Papers by Alaa Eldin ElHaweet
EGYPTIAN JOURNAL OF AQUATIC RESEARCH ASSESSMENT OF LAKE NASSER FISHERIES
Reproductive behaviour of the Red Sea immigrant Lagocephalus sceleratus (Gmelin, 1789) from the Mediterranean coast, Egypt
the present work aimed to study the reproductive strategy of the common lessepsian puffer fish La... more the present work aimed to study the reproductive strategy of the common lessepsian puffer fish Lagocephalus sceleratus (Gmelin, 1879) from the Egyptian Mediterranean Waters during 2012 as it is a famous migratory species has an importance in the field of fisheries and ecology of aquatic ecosystem. The obtained results illustrated seven maturity stages of gonads as; I- Thread like stage: II- Immature stage (Virgin stage), III- Maturing stage (Developing Virgin and recovering spent), IV - Nearly ripe stage, V- Fully ripe; VI-Spawning stage, VII- Spent stage. Sex ratio, exhibited males had higher number than females representing 52.44 % of the total fishes with sex ratio 1: 0.91. Fish length corresponding to 50% maturation was 38.5 cm for males and 41 cm for females. The corresponding ages (age at first maturity) are equal to 2.14 and 2.27 years for male and female respectively. The gonado somatic index (GSI) increased from April for both sexes with peak in June (8.567±4.729) for males...
The first meeting of the EASTMED Permanent Working Group on Stock Assessment was held in Demre (T... more The first meeting of the EASTMED Permanent Working Group on Stock Assessment was held in Demre (Turkey), from 27 June to 1 July 2011. It was attended by experts from Egypt, Gaza Strip and West Bank, Greece, Lebanon and Turkey, as well as one representative of the European Commission, FAO staff and consultants. The meeting had three main general objectives i) to identify candidate shared stocks and priority stocks in the region, which are in need of scientific advice from stock assessments and to prioritise these stocks at sub-regional and national level; ii) to determine the main data available for stock assessment purposes, identify the gaps in data collection and suggest actions to fill the gaps; iii) to identify the most adequate approaches for the estimation of growth parameters and suitable models to assess the stocks in the region according to the data available. During the meeting the experts presented information on the biology and fisheries of commercial stocks and potentia...
Egyptian fisheries has seen a dramatic change in the last decades, with a considerable expansion ... more Egyptian fisheries has seen a dramatic change in the last decades, with a considerable expansion of the trawl fishery. This study tried to understand the present situation of Egyptian fisheries from the socio-economic perspective. The results show that the fleet is dominated by trawlers which represent the backbone of the fleet both in terms of technical characteristics and activity, making Egypt an exceptional case in the Mediterranean, where the fleets are generally dominated by small-scale fisheries. The fish prices are lower when compared to Europe, however when one considers the macroeconomic structure of the country, seafood is quite expensive for the local population. When one considers the national average, fisheries is a reasonably profitable activity, however it is important to note that this profitability comes from the fact that the industry is heavily subsidized by the low cost of fuel, which is one of the main operating costs. The problem in Egyptian fisheries is the o...
FAO fisheries circular = FAO circulaire sur les pêches = FAO circular de pesca
This protocol is the result of two training courses which were conducted in Egypt in November 201... more This protocol is the result of two training courses which were conducted in Egypt in November 2010 in Port Said and in June 2012 in Alexandria. A pilot survey first on Catch and Effort data which was then followed by biological sampling has been started in Egypt with the Support of the EastMed project. The aim of the protocol is to assist the data collectors both in the field and in the laboratories to conduct sampling during the pilot phase. The first part of this document contains guidelines on the routine collection of catch and effort data from the ports of Alexandria, Damiette, Kafr-El-Sheikh, Madiaa and Port Said. The second part of the document describes guidelines for the collection of biological data including length, weight, sex, sexual maturity, gonad weight and hard structures for age reading. It also includes guidelines on sampling frequencies and number of samples to be collected for catch, effort and biological data. The protocol will also serve as a basis if Egypt in...
