Manal Sabrah | Cairo University / Albert Ludwig Universitaet Freiburg (original) (raw)

Papers by Manal Sabrah

Research paper thumbnail of Fisheries biology assessment of the European hake, Merluccius merluccius (Linnaeus, 1758), from Egyptian Mediterranean deep sea waters

Egyptian Journal of Aquatic Biology and Fisheries

The European hake fish Merluccius merluccius (Linnaeus, 1758) is belonging to family Merluccidae ... more The European hake fish Merluccius merluccius (Linnaeus, 1758) is belonging to family Merluccidae of genus Merluccius, widely distributed in the Eastern Atlantic, the Mediterranean Sea and the southern coast of the Black Sea (Froese and Pauly, 2016). The European hake is one of the most important target species for trawlers of a highly commercial value and elevated price; therefore it is intensively exploited in both the Atlantic and Mediterranean basins (Oliver and Massutí, 1995; Boudjadi and Rachedi, 2021). The European hake is found in a wide depth range from the coastline to 1000 m depth (Cohen et al., 1990; Philips, 2012) and also on the muddy bottoms (Froese and Pauly, 2016). In the Egyptian Mediterranean deep sea, European hake was caught at ARTICLE INFO

Research paper thumbnail of A comprehensive evaluation of water quality and its potential health risks using physicochemical indices in coastal areas of the Gulf of Suez, Red Sea

Ocean & Coastal Management

The Gulf of Suez plays a significant role in Egypt's economy and strategic positi... more The Gulf of Suez plays a significant role in Egypt's economy and strategic position in the region, making it a critical waterway domestically and internationally due to being an essential hub for Egypt's oil and gas industry, housing numerous offshore oil and gas fields in the region. This paper aimed to comprehensively present the environmental status of the Gulf of Suez, the Red Sea, and pollution sources using one of the most fundamental ways to evaluate a water body. The Water Quality Index (WQI) measures nitrate levels in marine water and determines their potential harm to human health and the ecosystem. Excessive amounts of nitrate can pose noncarcinogenic health risks. Trophic state index (TSI), trophic index (TRIX), and Organic Pollution Index (OPI) are practical applications for surface water quality investigation and categorization based on contamination level. Principal Component Analysis (PCA), and Cluster Analysis (CA), were used to get better information for the studies on the water quality of surface waters. This study tested 38 subsurface locations during February 2021 for physical, chemical, microbiological, and nutritional salts. The WQI revealed that 71.23% of seawater samples were classified as having good water quality. However, TRIX and TSI metrics indicated eutrophication, with an average mean of 55.20, categorizing the water quality fairly. OPI values ranged between (3.50-3.75) which can be classified as moderate water quality. Finally, the current study's findings indicated the NO 3 − non-carcinogenic health hazards (HQ < 1) in all groups, but children are at a higher risk of NO 3 − exposure. Therefore, it can be concluded that Periodic assessments of water quality and strict regulations are necessary to safeguard this vital resource from pollution and ensure the well-being of future generations.

Research paper thumbnail of Morphological and SEM identification for mixed parasitic infestations in Nemipterus japonicus from the Western Gulf of Suez, Red Sea, Egypt

The Egyptian Journal of Aquatic Research

Research paper thumbnail of Observation on Biological Traits of Striped Goatfish (Upeneus vittatus) and Freckled Goatfish (Upeneus tragula) from the Gulf of Suez, Egypt

Abstract: Age, growth, reproduction, nutrition and mortality parameters of goat fish U. vittatus ... more Abstract: Age, growth, reproduction, nutrition and mortality parameters of goat fish U. vittatus and U. tragula from the Gulf of Suez were evaluated. The estimated life span of the investigated species was three years using the fish scales reading. The Von Bertalanffy growth parameters were L4 = 19.8 and 18.7 cm TL and K = 0.598 and 0.648 year G for the two studied species respectively. The total, natural and fishing mortality rates were1 recorded. The exploitation ratio was estimated as E = 0.56 and 0.60 for the two species respectively. Following the variations in monthly gonado-somatic index and the maturity stages indicated that the two species spawn once a year in spring. The length at 50 % sexual maturity was estimated and the results indicated that L were50 laid between 11.0-12.0 cm TL for males and females of the two species, respectively. The analysis of the gut contents revealed that U. vittatus and U. tragula were feed mainly on crustaceans (shrimps and crabs made the bul...

Research paper thumbnail of Fisheries biology of the Red Sea goatfish Parupeneus forsskali (Fourmanoir & Guézé, 1976) from the northern Red Sea, Hurghada, Egypt

The Egyptian Journal of Aquatic Research, 2015

This study represents the first assessment and evaluation of age, growth, mortality and sexual ma... more This study represents the first assessment and evaluation of age, growth, mortality and sexual maturity for Parupeneus forsskali in order to support the development of effective management plans. Samples were collected from the commercial landings in Hurghada fishing port, between May 2010 and June 2011. Age was determined for 456 samples using otoliths, scales and length frequency analysis. Growth parameters were estimated by applying the von Bertalanffy growth function. The asymptotic length (L 1), the growth rate (K) and (t 0) were estimated as 30.0 cm; 0.38 year À1 and À0.434 year respectively. The annual total mortality (Z), natural mortality (M) and fishing mortality (F) were estimated at 2.76/year, 0.9/year and 1.86/year. It is shown that the resource of P. forsskali in the Red Sea is overfished, since the present (F) was greater than the target biological reference points (F opt = 0.43 and F limit = 0.57) and the exploitation ratio (E) 0.67 was intensively over than the predicted value (E 0.5 = 0.34 and E max = 0.58).

