Implementation of the spring rearing of the pearl oystercatcher in the project ATCZ37 Malsemuschel "Support of the natural habitat and occurrence of the pearl oystercatcher (Margaritifera margaritifera) in the Malše basin"

The subject of the work is the rearing of juvenile river pearls in the spring breeding cycle according to the so-called Czech method of semi-natural rearing (see Appendix 7 of the Rescue Program for River Pearls, Margaritifera margaritifera, in the Czech Republic, freely downloadable on the website of AOPK CR http://www.zachranneprogramy.cz/perlorodka-ricni/zachranny-program-zp), care of juvenile pearls in the 1st to 3rd growth period and selection of individuals suitable for bioindicative evaluation of the habitat according to Appendix 8 of the Rescue Program. The spring rearing cycle includes collection of larvae (glochidia) in the stream in late summer, controlled fish infestation, care of fish until release of juvenile pearlfish, and care of juvenile pearlfish until the end of August of the following year. Natural release of pearls in the spring; when the work is handed over, the mother-of-pearls are in their first growth period. Cultured pearl oysters must genetically come from glochidia taken from the original population in the Blanice basin (conservation unit 1 according to Appendix 2 of the Rescue Program for river pearl oysters, Margaritifera margaritifera, in the Czech Republic). The breeding output will be at least 5,000 individuals in the 1st growth period (so-called category 0+ according to the Rescue Program). The supplier will hand over to the customer all cultured mother-of-pearl even beyond this number. Care means providing care for mother-of-pearls from rearings from previous years, i.e. in 2-3 years. growth period. Their breeding is carried out in cages in the Blanica stream. Care includes maintenance of cages to maintain their permanent flow rate, control of cages and their relocation according to the current development of conditions in the stream so that the annual mortality does not exceed 20%. This condition cannot be applied in case of adverse weather conditions or an accident on the stream. Before handing over the work, the supplier will divide the reared pearls according to the following criteria: in the first growth period, the length of the shells exceeds/does not exceed the average length of a random sample from the given rearing cycle; in the second growth period, the length of the shells is/is not in the range of 800-1120 µm. Cultured pearls will be used at Place of performance: Praha Contract type: Služby Procedure regime: VZ malého rozsahu Awarded to: GAMMARUS CZ, s.r.o. Awarded contract value: 300,080.00 CZK