IMPACT OF POLLUTION ON PRODUCTIVITY AND FISHERIES OF FISHERIES OF LAKE MARIUT, EGYPT
Magdy
Khalil
Zoology Department, Faculty of Science, Ain Shams university, Cairo, Egypt.
(Received Oct. 19,1997)
author
text
article
1998
eng
Y\/ater quality characteristics of Lake Mariut (Egypt) were investigated during the period from April 1996 to March 1997. A comparison of nutrient salts and oxygen concentrations during late 1950's with those of the present study, indicated a pattern of increasing eutroptucation and organic pollution and dominance of the sewage, industrial and agricultural wastewaters on the ecology of the lake. In the polluted main basin, the water showed much higher concentration* of some heavy metals such as iron, copper and zinc. Accumulation levels of heavy metals in fish muscles are within the legal limits of WHO standards.In response to the heavy pollution, the primary production and fertility of the main basin of the lake were reduced to about I/3 of that recorded in 1961. The average annual fish production declined from 1850 kg ha in 1970's to only 461 kg ha in 1996, and more declining is expected in the near future, unless a management programme is applied to conserve this vital ecosystem.
Egyptian Journal of Aquatic Biology and Fisheries
The Egyptian Society for the Development of Fisheries and Human Health (ESDFHH)
1110-6131
2
v.
2
no.
1998
1
17
https://ejabf.journals.ekb.eg/article_1621_c5ee93de87b72719f6835f1e045af7f4.pdf
dx.doi.org/10.21608/ejabf.1998.1621
EFFECT OF GONADAL INFECTION BY NEMATODE PARASITE ON THE FECUNDITY OF THE SEA BREAM LETHRINUS NEBULOSUS IN RAS MOHAMED MARINE PARK (NORTHERN RED SEA)
Mahmoud
Hanafy
Marine Science Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
author
Ali
Gab-Alla
Marine Science Department, Faculty of Science, Suez Canal University, Ismailia, Egypt
author
text
article
1998
eng
The sea bream Lethrinus nebulosus was sampled during the spawning season of 1996 (May-July) in Ras Mohamed Marine Park. Out of 119 specimens collected (46 females and 73 males), 11 females (23.9 %of examined females) were found to be parasitized by unidentified nematode. This parasite is found to be specific for fish ovary, causing a reduction in the absolute fecundity of the infected females compared with normal ones (averaged 4.97 x 105 and 7.54 x 105 eggs/female, respectively).In all infected females, 2-4 nematode worms of 30-40cm in length / each ovarian lobe, were coiled together in a mass occupying the ovarian lumen and seemed to block the oviduct preventing egg releasing. Histological examination showed that ovaries of heavily infected females did not contain mature ova with a depression of the vitellogensis process. All infected ovaries were characterized by certain degrees of atresia depending upon the level of infection. The synchronization between reproduction of the fish and the parasite, and the parthenogenetic nature of the parasite are thought to increase the biological potential of the parasite to colonize and infect other host individuals and possibly other populations.
Egyptian Journal of Aquatic Biology and Fisheries
The Egyptian Society for the Development of Fisheries and Human Health (ESDFHH)
1110-6131
2
v.
2
no.
1998
19
34
https://ejabf.journals.ekb.eg/article_1622_349dbaf74b8550e29cea770bdb905598.pdf
dx.doi.org/10.21608/ejabf.1998.1622
CILIATES OF THE GENERA TRICHODINA, TRIPARTIELLA AND PARATRICODINA INVADING THE NILE FISH CLARIAS LAZERA AND OREOCHROMIS NILOTICUS
Said
Noor El-Din
Zoology Department, Faculty of Science, Tanta University
author
El-Said
Naeim
Zoology Department, Faculty of Science, Tanta University,
author
text
article
1998
eng
Five ectoparastic ciliate species belongng to the genera Trihodina, Tripastiella and Partinchodenia were found on the gills of Clarias lazera and Oreochromis niloticus from the River Nile branches at Tanta city, Egypt. These ciliates include Trichodina maritinkae Basson and Van As, 1991, T. magna Van As and Basson, 1989 and T. centrostrigeata Basson ef.a/.,1983, one species of the genus Tripariiella ( first record in Africa ), namely 71 cichlidarum Basson etaLt 1983 and one species of the genus Paratrichodina namely P. africana Kazubski and EI-Tantawy.1986. Full descriptions and systematic positions of collected species are given and discussed .
Egyptian Journal of Aquatic Biology and Fisheries
The Egyptian Society for the Development of Fisheries and Human Health (ESDFHH)
1110-6131
2
v.
2
no.
1998
35
49
https://ejabf.journals.ekb.eg/article_1623_7d1320cea2cd42aeb6a430f7e76033e8.pdf
dx.doi.org/10.21608/ejabf.1998.1623
DISTRIBUTION AND SALINITY RANGES OF ZOOPLANKTON ORGANISMS AT EL-FAYOUM DEPRESSION (EL-FAYOUM-EGYPT)
Adel
A. Mageed
National Institute of Oceanography and Fisheries, 101 Kasr AL~Ainy st, Cairo, Egypt
author
text
article
1998
eng
Distribution and salinity ranges of the different zooplankton species at Ei Fayoum depression (El Wadi drain, Wadi El-Rayan Lakes, Fish Farms, Lake Qaroun, and EMISAL company ponds were discussed 18 species of Protozoa, 39 of Rotifera, 10 of Cladocera, 9 of Copepoda and only one Branchiopod were found, Moreover, the Tardigrad Macrobiotus macronyx and the Qstracod Cyprideis torosa in addition to the larvae of some benthic invertebrates were also obtained.Water of the studied area had a salinity range from 1.7 to 322 %o. In distribution, the species numbers were mostly decreased with increasing salinity. Some species werefoundtobeeujyhalineas5racA/o«usj7//caft'to (1.7-127.7 %o), Hexarthra oxyuris (2.5-73J%o),Keratellatropicaand!C valga { 1.7-42 %o for the two species ), while all the Cladocera were stenohaline. On the other hand, thirteen species were endemic to its area.
