scholarly journals Mollusc fisheries and length–weight relationship in Tonle Sap flood pulse system, Cambodia

2018 ◽  
Vol 54 ◽  
pp. 34 ◽  
Author(s):  
Peng Bun Ngor ◽  
Ratha Sor ◽  
Leang Hour Prak ◽  
Nam So ◽  
Zeb S. Hogan ◽  
...  
Keyword(s):  
Annual Variation ◽  
Flood Pulse ◽  
Growth Patterns ◽  
Water Levels ◽  
Relationship Analysis ◽  
Weight Relationship ◽  
Daily Data ◽  
Tonle Sap ◽  
Mollusc Species ◽  
One Year

Molluscs are important for ecological function, livelihoods and fisheries, but are often forgotten in research and management. Here, we investigated intra-annual variation in the landing and growth patterns of three mollusc species, i.e., Corbicula moreletiana, Pila virescens and Pila ampullacea, using one-year daily data on landing catches and values, recorded in Kampong Chhnang province of Tonle Sap (TS) Lake. Overall, 8330 tonnes with a first sale landing value of US$ 1.4 million for the three species were reported. Also, we found that C. moreletiana was abundant during the dry season with high temperature and less precipitation. By contrast, the two Pila species were abundant from the early rainy to early dry seasons when precipitation and water levels increase. The length–weight relationship analysis indicated that a faster growth in weight of Pila species occurred in the rainy season, and a general negative allometric growth was observed for the three species. This implies that their populations were intensively fished. Our preliminary results suggest that molluscs in the TS Lake (i) are important resources in support of people's livelihoods, (ii) respond differently to intra-annual variation in temperature, precipitation and hydrology and (iii) are being intensively exploited with significant reduction in growth rate. Therefore, it is necessary to conduct further comprehensive research describing status of mollusc stocks and their ecology to support long-term management and conservation of this important aquatic fauna. Our study contributes to establishing the first important baseline data and information on key mollusc species for the TS.

scholarly journals Fly fish growth pattern (Decapterus spp) in Likupang Water, Nort Sulawesi

2019 ◽  
Vol 7 (1) ◽  
pp. 113
Author(s):  
Inggrid M. F Akerina ◽  
Silvester B. Pratasik ◽  
Nego E. Bataragoa
Keyword(s):  
Size Distribution ◽  
Growth Pattern ◽  
Growth Patterns ◽  
Fish Growth ◽  
Purse Seine ◽  
Relationship Analysis ◽  
Weight Relationship ◽  
Fish Samples

This study was aimed to find out the size distribution of scad (Decapterus spp) caught by Likupang fishermen and to find out theirgrowth patterns. Fish samples were collected by traditional purse seine fishermen in Likupang waters. Total catches were 139 individuals consisting of 89 D. macarellus and 50 D. macrosoma.The former was dominated by size of 19.2-20.6 cm, while the latter was dominated by size of 13.1-14.1 cm. Length-weight relationship analysis showed that the growth patterns of D. macarellus and D. Macrosoma were isometric meaning that the increase in length is consistent with weight gain.Keywords: Likupang, Decapterus spp and growth patternsABSTRAKPenelitian ini bertujuan untuk mengetahui distribusi ukuran ikan layang (Decapterus spp) yang ditangkap oleh nelayan Likupang and untuk menduga pola pertumbuhannya. Sampel ikan diperoleh nelayan tradisional pukat cincin di perairan Likupang.Total hasil tangkapan adalah 139 ekor terdiri dari 89 ekor  D. macarellus dan 50 D. macrosoma. Hasil tangkapan D. macarellus didominasi oleh kelas ukuran 19,2-20,6 cm, sedangkan D. macrosomadidominasi oleh kelas ukuran 13,1-14,1 cm. Analisis hubungan panjang berat menunjukkan bahwa pola pertumbuhan ikan D. macarellusdan D. macrosoma bersifat isometrik yang artinya pertambahan panjang selaras dengan pertambahan berat.Kata kunci: Likupang, Decapterus spp dan Pola pertumbuhan

scholarly journals Dams on Mekong tributaries as significant contributors of hydrological alterations to the Tonle Sap Floodplain in Cambodia

