Gamal Othman El-Naggar

• PhD
• Researcher at Central Laboratory for Aquaculture Research

This study evaluates the performance of different tilapia pond culture practices in Egypt. Sixty farms were surveyed in the main farming areas. Production inputs and outputs data obtained from tilapia monoculture, tilapia and mullet, and tilapia polyculture systems. A production function was employed to compare resource use efficiency amongst the s...

Perception is the bed rock to really apprehend the assertiveness and interpretations of the farmers which are the grass root receptors or benefactors of the effects of climate change. Individual perception and knowledge on climate change varies according to geographical location, occupation, political and socio-economics, ecological, cultural backg...

Introduction: Fish yields from aquaculture exceeded one million tonnes per annum ranking Egyptian aquaculture 8th among the top fish producing countries in the world by 2014 (FAO, 2016). Tilapia production leads the way and Egypt is the third largest producer globally after China and Indonesia. In this study, fish samples of the Nile tilapia (Oreoc...

Empirical observations and climate models both indicate that global climate and ocean conditions have been changing over the last 100 years and will likely change more rapidly in the future. This study examined the perceptions of fish farmers in rainfed (blue water) and irrigated (green water) aquaculture in Africa. South West Nigeria and Egypt wer...

The Swiss Agency for Development and Cooperation (SDC)-funded Improving Employment and Income through Development of Egypt’s Aquaculture Sector (IEIDEAS) project was implemented by WorldFish in partnership with CARE Egypt and the Egyptian Ministry of Agriculture and Land Reclamation from 2011 to 2014 and later extended to November 2015. The project...

Many tilapia (Oreochromis spp.) farmers produce all-male populations because of the superior growth rate of males compared to females. To investigate differences in body weight at harvest of males and females among different tilapia strains, we analyzed data from 62,787 individuals collected from pedigreed breeding programs of O. niloticus (GIFT fr...

This study was carried out to evaluate the value chain performance of the aquaculture feed sector in Egypt, in terms of value addition, employment and profitability. The strengths and weaknesses of each link of the value chain were assessed and appropriate upgrading, management and development strategies were suggested. Quantitative data were colle...

This study was carried out in order to understand the technical and economic characteristics of different Egyptian Nile tilapia (Oreochromis niloticus) hatchery systems. Hatchery operators at fifty tilapia hatcheries in four governorates were interviewed and four focus group discussions were held with 61 participants in March 2012. Technical charac...

Expansion of Egypt's aquaculture industry has been matched by the development of a large number of tilapia hatcheries all producing sex-reversed all-male fry and fingerlings. In order to map the fish seed value chain in Egypt, operators of fifty tilapia hatcheries in four governorates (Kafr el-Sheikh, Behera, Sharkia and Fayoum) were interviewed. T...

Econometric techniques were used to estimate a production function for tilapia pond culture in El-Fayum Governorate, Egypt, utilizing cross-sectional field data. Explanatory variables were feed, initial stocking weight, and pond size. The function was used to examine returns to scale, estimate the productivity of feed and initial stocking weight, a...

The Abbassa selection line (developed by selective breeding) and the Kafr El Sheikh commercial strain (widely used in Egypt), both Oreochromis niloticus, were compared at two stocking densities (two and four fish m−2). Harvest weight, length, depth, width and head length were recorded. The Abbassa line showed a superior harvest weight (28 per cent)...

Egypt's aquaculture production (705,490 tonnes in 2009) is by far the largest of any African country and places it 11th in terms of global aquaculture production. The aquaculture sector in Egypt is now a mature one having developed over a period of more than 30 years, but the financial performance of the sector is not well understood or documented,...

Egypt's aquaculture production (921,585 tonnes in 2010) is by far the largest of any African country and places it 11 th in terms of global production. Despite the fact that the aquaculture sector in Egypt is now a mature one having developed over a period of more than 30 years, the economic performance of the sector is not well understood or docum...

This report describes a study done in 2010 by researchers of the WorldFish Center on water use in Egyptian farms that apply aquaculture – agriculture integration. Two of the four farms that were monitored derived the main income from farming and selling fish, the two other farms were mainly agricultural farms that used reservoirs that were built to...

EXECUTIVE SUMMARY Egypt’s aquaculture production (705,490 tonnes in 2009) is by far the largest of any African country and places it 11th in terms of global production. The aquaculture sector makes a significant contribution to income, employment creation and food security in the country, all of which are national priority areas given low per capit...

Value-Chain Analysis of Egyptian Aquaculture Graeme Macfadyen , Ahmed Mohamed Nasr Allah , Diaa Abdel Reheem Kenawy , Mohamed Fathi Mohamed Ahmed , Hussien Hebicha , Ahmed Diab , Samy Mohmed Hussein , Ramadan Mohamed Abouzied , and Gamal el Naggar . Executive Summary Egypt’s aquaculture production (705,490 tonnes in 2009) is by far the largest of a...

Twelve 400 m2 earthen ponds were used to test the effect of Nile tilapia, Oreochromis niloticus, African catfish, Clarius gariepinus, monoculture and polyculture on water quality, fish production and economic performance across a range of stocking ratios: 100% tilapia + 0% catfish, 75% tilapia + 25% catfish, 50% tilapia + 50% catfish, and 0% tilapi...