Research paper thumbnail of Fishery status of the longnose parrotfish, Hipposcarus harid (Forsskal, 1775) in the southern Red Sea, Shalateen, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Research paper thumbnail of Biological aspects and exploitation of Plectorhinchus gaterinus (Forsskal, 1839) (F: Haemulidae) from the northern Red Sea, El-Tor, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Research paper thumbnail of International Journal of Fisheries and Aquatic Studies 2015; 3(1): 68-74 Population structure of Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816), from the Suez Bay, Gulf of Suez, Egypt

An investigation on Age, growth, and stock assessment of the Indian mackerel, Rastrelliger kanagu... more An investigation on Age, growth, and stock assessment of the Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816) was studied "between" September 2012 to May 2013 from the Suez Bay. The length of the fish in samples ranged from 15.5cm to 32.5cm of TL. The common equation of length-weight relationship estimated for combined sexes was W=0.0053*L 3.2135. Von Bertalanffy growth parameters were estimated as L∞ = 33.79 cm, K = 0.428 year-1 and t0 =-0.868 year. The growth performance index was estimated as 2.672. The annual total mortality (Z), natural mortality (M)were calculated as 1.917/year and 0.72/year respectively while Fishing mortality (1.197/year) was higher than the biological reference points (Fopt =0.60 and Flimt. =0.80), additionally the exploitation rate (0.62) was higher than the exploitation rate (E0.5 = 0.39) which maintain 50% of the stock biomass as spawning stock this results indicate that population of Rastrelliger kanagurta is overexploited in the Suez Ba...

Research paper thumbnail of Fishery status of the longnose parrotfish, Hipposcarus harid (Forsskal, 1775) in the southern Red Sea, Shalateen, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Research paper thumbnail of Biological aspects and exploitation of Plectorhinchus gaterinus (Forsskal, 1839) (F: Haemulidae) from the northern Red Sea, El-Tor, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Research paper thumbnail of Population Biology and Dynamics of Fringelip Mullet Crenimugil crenilabis, Forsskål, 1775 from Southern Red Sea, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

This study was conducted to assess the biological characteristics and growth pattern of Crenimugi... more This study was conducted to assess the biological characteristics and growth pattern of Crenimugil crenilabis for the first attempt in the Egyptian Red Sea. C. crenilabis is a rewarding fish in the Red Sea small scale fishery. 350 samples were obtained seasonally during the period 2017 to 2018 from the commercial fishery operating in Shalatin, southern Egyptian Red Sea. Total length was varied from 24.0 to 49.4 cm (35.0 cm mean, SD: 4.75) and total weight ranged from 157.0 to 1265.0 g (476.58 g mean, SD: 214.47). The weight at length relationship showed an isometric growth pattern (b= 3.052). The von Bertalanffy growth constants K and L∞ were estimated using ELEFAN I method. The growth parameters were found to be K= 0.36/year and L∞=51.5 cm. The annual total mortality coefficient (Z), natural mortality (M) and fishing mortality (F) were estimated to be 1.26, 0.73 and 0.53/ year respectively. The length at first capture (L c) was calculated at 35.65 cm, while the length at first maturity (L m50) was found to be 32.7 for males and 33.3 cm for females. The exploitation rate of C. crenilabis was determined as 0.42, indicating the under-exploited level where the maximum exploitation level reported was 0.5. Thus the study recommended preserving the current level of exploitation rate to conserve the population stock of C. crenilabis from the breakdown.

Research paper thumbnail of Basic Parameters for Assessment and Management of the Short-Finned Squid Illex coindetii (Verany, 1839) (Cephalopoda, Ommastrephidae) from the deep water off the Egyptian Mediterranean Sea

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Short-Finned Squid Growth parameters Mortality Spawning period This research is the first study o... more Short-Finned Squid Growth parameters Mortality Spawning period This research is the first study of Illex coindetii from the deep sea fishing ground adopted in the Egyptian Mediterranean Sea. That assist to prevent stock reduction by estimation of growth parameters, mortality, and size at maturity which taken as a reference point of minimum legal size to prevent stock depletion. Specimens of Illex coindetii were collected from bottom trawl vessels at 250:850 m depths from the Egyptian Mediterranean Sea. A total of 370 Illex coindetii individuals 189 males and 157 females and 24 unidentified sexes were carried out seasonally in 2016. The length-weight relationship showed negative allometry for females and sexes combined "b" 2.01, 2.64 and positive allometric growth for males "b"3.16. There has been a difference between the sexes with concern length-weight relationships with males being smaller and lighter than females. Age was determined using length frequency analysis. The asymptotic length (L ∞), the growth rate (K) and (t 0) were estimated as 21 cm, 0.570 year-1 and-0.341 years for males, 31.5 cm, 0.22 year-1 and-0.755 year for females and 31.5 cm,0.28 year-1 and-0.587year for sexes combined respectively. The annual total mortality (Z), natural mortality (M) and fishing mortality (F) were estimated at 2.94, 1.05 and 1.89/year for males while those of females were 2.76, 0.746 and 2.02 and 2.79, 0.74, 2.05/year for the sexes combined respectively.ML 50 was estimated as, 14.35 cm for females and 11.51 cm for males. Two peaks in GSI were attained of mature females, one in spring and the other in autumn. The result of the exploitation rate of the sexes combined (0.73) indicated overexploitation which was higher in females (0.73) than males (0.64).

