Discussion
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reproduction in the Lake. Therefore, we have to put into the Lake, every year, big quantities of little
fish from breeding ponds.
D.W. Rosenblatt, USA
Should not the fish be harvested to add to the food supply? Can Tilapia hybrids of single sex be
used, so that the fish will not multiply excessively - thereby producing fish more suitable for human
consumption?
H. Leventer
For our purpose 50-300 gr. fish give good results. High multiplication is a problem and we cannot
solve it by populating the reservoir with a single sex, as it is done in fish ponds in Israel. Single fish
arrive from Lake Kinneret and two years is a sufficient period to create a large population. Fish ponds
are emptied every year and in this way the number of fish is controlled.
J. Blok, Netherlands
It is well known that accumulation of heavy metals may occur in algae and animals. How were the
concentrations in the organisms of the ecosystem described?
H. Leventer
This was not of our primary interest, as in the watershed of Lake Kinneret there are no heavy
metals mines, neither chemical or metallurgical industries. The concentration of heavy metals in Lake
Kinneret is very low.