FAO fisheries circular = FAO circulaire sur les pêches = FAO circular de pesca
This study was implemented after the EastMed 2nd co-ordination meeting on the 5-6th April, Antaly... more This study was implemented after the EastMed 2nd co-ordination meeting on the 5-6th April, Antalya, Turkey (EastMed 2012), where the participants agreed to have a preliminary assessment of the socio-economic situation of the Egyptian fisheries sector. In order to undertake such an assessment several information was gathered, from literature, from several fishers and other stakeholders, and a sampling survey in order to investigate the main socio-economic characteristics of the motorized fishing vessels by type of fishery. In general the study found that the value of capture fisheries produced by the motorized fleet in the Mediterranean was $182 million generating a net profit of $42.5 million. The ex-vessels prices ranged between $2.4/Kg and $4.3/Kg, and the first sale of seafood products occurred mostly through the auction markets (56%) and through the wholesalers (40%). The revenue of the fleet provided an annual salary of about $2,662 per fisher to about 22,173 fishers, which is ...
How does an outnumbered small scale fleet perform? The case in Egypt
The area investigated covered Abu Qir Bay in the coast of Mediterranean
Sea in northern Egypt. Sa... more The area investigated covered Abu Qir Bay in the coast of Mediterranean
Sea in northern Egypt. Sampling and analysis of macrobenthos and fishes
were carried out in four of five sampling trips (October 2003, January
2004, March 2004, May 2004 and July 2004). The community composition,
distribution and diversity of macrobenthos and fishes in the Bay were
calculated.
Fourty four species were collected from the sampling area during the whole
period of study. Eighteen mollusc species, seventeen arthropod species, five
annelid species, two ascidiacean, one hydrozoan and one bryozoan were recorded.
The data analysis of macrobenthic community showed that Edku
Coast site was the poorest site while Rosetta is the highest populated site.
Concerning monthly variations, October was the most productive month for
Annelida and Arthropoda while July was the least favoured month for all
groups. Comparison of the annual fluctuation in species diversity of macrobenthos
(number of species recorded) in some parts of the Egyptian Mediterranean
coastal zones showed that there was a decrease of species diversity in
the bay over the periods surveyed.
Eighty four fish species were identified from collections made in the study
zone at different sampling sites. Marine species dominated all samples. Catadromous
species were found all year round. Seasonal variation in the density
and number of the major fish groups showed similar general patterns
in all sites. Overall, the Abu Qir site showed higher richness and diversity
values than the other sites. Edku Coast was next in order of species richness
but last in diversity values while Lake Edku showed the lowest richness and
medium diversity values.
Species composition for a total of 14432 tonnes of sardine landings at four landing sites during ... more Species composition for a total of 14432 tonnes of sardine landings at four landing sites during 1997 and 1998 was determined. Three species, Sardinella aurita, Sardina pilchardus and Sardinella maderensis were found mainly constituting the whole sardine catch. Data-based estimates of growth parameters Loo, K & h) and mortality coefficients (Z, F & M) were estimated length structured virtual population analysis (VPA) revealed that the respective stock biomass of the three species (S. aurita, S. pilchardus and S. rnaderemis) increased &om 1805.17, 252.96 and 242.48 tonnes in 1997 to 3415.82, 3768.11 and 330.31 tonnes respectively in 1998.
Results were discussed in order to establish a database that can help eventually, in the realization of prediction models for sardine fisheries along the Egyptian Mediterranean coastal zone.
t The exploitation status of Saurida undosquamis (Richardson, 1848) from the Egyptian
Mediterrane... more t The exploitation status of Saurida undosquamis (Richardson, 1848) from the Egyptian
Mediterranean coast was assessed. Fish samples (3444 specimens) that ranged between 9 and
36 cm total length were collected from commercial trawlers. The information used for the assessment
of the stock consisted of catch length structure, length–weight relationship and Von Bertalanffy’s
growth parameters. The vector of natural mortality (M) by age was calculated using the
PROBIOM Excel spreadsheet while total (Z) and fishing (F) mortalities, length cohort analysis
and Beverton and Holt Yield per recruit analysis were performed by FiSAT, LFDA and Vit 4
win programs in order to estimate the limit and target reference points of stock exploitation.
