana ◽  
Ethiopian Highlands ◽  
Omo River ◽  
The Impact ◽  
Modelling Approach

&lt;p&gt;The formation of the East African Rift System led to the emergence of large topographical contrasts in southern Ethiopia. This extreme topography is in turn responsible for an extreme gradient in the distribution of precipitation between the dry lowlands (~500 mm a&lt;sup&gt;-1&lt;/sup&gt;) in the surrounding of Lake Turkana and the moist western Ethiopian Highlands (~2,000 mm a&lt;sup&gt;-1&lt;/sup&gt;). As a consequence, the prevailing vegetation is fractionated into a complex mosaic that includes desert scrubland along the Lake Turkana shore, woodlands and wooded grasslands in the Omo-River lowlands and the paleo-lake Chew Bahir catchment, afro-montane forests of the Ethiopian Highlands, and afro-alpine heath in most elevated parts. During the past 25 ka, southern Ethiopia has been exposed to significant climate changes, from a dry and cold Last Glacial Maximum (LGM, 25-18 ka BP) to the African Humid Period (AHP, 15-5 ka BP), and back to present-day dry conditions. These shifts in temperature and precipitation may have affected the vegetation pattern and landscape in the area, but environmental data especially from LGM times are rare. This is because in times of a dry climate the paleo-lake Chew Bahir was dried up and hence the climate record in lake sediments was interrupted.&lt;/p&gt;&lt;p&gt;In this study, we investigate the hydrological conditions during the LGM using a previously-developed lake balance model (LBM) for southern Ethiopia, which is now coupled with a new predictive vegetation model (PVM) to better understand the biosphere-hydrosphere interactions and thus possible precipitation thresholds. The PVM is based on the method of boosted regression trees using elevation and monthly precipitation as input to predict land-cover, tree-cover and vegetation greenness for a ~1 km grid covering the Omo-River, paleo-lake Chew Bahir, Lake Chamo and Lake Abaya catchments. We linked the PVM and the resulting land surface parameters with the LBM to model the impact of a changing land-cover to the actual evaporation. Furthermore, we used the glycerol dialkyl glycerol tetraethers (GDGT) based paleo-temperature and tropical lapse rate reconstructions from Mount Kenya to consider the orographic temperature distribution in southern Ethiopia during the LGM. Using both, we simulated different precipitation amounts from 100% to 50% compared to the modern-day multi-annual averages and their effect on vegetation and lake levels of paleo-lake Chew Bahir. Our biosphere-hydrosphere modelling approach suggests 25 to 30% lower moisture availability during the LGM compared to the modern conditions and provides a high-resolution spatial reconstruction of the potential prevailing vegetation in the southern Ethiopian region.&lt;/p&gt;

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