Research paper thumbnail of Sexual maturity, spawning activity, sex ratio and fecundity of two Mullidae species dwelling the Gulf of Suez, Red Sea

The Egyptian Journal of Aquatic Research, 2017

Upeneus guttatus and Upeneus pori are the most common Mullidae species inhabiting the Gulf of Sue... more Upeneus guttatus and Upeneus pori are the most common Mullidae species inhabiting the Gulf of Suez and mainly caught by the trawl fisheries. Reproductive biology of the two species was studied during the fishing period from September, 2013 to May 2015. The monthly gonad maturity development and the monthly gonado-somatic index (GSI) sequence of U. guttatus and U. pori revealed prolonged spawning activities throughout spring and summer seasons. The sex ratio was 1:2 for the two species in favor of females; it differed statistically from the expected 1:1 (X 2 = 65.4 in U. guttatus and 70.4 in U. pori). The length at which 50% of the population attains sexual maturity (L m50) is 11.35 ± 0.32 and 11.47 ± 0.25 cm for males and females respectively in U. guttatus, where it was 10.56 ± 0.21 cm in males and 10.60 ± 0.18 cm in females of U. pori. Absolute fecundity increased as the fish length and weight increases. Observed absolute fecundity ranged from 142,925 ± 5621 to 86,940 ± 3364 eggs for the length range of 12.0-18.0 cm in U. guttatus and from 8773 ± 560 to 71,400 ± 3219 eggs in total lengths of 11.0-16.0 cm for U. pori, with a low value of standard error ranging between 0.28% and 4.9% in both species and high correlation coefficient (R 2 > 0.96).

Research paper thumbnail of Biological aspects of some Goatfish (Mullidae) from the southern Egyptian Red Sea; Hurghada to Shalateen

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Goatfish or Red Mullets are considered to be the most important economical family associated the ... more Goatfish or Red Mullets are considered to be the most important economical family associated the Egyptian Red Sea coral reefs. It is the first time to appraise the difference between the biological parameters for different goatfish species in the Egyptian Red Sea. The current study was designed to evaluate the biological characteristics of some Goatfish collected seasonally from the commercial artisanal fishery operating in the Egyptian Red Sea during the period from autumn 2016 to summer 2018. The study based on five Mullidae species belonged to three different genera: Mulloidichthys flavolineatus (Lacepède, 1801), Mulloidichthys vanicolensis (Valenciennes, 1831), Upeneus moluccensis (Bleeker, 1855), Parupeneus cyclostomus (Lacepède, 1801), and Parupeneus frosskali (Fourmanoir & Gue´ze´, 1976). P. frosskali and M. vanicolensis were the most dominant species; constituted 28.13% and 20.31% of the total goatfish catch, respectively. The seasonal occurrence of different Mullidae species revealed that all species were recorded by rational percentages in spring and summer. The growth parameters (L∞ and K) were determined for all species by applying the von Bertalanffy growth function. By following the seasonal Gonado-somatic index (GSI) for different species uncover spawning period occurred between spring and summer. The lengths at first sexual maturity were determined as 18.

Research paper thumbnail of Fisheries Biology of the Slender Emperor Lethrinus variegatus (valenciennei, 1830) inhabitant in the Gulf of Suez, Egyptian Red Sea

Egyptian journal of aquatic biology and fisheries, 2021

Kerm or Dereny [Lethrinus variegatus (valenciennei, 1830)] is the local name in the Egyptian mark... more Kerm or Dereny [Lethrinus variegatus (valenciennei, 1830)] is the local name in the Egyptian market. L. variegatus is known as slender emperor or scavengers belonging to Family Lethrinidae, Order Perciformes. Family Lethrinidae is known as emperors or scavengers; it consists of 5 genera including 41 species and found in sandy and weedy areas in tropical waters (Berg, 1958; Sabrah, 1998). Appearance of L. variegatus is correlated to the coral reef mainly in 1.01.5 m depth (Smith, 1986).

Research paper thumbnail of Observation on Biological Traits of Striped Goatfish (Upeneus vittatus ) and Freckled Goatfish (Upeneus tragula) from the Gulf of Suez, Egypt

Age, growth, reproduction, nutrition and mortality parameters of goat fish U. vittatus and U. tra... more Age, growth, reproduction, nutrition and mortality parameters of goat fish U. vittatus and U. tragula from the Gulf of Suez were evaluated. The estimated life span of the investigated species was three years using the fish scales reading. The Von Bertalanffy growth parameters were L∞ = 19.8 and 18.7 cm TL and K = 0.598 and 0.648 year for the two studied species respectively. The total, natural and fishing mortality rates were 1 recorded. The exploitation ratio was estimated as E = 0.56 and 0.60 for the two species respectively. Following the variations in monthly gonado-somatic index and the maturity stages indicated that the two species spawn once a year in spring. The length at 50% sexual maturity was estimated and the results indicated that L were 50 laid between 11.0-12.0 cm TL for males and females of the two species, respectively. The analysis of the gut contents revealed that U. vittatus and U. tragula were feed mainly on crustaceans (shrimps and crabs made the bulk of the di...