The results revealed that the average fishing level of S. undosquamis (0.575) was higher than the
biological reference points F0.1 (0.247) and Fmax (0.368). Moreover the ratio between Fc and F0.1 was
2.326 indicating that, the S. undosquamis stock in the Egyptian Mediterranean coast is in a state of
high overfishing and severe overexploitation.
A research cruise was carried out to assess the fisheries and marine biodiversity of the Gulf of ... more A research cruise was carried out to assess the fisheries and marine biodiversity of the Gulf of Sallum, with a view for the protection, conservation, and management of its resources. To achieve this aim, the Egyptian Research Vessel “Salsabil” was used, deploying otter bottom trawl for fisheries data, CTD for collecting environmental parameters, and a bottom grab sampler for obtaining samples of benthos fauna. Moreover, diving was used to survey the under-water sea grass beds.
The Gulf of Sallum supports a wide range of ecosystems, from the rich sea grass meadows and rocky reefs of the coastal zone, to the little seamounts. It is thus considered as a great resource for many economic fish species.
Seagrass plants were found forming from scattered small areas to dense vegetation that covered extended areas of the sea floor. The macrobenthic community in the investigated area consisted from 57 species belong to seven groups, while fish populations contained more than 90 species. Species Richness was closely correlated to depth, organic matter concentrations and sediment characteristics.
Some invasive polychaete and introduced fish species were recorded in the present study, moreover few considered as threatened species.
Using GIS analysis to the survey result showed that diversity of seagrass beds, benthic fauna and fish species in the Gulf could be divided into two sections. First section lies to the west of 25º 30’E longitude; contains the highest species composition, while second section (eastward of 25º 30’ E) contains the lowest species composition.
It was highly recommended, therefore, to declare the first section as a marine protected area (MPA). As the results of this study, the Gulf of Sallum was declared as the first marine Egyptian protected area in the Mediterranean Sea by the Egyptian Prime Minister's decision No. 533 for the year 2010.
Reproductive biology of Euthynnus alletteratus was described based on 628 fishes that were collec... more Reproductive biology of Euthynnus alletteratus was described based on 628 fishes that were collected from Abu Qir landing site between October 2006 and September 2007. Only 146 specimens were sexually distinguished (102 females, 44 males) and the others were immature. The sex ratio was estimated as M: F 1:2.3. Size at first sexual maturity was estimated as 42cm. Spawning season was investigated based on monthly observation of gonadal maturity stages and gonad-somatic index (GSI). The spawning season extends from June to August with a highest GSI value in June.The fork length (FL)–gutted weight (GW) relationship was estimated as GW=0.052 FL2.639 for combined sexes. Condition factor (K) was calculated using the gutted weight of all samples (regardless of sex) with an average of 1.3. Management plan is important to overcome the high percentage of immature fishes in the catch off Alexandria water. Extending closed season to July and increasing the length at capture to 44cm are important for enhancing the chance of spawning at least once during its life.
The rate of fish invasion into the Mediterranean Sea has increased in recent decades; collectivel... more The rate of fish invasion into the Mediterranean Sea has increased in recent decades; collectively
they have significant ecological and economic impacts in the eastern Mediterranean. One
of this species is Japanese thread fin bream Nemipterus japonicus that gradually get abundance in
the Egyptian Mediterranean coast bottom trawl catch.
During 2011, monthly samples of N. japonicus caught off Abu Qir area, Alexandria-Egypt, were
used to estimate some biological parameters of this immigrant species.
Females were more in abundance than male in the catch deviated to smaller size than male.
Spawning season extended from April to November with highest activities in July. Maximum
observed age was 3 years for both sexes with no significant difference between their lengths at
age. Length-at-age was fitted to the Von Bertalanffy growth models. Present results of the Mediterranean
Sea population showed lower biological (e.g. growth and longevity) condition comparing to
original indo-pacific population.