2014 ◽  
Vol 11 (2) ◽  
pp. 2177-2209 ◽  
Author(s):  
M. E. Arias ◽  
T. Piman ◽  
H. Lauri ◽  
T. A. Cochrane ◽  
M. Kummu
Keyword(s):  
Environmental Flows ◽  
Numerical Models ◽  
Flood Pulse ◽  
Economic Incentives ◽  
Water Levels ◽  
Surface Hydrology ◽  
Development Scenarios ◽  
Tonle Sap ◽  
Hydropower Potential ◽  
Annual Water

Abstract. River tributaries have a key role in the biophysical functioning of the Mekong Basin. Of particular attention are the Sesan, Srepok, and Sekong (3S) rivers, which contribute nearly a quarter of the total Mekong discharge. Forty two dams are proposed in the 3S, and once completed they will exceed the active storage of China's large dam cascade in the upper Mekong. Given their proximity to the lower Mekong floodplains, the 3S dams could alter the flood-pulse hydrology driving the productivity of downstream ecosystems. Therefore, the main objective of this study was to quantify how hydropower development in the 3S would alter the hydrology of the Tonle Sap floodplain, the largest wetland in the Mekong and home to one of the most productive inland fisheries in the world. We coupled results from four numerical models representing the basin's surface hydrology, water resources development, and floodplain hydrodynamics. The scale of alterations caused by hydropower in the 3S was compared with the basin's definite future development scenario (DF) driven by the upper Mekong dam cascade. The DF or the 3S development scenarios could independently increase Tonle Sap's 30 day minimum water levels by 30 ± 5 cm and decrease annual water level fall rates by 0.30 ± 0.05 cm d−1. When analyzed together (DF + 3S), these scenarios are likely to eliminate all baseline conditions (1986–2000) of extreme low water levels, a~particularly important component of Tonle Sap's environmental flows. Given the ongoing trends and large economic incentives in the hydropower business in the region, there is a high possibility that most of the 3S hydropower potential will actually be exploited and that dams would be built even in locations where there is a high risk of ecological disruptions. Hence, retrofitting current designs and operations to promote sustainable hydropower practices that optimize multiple river services – rather than just maximize hydropower generation – appear to be the most feasible alternative to mitigate hydropower-related disruptions in the Mekong.

scholarly journals Length-weight relationship, condition factor, and distribution of spotted barb (Barbodes binotatus Valenciennes, 1842) in Lake Tamblingan Bali

2021 ◽  
Vol 21 (2) ◽  
pp. 185-197
Author(s):  
Nyoman Dati Pertami ◽  
I Nyoman Yoga Parawangsa
Keyword(s):  
Aquatic Plants ◽  
Condition Factor ◽  
Mesh Size ◽  
Growth Patterns ◽  
Fish Sample ◽  
Allometric Growth ◽  
Volcanic Lake ◽  
Relationship Analysis ◽  
Weight Relationship ◽  
Endorheic Basin

Tamblingan Lake is a volcanic lake located in the caldera of  Mount Lesung a rain-fed lake in a confined endorheic basin and there is no inflow or outflow. Nyalian is a type of fish from the Cyprinidae family that is  quite common compared to other fish in its class in Tamblingan Lake. Information on the growth and distribution of these fish parameters in Tamblingan Lake does not exist. This study aims to analyze and explain the growth patterns of  Barbodes binotatus, especially the length-weight relationship, condition factor, and their distribution in the waters of  Tamblingan Lake. The research was conducted in Tamblingan Lake from January to June 2019 using a modify gill nets with the mesh size  0.5; 1.0; 1.5; 2.0; 2.5; 3.0 in centimeter. The sampling done in five locations. The length-weight relationship analysis used the power regression. The fish sample found was 204 individuals during the study with a range of total length was 5.2 – 15.0 cm. The equation of length-weight relationship is W = 0.0051 L3.387. The value of b formed based on this equation is 3.387 with a positive allometric growth pattern.The condition factor values ranged from 0.587 to 1.246. Barbodes binotatus spread in the litoral area where there are many aquatic plants. This information of nyalian fish could use as the basis for fish resource management in Tamblingan Lake.