Research paper thumbnail of Family Belonidae from the Suez Canal, Egypt: Age, growth, mortality, exploitation rate and reproductive biology

The Egyptian Journal of Aquatic Research, 2017

This is the first attempt to study the biological characteristics and basic population parameters... more This is the first attempt to study the biological characteristics and basic population parameters of two important Belonidae species, Tylosurus acus and Tylosurus crocodilus from the Suez Canal. The length– weight relationship was estimated as W = 0.0005TL3.26 for T. acus and W = 0.0007TL3.21 for T. crocodilus. The growth parameters of T. acus were computed as L∞ = 79.85 cm, k = 0.44 year–1, t0 = –0.58 years, while the annual total, natural and fishing mortality were 1.70, 0.72 and 0.98 respectively with an exploitation rate of 0.58. While in T. crocodilus the VBGPs were L∞ = 113.0 cm, k = 0.30 year–1, t0 = –0.46 years, the annual total, natural and fishing mortality were 1.27, 0.51 and 0.76 respectively with an exploitation rate of 0.60. The female's length at first maturity of T. acus was estimated to be 47.3 cm and 51.7 cm for T. crocodilus. Monthly variations in Gonado-somatic index revealed that the spawning season of the two species takes place in spring. Results of exploi...

Research paper thumbnail of Population structure of Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816), from the Suez Bay, Gulf of Suez, Egypt

An investigation on Age, growth, and stock assessment of the Indian mackerel, Rastrelliger kanagu... more An investigation on Age, growth, and stock assessment of the Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816) was studied “between” September 2012 to May 2013 from the Suez Bay. The length of the fish in samples ranged from 15.5cm to 32.5cm of TL. The common equation of length-weight relationship estimated for combined sexes was W=0.0053*L 3.2135 . Von Bertalanffy growth parameters were estimated as L∞ = 33.79 cm, K = 0.428 year- 1 and t0 = -0.868 year. The growth performance index was estimated as 2.672. The annual total mortality (Z), natural mortality (M)were calculated as 1.917/year and 0.72/year respectively while Fishing mortality (1.197/year) was higher than the biological reference points (Fopt =0.60 and Flimt. =0.80), additionally the exploitation rate (0.62) was higher than the exploitation rate (E0.5 = 0.39) which maintain 50% of the stock biomass as spawning stock this results indicate that population of Rastrelliger kanagurta is overexploited in the Suez Bay ecosy...

Research paper thumbnail of Reproductive biology of the milk shark Rhizoprionodon acutus (Carcharhinidae) off the coast of Senegal

African Journal of Marine Science, 2013

Despite the considerable commercial value of the milk shark Rhizoprionodon acutus (Rüppell 1837) ... more Despite the considerable commercial value of the milk shark Rhizoprionodon acutus (Rüppell 1837) along the Senegal coast, there are few data on its biology. Milk sharks examined in this study were caught by small-scale fisheries on the Senegalese coast from May 2009 to February 2011 at eight landing locations. Landings were higher during the warm season (May–October) (71.5%), and lower during the cold season (November–April) (28.5%). The largest landings were recorded in the central area (36.9%) and the smallest in the coastal area of the Casamance (South-West Senegal) (0.6%). The observed size of individuals ranged from 31 to 113 cm (total length, TL), and the total weight from 150 to 8 500 g. Landings mostly included small individuals with a modal size of 50 cm TL for males and 60 cm TL for females. A reduction in the size range of milk sharks in the study area was consistent with those studied elsewhere. Females were more abundant than males (sex ratio 1.65F:1M). Mature individuals were dominant at the northern landing sites whereas immature individuals were more abundant in the southern regions. Our observations suggest a possible seasonal migration towards the north for reproductive purposes. The size at first sexual maturity was 92 cm TL for females and 82 cm TL for males. The gonadosomatic index, nidosomatic index and hepatosomatic index peaked from May to August, indicating that the reproductive period is during the warm season. Milk sharks off the coast of Senegal appear to have an annual reproductive cycle. Ovarian fecundity varied from 2 to 8 follicles and uterine fecundity from 2 to 7 embryos. Parturition occurred between May and June. Moreover, the presence of mature spermatozoa in the oviducal glands during the warm season supports the notion that mating takes place during that period.

Research paper thumbnail of Genetic divergence in Trachurus indicus (Nekrasov, 1966) and Decapterus maruadsi (Temminck & Schlegel, 1843) , Family: Carangidae dwelling the Gulf of Suez, Red Sea

Egyptian Journal of Aquatic Biology and Fisheries, Oct 29, 2019

Gulf of Suez Microsatellite genetic divergence Family Carangidae is widely distributed in the Atl... more Gulf of Suez Microsatellite genetic divergence Family Carangidae is widely distributed in the Atlantic, Indian and pacific Oceans. Two morphologically similar species, Trachurus indicus and Decapterus maruadsi, were collected and recognized from the Gulf of Suez. The two species have no distinct differences morphologically. Microsatellite DNA markers revealed that the populations of the two species represented distinct genetic divergence. This genetic diversity study showed that the populations of the two species are not related to each other. Overall, this study reveals high genetic diversity of T. indicus and D. maruadsi populations. Further studies on the genetic structure of these two species, are needed not only to understand the evolutionary history of the species, but also to improve the knowledge-based fishery management programs of this important biological resources.

