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

<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>

2020 ◽  
Vol 8 ◽  
pp. 39-52
Author(s):  
Kumar Khatri ◽  
Bibhuti Ranjan Jha ◽  
Smriti Gurung ◽  
Udhab Raj Khadka

This review describes the current status of freshwater fish diversity, their IUCN categories and threats to fish fauna in Nepal. The freshwater systems of the country are known to harbor over 220 fish species, thereby indicating a rich ichthyofaunal diversity. However, this number varies from author to author. Cyprinidae is the most common and dominant taxon. A total of 15 endemic and 15 exotic fish species have been reported. A total of 34 fish species have been listed under the IUCN Red List threatened categories. Major threats to fish include damming and pollution. Fish diversity studies have mainly focused on inventories only. Studies focusing on river longitudinal aspects, the inclusion of spatio-temporal aspects, and rigorous taxonomic studies combined with genetic studies are crucial to develop strategic conservation measures of fish fauna in Nepal.


2012 ◽  
Vol 4 (1) ◽  
pp. 123-126 ◽  
Author(s):  
Arti Sharma ◽  
S. P. S. Dutta

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.


2015 ◽  
Vol 20 (3) ◽  
pp. 170 ◽  
Author(s):  
Ahmad Zahid ◽  
M.F. Rahardjo ◽  
Lenny S Syafei ◽  
Rini Susilowati

Pengetahuan mengenai ekologi trofik merupakan dasar dalam memahami ekosistem secara keseluruhan yang dapat dijelaskan melalui pola hubungan trofik interspesies ataupun interserikat. Penelitian bertujuan untuk menjelaskan ekologi trofik meliputi indeks trofik dan jenis makanan dominan, serikat dan tingkat trofik, dan variasi spasial dan temporal komunitas ikan di estuari Segara Menyan. Pengambilan ikan contoh dilakukan setiap bulan pada zona berbeda. Ikan contoh dipisahkan berdasarkan waktu dan lokasi pengamatan, dianalisis isi saluran pencernaannya. Analisa data meliputi indeks vakuitas, jumlah total organisme makanan, jenis makanan dominan, luas relung makanan, dan tingkat trofik.  Pada pengamatan 106 spesies ikan, sebanyak 1-380 saluran pencernaan ikan diamati. Sebanyak lima dari 106 spesies memiliki nilai indeks vakuitas “0” dan jumlah makanan yang dikonsumsi bervariasi mulai dari empat hingga 27 jenis makanan. Secara umum, luas relung ikan adalah rendah berkisar 0,20-0,78 dan kebanyakan berada pada kisaran 0,20-0,48. Zooplankton merupakan jenis makanan paling dominan dikonsumsi oleh ikan. Komunitas ikan dikelompokkan dalam tujuh serikat trofik, yaitu detritivora, fitoplanktivora, zooplanktivora, zoobentivora, moluskivora, krustasivora, dan pisivora. Tingkat trofik komunitas ikan berkisar 2,05-4,73. Faktor perubahan ontogenetik, persediaan makanan, karakteristik habitat, dan ruaya beberapa spesies ikan memengaruhi variasi spasio-temporal jejaring makanan di Segara Menyan. Kata kunci: interaksi trofik, laguna, ikan, variasi spasio-temporal, serikat trofik Knowledge of trophic ecology is one way to understanding the whole ecosystem which explained by trophic relationship pattern (interspecies or interguild). The objective research was described of the trophic ecology, i.e. trophic index and dominant prey, trophic guild and trophic level, and spatio-temporal variation of fish community in Segara Menyan coastal lagoon. Fish were collected monthly for one year at three zones. Fish samples were placed in separate labelled plastic bags according to the time scale and location sampling, then gut contents were analyzed. The data of vacuity index, number of prey, prey dominant, diet breadth, and trophic level were analyzed. For each of 106 fish species, between 1 and 380 stomachs, were examined. The vacuity index was also different among species. Five of 106 species had a vacuity index of “0” and total number of food items consumed varied between fish species, ranging from three items to 27 items. The overall diet breadth (Bi) was relatively low among species, ranging from 0.20 to 0.78, with most of them between 0.20 and 0.48. Calanoid copepods comprised the most common food item consumed by all the fishes examined. Fishes occurring can be broadly categorized into seven different trophic guilds. The trophic level of fish communities ranged from 2.05 to 4.73. Spatio-temporal variation of food web was influenced of ontogenetic shift, food availability, habitat characteristic, and migration of some species in Segara Menyan coastal lagoon. Keywords: trophic interaction, lagoon, fishes, spatio-temporal variation, trophic guild


Caldasia ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 139-151
Author(s):  
Eduardo Villarreal ◽  
Neis Martínez ◽  
Catalina Romero-Ortiz

