Effects of incubation water hardness and salinity on egg hatch and fry survival of Nile tilapiaOreochromis niloticus(Linnaeus)

Abstract

This study examined the effects of water hardness and salinity on yolk sac larvae and swim‐up fry survival of Nile tilapia, Oreochromis niloticus (Chitralada strain), eggs during artificial incubation. Four experiments were conducted to evaluate the effects of hardness, salinity and the sources of saline incubation water. High water hardness treatments (500–4200 mg L−1 as CaCO3) resulted in higher yolk sac larvae and swim‐up fry survival than low water hardness treatments (50.0 and 132 mg L−1 as CaCO3); although yolk sac larvae and swim‐up fry survival did not differ among the high or low hardness treatments. Salinity of 4.0 g L−1 using seawater, and 4.0 and 8.0 g L−1 using unprocessed common salt resulted in the higher survival rate of yolk sac larvae and swim‐up fry than other salinity treatments. Yolk sac larvae and swim‐up fry survival was found to decrease with the increase in salinity and increase with the increase in water hardness. The present study demonstrated the positive effects of increased water hardness level (>132 mg L−1) on yolk sac larvae and swim‐up fry survival. The study also showed that seawater salinity of 4 g L−1 was the most appropriate salinity level for incubating Nile tilapia eggs.

Salinity on artificial reproduction of silver catfish (Rhamdia quelen)

“…In general, freshwater teleost embryos tolerate low salinity. BART et al (2013) demonstrated that incubation of Nile tilapia embryos at 4‰ presents higher hatch rate than at freshwater or at 12‰. However, according to the results of the present study, it is not possible to perform fertilization and incubation of silver catfish in low salinity media.…”

Efficacy of formalin, iodine and sodium chloride in improvement of egg hatching rate and fry survival prior to the onset of exogenous feeding in yellow perch

“…On the contrary, Bart et al . () and Yahya, Rasha and Eletreby () found that 4 and 1.5 g L −1 sodium chloride increased the egg hatching rate of Nile tilapia Oreochromis niloticus and C. carpio respectively. A shorter exposure time to disinfectant could reduce stress on the eggs and allow the safe application of the chemicals (Rach, Gaikowski & Ramsay ).…”

“…Our findings are in agreement with Froelich and Engelhardt (1996), Rasowo et al (2007), and Hanjavanit, Panchai, Kitancharoen and Hatai (2013) who recorded that 2.0% salt or higher decreases the hatching rate. On the contrary, Bart et al (2013) and Yahya, Rasha and Eletreby (2014) found that 4 and 1.5 g L À1 sodium chloride increased the egg hatching rate of Nile tilapia Oreochromis niloticus and C. carpio respectively. A shorter exposure time to disinfectant could reduce stress on the eggs and allow the safe application of the chemicals (Rach, Gaikowski & Ramsay 2000).…”

“…Sodium chloride (salt) has been proved as a safe, effective and economical disinfectant for controlling fungal and bacterial infection in freshwater fin and shellfish aquaculture and hence increasing the hatching rate (Policar, Smyth, Flanigan, Kouba & Koz ak 2011;Bart, Prasad & Thakur 2013;Sarkheil, Rafiee, Amiri & Farhangi 2014).…”

Evaluating quality of Nile tilapia (Oreochromis niloticus) eggs and juveniles from different commercial hatcheries

“…Korsgan, 1991). It is accepted that salinity resistance is related to the interaction of factors such as temperature, pH (Hui et al, 2014) and hardness (Bart et al, 2013), which could affect hatching rate, length, yolk sac size, embryogenesis, survival, growth and oxygen consumption of tilapia (Rodríguez-Montes de Oca et al, 2015;Fridman et al, 2013). We concluded that juvenile growth, carbohydrate content in eggs and juveniles, and resistance to salinity stress are adequate criteria to assess the quality of eggs and juvenile of Nile tilapia from broodstock of different origin.…”