scholarly journals The Natural History of the Satellite Lakes of Lake Malawi

2019 ◽  
Author(s):  
George Turner ◽  
Benjamin P Ngatunga ◽  
Martin J Genner
Keyword(s):  
Fish Species ◽  
Adaptive Radiation ◽  
Management Practices ◽  
Fish Fauna ◽  
Lake Malawi ◽  
Model Systems ◽  
Native Fish ◽  
Fish Diversity ◽  
Crater Lakes ◽  
Cichlid Fishes

Large, long-lived lakes, such as Lake Baikal and the African Great Lakes are known for their diverse endemic faunas. Nearby smaller isolated lakes have long been hypothesised to facilitate allopatric speciation, such as Lake Nabugabo at the edge of Lake Victoria, helping seed the radiation in the large lakes. Furthermore, crater lakes, formed by volcanic activity are often deep, long-lived and relatively isolated, and often host a number of closely-related endemics, becoming model systems for testing theories of sympatric speciation and adaptive radiation, such as Lakes Barombi Mbo in Cameroon, and Apoyo in Nicaragua. Here we report on studies of 9 crater lakes in southern Tanzania: Lakes Ikapu, Ilamba, Itamba, Itende, Kingiri, Kyungululu, Masoko (=Kisiba), Ndwati and Ngozi, plus the shallow satellite lakes Chikukutu and Chilingali in central Malawi. Additional notes are presented about fish species present in nearby river systems. The lakes differ considerably in surface area, depth and water chemistry. No permanently aquatic animals were observed in Lake Ngozi, the largest of the lakes, nor in Lake Ndwati. All of the other 7 craters lakes were found to contain cichlid fishes, comprising a total of 29 populations of which 24 are considered likely to be native, many meriting recognition as distinct species. At least one lake (Masoko) contains a diverging pair of cichlid ecomorphs likely to be undergoing sympatric ecological speciation. Another case might be the dwarf and large ecomorphs of Rhamphochromis in Lake Kingiri. In addition, 4 crater lakes are reported to contain members of other fish families: Clariidae, Cyprinidae, Danionidae and Procatopodidae. The lakes also hosted a variety of macro-invertebrates, including crabs, bivalves and gastropods. There is evidence of repeated attempts to stock all of these lakes with non-native fish species, in at least one case leading to the establishment of breeding populations of two species. This represents a major threat to these unique ecosystems. In Malawi, Lakes Chilingali and Chikukutu were recently joined as a result of damming of the outflow of the former. This ‘large Chilingali’ hosted a diverse fish fauna, including two apparently endemic haplochromine cichlid fishes of the genera Lethrinops and Rhamphochromis. The lake was heavily fished and attempts had been made to stock cages for tilapia culture using non-native populations of species already present in the lake. However, the dam was allowed to erode and it finally collapsed in 2011-13, resulting in the restoration of the previous condition of two inter-connected lakes. Little is known of the pre-impoundment lakes, but post-collapse, the lakes became shallow and swampy, with apparently greatly reduced fish diversity. Neither endemic species could be found when the lakes were sampled in 2016. Our work has indicated that the satellite lakes of Lake Malawi are important reservoirs of biodiversity that can play a major role in our understanding of speciation and adaptive radiation, but they are fragile systems currently threatened by poor management practices including intentional stocking of non-native fish.

scholarly journals Differences in sensitivity of native and exotic fish species to changes in river temperature

2011 ◽  
Vol 57 (6) ◽  
pp. 852-862 ◽  
Author(s):  
R.S.E.W. Leuven ◽  
A.J. Hendriks ◽  
M.A.J. Huijbregts ◽  
H.J.R. Lenders ◽  
J. Matthews ◽  
...  
Keyword(s):  
Exotic Species ◽  
Fish Species ◽  
Native Species ◽  
Temporal Trends ◽  
Fish Fauna ◽  
Native Fish ◽  
Fish Diversity ◽  
Exotic Fish ◽  
River Temperature ◽  
Exotic Fish Species