The purpose of this study was to examine the effect of some immunostimulants and probiotics on the survival rate, final weight, and disease resistance of overwintered tilapia fry. There were five treatments: T1 (control) fed a balanced diet (35% protein) without additives. Treatments 2 to 5 were fed diets supplemented with 4% garlic, 4 g/kg Echinac...

To determine the appropriate fertilization method that optimizes nutrient inputs, minimizes financial/environmental costs and ultimately maximizes fish production, this work was conducted in twenty earthen ponds of 2000 m 2 each, at the WorldFish Center, Egypt, for 195 days. A polyculture of Nile tilapia (Oreochromis niloticus), silver carp (Hypoph...

The purpose of this study was to examine the effect of some immunostimulants and probiotics on the survival rate, final weight, and disease resistance of overwintered tilapia fry. There were five treatments: T1 (control) fed a balanced diet (35% protein) without additives. Treatments 2 to 5 were fed diets supplemented with 4% garlic, 4 g/kg Echinac...

This study was conducted to investigate the effect of replacing fishmeal with soybean meal in diets with different levels of dietary protein on the production economics of Nile tilapia (Oreochromis niloticus L.). Sixteen 0.2 hectare earthen ponds were used for the experiment. Ponds were randomly assigned in groups of four ponds each to one of the f...

This paper examines the economic analysis of fish farming in Behera Governorate of Egypt. Sample survey of 15 farmers representing the fish farming community in the area was used. The study was conducted from May 2004 to July 2005 covering one production season. The study result revealed that the average age of fish operators was 43 years, majority...

our plant based immunostimulants (Echinacea purpurea 0.25 and 1.0 ppt, Allium sativum 3 %, Nigella sativa 3% and Origanum marjorana 2 and 3% and mixture of Allium sativum , Nigella sativa 3:1, 1:3 and 3:3%, respectively) were tested as feed additives for their effect on the survival and growth of 1600 Oreochromis niloticus. The mean weights of fish...

Semipurified diets containing either no ascorbic acid or supplemental amounts of 11, 22, 44 and 132 mg/kg from Gascorbic acid (AA), L-ascorbyl-2-monophosphate (AAP) or L-ascorbyl-2-sulfate (AAS) were fed to channel catfish fingerlings (13 ± 2.1 g average initial weight) in aquaria. After a feeding period of 14 wk, weight gain was measured and ascor...

Studies were conducted to determine the effect of stocking size and density of prawns in polyculture. In one experiment, postlarval prawns (av. wt. 0.02 g) were stocked in six 0.02 ha earthen ponds at 35,00O/ha. Two ponds were stocked with tilapia fry (av. wt. 0.14 g) and two were stocked with tilapia fingerlings (av. wt. 30.1 g), each at 10,000/ha...

The development of a reliable methodology for spawning of African catfish, Clarias gariepinus without the use of hormone injections would greatly improve the prospects of aquaculture in Africa. Earlier work has shown that it is possible to produce C. gariepinus fingerlings by subjecting the broodfish to a physical stress of reduced water depth and/...

This paper describes the factors influencing fish farming productivity in Behera, Egypt. Sample survey of 15 farmers representing the fish farming community in the area was used. The study was conducted from May 2004 to July 2005 covering one production season. The study results revealed that the average age of fish operators was 43 years, majority...

This paper describes the factors influencing fish farming productivity in Behera, Egypt. Sample survey of 15 farmers representing the fish farming community in the area was used. The study was conducted from May 2004 to July 2005 covering one production season. The study results revealed that the average age of fish operators was 43 years, majority...

The present study aimed to ga in detailed information on the distribution of some heavy metals (Cu, Pb, Zn, Fe and Cd) among the major components of the aquatic ecosystem (water, sediment and fish " Oreochromis niloticus ") of Damietta district at the area of El-Bostan. Such information is needed to identify the effect of fish cages on the aquatic...

Photoperiod, crude protein level and water temperature were studied for their effects on reproductive performance and egg hatchability in Nile tilapia (Oreochromis niloticus). Photoperiod was either natural (12h illumination: 12h dark) or complete darkness during 24 hours. Crude protein was in diets at 20%, 30% or 40%. Water temperature during spaw...

An 8-week feeding study was conducted to determine the potassium requirement of juvenile channel catfish. Six dietary levels of potassium ranging from 0.01 to 0.49% were fed to triplicate groups of catfish (initial average weight of 16.6 g) in flow-through aquaria at a water temperature of 26.7 ± 1.1 °C. The rearing water contained 4 mg/l potassium...

Channel catfish (Ictalurus punctatus) fingerlings (13 g average initial weight) were fed semipurified diets supplemented with 0, 0.06, 0.12, 0.24 and 0.72 mmol/kg (0, 11, 22, 44 or 132 mg/kg) of ascorbic acid molar equivalent supplied by either L-ascorbic acid, L-ascorbyl-2-monophosphate (Mg salt) (AAP), or L-ascorbyl-2-sulfate (K salt) (AAS). Afte...

The effects of fertilizer types and stocking density were investigated on water quality parameters that expected to affect growth performance of the polyculture of Nile tilapia (Oreochromis niloticus), African catfish (Claris gariepinus) and silver carp (hypophthalmichthys molitrix). The stocking ratios of the three species were 85% tilapia: 15% ca...