scholarly journals Composition and Abundance of Drifting Fish Eggs on the Upper Reaches of Xijiang River, China, after the Formation of the Cascade Reservoirs

2020 ◽  
Author(s):  
Gao Minghui ◽  
Wu Zhiqiang ◽  
Tan Xichang ◽  
Huang Liangliang ◽  
Huang Haibo ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Life History Strategies ◽  
Effective Management ◽  
Fish Eggs ◽  
Spawning Period ◽  
Fish Resources ◽  
Management Actions ◽  
Xijiang River ◽  
Distribution Of Fish ◽  
Natural Channel

AbstractTo develop effective management actions of riverine fisheries, it is important to monitor how fish resources (i.e., eggs) are recruited in the upper reaches of natural rivers, particularly where dams have been constructed, which potentially hinder life-history strategies. Here, we aimed to determine the State of drifting fish eggs resources, and the underlying environmental factors regulating the presence of fish eggs in the upper reaches of a river (Laibin section of Xijiang River, China). Based on surveys conducted over one spawning period (2016), we set out to: (1) describe the composition and abundance of drifting fish eggs in the 150 km Lainbin section under a dam control, and (2) analyze how the composition and distribution of fish eggs was correlated with environmental factors. A total of 15157 eggs belonging to two orders, four families, and 18 species were collected. Comparison of these data with historical records in the same area showed that the community structure of drifting eggs has changed considerably. Previously, the community was dominated by larger-bodied species, rather than the smaller species documented in 2016. Eggs were primarily detected between May and August. In the natural channel, the greatest abundance of eggs occurred during May and June. In comparison, the greatest abundance of eggs downstream of the dam was detected in July. The results of this study provide important information for water conservancy institutions towards managing regions containing dams to maintain the ecology of rivers and protect important fish resources.

Structure and distribution of fish resources in the Yellow Sea off Shandong during spring and autumn 2006

2013 ◽  
Vol 18 (6) ◽  
pp. 1335-1342
Author(s):  
Zhenbo LU ◽  
Bingqing XU ◽  
Fan LI ◽  
Mingyi SONG ◽  
Huanjun ZHANG ◽  
...  
Keyword(s):  
Yellow Sea ◽  
The Yellow Sea ◽  
Fish Resources ◽  
Distribution Of Fish

scholarly journals HUBUNGAN KEPADATAN IKAN DENGAN KONDISI LINGKUNGAN PERAIRAN ESTUARI DI KABUPATEN BANYUASIN

2017 ◽  
Vol 23 (2) ◽  
pp. 111
Author(s):  
Aroef Hukmanan Rais ◽  
Rupawan Rupawan ◽  
Herlan Herlan
Keyword(s):  
Water Temperature ◽  
Significant Contribution ◽  
Aurelia Aurita ◽  
Total Biomass ◽  
Biomass Distribution ◽  
Phytoplankton Abundance ◽  
Biomass Density ◽  
Fish Resources ◽  
Salinity Water ◽  
Distribution Of Fish