Abstract This paper describes the effects that temperature changes in the Rhine river distributaries have on native and exotic fish diversity. Site-specific potentially affected fractions (PAFs) of the regional fish species pool were derived using species sensitivity distributions (SSDs) for water temperature. The number of fish species in the river distributaries has changed remarkably over the last century. The number of native rheophilous species declined up until 1980 due to anthropogenic disturbances such as commercial fishing, river regulation, migration barriers, habitat deterioration and water pollution. In spite of progress in river rehabilitation, the native rheophilous fish fauna has only partially recovered thus far. The total number of species has strongly increased due to the appearance of more exotic species. After the opening of the Rhine-Main-Danube waterway in 1992, many fish species originating from the Ponto-Caspian area colonized the Rhine basin. The yearly minimum and maximum river temperatures at Lobith have increased by circa 4 0C over the period 1908-2010. Exotic species show lower PAFs than native species at both ends of the temperature range. The interspecific variation in the temperature tolerance of exotic fish species was found to be large. Using temporal trends in river temperature allowed past predictions of PAFs to demonstrate that the increase in maximum river temperature negatively affected a higher percentage of native fish species than exotic species. Our results support the hypothesis that alterations of the river Rhine’s temperature regime caused by thermal pollution and global warming limit the full recovery of native fish fauna and facilitate the establishment of exotic species which thereby increases competition between native and exotic species. Thermal refuges are important for the survival of native fish species under extreme summer or winter temperature conditions.

scholarly journals Rapid expansion and biodiversity impacts of the red devil cichlid (Amphilophus labiatus, Günther 1864) in Lake Sentani, Papua, Indonesia

2018 ◽  
Vol 19 (6) ◽  
pp. 2096-2103 ◽  
Author(s):  
HENDERITE L. OHEE ◽  
PUGUH SUJARTA ◽  
SURIANI BR. SURBAKTI ◽  
HOLLY BARCLAY
Keyword(s):  
Fish Species ◽  
Fish Fauna ◽  
Wiener Index ◽  
Rapid Expansion ◽  
Native Fish ◽  
Fish Diversity ◽  
Exotic Fish ◽  
Dominant Fish ◽  
Total Fish ◽  
Trophic Niches

Ohee HL, Sujarta P, Br Surbakti S, Barclay H. 2018. Rapid expansion and biodiversity impacts of the red devil cichlid (Amphilophus labiatus, Günther 1864) in Lake Sentani, Papua, Indonesia. Biodiversitas 19: 2096-2103. The red devil cichlid (Amphilophus labiatus, Günther 1864) is one of ten exotic fish species inhabiting Lake Sentani. It is believed to be one of the most important threats to the native fish of Lake Sentani. This study aimed to document the distribution of red devil cichlids and the impacts of this species on native fish fauna. Fish were sampled in six locations in Lake Sentani using gill nets during February and March 2018. Fish species and abundance were recorded and used to calculate the relative abundance, dominance, species evenness, Shannon Wiener Index (H’) and the correlation between introduced and native fish species. A total of 836 fish belonging to 12 species were recorded across Lake Sentani. Mean fish diversity (H’=0.57) and evenness (E= 0.25) were low. The red devil cichlid is the most abundant fish recorded during our surveys (87.2% of total fish collected) and is now the most dominant fish in the lake (C=0.76). Moreover, it has colonized all areas sampled within the lake because of its ability to colonize new habitat and to successfully exploit a large diversity of trophic niches. However, Amphilophus labiatus was not found to be significantly correlated to native fish between different sites in Lake Sentani. The existence of endemic and native fish in Lake Sentani is now seriously threatened by the presence of the red devil cichlid throughout this lake.

scholarly journals Advancing improvement in riverine water quality caused a non-native fish species invasion and native fish fauna recovery

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Łukasz Głowacki ◽  
Andrzej Kruk ◽  
Tadeusz Penczak
Keyword(s):  
Water Quality ◽  
Fish Species ◽  
Native Species ◽  
Interference Competition ◽  
Fish Fauna ◽  
Species Traits ◽  
Native Fish ◽  
Biological Degradation ◽  
Species Invasion ◽  
Prussian Carp

AbstractThe knowledge of biotic and abiotic drivers that put non-native invasive fishes at a disadvantage to native ones is necessary for suppressing invasions, but the knowledge is scarce, particularly when abiotic changes are fast. In this study, we increased this knowledge by an analysis of the biomass of most harmful Prussian carp Carassius gibelio in a river reviving from biological degradation. The species' invasion followed by the invasion's reversal occurred over only two decades and were documented by frequent monitoring of fish biomass and water quality. An initial moderate improvement in water quality was an environmental filter that enabled Prussian carp’s invasion but prevented the expansion of other species. A later substantial improvement stimulated native species’ colonization of the river, and made one rheophil, ide Leuciscus idus, a significant Prussian carp’s replacer. The redundancy analysis (RDA) of the dependence of changes in the biomass of fish species on water quality factors indicated that Prussian carp and ide responded in a significantly opposite way to changes in water quality in the river over the study period. However, the dependence of Prussian carp biomass on ide biomass, as indicated by regression analysis and analysis of species traits, suggests that the ecomorphological similarity of both species might have produced interference competition that contributed to Prussian carp’s decline.