Egyptian Journal of Aquatic Biology and Fisheries
The Egyptian Society for the Development of Fisheries and Human Health (ESDFHH)
1110-6131
2
v.
2
no.
1998
51
71
https://ejabf.journals.ekb.eg/article_1624_3ea41ab203ceed3a7be635608cec0af0.pdf
dx.doi.org/10.21608/ejabf.1998.1624
ON THE EPIFOULNG OF PFARL OYSTER (PINCTADA RADIATA) IN QATARI WATER ARABIAN GULF AND ITS INFLUENCE ON THE FLESH GROWTH
Saad
Mohammed
Marine Science Dept, Faculty of Science, Suez Canal Univ. Ismailia,
Egypt
author
text
article
1998
eng
Epifouling assemblages. on pearl oyster shells in onshore and offshore'oyster beds, at Qatari water, Arabian Gul£ were investigated in relation to oyster size and flesh growth. Onshore oysters had great biofoulers and low growth parameters than offshore ones. In both beds, biofoulers were dominated by sponges, thorny oysters, polychaetes and red algae. Of these, the serpulid worm (Serpula vermicularis) and the thorny oyster (Spondylus marisrubri) were the most pronounced particularly in onshore oysters. Density of biofouler settlement increased with shell surface areas. Most biofoulers tended to settle on dorsal side of the pearl oyster except the tube worms which preferred the ventral side.
Egyptian Journal of Aquatic Biology and Fisheries
The Egyptian Society for the Development of Fisheries and Human Health (ESDFHH)
1110-6131
2
v.
2
no.
1998
73
85
https://ejabf.journals.ekb.eg/article_1625_85d12389440ed4e29f3b8d20063c7542.pdf
dx.doi.org/10.21608/ejabf.1998.1625
MACROBENTHIC INVERTEBRATES IN RELATION TO SEDIMENT PROPERTIES IN SOME FISH FARMS.
Mohamed
A. Fishar
National institute of Oceanography and fisheries AUKcmaterAl-Khqyria, Egypt
author
Ragab
Abdel-Regal
National institute of Oceanography and fisheries AUKcmaterAl-Khqyria, Egypt
author
text
article
1998
eng
Mechanical analysis, some chemical properties of sediment, composition and distribution of macrobenthic invertebrates were studied in ten fish ponds at El-Fayoum Govemorate (Egypt). The study showed that the nature of sediment ranged between sandy loam and clayey soils, while the sediment pH lied in the alkaline side. The community of benthos was represented by four groups (Annelida, Crustacea, Insecta and MoUusca).The most important factors affecting the composition and distribution of benthic community include nature of the bottom sediment, soil salinity, and its organic matter content, besides the number of rearing stocked fishes,
Egyptian Journal of Aquatic Biology and Fisheries
The Egyptian Society for the Development of Fisheries and Human Health (ESDFHH)
1110-6131
2
v.
2
no.
1998
87
100
https://ejabf.journals.ekb.eg/article_1626_7d5fa4fd3d192c1fd06fdf859b5d9ee0.pdf
dx.doi.org/10.21608/ejabf.1998.1626
SOME BIOLOGICAL CHARACTERS OF CHUB MACKEREL (SCOMBER JAPONICUS, HOUTTUYAN, 1782) FROM THE MEDITERRANEAN WATERS OF EGYPT
S.
Rizkalla
National Institute of Oceanography and Fisheries, Alexandria, Egypt
author
text
article
1998
eng
Fishes of chub-mackerel (Scomber japonicus, Houttuyan, 1782) are mainly caught by purse-seine nets using light attraction. The structure of S. japonicus catch in the Egyptian Mediterranean waters showed that tlus species attains ages not exceeding more than four years. Fishes of age group II dominated the catch, whereas those having age groups 0 (juveniles) and I were absent. The length of51 japonicus reached 25.9 cm during its second year of life. This was followed by a slight increase in length during the third and fourth years reaching 29.6 cm and 32.2 cm respectively. The back calculated weight for £ japonicus showed gradual increase in weight as the fish gets older, where weight at the fourth year (252.56 g) was nearly twice that obtained during the second year (133.36 g). The theoretical length (LM) and weight (W*,) calculated by von Bertalanfly equations were 39.42 cm and 453.24 g respectively. The values of condition factor, hepato-somatic and gonado-somatic indices were minimum in August following the end of the spawning season which extends from May to July. The shoals of S* japonicus were characterized by lacking immature fishes, so the length and age at the first sexual maturity cannot be determined. The relative fecundity of this species showed that a female produces from 382 to 625 eggs per gram of body weight.
Egyptian Journal of Aquatic Biology and Fisheries
The Egyptian Society for the Development of Fisheries and Human Health (ESDFHH)
1110-6131
2
v.
2
no.
1998
101
116
https://ejabf.journals.ekb.eg/article_1627_ed007c804c3ccc91c988dfe1ec907488.pdf
dx.doi.org/10.21608/ejabf.1998.1627