Effects of water temperature on growth and sex ratio of juvenile Nile tilapia Oreochromis niloticus (Linnaeus) reared in geothermal waters in southern Tunisia

2008 ◽  
Vol 33 (2) ◽  
pp. 98-105 ◽  
Author(s):  
M.S. Azaza ◽  
M.N. Dhraïef ◽  
M.M. Kraïem
2020 ◽  
Vol 6 (3) ◽  
pp. 431-437
Author(s):  
Mohammad Ashaf Ud Doulah ◽  
SM Majharul Islam ◽  
Mohammad Shadiqur Rahman ◽  
Md Shariful Islam ◽  
Mohammad Harun Or Rashid ◽  
...  

The study was carried out to identify the parasite and causative diseases on cage reared tilapia at Bakerganj upazila, Barisal district. The infected tilapia fishes were collected from the cages and brought to the laboratory to find out signs, symptoms and infection area on the fish body. Physico-chemical parameters of water, such as water temperature, pH, dissolved oxygen, nitrate, phosphate and ammonia were monitored fortnightly. The values of water temperature (°C), pH, dissolved oxygen (mg/l), nitrate (mg/l), phosphate (mg/l) and ammonia (mg/l) were 32.4±2.1, 6.2±0.3, 7.52±0.4, 0.028±.008, 11.30±2.26 and 0.09±0.02, respectively but the concentration of nitrate was so higher during the study time. Eleven species of parasites namely, Chilodonella sp, Trichodiniasp., Gyrodactylussp.,Cichlidogyrus sp., Capillariasp, Orientocreadium sp, Eustrongylidae sp, Allocreadium sp, Euclinostomum sp, Tylodelphys sp. and Metagonimus spwere were identified. Parasites were found on all the examined parts of the fish body but gill showed the most infested area of the host. Highest mortality rate was occurred in the month of October and lowest mortality rate was in July. In this circumstance, proper management system and handling are best ways to prevent diseases and reduce the mortality rate of tilapia on cage farming in the southern area. Res. Agric., Livest. Fish.6(3): 431-437, December 2019


2010 ◽  
Vol 17 (3) ◽  
pp. e683-e690 ◽  
Author(s):  
S. XIE ◽  
K. ZHENG ◽  
J. CHEN ◽  
Z. ZHANG ◽  
X. ZHU ◽  
...  

2021 ◽  
Vol 9 (02) ◽  
pp. 72-76
Author(s):  
Mouhamadou Amadou Ly ◽  
◽  
Abdoulaye Ngom ◽  
Ahmadou Bamba Fall ◽  
Ousmane Diouf ◽  
...  

This present study was conducted to determine fry production in different male-female sex ratios of Oreochromis niloticusbroodstock in order to improve fry production, which handicapped the development of fish farming in northern Senegal. A total of 180 broodfish (47 males and 133 females) were stocked at a density of 2 fish /m2and was replicated three times for each sex ratio of 1:2, 1:3and 1:4 (male : female). Mean body weight ranges from 136.47±2.13 and 107.27±2.14 g for female and male O. niloticusbroodstock, respectively. The experiment was conducted for 90 days and the broods were fed on commercial diet containing 32% crude protein.Fish were held in 9 rectangular tanks of 30 m3 each (10 × 3 × 1) and half-filled. The results showed that number of fry produced at different sex ratios were significantly different, with sex ratio of 1:2 producing a highest number of fry (279.67) per female, followed by the 1:3and 1:4 treatment recorded the lowest.Broodstock sex ratios also did not affect female survival rates and all treatments had 100% survival rates. Temperature, dissolved oxygen and pH values obtained were suitable for good water quality and normal tilapia reproduction.In conclusion, the results of the present study recommend to stock Oreochromis niloticus brooders when stocked at a density of 2 fish /m2 at a sex ratio of 1 male : 2 female in order to obtain the highest fry production.


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