scholarly journals Present and past status of fish fauna of river Basantar, an important tributary of the river Ravi, in Samba district, Jammu (J&K)

2012 ◽  
Vol 4 (1) ◽  
pp. 123-126 ◽  
Author(s):  
Arti Sharma ◽  
S. P. S. Dutta
Keyword(s):  
Environmental Factors ◽  
Fish Species ◽  
Fish Fauna ◽  
Fish Diversity ◽  
Anthropogenic Pressure

Icthyofaunal study of river Basantar, an important tributary of river Ravi in Samba district, Jammu (J&K) has revealed the existence of 35 fish species belonging to 5 orders, 10 families and 25 genera. There is dominance of Cypriniformes (18 spp.) followed by Siluriformes (10 spp.), Perciformes (4 spp.), Synbrachiformes (2 spp.) and Osteoglossiformes (1 sps.). Present record of 35 fish species when compared with the earlier report of 59 fish species reveals a decline in fish diversity and is caused by environmental factors and anthropogenic pressure.

scholarly journals Keanekaragaman Jenis Ikan di Sepanjang Sungai Boyong – Code Propinsi Daerah Istimewa Yogyakarta

2016 ◽  
Vol 1 (1) ◽  
pp. 21 ◽  
Author(s):  
Tri Trijoko ◽  
Donan Satria Yudha ◽  
Rury Eprilurahman ◽  
Setiawan Silva Pambudi
Keyword(s):  
Fish Fauna ◽  
Native Fish ◽  
Fish Diversity ◽  
Sampling Area ◽  
Anabas Testudineus ◽  
Merapi Volcano ◽  
Starting Point ◽  
Introduced Fishes ◽  
Middle Stream ◽  
Channa Striata

The diversity of freshwater fishes which inhabit in the river of Daerah Istimewa Yogyakarta is not yet well documented. Complete documentation is needed as starting point and continuous research on the fish diversity in DIY. Boyong-Code River flows across the DIY, and it upstream is located on the hillside of Merapi volcano. The Code River upstream is called Boyong River. The research was aimed to acquire data about the diversity of fish fauna along the Boyong-Code River in the DIY. Further, the research purpose is to know which species are rare, potential for aquaculture, and introductive. Samples are taken along the Boyong-Code River starting from upstream to downstream. Samples were collected using Purposive Random Sampling methods with fishnets. Sampling area generally divided into three location i.e., upstream, middle-stream and downstream. Species diversity of fish in the Boyong-Code River is consisted of 24 species, with 5 introductive species. There are eleven native fish species which are potential for cultivation (aquaculture), i.e.: Barbodes binotatus, Mystacoleucus obtusirostris, Rasbora lateristriata, Rasbora argyrotaenia, Barbonymus balleroides, Osteochilus vittatus, Hampala macrolepidota, Anabas testudineus, Channa striata, Clarias leiacanthus and Clarias batrachus. The Boyong-Code River is a decent habitat for fishes. Many introduced fishes starting to invade the Boyong-Code River intentionally or unintentionally by human

scholarly journals The Species Composition and Distribution Patterns of Non-Native Fishes in the Main Rivers of South China

2020 ◽  
Vol 12 (11) ◽  
pp. 4566
Author(s):  
Dang En Gu ◽  
Fan Dong Yu ◽  
Yin Chang Hu ◽  
Jian Wei Wang ◽  
Meng Xu ◽  
...  
Keyword(s):  
Species Composition ◽  
Fish Species ◽  
South China ◽  
Management Practices ◽  
Distribution Patterns ◽  
Freshwater Ecosystems ◽  
Native Fish ◽  
Species Number ◽  
Feeding Strategies ◽  
Native Fishes

Non-native fish invasions are among the greatest threats to the sustainability of freshwater ecosystems worldwide. Tilapia and catfish are regularly cultured in South China which is similar to their climate in native areas and may also support their invasive potential. We systematically collected fish from eight main rivers of South China, from 2016 to 2018, to investigate and analyse species’ composition and the distribution of non-native fishes. The data reveal that non-native fishes are widespread and abundant in the sampled rivers: of the 98,887 fish collected, 11,832 individuals representing 20 species were not native, which were distributed in the 96% sampled sites. Of the non-native fish species, 17 are used in aquaculture and 19 are native to the tropics; 13 are omnivores while the other seven are predators. Based on dissimilarity of the non-native fish species distributions across the eight rivers, the different rivers could be divided into four assemblages. Geographical isolation and temperature were identified as affecting the distribution patterns of non-native fishes, thereby influencing fish species composition, species number, dominant species, and distribution variations in the South China rivers. Species composition of the non-native fishes in these rivers are related to their introduction vector, compatibility with their native habitat, and feeding strategies. Their distribution was mainly influenced by geographical location and temperature. To mitigate the impacts of non-native fish, a series of stricter management practices, systematic monitoring, and more research are needed.