Research paper thumbnail of Fisheries biology assessment of the European hake, Merluccius merluccius (Linnaeus, 1758), from Egyptian Mediterranean deep sea waters

Egyptian Journal of Aquatic Biology and Fisheries

The European hake fish Merluccius merluccius (Linnaeus, 1758) is belonging to family Merluccidae ... more The European hake fish Merluccius merluccius (Linnaeus, 1758) is belonging to family Merluccidae of genus Merluccius, widely distributed in the Eastern Atlantic, the Mediterranean Sea and the southern coast of the Black Sea (Froese and Pauly, 2016). The European hake is one of the most important target species for trawlers of a highly commercial value and elevated price; therefore it is intensively exploited in both the Atlantic and Mediterranean basins (Oliver and Massutí, 1995; Boudjadi and Rachedi, 2021). The European hake is found in a wide depth range from the coastline to 1000 m depth (Cohen et al., 1990; Philips, 2012) and also on the muddy bottoms (Froese and Pauly, 2016). In the Egyptian Mediterranean deep sea, European hake was caught at ARTICLE INFO

Research paper thumbnail of A comprehensive evaluation of water quality and its potential health risks using physicochemical indices in coastal areas of the Gulf of Suez, Red Sea

Ocean & Coastal Management

The Gulf of Suez plays a significant role in Egypt's economy and strategic positi... more The Gulf of Suez plays a significant role in Egypt's economy and strategic position in the region, making it a critical waterway domestically and internationally due to being an essential hub for Egypt's oil and gas industry, housing numerous offshore oil and gas fields in the region. This paper aimed to comprehensively present the environmental status of the Gulf of Suez, the Red Sea, and pollution sources using one of the most fundamental ways to evaluate a water body. The Water Quality Index (WQI) measures nitrate levels in marine water and determines their potential harm to human health and the ecosystem. Excessive amounts of nitrate can pose noncarcinogenic health risks. Trophic state index (TSI), trophic index (TRIX), and Organic Pollution Index (OPI) are practical applications for surface water quality investigation and categorization based on contamination level. Principal Component Analysis (PCA), and Cluster Analysis (CA), were used to get better information for the studies on the water quality of surface waters. This study tested 38 subsurface locations during February 2021 for physical, chemical, microbiological, and nutritional salts. The WQI revealed that 71.23% of seawater samples were classified as having good water quality. However, TRIX and TSI metrics indicated eutrophication, with an average mean of 55.20, categorizing the water quality fairly. OPI values ranged between (3.50-3.75) which can be classified as moderate water quality. Finally, the current study's findings indicated the NO 3 − non-carcinogenic health hazards (HQ < 1) in all groups, but children are at a higher risk of NO 3 − exposure. Therefore, it can be concluded that Periodic assessments of water quality and strict regulations are necessary to safeguard this vital resource from pollution and ensure the well-being of future generations.

Research paper thumbnail of Morphological and SEM identification for mixed parasitic infestations in Nemipterus japonicus from the Western Gulf of Suez, Red Sea, Egypt

The Egyptian Journal of Aquatic Research

Research paper thumbnail of Observation on Biological Traits of Striped Goatfish (Upeneus vittatus) and Freckled Goatfish (Upeneus tragula) from the Gulf of Suez, Egypt

Abstract: Age, growth, reproduction, nutrition and mortality parameters of goat fish U. vittatus ... more Abstract: Age, growth, reproduction, nutrition and mortality parameters of goat fish U. vittatus and U. tragula from the Gulf of Suez were evaluated. The estimated life span of the investigated species was three years using the fish scales reading. The Von Bertalanffy growth parameters were L4 = 19.8 and 18.7 cm TL and K = 0.598 and 0.648 year G for the two studied species respectively. The total, natural and fishing mortality rates were1 recorded. The exploitation ratio was estimated as E = 0.56 and 0.60 for the two species respectively. Following the variations in monthly gonado-somatic index and the maturity stages indicated that the two species spawn once a year in spring. The length at 50 % sexual maturity was estimated and the results indicated that L were50 laid between 11.0-12.0 cm TL for males and females of the two species, respectively. The analysis of the gut contents revealed that U. vittatus and U. tragula were feed mainly on crustaceans (shrimps and crabs made the bul...

Research paper thumbnail of Fisheries biology of the Red Sea goatfish Parupeneus forsskali (Fourmanoir & Guézé, 1976) from the northern Red Sea, Hurghada, Egypt

The Egyptian Journal of Aquatic Research, 2015

This study represents the first assessment and evaluation of age, growth, mortality and sexual ma... more This study represents the first assessment and evaluation of age, growth, mortality and sexual maturity for Parupeneus forsskali in order to support the development of effective management plans. Samples were collected from the commercial landings in Hurghada fishing port, between May 2010 and June 2011. Age was determined for 456 samples using otoliths, scales and length frequency analysis. Growth parameters were estimated by applying the von Bertalanffy growth function. The asymptotic length (L 1), the growth rate (K) and (t 0) were estimated as 30.0 cm; 0.38 year À1 and À0.434 year respectively. The annual total mortality (Z), natural mortality (M) and fishing mortality (F) were estimated at 2.76/year, 0.9/year and 1.86/year. It is shown that the resource of P. forsskali in the Red Sea is overfished, since the present (F) was greater than the target biological reference points (F opt = 0.43 and F limit = 0.57) and the exploitation ratio (E) 0.67 was intensively over than the predicted value (E 0.5 = 0.34 and E max = 0.58).