Multidecadal variability of the Tonle Sap Lake flood pulse regime

2021 ◽  
Author(s):  
Aifang Chen ◽  
Junguo Liu ◽  
Matti Kummu ◽  
Olli Varis ◽  
Qiuhong Tang ◽  
...  
Keyword(s):  
Flood Pulse ◽  
Pulse Regime ◽  
Multidecadal Variability ◽  
Tonle Sap Lake ◽  
Tonle Sap

scholarly journals Simulation and Assessment of Groundwater for Domestic and Irrigation Uses

2019 ◽  
Vol 5 (9) ◽  
pp. 1877-1892 ◽  
Author(s):  
Majed Rodhan Hussain ◽  
Basim Sh. Abed
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Water Quality Assessment ◽  
Alluvial Fan ◽  
Water Levels ◽  
Specific Yield ◽  
Annual Rainfall ◽  
Steady State Condition ◽  
Groundwater Samples ◽  
One Year

The alluvial fan of Mandali located between latitude 30˚45’00” N longitude 45˚30’00” E in east of Diyala Governorate, Iraq. Thirty-five wells were identified in the study area with average depth of 84 m and estimated area of 21550 ha. A three-dimensional conceptual model was prepared by using GMS program. From wells cross sections, four geological layers have been identified. The hydraulic conductivity of these layers was calculated for steady state condition, where the water levels for nine wells distributed over the study area were observed at same time. Afterward, PEST facility in the GMS was used to estimate the aquifer hydraulic characteristics. Other characteristics such as storage coefficient and specific yield have been determined from one year field observations that were collected by General Authority of Groundwater, Diyala Governorate. Also, the observations were used for calibration of unsteady state model. Then wells were hypothetically redistributed and increased to 103 wells, assuming a distance of 1500 m between the wells, a well productivity rate of were 7 l/s, annual rainfall rate was used for recharging. Three different wells operating times were suggested and these 6, 12, and 18 hr/day with total discharge of 150, 300, 450 m3/day and maximum drawdown of 7, 11, and 20 m respectively. For water quality assessment, the collected groundwater samples were analysed at the laboratory.  Results showed that the TDS in all wells was ranged from 1000-3000 mg/l but TDS in well number 18 was exceeded 3000 mg/l which indicate that the groundwater in this well is not recommended to be used for irrigation. According to Iraqi standard for drink (IQS 2009), it can be used for drinking if saline treatment units were provided.

scholarly journals The problems of overexploitation of aquifers in semi-arid areas: the Murcia Region and the Segura Basin (South-east Spain) case

2012 ◽  
Vol 9 (5) ◽  
pp. 5729-5756 ◽  
Author(s):  
T. Rodríguez-Estrella
Keyword(s):  
Water Quality ◽  
Water Levels ◽  
Arid Areas ◽  
Karstic Aquifer ◽  
Autonomous Region ◽  
Groundwater Reserves ◽  
One Year ◽  
Semi Arid ◽  
Overexploited Aquifer ◽  
Poor Management

Abstract. A general analysis of the problems arising from aquifer exploitation in semi-arid areas such as the Autonomous Region of Murcia, which belongs to the Segura Basin is presented, with particular reference to the Ascoy-Sopalmo aquifer, which is the most overexploited aquifer in Spain. It has suffered intense overabstraction over the last forty years, given renewable water resources of 2 Mm3 yr−1 and abstractions amounting to as much as 55 Mm3 yr−1. This has resulted in the drying of springs, continuous drawdown of water levels (5 m yr−1); piezometric drops (over 30 m in one year, as a consequence of it being a karstic aquifer); increase in pumping costs (elevating water from more than 320 m depth); abandoning of wells (45 reduced to 20), diminishing groundwater reserves, and deteriorating water quality (progressing from a mixed sodium bicarbonate-chloride facies to a sodium chloride one). This is a prime example of poor management with disastrous consequences. In this sense, a series of internal measures is proposed to alleviate the overexploitation of this aquifer and of the Segura Basin, with the aim of contributing to a sustainable future.

scholarly journals Changes in composition of aquatic bird assemblages associated with changing in water levels in the Aquatic Terrestrial Transitional Zone of the Pantanal wetland Brazil

2020 ◽  
Vol 9 (10) ◽  
pp. e4479108555
Author(s):  
Josué Ribeiro da Silva Nunes ◽  
Carolina Joana da Silva ◽  
Solange Kimie Ikeda-Castrillon ◽  
Nilo Leal Sander
Keyword(s):  
Aquatic Macrophyte ◽  
Transitional Zone ◽  
High Water ◽  
Flood Pulse ◽  
Water Levels ◽  
Aquatic Birds ◽  
Mato Grosso ◽  
Paraguay River ◽  
The Difference ◽  
Pantanal Wetland

