Mass culture and water quality parameters of Acartia tonsa (Dana, 1849)

Since Acartia tonsa is an important alternative live feed source against Artemia and rotifer, its culture draws attention. The tolerance of A. tonsa to different temperature ranges and tolerance against nitrogenous compounds have been determined to find out the optimum culture conditions. This thesis is comprised of three main studies; In the first study, A. tonsa nauplii and adult were exposed to different concentrations of ammonia in a series of acute toxicity tests by the static renewal method at different temperature (18°C, 23°C and 28°C) and salinity (10‰, 20‰ and 30‰) combinations at a pH of 8.1. Lower temperature and high salinity clearly increased the tolerance of the copepod to total ammonia nitrogen (TAN) and unionized ammonia (NH3) (P<0.01). 48-h LC50 values of TAN and NH3 were calculated as 2.75 mg/ L-1 and 0.17 mg/ L-1 for the nauplii stage at a temperature of 28°C and a salinity of 30‰, respectively. 96-h LC50 values of TAN and NH3 were estimated for the adult stage at the same temperature and salinity. The safe limits of TAN-NH3 for nauplii and adult stage were estimated to be 0.275-0.017 mg/L-1 and 0.867-0.069 mg/L-1 at the temperature of 28°C and salinity of 30‰, respectively. This study indicated A. tonsa nauplii more sensitive to ammonia than the adult stage. In the second study, tolerance of A. tonsa nauplii and adult to nitrite (NO2-) was determined relating to temperature and salinity. The copepods were exposed to different NO2- concentrations in a series of acute toxicity tests by the static renewal method at different temperatures (18°C, 23°C and 28°C) and salinity (10‰, 20‰ and 30‰) combinations at a pH of 8.1. Lower temperature and high salinity levels clearly increased tolerance of nauplii and adults to NO2- (P<0.01). 48-h LC50 values of NO2- were calculated as 21.9 mg/L-1 for the nauplii stage at a temperature of 28°C and a salinity of 30‰, respectively. 96-h LC50 value of NO2- was estimated as 43.4 mg/L-1 at the same temperature and salinity. The safe limits of NO2- for nauplii and adult stage were estimated to be 2.2 mg/L-1 and 4.3 mg/L-1 at the temperature of 28°C and salinity of 30‰, respectively. This study indicates A. tonsa nauplii more sensitive to nitrite than the adult stage. In the third study, the thermal tolerance of A. tonsa was estimated using dynamic and static thermal methodology. Dynamic and static thermal polygon areas of this species were calculated as 495 °C2 and 267 °C2 for the nauplii stage, while the adult stage had 747 °C2 and 411 °C2 dynamic and static thermal polygon areas, respectively. It was determined that A. tonsa was more resistant copepod species to both high and low lethal temperatures with its resistance zone of 105°C2 and 131°C2 for nauplii and adult, respectively. A. tonsa nauplii acclimated to 18°C, 23°C and 28°C have CTMin-CTMax of 6.8-26.1 °C, 8.6-29.4 °C and 11.7-34.1 °C, respectively, while this species at the adult stage have CTMin-CTMax of 4.4-30.3 °C, 6.3-32.2 °C and 9.9-35.9 °C at acclimation temperatures mentioned above. It is estimated that its broad dynamic and static thermal tolerance polygon areas and consequently, its large thermal limits might provide A. tonsa to survive extreme water temperature in their natural environment.