The spread of exotic fish species in Italian rivers and their effect on native fish fauna since 1990

Biodiversity ◽  
2020 ◽  
pp. 1-9
Author(s):  
Luciano Bani ◽  
Valerio Orioli ◽  
Stefania Trasforini ◽  
Cesare Mario Puzzi ◽  
Andrea Sibilia ◽  
...  
Keyword(s):  
Fish Species ◽  
Fish Fauna ◽  
Native Fish ◽  
Exotic Fish ◽  
Exotic Fish Species

scholarly journals SPATIO-TEMPORAL VARIATION OF THE ICHTHYOFAUNA IN THE ESTUARY FROM MANAMO CHANNEL, ORINOCO RIVER DELTA, VENEZUELA

2019 ◽  
Vol 12 (45-48) ◽  
Author(s):  
Ángel Marval-Rodríguez ◽  
José Alió-Mingo ◽  
Yorlen Carvajal ◽  
Douglas Altuve ◽  
Germán Vizcaíno
Keyword(s):  
Temporal Variation ◽  
Fish Species ◽  
Rainy Season ◽  
Fish Fauna ◽  
Commercial Application ◽  
Fish Diversity ◽  
Dry Period ◽  
Structural Dynamic ◽  
Orinoco River ◽  
Spatio Temporal

<p>The delta of Orinoco River constitutes a long estuarine extension of a great importance to fisheries at Venezuela, because, it is an indispensable area for reproduction, feeding and growing of several fish species, most of them with a commercial application. The purpose of this research was to identify and analyze the changes in fish diversity and the structural dynamic of the community at four zones of channel Manamo, during dry and rainy season. Samples were taken on March and May for dry period and July and August for rainy season. A total of 48 species were identified, grouped into 24 families and 42 genera. The diversity was higher in Bajo del Medio during the dry season (2.58 bits/ind), decreasing to 1.66 bits/ind in el Pajar (rains). The PERMANOVAS analyzes showed statistical differences in the composition of species with respect to the climate season (psed-F = 0.0365, <em>p</em> &lt;0.05), but not between the sampling stations (psed-F 0.6668; <em>p</em> &lt; 0.05). The results indicated that the fish fauna of the region is composed of elements characteristic of an estuary, being the climate seasons the most important factors for the evaluated group and this reflects the seasonal nature of this community.</p>

scholarly journals Diversity, potentiality, and conservation status of fish fauna in the upper Mahakam’s tributaries, East Kalimantan

2019 ◽  
Vol 19 (3) ◽  
pp. 391
Author(s):  
Jusmaldi Jusmaldi ◽  
Nova Hariani ◽  
Norbeta Doq
Keyword(s):  
Fish Species ◽  
Diversity Index ◽  
Conservation Status ◽  
Fish Fauna ◽  
Iucn Red List ◽  
Fish Diversity ◽  
East Kalimantan ◽  
Wiener Diversity Index ◽  
Data Deficient ◽  
Almost All

Diversity, potentiality and conservation status of fish fauna in upper Mahakam’s tributaries of east Kalimantan is unknown. The purposes of this study were to analysis species diversity, determine potentiality and conservation status of fish fauna in upper Mahakam’s tributaries, east Kalimantan. Fish sampling with purposive method was conducted in four tributaries, i.e Tepai River, Pahangai River, Danum Parai River, and Meraseh River for one month. Fishes were collected by several gears type. The results of this research showed that the total number of fish caught was 820 individuals; consist of 26 species, 7 families, and 4 orders. The Cyprinidae was the most dominant family found in all tributaries. The Shannon-Wiener diversity index in four tributaries were varied and ranging from 1.749-2.087. The highest fish diversity was recorded at Maraseh River followed by Pahangai River, Danum Parai River, and Tepai River. The low fish diversity was discovered at Tepai River may be due to differences in substrate type, water velocity, and water depth as compared to the Maraseh River, Pahangai River, Danum Parai River. The fish species similarity coefficient between four tributaries ranged from 0.606-0.842 and the highest dissimilarity was found between Tepai River and Danum Parai River. Almost all fishes categorized as edible fish for local consumption. Syncrossus hymenophysa and Gastromyzon lepidogaster have potential as ornamental fish. Regarding IUCN red list status, six fish species were grouped into least concern status, two species as data deficient, one species as near threatened, one species as endangered species and 16 other species were not on the list.

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