The Pantanal wetland Mato Grosso, Brazil is among the largest floodplains in the world, with a mosaic of different habitats and rich aquatic and terrestrial biota. The habitat mosaics are found in the Chacororé and Sinhá Mariana lake System. These parental lakes of the Cuiabá River, a left tributary of the Upper Paraguay River, are known for their aquatic productivity and scenic beauty. The characteristics of these lakes and their floodplains are showed through the difference between their waters, the diversity of the aquatic macrophytes communities, fish communities and aquatic birds. Our study looked at changes in limnological variables as well as diversity of aquatic birds, during high water or flooded phase; medium water or receding phase; and the low water or dry phase. We used a temporary small lagoon in the floodplain of this system as our study area. The flood pulse is the main ecological factor affecting the Pantanal; it modifies ecological process and species composition. The water depth decreases during the season, decreasing electrical conductivity, dissolved phosphate and nitrate, water transparency, dissolved oxygen and biomass of aquatic macrophyte; and increasing calcium, total phosphorus and total nitrogen. We also observed increase in species richness and abundance of aquatic birds during the receding phase. Results show that the number of species (density) of aquatic birds increased from 10 to 30 species and the numbers of individuals from 40 to 936. The maximum richness and abundance of aquatic birds was registered during the receding phase.

scholarly journals Length-weight relationship of Threadfin Bream (Nemipterus sp.) in Village Malang Rapat Waters, Bintan Regency, Riau Island

2020 ◽  
Vol 13 (2) ◽  
pp. 449
Author(s):  
Rapita Rapita ◽  
Susiana Susiana ◽  
Rochmady Rochmady
Keyword(s):  
Growth Patterns ◽  
Allometric Growth ◽  
Fish Resources ◽  
Weight Relationship ◽  
Relationship Of

Village Malang Rapat waters are have the potential and habitat of kurisi fish resources (Nemipterus sp.). The research was to determine the length-weight relationship of kurisi fish (Nemipterus sp.) in Village Malang Rapat. Sampling of kurisi fish (Nemipterus sp.) in two months (October-November 2020) is taken once a week based on fishing grounds and habitat. Length-weight relationship of female and male kurisi fish (Nemipterus sp.) were y = 1,1568x2,0659 and y = 1,2123x1,8971 respectively, based on this value show that female and male kurisi fish (Nemipterus sp.) in Village Malang Rapat waters have negative allometric growth patterns (b < 3).

scholarly journals Movements of the Eastern Ribbonsnake (Thamnophis sauritus) in Nova Scotia

2016 ◽  
Vol 129 (4) ◽  
pp. 379
Author(s):  
T. L. Imlay ◽  
J. Saroli ◽  
T. B. Herman ◽  
S. W. Mockford
Keyword(s):  
Nova Scotia ◽  
Annual Variation ◽  
Prey Availability ◽  
Home Range Size ◽  
Water Levels ◽  
Suitable Habitat ◽  
Home Ranges ◽  
Daily Movement ◽  
The Status ◽  
Best Fit

The disjunct Eastern Ribbonsnake (Thamnophis sauritus) population in southwest Nova Scotia is listed as “threatened” by the committee on the Status of Endangered Wildlife in Canada. A study of the movements of the species at two lakeshore locations known to support a high density of Eastern Ribbonsnakes was undertaken in 2007 and 2008. Average seasonal movements at both sites ranged from 17 m to 84 m for juvenile snakes and 21 m to 130 m for adults; one neonate was recaptured during the study after travelling 32 m. The maximum distance travelled by an individual snake was 391 m in one season. The best-fit model to explain differences in daily movement patterns included year (P = 0.041), indicating that there is annual variation in the movements of this species. Low recapture rates precluded accurate estimates of home-range size, which varied roughly from 0.16 ha to 0.78 ha. Both movements and home ranges were larger than previously documented in Nova Scotia, but maximum distances travelled were consistent with a previous study in Michigan. Most documented movements were along the lakeshore within contiguous, suitable habitat. More work is needed to understand the frequency of large movements and triggers that initiate movements, e.g., changes in water levels, habitat suitability, or prey availability.

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