This study highlighted the occurrence of a pelagic longline fishery targeting albacore in the Eas... more This study highlighted the occurrence of a pelagic longline fishery targeting albacore in the Eastern Mediterranean Sea
off Egypt. Species selectivity of the fishing method was assessed. Catch per unit effort “CPUE”, size frequency and lengthweight
relationship were estimated for the the target species. This fishing method was found to be highly selective for
albacore, where its catch represented about 93.5 % of the total landed catch. The major by-catch species were swordfish
Xiphias gladius (2.5 %) and the little tunny Euthynnus alletteratus (2.4 %). Skipjack Katsuwonus pelamis, dolphinfish
Coryphaena hippurus, Bigeye thresher Alopias superciliosus, and oilfish Ruvettus pretiosus represented collectively, 1.5 % of
the total landed catch. The fork length of albacore ranged from 54 to 138 cm, with an average of 79.1 ± 7.2 cm. Total weight
ranged from 4 t 40 kg with an average of 8.8 ± 7.2 kg. The length-weight relationship was determined to be W = 5.26 x 10-5 L
2.75 (W in kg, L in cm). The CPUE for albacore ranged from 7 to 22 fish / 1000 hooks for the different fishing trips, with an
average CPUE of 12 fish / 1000 hooks (SE ±4.4).
Qarun Lake is a closed salty basin located about 90km southern Cairo Egypt,
cover an area of 230k... more Qarun Lake is a closed salty basin located about 90km southern Cairo Egypt,
cover an area of 230km2 with annual production of about 3000 tonnes. The present
study assessed the lake fishery for better management purpose. Data, information and
samples were collected through 42 field trips and 311 fishermen interviews during
fishing season (2010-2011). The lake was divided into three sub-areas, east, middle
and west. It was found that the fishing gears used in the lake were; 1-Trammel nets
with four types differed in their dimensions, mesh sizes and mainly targeting Mugil
cephalus, Tilapia zillii, Solea spp. and Liza spp. 2- Seine nets with three types that
were targeting M. cephalus, anchovy and shrimp. 3- Others fishing methods (Fishing
aggregation system, traps and hooks) targeting mainly T. zillii. For each gear and
methods used, the species composition (target and by-catch) and catch per unit effort
were estimated according to sub-area and season. It is realized that middle area was
more productive with higher species diversity. The present study recommends
prohibiting traps in spring and all seine nets except Gahzl Zardina during summer in
west and improving the fish catch and effort statistics for sustainable management of
this valuable resource.
QUATIC macrophytes are important to managers of captive fisheries in inland waters. Construction ... more QUATIC macrophytes are important to managers of captive fisheries in inland waters. Construction of the Aswan High Dam created a lake, which extends for 480 km; 300 km within the Egyptian borders (Lake Nasser). We investigated the impact of composition, structure, and distribution of aquatic macrophytes on the production and diversity of fish in Lake Nasser. Macrophytes, fish, and water were sampled from four stations in Lake Nasser (Kalabsha, Garf Hussein, Kurusku and Tushka) representing different bottom habitats, either in texture or in steepness, of the lake, which are important to submerged plants distribution and abundance, and hence their associated fish. At each site, submerged macrophytes were collected from shallow and deep water, down to the depth limit of plants colonisation. The plants were identified and the mean dry weight standing crop was calculated for each species. Fish were sampled using both trammel and floating-gill nets. For each fishing method, total weight of the catch, total weight of each species and number of individuals per species were determined. A one-litre surface-water sample was collected from each station and temperature, dissolved oxygen, pH, electrical conductivity, Secchi disc transparency, carbonate, and bicarbonate were measured. Three macrophyte communities were detected: a) Myriophyllum spicatum; b) Myriophyllum spicatum - Potamogeton schweinfurthii; and c) Myriophyllum spicatum - Najas horrida - Najas marina. Thirteen fish species were recorded. Oreochromis niloticus dominated the trammel-net catch in all regions and the floating gill-net catch at Garf Hussein. O. niloticus dominated the littoral semi-pelagic zone (>10 m depth), while Lates niloticus was co-dominant. The lateral pelagic zone (<10 m depth) is dominated by L. niloticus and O. niloticus in the northern sector and Hydrocynus forskalii, Sarotherodon galilaeus and Tilapia zillii in the southern sector. CCA indicates that temperature, dissolved oxygen, transparency, carbonates and bicarbonates are the most important water variables influencing the distribution of macrophytes and their associated in fish in the littoral semi-pelagic, while water pH, bicarbonate, and carbonates are the most influential variables in the lateral pelagic zone. PCA indicates that the three submerged macrophyte communities recognized and fish characterizing each of them