Estuari di wilayah Kabupaten Banyuasin dengan potensi biodiversitas sumber daya ikan yang tinggi, merupakan wilayah penangkapan yang potensial dan berkontribusi besar terhadap poduksi perikanan Provinsi Sumatera Selatan. Distribusi biomassa sumber daya ikan di wilayah estuari sangat dinamis dan dipengaruhi oleh parameter salinitas dan suhu perairan pada suatu lingkungan perairan. Penelitian ini bertujuan untuk mengetahui kondisi kepadatan biomassa ikan dalam hubungannya dengan kondisi lingkungan perairan di wilayah perairan estuari Kabupaten Banyuasin.Pengambilan sampel ikan dilakukan dengan percobaan penangkapan menggunakan alat tangkap trawl mini yang diopeasikan di tiga wilayah estuari yaitu Sungai Banyuasin, Sungai Musi dan Sungai Upang. Pada masing-masing wilayah estuari ditentukan sebanyak empat lokasi sampling. Frekuensi pengambilan sampel dilakukan sebanyak empat kali yaitu pada Maret, Juni, Agustus dan Oktober agar mewakili kondisi musiman.Parameter lingkungan yang dianalisa adalah salinitas, suhu perairan, kecerahan, nitrat, amoniak, total fosfat dan kelimpahan fitoplankton. Hasil penelitian menunjukkan sebanyak 87 spesies ikan telah teridentifikasi. Diperoleh nilai kepadatan biomassa 332,13 – 861,49 kg/km2 di estuari Upang, 590,51 – 2.235,04 kg/km2 di estuari Musi dan 1.296,4 - 33.714,88 kg/km2 di estuari Banyuasin. Spesies ubur-ubur (Aurelia aurita) mendominasi tangkapan pada Agustus hingga Oktober yang mencapai 77,22% dari biomassa total ikan dikarenakan lingkungan yang sesuai untuk keperluan pertumbuhannya. Kepadatan biomassa ikan berkorelasi positif dengan parameter salinitas dan kelimpahan fitoplankton, dan berkorelasi negatif terhadap parameter amoniak. Estuaries of Banyuasin district has a high biodiversity of fish resources and significant contribution to the fisheries production in the South Sumatera Province. The biomass distribution of fish in the estuary fluctuated and probably affected by by salinity and water temperature. This research aims to investigate the correlation between biomass density and environment condition in the estuary of Banyuasin Regency. Sampling was conducted through experimental fishing used a mini trawl that operated in three estuary areas, such as: Banyuasin Rivers, Musi Rivers, and Upang Rivers. Every estuary area was replicated for four sampling sites. Samples were collected during March, June, August and October. The waters parameters analyzed were salinity, water temperature, transparency, nitrate, ammonia, phosphate total, and phytoplankton. The results showed that about 87 species of fish have been identified. The biomass density was 332,13 – 861,49 kg/km2 in estuary Upang, 590,51 – 2.235,04 kg/km2 in estuary Musi and 1.296,4 - 33.714,88 kg/km2 in estuari Banyuasin. A jelly fish (Aurelia aurita) is dominated in August to October, up to 77.22% of total biomass. The biomass density of fish was positively correlated with salinity and phytoplankton abundance, whereas negatively correlated to ammoniac condition.

scholarly journals Application of an Integrated Assessment Scheme for Sustainable Waste Management of Electrical and Electronic Equipment: The Case of Ghana

2020 ◽  
Vol 12 (8) ◽  
pp. 3191
Author(s):  
Mentore Vaccari ◽  
Fabiola Zambetti ◽  
Margaret Bates ◽  
Terry Tudor ◽  
Teklit Ambaye
Keyword(s):  
Developing Countries ◽  
Environmental Factors ◽  
Waste Management ◽  
Personal Protective Equipment ◽  
Integrated Assessment ◽  
Electronic Equipment ◽  
Protective Equipment ◽  
Effective Management ◽  
Waste Streams ◽  
Development And Utilization

The effective management of solid waste, including waste electrical and electronic equipment (WEEE) in developing countries poses significant challenges. This paper reports on the development and utilization of a multi-criteria tool to improve the management of WEEE in Agbogbloshie, in Ghana. The tool was able to successfully evaluate key economic, social and environmental factors faced by workers and to suggest areas for improvement. In particular, the evaluation and comparison of different scenarios suggested that the best solution is the evolution from informal to formal management of WEEE, with workers provided with personal protective equipment, and the introduction of refurbishment activities, with the sale of components in the second-hand market. While it would require further use in other contexts, the tool could be adapted and employed for a range of other waste streams and in other developing countries.

