Books by Sahar F Mehanna
The trawl fishery off Egyptian Mediterranean waters consists of 1,400 vessels, yielding a total a... more The trawl fishery off Egyptian Mediterranean waters consists of 1,400 vessels, yielding a total annual landing of approximately 16,000 t. The bogue (Boops boops) is a target species for this fishery, with annual landings oscillating between 1,222 and 3,980 t during the last 18 years. The stock of Boops boops in the Egyptian Mediterranean waters has been assessed using a 3 years length frequency data (2007–2009) from the trawl fishery. The vector of natural mortality by age was calculated from Caddy's formula, using the PROBIOM Excel spreadsheet Abella AJ, Caddy JF, Serena F (Aquat Living Resourc 10:257–269, 1997). The method applied was a tuned virtual population analysis (VPA), applying the Extended Survivor Analysis (XSA) method on the period 2007–2009 and Y/R analysis on the pseudo-cohort 2007–2009. The software used was the VIT program. Results showed that the stock is over exploited, being the fishery operating below the optimal yield level since the current Y/R is lower than the maximum. Results suggest a decreasing trend in the average fishing mortality during the study period by about 40 %.
Bardawil Lagoon: Ecology and Fisheries
Papers by Sahar F Mehanna
Egyptian Journal of Aquatic Biology and Fisheries, 2020
Egyptian Journal of Aquatic Biology and Fisheries , 2025
Bardawil lagoon is one of the northern lakes in Egypt and has an exceptional significance where i... more Bardawil lagoon is one of the northern lakes in Egypt and has an exceptional significance where it is the least polluted wetland in Egypt and represents one of the least polluted lagoons in the whole Mediterranean region. The catch in Bardawil lagoon is composed of a high-valued fish species like grey mullet, soles, seabass, seabream, eel, meager and grouper. The lagoon covered a total surface area of about 650 Km2 and employing more than 4,000 fishermen. In 2022, 4283 tons were landed from the lagoon, achieving more than 350 million Egyptian pounds. A number of fishing methods are used in the lagoon including trammel nets (Dabba), veranda nets (El-Bouss), lines (sinnar), dubdeiba, crab nets, and dahbana nets. The fishery statistics (catch and effort data) are necessary in the stock assessment studies, as they constitute the basic input for the surplus production models SPMs which established to determine the equilibrium or sustainable yield that may be harvested from a fishery for a given level of effort. The present work was undertaken to evaluate the fishery status of Bardawil lagoon fishery as well as to estimate the maximum sustainable yield for four commercial stocks; soles, grey mullet, crabs and shrimp. The study will help fishery managers to develop and implement the fisheries regulations in the lagoon.
Egyptian Journal of Aquatic Biology and Fisheries, 2024
The Blue Revolution aims to provide a sustainable food source for
disadvantaged populations, focu... more The Blue Revolution aims to provide a sustainable food source for
disadvantaged populations, focusing on fish as a rich source of fat and high quality protein. To improve fish consumption recommendations, it is essential to consider local consumption patterns, fish contamination levels, nutrient content, and the nutritional status of the target population. This requires conducting risk-benefit analyses at regional, national, or subnational levels. This study examined several biological and physiological parameters of the common bony fish species captured by trawling nets, specifically: Diplodus sargus, Xyrichtys novacula, Trachurus trachurus, Saurida lessepsianus, Fistularia commersonii, Pagellus erythrinus, Pagellus bellottii, Mullus surmuletus, Boops boops, and Scomber japonicus. Key parameters investigated included total weight, total length, age determination, and food and feeding habits. The results revealed significant differences (P< 0.05) in the accumulation of minerals (Na, Ca, Mg, and Fe) in the white muscles among the examined species. Mean values for these minerals ranged from
160.8 to 289.6μg/ g wet weight for Na; 334.8 to 574.3μg/ g for Ca; 290.9 to 489.0μg/ g for Mg; and 3.3 to 35.1μg/ g for Fe. The accumulation of essential metal selenium (Se) ranged from 0.7 to 4.3μg/ g wet weight, while levels of toxic metals (Cd and Pb) were below detectable limits, except for Pb in D. sargus, which was measured at 0.21 ± 0.01μg/ g wet weight. Additionally, total protein, total cholesterol, low-density lipoprotein (LDL), and triglycerides ranged from 15.5 to 21.9mg/ dl; 9.8 to 21.1mg/ dl; 0.9 to 9.0mg/dl; and 11.6 to 118.2mg/ dl, respectively, based on wet weight tissue. The status of prooxidation and antioxidant levels was also investigated. These examined species are rich sources of lipids, protein, and trace minerals that are vital for human health. Fish from this study location do not pose a health risk to humans when consumed.