Fishery and Population characteristics of Euthynnus alletteratus (Rafinesque 1810) were studied u... more Fishery and Population characteristics of Euthynnus alletteratus (Rafinesque 1810) were studied using 695 fishes
collected from landing site in Eastern Coast of Mediterranean Sea off Alexandria, Egypt. Eight age groups were recorded
using vertebrae. Von Bertalanffy growth parameters were estimated as L∞ = 123.4 cm, K = 0.16 year-1 and t0 = -0.59 year. The
rate of total mortality (Z), natural mortality (M) and fishing mortality (F) were 1.996, 0.396 and 1.6 respectively. Length at
first capture was estimated as 34cm (1.4 year). The results indicate that population is overexploited (E = 0.802) and suffering
from high fishing pressure. Cohort analysis and yield per recruit analysis realized that E. alletteratus stock of the Eastern
Coast of Alexandria needs a new management strategy for sustainable yield.
Four fisheries surveys were carried out in Lake Nasser, the largest lake in Egypt (about 6000 km2... more Four fisheries surveys were carried out in Lake Nasser, the largest lake in Egypt (about 6000 km2), in order to assess the lake fisheries during the period from March 2006 to March 2008. Random fishing boats were inspected to investigate their fishing gears and methods (e.g. trammel and gill nets) and their catches.
Artisanal fishery in the lake is conducted nearer to the shoreline in areas not more than 15m deep targeting only 6 species. The most dominant species were; Tilapia group (O. niloticus, S. galilaeus, and T. zillii), pelagic fishes (A. dentex and H. forskalii) and L. niloticus. A size-range of each species and their distribution pattern in different areas of the lake was described for the major fish species in the lake. The time series of size distribution showed high exploitation rate for most important commercial species in the Lake.
Catch per unit effort (CPUE) of different fishing methods in the Lake was estimated as the catch in Kg of fish by 50m length of the nets per night or shot. The results indicate that the southern part of the lake is more productive for gill net while the opposite is recorded for trammel net.
Unreported landings are still considered to be a major problem in the landing estimate of the lake which is used as a tool for fisheries management.
Options for the management of Lake Nasser fishery are suggested.
Scales reading and length frequency distribution were used for age determination and
growth estim... more Scales reading and length frequency distribution were used for age determination and
growth estimation of Boops boops (Bogue) stock of Western Mediterranean Coast of
Egypt. Age determination using scale was done and the time of annulus formation was
detected by the marginal increment index. Bhattacharya’s method was used for length
frequency analysis. Both methods showed 6 age groups. ANOVA test revealed
insignificant differences between both estimates of length at age results. Growth parameters
estimated using length-at-age data from both methods confirming the age determination
results. Growth performance index indicated high similarity between the two estimates. The
results revealed the compatibility of length frequency distribution to scale reading for stock
assessment studies of bogue stock in Western Mediterranean Coast of Egypt.
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Papers by Alaa Eldin ElHaweet
Sea in northern Egypt. Sampling and analysis of macrobenthos and fishes
were carried out in four of five sampling trips (October 2003, January
2004, March 2004, May 2004 and July 2004). The community composition,
distribution and diversity of macrobenthos and fishes in the Bay were
calculated.
Fourty four species were collected from the sampling area during the whole
period of study. Eighteen mollusc species, seventeen arthropod species, five
annelid species, two ascidiacean, one hydrozoan and one bryozoan were recorded.