Catchment-wide survival of wild- and hatchery-reared Atlantic salmon smolts in a changing system

2015 ◽  
Vol 72 (9) ◽  
pp. 1352-1365 ◽  
Author(s):  
Daniel S. Stich ◽  
Michael M. Bailey ◽  
Christopher M. Holbrook ◽  
Michael T. Kinnison ◽  
Joseph D. Zydlewski
Keyword(s):  
Environmental Factors ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Dam Removal ◽  
Migratory Species ◽  
Hydropower Generation ◽  
Multistate Model ◽  
Management Actions ◽  
Coastal Systems ◽  
Penobscot River

We developed a hierarchical multistate model to estimate survival of Atlantic salmon (Salmo salar) smolts in the Penobscot River, USA, over a decade during which two mainstem dams were removed from the catchment. We investigated effects of (i) environmental factors, (ii) rearing history, and (iii) management actions, including dam removal, turbine shutdown, and installation of new powerhouses. Mean ± SD smolt survival per kilometre was higher through free-flowing reaches of the catchment (0.995 ± 0.004·km−1) than through reaches containing dams that remain in the system (0.970 ± 0.019·km−1). We observed maximum survival between 12 and 17 °C and at intermediate discharges (1200 m3·s−1). Smolt survival increased concurrent with dam removal and decreased following increases in hydropower generation. The greatest increase in smolt survival followed seasonal turbine shutdowns at a dam located on the largest tributary to the Penobscot River, while other shutdowns had little influence. Our model provides a useful tool for assessing changes to survival of migratory species and will be useful for informing stocking plans to maximize numbers of smolts leaving coastal systems.

scholarly journals Relationship between childhood (un)predictability and life milestones in young Brazilians

2017 ◽  
Vol 11 (1) ◽  
pp. 92-101
Author(s):  
Cézar Donizetti Luquine Júnior ◽  
Anna Beatriz Carnielli Howat-Rodrigues ◽  
Patrícia Izar
Keyword(s):  
Life History ◽  
Environmental Factors ◽  
Life History Strategies ◽  
Data Support ◽  
Childhood Environment ◽  
First Child ◽  
The Family ◽  
Formal Employment

The present study sought to investigate whether perceived family unpredictability affects the development of life history strategies in both the reproductive and somatic domains by evaluating the ages at which life milestones occurred. In this study 211 young Brazilians answered a 10-item instrument that contained future milestones, the Family Unpredictability in Childhood, and a sociodemographic questionnaire. Not all participants had already achieved the milestones. Earlier ages of giving birth to the first child, marrying, starting a family, and at first formal employment were correlated with greater unpredictability scores. Significant correlations were found more frequently for the participants who had already met the milestones. Data support the importance of the childhood environment for later development. Results suggest that data obtained based on the ages at which milestones occurred and ages at which milestones are expected to occur may present important differences with regard to the influence of environmental factors.

The role of wind-forcing in the distribution of larval fish in Galway Bay, Ireland

2012 ◽  
Vol 93 (2) ◽  
pp. 471-478 ◽  
Author(s):  
Stephen Comerford ◽  
Deirdre Brophy
Keyword(s):  
Environmental Factors ◽  
Generalized Linear Model ◽  
Larval Fish ◽  
Juvenile Fish ◽  
Residual Circulation ◽  
Tidal State ◽  
Merlangius Merlangus ◽  
Sampling Season ◽  
Distribution Of Fish

The ichthyoplankton of Galway Bay was sampled over the spring and summer of 2007 and 2008 to determine what environmental factors influenced the distribution of larval and early juvenile fish. A total of 549 fish representing 27 taxa were caught. Catches decreased throughout each sampling season, and were generally poor in 2007. Catches were numerically dominated by sprat (Sprattus sprattus), dab (Limanda limanda), sand eel (Hyperoplus immaculatus) and whiting (Merlangius merlangus). Environmental factors driving distribution of fish were modelled using a binomial generalized linear model. The strength and direction of wind in the five days preceding sampling was the only significant environmental factor. Sustained onshore winds increased the probability of encountering larval fish in the areas sampled. The rainfall, tidal state, tow depth and wind conditions during sampling were not significant. Among the parameters measured it appears that onshore winds sufficiently strong to overcome the residual circulation are the main physical driver for the distribution of larval fish in Galway Bay.

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