Egyptian Journal of Aquatic Biology and Fisheries, May 1, 2024
The sustainability of Egyptian Nile River fisheries
Elsevier eBooks, 2024
Egyptian Journal of Aquatic Biology and Fisheries, 2024
Egyptian Journal of Aquatic Biology and Fisheries, Oct 31, 2023
Egyptian Journal of Aquatic Biology and Fisheries, Aug 31, 2023
Impact of Some Environmental Condition on Water Quality and Some Heavy metals in Water From Bardawil Lake
Bardawil Lake has a great economic and global reputation because of its production from high-qual... more Bardawil Lake has a great economic and global reputation because of its production from high-quality fish which is exported to Europe. So it is important to follow-up water and soil properties and quality of the fish, so as not to suffer this lake like the rest of other Egyptian lakes from the deterioration of water quality and fish product quality. The lake has been divided into 12 terminal sites for periodic sampling (monthly) of water. Field analyses was done during the samples collection and then transported to the laboratory in plastic containers inside Ice Box for analyses. The most important results obtained are as follows: Differences in temperature between the studied sites were changed due to the time of sampling, only the differences between months were statistically significant. The differences among the sites in the pH values of the sampled water at the same month low either among months were significantly different. There are no significant differences (P>0.05) amon...
POPULATION DYNAMICS OF GILTHEAD BREAM Sparus aurata IN THE BARDAWIL LAGOON, NORTH SINAI, EGYPT
A total of 3483 gilthead bream Sparus aurata was collected from Bardawil lagoon fishery between 2... more A total of 3483 gilthead bream Sparus aurata was collected from Bardawil lagoon fishery between 2010 and 2011. Total length ranged from 13 to 31.5 cm while total weight varied from 22 to 400 g. The length-weight relationship parameters were a = 0.0244 and b = 2.7984. The age distribution covered age groups 0 to IV and the parameters of the von Bertalanffy growth model were K = 0.4 year -1 , L∞ = 35.5 cm and W∞ = 531 g. The mortality estimates were 2.73 year -1 for total mortality (Z), 0.6 year -1 for natural mortality (M) and 2.13 year 1 for fishing mortality (F). The value of exploitation rate (E) indicated that the population has been heavily exploited. The catch of gilthead seabream in Bardawil lagoon composed mainly of small sized individuals where up to 70% of this species lie in age group I. Yield per recruit analysis revealed over-fished stock conditions particularly due to small fish being effectively unprotected by the current minimum size regulations.
Stock assessment of the common cuttlefish, Sepia officinalis in the Southeastern Mediterranean, Egypt
The common cuttlefish (Sepia officinalis) is an important commercial resource and one of the most... more The common cuttlefish (Sepia officinalis) is an important commercial resource and one of the most appreciated cephalopod in the Egyptian Mediterranean waters. It is a target species for the trawl fishery in Port Said fishing ground contributing about 10% of the total annual landings. The stock of Sepia officinalis in the southeastern Mediterranean (Port Said waters) has been assessed using a three years length frequency data (2008-2010) collected monthly from the trawl fishery at the fishing harbor of Port Said city. By applying the Y/R analysis on the pseudo-cohort 2008-2010 using the VIT program, it is noticed that this stock is over exploited, being the fishery operating below the optimal yield level since the current Y/R is lower than the maximum. Results suggest a decreasing trend in the average fishing mortality along the studied period by about 30-40%.
Spatio-temporal variations in the distribution and abundance of demersal fishes in the Egyptian Mediterranean waters
Fin-fish are the mainstay of subsistence and marine fisheries in Egypt, comprising a major compon... more Fin-fish are the mainstay of subsistence and marine fisheries in Egypt, comprising a major component of the protein diet of Egyptian people in the coastal areas. These resources are also becoming an important source of income for inhabitants of many coastal communities. The spring 2008 trawl survey carried out by NIOF research vessel &quot;Salsabil&quot; covered the area from Alexandria and extended east along the eastern seaboard to El-Arish and west along the western seaboard to El-Salloum. The sites and routs of trawling were detected based on the bottom relief, currents and sea state and covered all fishing grounds allover the Egyptian sector of Mediterranean. The following depths are fixed in all areas as strata limits: 10-50 m, 50-100 m and 100-200 m. This trawling survey revealed that, most of the west not suitable for trawling due to its rocky bottom which leads to cutting the net. A total of 50 species of bony fishes belong to 26 families, 5 species of cartilaginous fishes belong to 4 families and 5 species of invertebrates belong to 3 families were counted in the west during the survey, while a total of 72 species of bony fishes belong to 36 families, 4 species of cartilaginous fishes belong to 2 families and 12 species of invertebrates belong to 7 families were counted in the east and their size estimated for biomass estimates. The survey results will greatly increase our understanding of the status of these critically important marine resources, and help provide a scientific basis for their effective management.