The data analysis of macrobenthic community showed that Edku
Coast site was the poorest site while Rosetta is the highest populated site.
Concerning monthly variations, October was the most productive month for
Annelida and Arthropoda while July was the least favoured month for all
groups. Comparison of the annual fluctuation in species diversity of macrobenthos
(number of species recorded) in some parts of the Egyptian Mediterranean
coastal zones showed that there was a decrease of species diversity in
the bay over the periods surveyed.
Eighty four fish species were identified from collections made in the study
zone at different sampling sites. Marine species dominated all samples. Catadromous
species were found all year round. Seasonal variation in the density
and number of the major fish groups showed similar general patterns
in all sites. Overall, the Abu Qir site showed higher richness and diversity
values than the other sites. Edku Coast was next in order of species richness
but last in diversity values while Lake Edku showed the lowest richness and
medium diversity values.
Results were discussed in order to establish a database that can help eventually, in the realization of prediction models for sardine fisheries along the Egyptian Mediterranean coastal zone.
Mediterranean coast was assessed. Fish samples (3444 specimens) that ranged between 9 and
36 cm total length were collected from commercial trawlers. The information used for the assessment
of the stock consisted of catch length structure, length–weight relationship and Von Bertalanffy’s
growth parameters. The vector of natural mortality (M) by age was calculated using the
PROBIOM Excel spreadsheet while total (Z) and fishing (F) mortalities, length cohort analysis
and Beverton and Holt Yield per recruit analysis were performed by FiSAT, LFDA and Vit 4
win programs in order to estimate the limit and target reference points of stock exploitation.
The results revealed that the average fishing level of S. undosquamis (0.575) was higher than the
biological reference points F0.1 (0.247) and Fmax (0.368). Moreover the ratio between Fc and F0.1 was
2.326 indicating that, the S. undosquamis stock in the Egyptian Mediterranean coast is in a state of
high overfishing and severe overexploitation.
The Gulf of Sallum supports a wide range of ecosystems, from the rich sea grass meadows and rocky reefs of the coastal zone, to the little seamounts. It is thus considered as a great resource for many economic fish species.
Seagrass plants were found forming from scattered small areas to dense vegetation that covered extended areas of the sea floor. The macrobenthic community in the investigated area consisted from 57 species belong to seven groups, while fish populations contained more than 90 species. Species Richness was closely correlated to depth, organic matter concentrations and sediment characteristics.
Some invasive polychaete and introduced fish species were recorded in the present study, moreover few considered as threatened species.
Using GIS analysis to the survey result showed that diversity of seagrass beds, benthic fauna and fish species in the Gulf could be divided into two sections. First section lies to the west of 25º 30’E longitude; contains the highest species composition, while second section (eastward of 25º 30’ E) contains the lowest species composition.
It was highly recommended, therefore, to declare the first section as a marine protected area (MPA). As the results of this study, the Gulf of Sallum was declared as the first marine Egyptian protected area in the Mediterranean Sea by the Egyptian Prime Minister's decision No. 533 for the year 2010.
they have significant ecological and economic impacts in the eastern Mediterranean. One
of this species is Japanese thread fin bream Nemipterus japonicus that gradually get abundance in
the Egyptian Mediterranean coast bottom trawl catch.
During 2011, monthly samples of N. japonicus caught off Abu Qir area, Alexandria-Egypt, were
used to estimate some biological parameters of this immigrant species.
Females were more in abundance than male in the catch deviated to smaller size than male.