Research paper thumbnail of Fishery status of the longnose parrotfish, Hipposcarus harid (Forsskal, 1775) in the southern Red Sea, Shalateen, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Research paper thumbnail of Biological aspects and exploitation of Plectorhinchus gaterinus (Forsskal, 1839) (F: Haemulidae) from the northern Red Sea, El-Tor, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Research paper thumbnail of International Journal of Fisheries and Aquatic Studies 2015; 3(1): 68-74 Population structure of Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816), from the Suez Bay, Gulf of Suez, Egypt

An investigation on Age, growth, and stock assessment of the Indian mackerel, Rastrelliger kanagu... more An investigation on Age, growth, and stock assessment of the Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816) was studied "between" September 2012 to May 2013 from the Suez Bay. The length of the fish in samples ranged from 15.5cm to 32.5cm of TL. The common equation of length-weight relationship estimated for combined sexes was W=0.0053*L 3.2135. Von Bertalanffy growth parameters were estimated as L∞ = 33.79 cm, K = 0.428 year-1 and t0 =-0.868 year. The growth performance index was estimated as 2.672. The annual total mortality (Z), natural mortality (M)were calculated as 1.917/year and 0.72/year respectively while Fishing mortality (1.197/year) was higher than the biological reference points (Fopt =0.60 and Flimt. =0.80), additionally the exploitation rate (0.62) was higher than the exploitation rate (E0.5 = 0.39) which maintain 50% of the stock biomass as spawning stock this results indicate that population of Rastrelliger kanagurta is overexploited in the Suez Ba...

Research paper thumbnail of Fishery status of the longnose parrotfish, Hipposcarus harid (Forsskal, 1775) in the southern Red Sea, Shalateen, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Research paper thumbnail of Biological aspects and exploitation of Plectorhinchus gaterinus (Forsskal, 1839) (F: Haemulidae) from the northern Red Sea, El-Tor, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Research paper thumbnail of Population Biology and Dynamics of Fringelip Mullet Crenimugil crenilabis, Forsskål, 1775 from Southern Red Sea, Egypt

Egyptian Journal of Aquatic Biology and Fisheries, 2019

This study was conducted to assess the biological characteristics and growth pattern of Crenimugi... more This study was conducted to assess the biological characteristics and growth pattern of Crenimugil crenilabis for the first attempt in the Egyptian Red Sea. C. crenilabis is a rewarding fish in the Red Sea small scale fishery. 350 samples were obtained seasonally during the period 2017 to 2018 from the commercial fishery operating in Shalatin, southern Egyptian Red Sea. Total length was varied from 24.0 to 49.4 cm (35.0 cm mean, SD: 4.75) and total weight ranged from 157.0 to 1265.0 g (476.58 g mean, SD: 214.47). The weight at length relationship showed an isometric growth pattern (b= 3.052). The von Bertalanffy growth constants K and L∞ were estimated using ELEFAN I method. The growth parameters were found to be K= 0.36/year and L∞=51.5 cm. The annual total mortality coefficient (Z), natural mortality (M) and fishing mortality (F) were estimated to be 1.26, 0.73 and 0.53/ year respectively. The length at first capture (L c) was calculated at 35.65 cm, while the length at first maturity (L m50) was found to be 32.7 for males and 33.3 cm for females. The exploitation rate of C. crenilabis was determined as 0.42, indicating the under-exploited level where the maximum exploitation level reported was 0.5. Thus the study recommended preserving the current level of exploitation rate to conserve the population stock of C. crenilabis from the breakdown.

Research paper thumbnail of Basic Parameters for Assessment and Management of the Short-Finned Squid Illex coindetii (Verany, 1839) (Cephalopoda, Ommastrephidae) from the deep water off the Egyptian Mediterranean Sea

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Short-Finned Squid Growth parameters Mortality Spawning period This research is the first study o... more Short-Finned Squid Growth parameters Mortality Spawning period This research is the first study of Illex coindetii from the deep sea fishing ground adopted in the Egyptian Mediterranean Sea. That assist to prevent stock reduction by estimation of growth parameters, mortality, and size at maturity which taken as a reference point of minimum legal size to prevent stock depletion. Specimens of Illex coindetii were collected from bottom trawl vessels at 250:850 m depths from the Egyptian Mediterranean Sea. A total of 370 Illex coindetii individuals 189 males and 157 females and 24 unidentified sexes were carried out seasonally in 2016. The length-weight relationship showed negative allometry for females and sexes combined "b" 2.01, 2.64 and positive allometric growth for males "b"3.16. There has been a difference between the sexes with concern length-weight relationships with males being smaller and lighter than females. Age was determined using length frequency analysis. The asymptotic length (L ∞), the growth rate (K) and (t 0) were estimated as 21 cm, 0.570 year-1 and-0.341 years for males, 31.5 cm, 0.22 year-1 and-0.755 year for females and 31.5 cm,0.28 year-1 and-0.587year for sexes combined respectively. The annual total mortality (Z), natural mortality (M) and fishing mortality (F) were estimated at 2.94, 1.05 and 1.89/year for males while those of females were 2.76, 0.746 and 2.02 and 2.79, 0.74, 2.05/year for the sexes combined respectively.ML 50 was estimated as, 14.35 cm for females and 11.51 cm for males. Two peaks in GSI were attained of mature females, one in spring and the other in autumn. The result of the exploitation rate of the sexes combined (0.73) indicated overexploitation which was higher in females (0.73) than males (0.64).

