IMPACT OF DIFFERENT SALINITIES ON THE HATCHING AND SURVIVAL OF BRINE SHRIMP Artemia salina (LINNAEUS, 1758)
ABSTRACT
The present study was carried out to know the hatching percentage and survival rate of the Artemia salina (Brine shrimp) in different salinity which ranges between 0-40 ppt and freshwater (0 - 1 ppt), brackish water (25 - 28 ppt) and seawater (35 - 40 ppt) were used for this experiment. To conduct this experiment, 1.0 gram of Artemia cyst was taken to hatch out the artemia larvae with the various salinity concentrations viz., freshwater, brackish water and seawater and its pH range between 7.7-7.9, 7.2-7.5 and 7.2-7.5 respectively and the water temperature of these waters recorded as 27.5-28 oc. The experiment result reveals that higher hatching percentage observed in Brackish water (66%) followed by seawater (60%) and Freshwater (48%) and the higher survival rate was observed in brackish water (32%) followed by Seawater (17%). The ANOVA value shows that salinity influence (p>0.05) the survival rate of artemia nauplius.
MATERIALS AND METHODS
The present investigation was undertaken to study the hatching and survival rate of Artemia salina in the different salinities. In this experiment three different salinity waters were taken from different sources viz., Freshwater (0-1ppt) and (Seawater 35-40ppt). The brackish water (25-28ppt) was prepared by diluting the freshwater and seawater.The experiment was conducted with 1g of artemia and it was hydrated and aerated for 1 hour to soften the cyst. These soften Artemia cyst was further decapsulated with Sodium Hypochlorite (1gm cyst /15ml). Once the cyst colour changes from brown or grey to orange, then the cysts were filtered with 125 µm mesh screen and rinsed well with tap water and 1.0 % sodium thiosulfate used to neutralize the residual chlorine in the cysts. After the cyst encapsulation, encapsulated cysts were taken and stocked for decapsulation of cysts in different salinity tanks with 1 gram. The environmental parameters like salinity, temperature and pH were estimated 4 times per days and observed the survival and hatching percentage in different salinities until the survival of artemia nauplii.
RESULT
The result of the experiment shows that higher hatching and survival was observed in the brackish water which provides the high survival rate of 66% ie., 1.65x105 than that of seawater (60% ie., 1.50 x 105) and Freshwater (48% ie., 1.20x105). The survival and hatching rates are similar in the seawater and freshwater and these can be considered for artemia hatching. The Artemia nauplii once hatched are getting declined based on the period of the experiment. In the freshwater, it is observed that the percentage of survival rate 48%, 28% and "0" during 1st, 2nd and 3rd day of the experiment respectively and there was no survival of Artemia after 3rd day of hatching. The similar pattern of survival rate was observed in brackish water which shows 66%, 52%, 41% and 32% during 1st, 2nd, 3rd and 4th days of hatching respectively and it indicates the highest rate of survival than the freshwater and seawater and hatching percentage declined gradually and achieves 32% of survival after 3rd day. It shows that the preference has to be given to brackish water to hatch out the artemia cyst in the confined environment to get a better survival rate. The result of the survival and hatching rate of Artemia salina with different salinities and water quality parameters maintained in the experiment are shown in Table 1 & 2. The experiment result was tested with one-way ANOVA test to obtain the significance of survival rate (p>0.05) between the various salinities. It shows the significant difference in survival and hatching of Artemia salina in brackish water (p>0.05) than the freshwater and seawater.
