STUDIES ON SOME ECOLOGICAl. FACTORS AFFECTING TilE FISH PRODUCTION OF LAKE QARUN, EGYPT.

STUDIES ON SOME ECOLOGICAl. FACTORS AFFECTING TilE FISH
PRODUCTION OF LAKE QARUN, EGYPT.
S.A. ABDEL-MALEK*, MAGDY T. KHALIL** and ABDEL-HAY A. ALI*
*National Institute of oceanography and FiSheries, Cairo.
**,Zoology Dept., FaCUlty of Science, Ain Shams university, Calro, Egypt.
ABSTRACT
This study reveals the main factors! accounted for the
decline of fisheries in Lake Qarun.
Firstly, a considerable part of the ,;oastal are” i.e.
the spawning grour~s for the majority of fish species, has
been dried due to lowering of water level. Many nests and
egg masses are destroyed.
Secondly, during the period 1970-1977, some predatory
marine fish species were introduced into the Lake. It seems
that most of the transplanted fry are eaten by them.
Thirdly, the polluted drainage water contaminated with
pesticides, heavy metals and etc., has greatly affected the
Lake fisheries.
FinallY, the increase of water salinity may also
affect the growth rate of fishes in the Lake.
Some suggestions are recommended to solve the problems
confronting the fish production from Lake Qarun.