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Population Dynamics and Management of Two-barred Seabream Acanthopagrus bifasciatus in the Red Sea, Egypt
Samia Mohsen El-Mahdy,
Sahar Fahmy Mehanna,
Usama Mohammed Mahmoud,
Fahmy Ibrahim El-Gammal
Issue:
Volume 4, Issue 4, December 2019
Pages:
80-87
Received:
1 August 2019
Accepted:
25 October 2019
Published:
31 October 2019
Abstract: The present study is the first study on the population dynamics and management of the Acanthopagrus bifasciatus in the Egyptian sector of Red Sea. A total of 729 specimens were monthly collected from the Egyptian Red Sea during January 2015 to December 2015. Results showed that, the longevity of A. bifasciatus is 9 years in the Egyptian Red Sea and age group three was the most frequent one for combined sexes forming up to 26.61% of the total catch. The age group one was absent in the collected samples and the highest growth in length was observed at the end of the second year of life (24.6 cm) after which the annual increment decreases gradually with increase in age. The growth in weight was isometric. The length at first capture was 25.31 cm with corresponding age 2.22 year. The total, natural and fishing mortality were estimated as 1.99, 0.46 and 1.53 yr-1, respectively. The exploitation ratio E was estimated at 0.77 indicating a high level of exploitation. The yield per recruit analysis showed that the present level of fishing mortality is much higher than that gives the maximum yield per recruit by about 48% and the reduction of current level of fishing mortality coefficient from 1.53 to 0.8 / y will be associated with an increase in the yield per recruit from 242.71 to 250.56 g (≈3%).
Abstract: The present study is the first study on the population dynamics and management of the Acanthopagrus bifasciatus in the Egyptian sector of Red Sea. A total of 729 specimens were monthly collected from the Egyptian Red Sea during January 2015 to December 2015. Results showed that, the longevity of A. bifasciatus is 9 years in the Egyptian Red Sea and...
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Effects of Acute Concentrations of Vestaline® (pendimethalin) Herbicide on Histopathology of Liver and Gills of Exposed Clarias gariepinus Juveniles
Odo Joel Inya,
Manyi Manasseh Msugh-Ter,
Ebah Esther Eneyi
Issue:
Volume 4, Issue 4, December 2019
Pages:
88-92
Received:
28 October 2019
Accepted:
22 November 2019
Published:
2 December 2019
Abstract: This study was carried out to determine histopathological damages of liver and gills caused by acute concentrations of vestaline®(pendimethalin) herbicide on Clarias gariepinus using96-hour bioassay test. The toxicity was carried out using 180 healthy fish of mean weight 27.97±0.03g which were divided into six treatments with each treatment having ten fish and the setup was in triplicate. The concentrations of Vestaline®(pendimethalin) herbicide used were (0.0mg/l, 33mg/l, 82.5mg/l,115.5mg/l,148.5mg/l and 181.5mg/l). After the 96-hours, both gills and liver of the fish were removed from dead fish. Photomicrographs of the histological slides were taken.Histology of the liver in control sample showed normal hepatic tissue (Hepatocytes with granular cytoplasm) and round nucleus. Histology of the gills in control sample showed normal structure of the filaments and lamellae. The histology of the exposedliver Showed vacoulation of cytoplasm, rapture of hepatocytes, bile pigment disintegration, necrosis and cytoplasmic degeneration while the histology ofgills exposed to different concentrations of vestaline®(pendimethalin) herbicide showed marked distortion of the gills lamellae, hyperplasia of lamellar epithelium and necrosis. The acute concentrations confirmed that vestaline®(pendimethalin) herbicide is highly toxic to Clarias garienpinus and showed heightened damages at higher concentrations.
Abstract: This study was carried out to determine histopathological damages of liver and gills caused by acute concentrations of vestaline®(pendimethalin) herbicide on Clarias gariepinus using96-hour bioassay test. The toxicity was carried out using 180 healthy fish of mean weight 27.97±0.03g which were divided into six treatments with each treatment having ...
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Environmental Health Status of Some Aquatic Ecosystems in Badagry Division, Lagos, Nigeria
Mekuleyi Gabriel Olarinde,
Anetekhai Martins Agenuma,
Aderinola Oluwatoyin Joseph,
Adu Abosede
Issue:
Volume 4, Issue 4, December 2019
Pages:
93-102
Received:
10 October 2019
Accepted:
4 November 2019
Published:
4 December 2019
Abstract: The status of Agboju, Ajegunle, Topo and Gbaji water bodies in Badagry Division of Lagos State, Nigeria was evaluated between April and November 2018 in order to determine the suitability of the ecosystem to biota and safety of the aquatic resources for human consumption. Some environmental variables such as alkalinity, temperature, biochemical oxygen demand (BOD), conductivity, total dissolved solid (TDS), carbon (iv) oxide (CO2), total hardness, chemical oxygen demand (COD), turbidity, phosphate, dissolved oxygen (DO), pH, salinity, sulphate and nitrate, and some heavy metals (Fe, Cu, Zn, Pb, Cd and Cr) in water, sediment, aquatic plant (Eichhornia crassipes) and fish (Ethmalosa fimbriata) were measured using standard procedures. The results showed that BOD, COD, total hardness and turbidity values were above the standard permissible limits. Cd in water column of Agboju and Ajegunle, and Pb recorded from Agboju, Ajegunle and Topo, exceeded standard permissible limit. Cu (0.56±0.54), Zn (5.45±0.89), Pb (0.54±0.47) and Cr (0.455±0.375) contents in E. fimbriata (from Ajegunle) was slightly above permissible limits while Cd and Fe contents in the fish across the four stations were above permissible limits. Contamination factor, Index of geochemical accumulation and enrichment factor showed moderate degree of contamination of cadmium and Fe in the sediment. This preliminary study could be concluded that the biota can still survive in the ecosystems despite high contamination of the water bodies with metals. However, human consumption of several of E. fimbriata and water could cause health hazard. Therefore, urgent effort should be made by all users of the ecosystem to decline in discharging untreated waste into these water bodies.
