[Survey of the cycle of reproduction of red algae Gelidium sesquipedale (Turner) Thuret (case of the maritime zone of El Jadida-Jarf lasfer of Morocco)].

The industrial exploitation of the agarophyte, Gelidium sesquipedale, is an important part of the economy of Morocco, however the species is in danger of being overexploited. The development of research on the biological cycle of the species enbles a better understanding of environmental influencies on its reproduction periods and of the effect of pulling up on the growth of the thalli. This should assist in helping to avoid excessive collection of the species and to reinforce a period of rest where no collection takes place. The major are of collection supplying industries is the maritime sector of El Jadida - Jarf Lasfar. In order to study the methods of reproduction of G sesquipedale, a first series of experimentation was carried out by the INRH. Studies relating to biology and the effect of pulling up on the biometrics of the thalli of this species were carried out at two stations of the maritime zone El Jadida - Jarf lasfar: Moulay Abdellah and Sidi Bouzid during the period 2000-2002. The results obtained show that the fertile thalli are present all the year with a maximum reproductive activity in winter. The recruitment of the young slings takes place before the winter and occurs more in Sidi Bouzid. The regeneration and the growth of the thalli are carried out in spring and summer. To preserve this resource, it is necessary to put in place a system whereby one zone or area is allowed to rest whilst another area is cultivated for a year; whilst in the following year the rercise occurs.