Research paper thumbnail of Sexual maturity, spawning activity, sex ratio and fecundity of two Mullidae species dwelling the Gulf of Suez, Red Sea

The Egyptian Journal of Aquatic Research, 2017

Upeneus guttatus and Upeneus pori are the most common Mullidae species inhabiting the Gulf of Sue... more Upeneus guttatus and Upeneus pori are the most common Mullidae species inhabiting the Gulf of Suez and mainly caught by the trawl fisheries. Reproductive biology of the two species was studied during the fishing period from September, 2013 to May 2015. The monthly gonad maturity development and the monthly gonado-somatic index (GSI) sequence of U. guttatus and U. pori revealed prolonged spawning activities throughout spring and summer seasons. The sex ratio was 1:2 for the two species in favor of females; it differed statistically from the expected 1:1 (X 2 = 65.4 in U. guttatus and 70.4 in U. pori). The length at which 50% of the population attains sexual maturity (L m50) is 11.35 ± 0.32 and 11.47 ± 0.25 cm for males and females respectively in U. guttatus, where it was 10.56 ± 0.21 cm in males and 10.60 ± 0.18 cm in females of U. pori. Absolute fecundity increased as the fish length and weight increases. Observed absolute fecundity ranged from 142,925 ± 5621 to 86,940 ± 3364 eggs for the length range of 12.0-18.0 cm in U. guttatus and from 8773 ± 560 to 71,400 ± 3219 eggs in total lengths of 11.0-16.0 cm for U. pori, with a low value of standard error ranging between 0.28% and 4.9% in both species and high correlation coefficient (R 2 > 0.96).

Research paper thumbnail of Biological aspects of some Goatfish (Mullidae) from the southern Egyptian Red Sea; Hurghada to Shalateen

Egyptian Journal of Aquatic Biology and Fisheries, 2019

Goatfish or Red Mullets are considered to be the most important economical family associated the ... more Goatfish or Red Mullets are considered to be the most important economical family associated the Egyptian Red Sea coral reefs. It is the first time to appraise the difference between the biological parameters for different goatfish species in the Egyptian Red Sea. The current study was designed to evaluate the biological characteristics of some Goatfish collected seasonally from the commercial artisanal fishery operating in the Egyptian Red Sea during the period from autumn 2016 to summer 2018. The study based on five Mullidae species belonged to three different genera: Mulloidichthys flavolineatus (Lacepède, 1801), Mulloidichthys vanicolensis (Valenciennes, 1831), Upeneus moluccensis (Bleeker, 1855), Parupeneus cyclostomus (Lacepède, 1801), and Parupeneus frosskali (Fourmanoir & Gue´ze´, 1976). P. frosskali and M. vanicolensis were the most dominant species; constituted 28.13% and 20.31% of the total goatfish catch, respectively. The seasonal occurrence of different Mullidae species revealed that all species were recorded by rational percentages in spring and summer. The growth parameters (L∞ and K) were determined for all species by applying the von Bertalanffy growth function. By following the seasonal Gonado-somatic index (GSI) for different species uncover spawning period occurred between spring and summer. The lengths at first sexual maturity were determined as 18.

Research paper thumbnail of Fisheries Biology of the Slender Emperor Lethrinus variegatus (valenciennei, 1830) inhabitant in the Gulf of Suez, Egyptian Red Sea

Egyptian journal of aquatic biology and fisheries, 2021

Kerm or Dereny [Lethrinus variegatus (valenciennei, 1830)] is the local name in the Egyptian mark... more Kerm or Dereny [Lethrinus variegatus (valenciennei, 1830)] is the local name in the Egyptian market. L. variegatus is known as slender emperor or scavengers belonging to Family Lethrinidae, Order Perciformes. Family Lethrinidae is known as emperors or scavengers; it consists of 5 genera including 41 species and found in sandy and weedy areas in tropical waters (Berg, 1958; Sabrah, 1998). Appearance of L. variegatus is correlated to the coral reef mainly in 1.01.5 m depth (Smith, 1986).

Research paper thumbnail of Observation on Biological Traits of Striped Goatfish (Upeneus vittatus ) and Freckled Goatfish (Upeneus tragula) from the Gulf of Suez, Egypt

Age, growth, reproduction, nutrition and mortality parameters of goat fish U. vittatus and U. tra... more Age, growth, reproduction, nutrition and mortality parameters of goat fish U. vittatus and U. tragula from the Gulf of Suez were evaluated. The estimated life span of the investigated species was three years using the fish scales reading. The Von Bertalanffy growth parameters were L∞ = 19.8 and 18.7 cm TL and K = 0.598 and 0.648 year for the two studied species respectively. The total, natural and fishing mortality rates were 1 recorded. The exploitation ratio was estimated as E = 0.56 and 0.60 for the two species respectively. Following the variations in monthly gonado-somatic index and the maturity stages indicated that the two species spawn once a year in spring. The length at 50% sexual maturity was estimated and the results indicated that L were 50 laid between 11.0-12.0 cm TL for males and females of the two species, respectively. The analysis of the gut contents revealed that U. vittatus and U. tragula were feed mainly on crustaceans (shrimps and crabs made the bulk of the di...

