AQUACULTURE OF THE CRAYFISH AND THE CONTROL OF NATURAL HABITATS
Main researcher
: ERBEN, RADOVAN (11296) Assistants
LEINER, SREĆKO (79862)
PEURAČA, JASNA (165191)
TURK, MIRKO (65816)
PETERNEL, RENATA (94111)
FAŠAIĆ, KREŠIMIR (7070)
KLOBUČAR, GORAN IGOR VINKO (900420)
Type of research: applied Duration from: 09/29/93. Papers on project (total): 58
Papers on project quoted in Current Contents: 4
Institution name: Prirodoslovno-matematički fakultet, Prirodoslovni odjeli, Zagreb (119) Department/Institute: Department of Zoology Address: Rooseveltov trg 6 City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (0) 1 442 604
Phone: 385 (0) 1 442 607
Fax: 385 (0) 1 45 52 645
Phone: 385 (0) 1 442 804
E-mail: Goran.Klobucar@public.srce.hr
Summary: In controled waters in fishpond Draganići we started with
cultivation of autochthonous crayfish Astacus astacus by putting 6500
larvae in the pond with the aim of repopulation of natural waters of
Croatia. Aquaculture takes it for granted that habitat is prepared for
optimal survival ofcrayfish: water temperature about 20 degrees C,
pH=7,8, water hardness 158 Dh, disolved oxygen concentration between 5-6
mg/l, sanitary control of the water and adequate natural and artificial
food. The same species and invertebrates from the natural habitats were
used as test organisms in laboratory in order to establish water quality
of those habitats. Special atention was given to crab diseases caused by
viruses, bacteria, parasites and fungi as well as to their timely
detection and cure. That is why sanitary water control was continously
carried out as well as histopathological analyses of tissues and all
organs (especially of hepatopancreas and gonads) of cultivated animals
and those cought from among the few populations in natural waters. Apart
from these analyses, enzymatic and biochemical analyses were also carried
out with the aim of establishing physiological condition of the animals.
In controlled laboratory conditions mortality of all crayfish of all ages
was followed after their being influenced by various pollutants that have
perilous consequences for environment. The results made it possible: a)
polycultural cultivation, crayfish-fishes, which allows competitive
relationship, b) reintroduction of crayfish in natural habitats and
monitoring of dynamics of population and c) timely intervention in the
case of diseases appearance, be it in intensive cultivation or in
natural waters.
Keywords: crayfish Astacus astacus, pond system, repopulation, histopathology, water quality control, pollution awareness, forage management, test organisms, aquatic toxicity tests
Research goals: The aim of the proposed research and expected yield.
The prospects of the development of aquaculture in the first place the
cultivation of crayfish in our country and in the world are the following:
Planning of possible capacities of cultivation and preventing crayfish
from devastation (crayfish is one of the most threatened freshwater
representatives) from existing water ecosystems. Along with crayfish
breading chosen species of fish in polyculture should be bread as well in
accordance with competition in and the quality of the water (carp). To
solve the problems of crayfish larvae cultivation in the sense of the
development of methodology, especially the time spend with mother leading
to independent life and the beginning of teritorial behaviour. The
choosing of adequately composed food for separate stages of the
development of life cycle. By using preventive measures to prevent and
cure possible diseases of organisms in intensive cultivation. To use
economically the capacity of hatching grounds in polyculture by
cultivating larval stages of different species of fish together with the
cultivation of crayfish larvae in accordance with their spawning time. To
follow the level of pollution in the aquaculture and possible accumulation
in organisms. Proposal of the improvement of cultivation by using new
technological solutions in the proces of cultivation (the improvement of
hatching ground conditions, selection of adequate habitats and food,
control of the population density, age structure and relationship of
sexes, genetics, physico-chemical characteristics of the water etc.). To
insure satisfactory number of the animals which, owing to their biological
characteristics, can exist in natural waters. Reintroduction of
autochthonous species in the waters of Croatia, the preservation of these
species as well as monitoring of their adaptation in the conditions of
natural environment. Results of laboratory histopathological analyses were
used in the prevention of the diseases and also in the prevention of the
spreading of infectious diseases in autochthounous crayfish populations in
natural waters and in the intensive cultivation in mono and polyculture.
Listing of subchronical, chronical and lethal concentrations of possible
polutants in natural waters and aquaculture. For water quality tests in
natural habitats apart from Astacus astacus other aquatic invertebrates
were used.
COOPERATION - PROJECTS
Name of project
: sponzor projekta s pokusnim bazenima i
mrijestilištem Name of institution: Ribnjačarstvo Draganići City: Draganići, HR
COOPERATION - INSTITUTIONS
Name of institution
: Zavod za ribištvo Type of institution: State institute Type of cooperation: Systematic exchange of information City: 61000 - Ljubljana, SLO
Name of institution
: Dipartimento di Scienze della Produzione
Animale Type of institution: University/Faculty Type of cooperation: Systematic exchange of experts City: Udine, I
Name of institution
: Dipartimento di Biologia Type of institution: University/Faculty Type of cooperation: Occasional exchange of experts City: Trieste, I Other information about the project.