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vol-1TlLAPIA FISHERIE IN LAKE MARIUT.,
AGE AND GROWTH OF TILAPIA RILOTICA L.
IN THE ALKE
By
S. EJ,-ZARKA, A.H. SHAHEEN
Institute of Oceanography and Fisheries Alexandria
and
A.A. EL-ALEEM.
Head of the Departme11t of Oceanograply, Faculty of Science University
of Alexaadria.
INTRODUCTION
Tilapia is a freshwater fish of a very large family Oichlidae abounding in
Africa including Madagascar and extending to Syria, India and Oylon in Asia.
It is known also in central and south America. It is a prolific fish that reaches
its fu::;t maturity when it if> one year old. It is even of small size are acceptable
and delicious for human consumption.
Tilapia is an important source of protein food for the Egyptians. It is
abound in big quantities in the Nile, its tributiries and the Nile Delta Lakes.
Thi& fish provides about 70% of the total fish produc”Lion in Egypt, i.e. about
24000 tons are caught annually in Egypt, (E1-Zarka 1956). Therfore, Tilapia
is of major importance to the fbhery industry of tlJis country.
Because of the importance of tllis fish, extensive research program has
started in 1957 to sur”ey the fi::;lJeries of Tilapia in the inland waters of Egypt.
Various studies have been done on the Tilapia species, Tilapia nilotica L., Tilapia
galilaea Art. Tilapia zilli Gerv. EI-Zarka 1956, 1961, 1962; Jensen 1958;
Imam and Hashim 1960; EI-Bolock and Koura 1960; Elester and lemen 1960;
Rifaat, El-Zarka and Ezzat 1964; and Shaheen 1969.
The present paper is confined to the study of age and growth of Tilapia
nilotica L. in Lake Maruit. Age and growth are extremely important in the
practical fishery of a fisb for seIving such biological information as longevity,
age at first maturity, cakhable ~i7e, environmental suitability and other life
hi!ltory prOblems.
Studies were also completed concerning length-weight relatiom;hip and
condition factors for the other Tilapia species of Lake Mariut as well as Tilapia
nilotica L. of Lake Menzalah for studying the suitability of the different babitats.