Research paper thumbnail of Family Belonidae from the Suez Canal, Egypt: Age, growth, mortality, exploitation rate and reproductive biology

The Egyptian Journal of Aquatic Research, 2017

This is the first attempt to study the biological characteristics and basic population parameters... more This is the first attempt to study the biological characteristics and basic population parameters of two important Belonidae species, Tylosurus acus and Tylosurus crocodilus from the Suez Canal. The length– weight relationship was estimated as W = 0.0005TL3.26 for T. acus and W = 0.0007TL3.21 for T. crocodilus. The growth parameters of T. acus were computed as L∞ = 79.85 cm, k = 0.44 year–1, t0 = –0.58 years, while the annual total, natural and fishing mortality were 1.70, 0.72 and 0.98 respectively with an exploitation rate of 0.58. While in T. crocodilus the VBGPs were L∞ = 113.0 cm, k = 0.30 year–1, t0 = –0.46 years, the annual total, natural and fishing mortality were 1.27, 0.51 and 0.76 respectively with an exploitation rate of 0.60. The female's length at first maturity of T. acus was estimated to be 47.3 cm and 51.7 cm for T. crocodilus. Monthly variations in Gonado-somatic index revealed that the spawning season of the two species takes place in spring. Results of exploi...

Research paper thumbnail of Population structure of Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816), from the Suez Bay, Gulf of Suez, Egypt

An investigation on Age, growth, and stock assessment of the Indian mackerel, Rastrelliger kanagu... more An investigation on Age, growth, and stock assessment of the Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816) was studied “between” September 2012 to May 2013 from the Suez Bay. The length of the fish in samples ranged from 15.5cm to 32.5cm of TL. The common equation of length-weight relationship estimated for combined sexes was W=0.0053*L 3.2135 . Von Bertalanffy growth parameters were estimated as L∞ = 33.79 cm, K = 0.428 year- 1 and t0 = -0.868 year. The growth performance index was estimated as 2.672. The annual total mortality (Z), natural mortality (M)were calculated as 1.917/year and 0.72/year respectively while Fishing mortality (1.197/year) was higher than the biological reference points (Fopt =0.60 and Flimt. =0.80), additionally the exploitation rate (0.62) was higher than the exploitation rate (E0.5 = 0.39) which maintain 50% of the stock biomass as spawning stock this results indicate that population of Rastrelliger kanagurta is overexploited in the Suez Bay ecosy...

Research paper thumbnail of Reproductive biology of the milk shark Rhizoprionodon acutus (Carcharhinidae) off the coast of Senegal

African Journal of Marine Science, 2013

Despite the considerable commercial value of the milk shark Rhizoprionodon acutus (Rüppell 1837) ... more Despite the considerable commercial value of the milk shark Rhizoprionodon acutus (Rüppell 1837) along the Senegal coast, there are few data on its biology. Milk sharks examined in this study were caught by small-scale fisheries on the Senegalese coast from May 2009 to February 2011 at eight landing locations. Landings were higher during the warm season (May–October) (71.5%), and lower during the cold season (November–April) (28.5%). The largest landings were recorded in the central area (36.9%) and the smallest in the coastal area of the Casamance (South-West Senegal) (0.6%). The observed size of individuals ranged from 31 to 113 cm (total length, TL), and the total weight from 150 to 8 500 g. Landings mostly included small individuals with a modal size of 50 cm TL for males and 60 cm TL for females. A reduction in the size range of milk sharks in the study area was consistent with those studied elsewhere. Females were more abundant than males (sex ratio 1.65F:1M). Mature individuals were dominant at the northern landing sites whereas immature individuals were more abundant in the southern regions. Our observations suggest a possible seasonal migration towards the north for reproductive purposes. The size at first sexual maturity was 92 cm TL for females and 82 cm TL for males. The gonadosomatic index, nidosomatic index and hepatosomatic index peaked from May to August, indicating that the reproductive period is during the warm season. Milk sharks off the coast of Senegal appear to have an annual reproductive cycle. Ovarian fecundity varied from 2 to 8 follicles and uterine fecundity from 2 to 7 embryos. Parturition occurred between May and June. Moreover, the presence of mature spermatozoa in the oviducal glands during the warm season supports the notion that mating takes place during that period.

Research paper thumbnail of Genetic divergence in Trachurus indicus (Nekrasov, 1966) and Decapterus maruadsi (Temminck & Schlegel, 1843) , Family: Carangidae dwelling the Gulf of Suez, Red Sea

Egyptian Journal of Aquatic Biology and Fisheries, Oct 29, 2019

Gulf of Suez Microsatellite genetic divergence Family Carangidae is widely distributed in the Atl... more Gulf of Suez Microsatellite genetic divergence Family Carangidae is widely distributed in the Atlantic, Indian and pacific Oceans. Two morphologically similar species, Trachurus indicus and Decapterus maruadsi, were collected and recognized from the Gulf of Suez. The two species have no distinct differences morphologically. Microsatellite DNA markers revealed that the populations of the two species represented distinct genetic divergence. This genetic diversity study showed that the populations of the two species are not related to each other. Overall, this study reveals high genetic diversity of T. indicus and D. maruadsi populations. Further studies on the genetic structure of these two species, are needed not only to understand the evolutionary history of the species, but also to improve the knowledge-based fishery management programs of this important biological resources.