Abstract: The status of Agboju, Ajegunle, Topo and Gbaji water bodies in Badagry Division of Lagos State, Nigeria was evaluated between April and November 2018 in order to determine the suitability of the ecosystem to biota and safety of the aquatic resources for human consumption. Some environmental variables such as alkalinity, temperature, biochemical oxy...
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Feathers of Little Egret (Egretta garzetta) Fledglings as a Bio Monitoring Tool for Mercury, Arsenic, Cadmiumand Lead Pollution in Sri Lanka
Ravindra Lakshantha Jayaratne,
Inoka Chinthana Perera,
Devaka Keerthi Weerakoon,
Sarath Wimalabandara Kotagama
Issue:
Volume 4, Issue 4, December 2019
Pages:
103-113
Received:
15 July 2019
Accepted:
22 October 2019
Published:
10 December 2019
Abstract: The objective of this study is to establish a baseline set of data for heavy metal contaminants in diverse ecosystems in Sri Lanka using bird feathers as a bio monitoring tool. During May to July 2014 heavy metal concentration (Hg, As, Cd and Pb) was assessed in bird feathers and regurgitated materials of Little Egrets (Egretta garzetta) and water collected within the foraging areas at five heronries from three districts of Sri Lanka. A significant variation of Hg and As (p<0.05) was observed. But such a significant variation was not observed for Cd (p>0.05). Only As concentration of regurgitated materials show significantly variation between sites (p<0.05) whereas no significant variation in Hg and Cd (p>0.05). In all sites, for all four metals there were some significant variations of metal concentrations in water. Pb was only detected in water and no more in feathers and regurgitated materials. The concentration of Hg, As, Cd and Pb were generally within the normal background level and mostly below the threshold level that may affect bird survival and reproduction. According to the results of the present study, feathers of Little Egret fledglings can be used as a bio-monitoring tool to measure the bio accumulation of Hg, As and Cd except Pb with combination of metal concentration of their regurgitated materials and water that was collected from the surroundings of heronries.
Abstract: The objective of this study is to establish a baseline set of data for heavy metal contaminants in diverse ecosystems in Sri Lanka using bird feathers as a bio monitoring tool. During May to July 2014 heavy metal concentration (Hg, As, Cd and Pb) was assessed in bird feathers and regurgitated materials of Little Egrets (Egretta garzetta) and water ...
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An Overview of the Impact of Climate Change on Pathogens, Pest of Crops on Sustainable Food Biosecurity
Mbong Annih Grace,
Tembe-Fokunang Estella Achick,
Berinyuy Eustace Bonghan,
Manju Evelyn Bih,
Ngo Valery Ngo,
Mbah James Ajeck,
Galega Tangham Bobyiga Prudence,
Fokunang Charles Ntungwen
Issue:
Volume 4, Issue 4, December 2019
Pages:
114-124
Received:
25 October 2019
Accepted:
2 December 2019
Published:
10 December 2019
Abstract: Anthropogenic activities on the environment have intensified in the last century resulting in a devastating increase in greenhouse gases and triggering global climate oscillation. Global food productions have increase significantly by 50% in order to meet the anticipated demand of the world’s population by 2050. The challenges of food production increases are high and even harder if climate change as a global threat is not addressed. In the coming years, there could be more changes in the biosecurity of food crops due to escalating global climate change. The effects of climate change on plant pathogens and the diseases they cause have been reported in some pathosystems. Climatic changes have been predicted to affect pathogen development and survival rates with possible modification of host susceptibility, host-pathogen-vector interaction that could lead to changes in the impact of diseases on food crops. The climate change may affect not only the optimal conditions for infection but also host specificity and mechanisms of plant infection. Changes in the abiotic conditions are known to affect the microclimate surrounding plants and the susceptibility of plants to disease. These changing conditions are expected to affect microbial communities in the soil and canopy pathosystems, with the possibility of altering the beneficial effects of these communities. Since both the pathogens and host plants could be affected by the dramatic changes in the magnitude of disease expression in a given pathosystem, the geographical distribution of particular plant diseases, their economic importance in a given location, and the set of diseases that infect each crop are crucial to understand their etiology and level of virulence. These changes could affect the measures farmers take to efficiently manage these diseases, as well as the feasibility of cropping systems in particular regions. This review examines the effects of changes in temperature, CO2 and ozone concentrations, precipitation, and drought on the biology of pathogens and their ability to infect plants and survival in natural and agricultural environments. We also underpin the multiple aspects linked to the effects of climate change on crop plant diseases, including the impact of increasing concentrations of atmospheric CO2 and other gases, and how diseases can change under the alteration of atmospheric gases conditions in the future.
Abstract: Anthropogenic activities on the environment have intensified in the last century resulting in a devastating increase in greenhouse gases and triggering global climate oscillation. Global food productions have increase significantly by 50% in order to meet the anticipated demand of the world’s population by 2050. The challenges of food production in...
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