W calej tej dyskusji pojawia sie odwieczny problem braku (lub checi) zrozumienia przez wedkarzy czym sa wody Skarbu Panstwa.
Niezaleznie jak bardzo bysmy tego chcieli to taki Zalew Zegrzynski nalezy do Panstwa a PZW moze tylko dzierzawic go do swoich celow, ktore i tak musi realizowac wg zasad narzuconych przez wlasciciela. Tutaj nie ma co sobie oczu mydlic, ze jest inaczej.
Podstawowa funkcja zalewu nie jest sprawianie przyjemnosci braci wedkarskie bo tych funkcji jest wiecej. Jest tez np. rezerwuarem wody pitnej dla Warszawy.
Prawda jest , ze w wiekszosci polskich wod presja na drapiezniki jest ogromna i owszem C&R rosnie w sile ale nie zmienia to faktu, ze rownowaga pomiedzy drapieznikami i rybami spokojnego zeru jest zaklocona.
Nie chce sie odnosci do teorii spiskowej przedstawionej w tym temacie bo nie jestem w stanie tego ani potwierdzic ani temu zaprzeczyc.
Ja tez bylbym za tym aby zarybic drapieznikiem i to bardzo konkretnie aby sobie poradzil z nadmiarem drobnej bialej ryby, tylko ze wtedy na zamierzony efekt trzeba poczekac dluzej. Trzeba by tez zarybiac drapieznikiem dosc duzej wielkosci co bloby zbyt drogie. No i najlepiej byloby wprowadzic calkowity zakaz polowu drapieznikow na jakis czas (powiedzmy 2 lata)- wtedy to by sie dopiero lament podniosl
Jak ktos chce zglebic temat to na poczatek mozna poczytac np. to:
http://www.fao.org/3/a-y0814e.pdfJest tam kilka przykladow zarowno udanych jak i nie udanych biomanipulacji.
Moim zdaniem to co jest planowane/realizowane na ZZ nie moze sie udac.
Ponizej wklejam przykla udanej i nie udanej biomanipulacji:
3.1.2 Lake Breukeleveen
Lake Breukeleveen was the first large lake in the Netherlands to be biomanipulated.
The lake has a surface area of 180 ha, it is 1.5 meter deep and it suffered from a high
turbidity because of resuspended sediment and a high algal biomass, mainly consisting
of filamentous cyanobacteria (Van Donk et al., 1990). The fish community was
dominated by poorly growing bream and some pikeperch and roach (ca. 150 kg ha-1).
The pikeperch and eel stocks were exploited by one fisherman and some anglers, but
the fisherman had the fishing rights and issued licenses for fishing. Other important
recreation was sailing. The provincial water board decided to apply biomanipulation as
a restoration measure and paid all costs. The fish was removed by seining, the seine
being 550 meter long. The fisherman cooperated as he was paid for the job and
received all the pikeperch. The fish stocks were reduced by 60% and the following
summer the stock increased to its original size both by natural growth and by
immigration, because the fish barrier did not function well. The experiment was a
failure, with the fisherman having a nice profit but the local community paying the costs.
3.1.5 Frisian Lakes
The Frisian lakes are an interconnected system of lakes with a surface area of ca
10,000 ha, mean depth 2 m. They suffer from high algal biomass represented mainly
by the filamentous bluegreen Planktothrix agardhii. Prior to biomanipulation, the fish
community was dominated by bream, ruffe, smelt and roach with pikeperch as main
predator (Lammens 1986, 1999). The total biomass amounted to 180 kg ha-1. The lake
is mainly used for sailing and fishing. About 30 commercial fishermen exploit the eel
population and anglers fish for pikeperch and bream. The anglers and commercial
fishermen decided to start a fishery programme for a period of 5 years in order to
increase the catches of eel for the fishermen and the catches of pikeperch by anglers.
Part of the bream population was yearly removed to improve the food condition for eel.
Pikeperch > 60 cm was removed to improve the survival chances of pikeperch < 20 cm
and to keep the pikeperch population young. It was a biomanipulation experiment with
a different goal than water management. The annual seining removed 25-30% of the
bream stocks. The pikeperch > 60 cm was caught both with gill-nets and seines.
Pikeperch was sold and used to finance the whole operation. During the fishery
experiment the water quality improved as clear-water phases occurred more frequently
and lasted longer and aquatic vegetation started to colonize the lakes. The fish
community changed only with respect to size composition and year classes: the
average age and size of most fish species decreased, but the total biomass hardly
changed. Considering the positive results for both anglers and commercial fishermen,
and the improvement of water quality the benefits exceeded the costs
Przykladow jest znacznie wiecej w tym opracowaniu i wnioski mozna sobie samemu latwo wyciagnac.