Impacts of Excessive Fishing Effort and Heavy Metals Pollution on the Tilapia Production from Lake Manzalah
The lakes' fisheries play an important role in Egyptian economy. In the past they provided mo... more The lakes' fisheries play an important role in Egyptian economy. In the past they provided more than 50% of harvested fish in Egypt but now their contribution to the Egypt fish production decreased to 14.3% (2005-2012) and to only 12.5% in 2012. The Egyptian Mediterranean coast exhibits six lakes or lagoons which are situated along the Nile delta coast (Northern delta lakes) and to the east of the Suez Canal. These lakes are namely, from west to east, Mariut, Edku, Burullus, Manzalah, Port-Fouad and Bardawil. These six lakes provide about 77% of the harvested fish from the Egyptian lakes. Lake Manzalah, the largest northern Delta lakes and the most productive one, faced many challenges lead to seriously changes in its water quality and fish production as well as the catch composition. The present work investigated the impacts of water quality, heavy metals pollution and excessive fishing mortality on the Tilapia production from the lake and proposed some regulatory measurements ...
INOC- IIUM- International Conference on " Oceanography & Sustainable Marine Production: A Challenge of Managing Marine Resources under Climate Change, ICOSMaP”, Kuantan- Malaysia, 28-30 October 2013
Arabian scad (Trachurus indicus) distribution, biomass and biology were studied based on the samp... more Arabian scad (Trachurus indicus) distribution, biomass and biology were studied based on the samples collected during demersal fish survey conducted by RV “Al Mustaqila I” in the Arabian Sea coast of Oman between September 2007 and September 2008. This species was occurred in depths of 20 to 250 m with total length range of 3.5 – 38.6 cm (mean 16.37±5.11 cm, n= 6477), and weight range of 1.0-850.0 g (mean 75.93±65.12 g). The majority of catch was found on depths of 20-100 m and most commonly encountered at size of 11 and 25 cm TL. Differences in size between males (range: 6.6-35.3 cm; mean 18.18±5.02 cm, S.E. 0.10, n = 2592) and females (9.0-38.6 cm; mean 18.38±4.56 cm, S.E 0.09, n = 2417) were recorded. Length-Weight relationship was W = 0.0077 L 3.1833 for males and W = 0.0069 L 3.2192 for females indicating positive allometric growth. Males were outnumbered females during the whole surveys where the overall male to female ratio was 1: 0.93. The biomass and catch rate of the Arabi...
Management of invertebrate fisheries in the Gulf of Suez, Red Sea
International Journal of Science and Research (IJSR), 2016
Based on 120 males (225-550mmTL) and62 females (217-547 mm TL) of Acanthopagrusbifasciatus collec... more Based on 120 males (225-550mmTL) and62 females (217-547 mm TL) of Acanthopagrusbifasciatus collected from southern red Sea (Hurghada to shalateen), the morphometric and meristic characters were investigated. The results proved that, sexual dimorphism in A.bifasciatusfrom the Red Sea sector of Egypt was possible by using morphometric indices. Morphometric characters of the aforementioned species showed allometric growth except AIVCFL for males andCD, DIDCFL, VIAOFLandDIVOFLfor females. No sexual dimorphism was found to be in meristic characters of Acanthopagrusbifasciatus.
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Books by Sahar F Mehanna
Papers by Sahar F Mehanna
disadvantaged populations, focusing on fish as a rich source of fat and high quality protein. To improve fish consumption recommendations, it is essential to consider local consumption patterns, fish contamination levels, nutrient content, and the nutritional status of the target population. This requires conducting risk-benefit analyses at regional, national, or subnational levels. This study examined several biological and physiological parameters of the common bony fish species captured by trawling nets, specifically: Diplodus sargus, Xyrichtys novacula, Trachurus trachurus, Saurida lessepsianus, Fistularia commersonii, Pagellus erythrinus, Pagellus bellottii, Mullus surmuletus, Boops boops, and Scomber japonicus. Key parameters investigated included total weight, total length, age determination, and food and feeding habits. The results revealed significant differences (P< 0.05) in the accumulation of minerals (Na, Ca, Mg, and Fe) in the white muscles among the examined species. Mean values for these minerals ranged from
160.8 to 289.6μg/ g wet weight for Na; 334.8 to 574.3μg/ g for Ca; 290.9 to 489.0μg/ g for Mg; and 3.3 to 35.1μg/ g for Fe. The accumulation of essential metal selenium (Se) ranged from 0.7 to 4.3μg/ g wet weight, while levels of toxic metals (Cd and Pb) were below detectable limits, except for Pb in D. sargus, which was measured at 0.21 ± 0.01μg/ g wet weight. Additionally, total protein, total cholesterol, low-density lipoprotein (LDL), and triglycerides ranged from 15.5 to 21.9mg/ dl; 9.8 to 21.1mg/ dl; 0.9 to 9.0mg/dl; and 11.6 to 118.2mg/ dl, respectively, based on wet weight tissue. The status of prooxidation and antioxidant levels was also investigated. These examined species are rich sources of lipids, protein, and trace minerals that are vital for human health. Fish from this study location do not pose a health risk to humans when consumed.