The Dry Tropical Forest (DTF) is one of the most diverse yet threatened biomes of Colombia. There is limited information about the richness of the order Pseudoscorpiones (Arachnida) in this ecosystem in the country. Pseudoscorpions are ecologically interesting, as they may be good indicators of habitat conservation. However, it is still necessary to gather more knowledge related to its spatio-temporal variation. In this study, pseudoscorpion diversity variation was assessed in two fragments of the Dry Tropical Forest in the Caribbean region of Colombian: Reserva Campesina La Montaña (RCM) and Reserva La Flecha (RLF). Four samplings were carried out between March and September of 2016 to include the dry and rainy season. Pseudoscorpions were collected using litter sifting (SL) and manual capture (MC). A total of 260 individuals belonging to five families and eight species were collected. The most abundant was Pachyolpium granulatum (Olpiidae) and the richest family was Chernetidae. The collection methods were effective and complementary. Spatial variation was significant, but no temporal variation was observed however, there was a marked difference between the abundance at RCM in the dry season and the rainy season. In contrast, at RLF most individuals were found in the dry season in comparison with the rainy season. These new faunistic data is the first of its order in the Atlántico and Bolívar department.


2019 ◽  
Author(s):  
George Turner ◽  
Benjamin P Ngatunga ◽  
Martin J Genner

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.


2019 ◽  
Vol 11 (6) ◽  
pp. 308
Author(s):  
Yasmim Yathiara Gomes Araújo Morais ◽  
Patrícia Carneiro Souto ◽  
Sérvio Túlio Pereira Justino ◽  
Valdirene Henrique Nunes ◽  
Anderlon Arrais de Moraes Monte ◽  
...  

The litter is an important way of returning the organic matter to the soil, through the cycling of the nutrients, aiding in the development of the vegetation present in the ecosystems. The study aimed to estimate the spatio-temporal variation of deposition, accumulation and decomposition of the litter present in the preserved caatinga vegetation, located in the RPPN Fazenda Tamandu&aacute; in Santa Terezinha-PB, Brazil and the interference of climatic variables in the dynamics of these events. The research was conducted at RPPN Fazenda Tamandu&aacute;, in Santa Terezinha-PB, Brazil. The deposition of litter on 20 collectors of 1.0 m &times; 1.0 m was collected monthly in two periods: period I (August/2015 to July/2016) and period II (August/2016 to July/2017), the collected material was separated into leaves, branches + barks, reproductive and miscellaneous fractions. To estimate the rate of decomposition the litter accumulated on the forest floor was quantified using a 0.5 m &times; 0.5 m metal frame. The deposition of the total litter in periods I and II was 2,356.83 kg ha-1 and 1,163.67 kg ha-1, respectively. The leaf fraction was the one that contributed the most during the two collection periods. The analysis of the data allowed to conclude that the total litter deposition in the two periods is in line with the average production for the Caatinga. The increase in precipitation provided higher deposition of litter after the rainy season. Due to several factors, the decomposition of litter in the caatinga is slower than in other biomes.


2019 ◽  
Vol 19 (3) ◽  
pp. 391
Author(s):  
Jusmaldi Jusmaldi ◽  
Nova Hariani ◽  
Norbeta Doq

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.


2016 ◽  
Vol 16 (1) ◽  
Author(s):  
Alexandre Kannebley de Oliveira ◽  
Julio Cesar Garavello ◽  
Vinicius Vendramini Cesario ◽  
Rodrigo Torres Cardoso

The fish species composition of Sapucaí-Mirim River is herein reported and discussed in the faunistic context of Grande and Paranaíba river basins, both formers of the Paraná River. The Sapucaí-Mirim is an important tributary of this hydrographic system, flowing to the left bank of Grande River in a region occupied by the reservoir of the Porto Colombia hydroelectric power plant, at São Paulo state northeastern region, in southeastern Brazil. The poorly known fish diversity of the Sapucaí-Mirim River is presented on basis of sampling efforts conducted in the main river channel and three creeks located at the mid and lower sections of the basin, allowing comparisons of the fish fauna of these two sections in the light of available information of fish inhabiting Grande and Paranaíba river basins. The study of the fish composition resulted in the recognition of 68 species in the Sapucaí-Mirim River, belonging to 23 families distributed in seven orders, all commonly found in upper Paraná River basin: Characiformes (32 spp.), Siluriformes (25 spp.), Labriformes (4 spp.), Gymnotiformes (3 spp.), Cyprinodontiformes (2 spp.), Perciformes (one species) and Synbranchiformes (one species). Most of the species are representative of the native ichthyofauna, but the total diversity also includes allochthonous species, which were chiefly found in the lower stretch studied. Some species found in the Sapucaí-Mirim River require great areas for their maintenance, as do large-sized species, known to have migratory reproductive habits. Also, the diversity of small and medium-sized species found and their distinct morphological and biological attributes, allied to the occurrence of endangered fish species, indicate that the Sapucaí-Mirim River basin is an important place for fish diversity maintenance in the Grande River hydrographic system.


Author(s):  
Babita Selakoti

The present study deals with the ichthyofaunal diversity in the river Kosi at Almora district Uttarakhand. During the whole study period (Jan. 2013 to Dec. 2013) 12 species of fish fauna were observed. All the recorded fish species belonged to the families Cyprinidae and Botinae. Cyprinidae was the dominant family having 9 fish species out of the 12 species. The family Botinae comprised of 3fish species


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