title: Reproduction cycle and tolerance to temperature and salinity of Amyloodinium ocellatum (Brown, 1931) (Dinoflagellida).
abstract: Reproduction cycle and tolerance to temperature and salinity of Amyloodinium ocellatum (Brown, 1931) ( Dinoflagellida ) was investigated in the laboratory using postlarval Sparus aurata (L.) as fish host and by in vitro study of the parasite is reproductive stage. Trophont growth was linear by length and exponential by volume, continuous to detachment stage at the size of 50-90 microns in length. At 19-24 degrees C detachment occurred gradually during the 3-5th days after settlement. At 16 degrees C growth, as well as detachment, was delayed. However, by the 6-7th day trophonts still attached exceeded 100 microns in length. When detached, trophonts of any age and size were transformed into dividing tomonts . 24-hour old, less than 25 microns length trophonts , however, immediately sporulated with no division. The number of divisions to sporulation was related to the size at detachment. For reproduction, 18-30 degrees C was the optimal temperature range, although the minimal division time was at 23-27 degrees C. Divisions were delayed and sporulation was interrupted at 15 degrees C. Complete interruption of division and gradual mortality occurred at 8 degrees C. At 35 degrees C the reproduction process of the tomonts was severely damaged. Tolerance to salinity was dependent on ambient temperature and was the widest at 24-25 degrees C. Divisions occurred between 1-78 ppt, but uninterrupted division, full yield sporulation and effective infection of fish occurred only between 10 to 60 ppt. No division occurred above 80 ppt, however, short term incubation up to 4 days in salinities up to 180 ppt did not affect division potency. Wide variation in tolerance was, however, evident between tested population as well as individual tomont in each population.
mesh_terms: D000818:Animals; D004141:Dinoflagellida / Q000254:growth & development / Q000502:physiology*; D005399:Fishes / Q000469:parasitology; D012098:Reproduction; D012965:Sodium Chloride / Q000494:pharmacology; D013170:Spores; D013696:Temperature; D013997:Time Factors
chemical_list: D012965:Sodium Chloride