Spawning season extended from April to November with highest activities in July. Maximum
observed age was 3 years for both sexes with no significant difference between their lengths at
age. Length-at-age was fitted to the Von Bertalanffy growth models. Present results of the Mediterranean
Sea population showed lower biological (e.g. growth and longevity) condition comparing to
original indo-pacific population.
off Egypt. Species selectivity of the fishing method was assessed. Catch per unit effort “CPUE”, size frequency and lengthweight
relationship were estimated for the the target species. This fishing method was found to be highly selective for
albacore, where its catch represented about 93.5 % of the total landed catch. The major by-catch species were swordfish
Xiphias gladius (2.5 %) and the little tunny Euthynnus alletteratus (2.4 %). Skipjack Katsuwonus pelamis, dolphinfish
Coryphaena hippurus, Bigeye thresher Alopias superciliosus, and oilfish Ruvettus pretiosus represented collectively, 1.5 % of
the total landed catch. The fork length of albacore ranged from 54 to 138 cm, with an average of 79.1 ± 7.2 cm. Total weight
ranged from 4 t 40 kg with an average of 8.8 ± 7.2 kg. The length-weight relationship was determined to be W = 5.26 x 10-5 L
2.75 (W in kg, L in cm). The CPUE for albacore ranged from 7 to 22 fish / 1000 hooks for the different fishing trips, with an
average CPUE of 12 fish / 1000 hooks (SE ±4.4).
cover an area of 230km2 with annual production of about 3000 tonnes. The present
study assessed the lake fishery for better management purpose. Data, information and
samples were collected through 42 field trips and 311 fishermen interviews during
fishing season (2010-2011). The lake was divided into three sub-areas, east, middle
and west. It was found that the fishing gears used in the lake were; 1-Trammel nets
with four types differed in their dimensions, mesh sizes and mainly targeting Mugil
cephalus, Tilapia zillii, Solea spp. and Liza spp. 2- Seine nets with three types that
were targeting M. cephalus, anchovy and shrimp. 3- Others fishing methods (Fishing
aggregation system, traps and hooks) targeting mainly T. zillii. For each gear and
methods used, the species composition (target and by-catch) and catch per unit effort
were estimated according to sub-area and season. It is realized that middle area was
more productive with higher species diversity. The present study recommends
prohibiting traps in spring and all seine nets except Gahzl Zardina during summer in
west and improving the fish catch and effort statistics for sustainable management of
this valuable resource.
collected from landing site in Eastern Coast of Mediterranean Sea off Alexandria, Egypt. Eight age groups were recorded
using vertebrae. Von Bertalanffy growth parameters were estimated as L∞ = 123.4 cm, K = 0.16 year-1 and t0 = -0.59 year. The
rate of total mortality (Z), natural mortality (M) and fishing mortality (F) were 1.996, 0.396 and 1.6 respectively. Length at
first capture was estimated as 34cm (1.4 year). The results indicate that population is overexploited (E = 0.802) and suffering
from high fishing pressure. Cohort analysis and yield per recruit analysis realized that E. alletteratus stock of the Eastern
Coast of Alexandria needs a new management strategy for sustainable yield.
Artisanal fishery in the lake is conducted nearer to the shoreline in areas not more than 15m deep targeting only 6 species. The most dominant species were; Tilapia group (O. niloticus, S. galilaeus, and T. zillii), pelagic fishes (A. dentex and H. forskalii) and L. niloticus. A size-range of each species and their distribution pattern in different areas of the lake was described for the major fish species in the lake. The time series of size distribution showed high exploitation rate for most important commercial species in the Lake.
Catch per unit effort (CPUE) of different fishing methods in the Lake was estimated as the catch in Kg of fish by 50m length of the nets per night or shot. The results indicate that the southern part of the lake is more productive for gill net while the opposite is recorded for trammel net.
Unreported landings are still considered to be a major problem in the landing estimate of the lake which is used as a tool for fisheries management.
Options for the management of Lake Nasser fishery are suggested.
growth estimation of Boops boops (Bogue) stock of Western Mediterranean Coast of
Egypt. Age determination using scale was done and the time of annulus formation was
detected by the marginal increment index. Bhattacharya’s method was used for length
frequency analysis. Both methods showed 6 age groups. ANOVA test revealed
insignificant differences between both estimates of length at age results. Growth parameters
estimated using length-at-age data from both methods confirming the age determination
results. Growth performance index indicated high similarity between the two estimates. The
results revealed the compatibility of length frequency distribution to scale reading for stock
assessment studies of bogue stock in Western Mediterranean Coast of Egypt.