Reproduction Of Nile Tilapia Research Articles

Effect of climate change on growth and reproduction of Nile tilapia (Oreochromis niloticus, L.) from Bahr Shebeen Canal, Delta of Egypt.

Effect of climate change on growth and reproduction of Nile tilapia (Oreochromis niloticus, L.) from Bahr Shebeen Canal, Delta of Egypt.

Effects of biofloc technology on reproduction and ovarian recrudescence in Nile tilapia

The objectives of this study were to evaluate the reproductive cycle, morphological changes of ovary and mobilization of energy reserves in Nile tilapia reared with biofloc technology (BFT). In general, the growth and reproductive performance were highly similar between BFT and Control system (clear water). Difference between the systems was found in the hepatosomatic index (using mixed-effects models), which suggested that BFT can alter the energy mobilization in the post-spawning period. The absolute and relative fecundity, fertilization rate, number of larvae produced per female, gonadosomatic index, proportion of oogenesis cells, number of post-ovulatory and atretic follicles were similar between the two systems. We also did not detect a reduction in the reproductive cycle length in Nile tilapia reared in BFT. Because there was no evidence of the negative effects of BFT on Nile tilapia reproduction, we concluded that BFT might be used for breeder stocking of this species.

Survival, growth and reproduction of non-indigenous Nile tilapia, Oreochromis niloticus (Linnaeus 1758). I. Physiological capabilities in various temperatures and salinities

The physiological tolerances of non-native fishes is an integral component of assessing potential invasive risk. Salinity and temperature are environmental variables that limit the spread of many non-native fishes. We hypothesised that combinations of temperature and salinity will interact to affect survival, growth, and reproduction of Nile tilapia, Oreochromis niloticus, introduced into Mississippi, USA. Tilapia withstood acute transfer from fresh water up to a salinity of 20 and survived gradual transfer up to 60 at typical summertime (30°C) temperatures. However, cold temperature (14°C) reduced survival of fish in saline waters ≥10 and increased the incidence of disease in freshwater controls. Although fish were able to equilibrate to saline waters in warm temperatures, reproductive parameters were reduced at salinities ≥30. These integrated responses suggest that Nile tilapia can invade coastal areas beyond their point of introduction. However, successful invasion is subject to two caveats: (1) wintertime survival depends on finding thermal refugia, and (2) reproduction is hampered in regions where salinities are ≥30. These data are vital to predicting the invasion of non-native fishes into coastal watersheds. This is particularly important given the predicted changes in coastal landscapes due to global climate change and sea-level rise.

Exploitation of Nile Tilapia in a Closed‐System Public Fishing Reservoir in Northern Arkansas

AbstractNile tilapia Oreochromis niloticus have been stocked as a forage species annually since 2001 in Lake Hogue, a 101‐ha, closed‐system public fishing reservoir in northeastern Arkansas. A mail‐in reward tag study was implemented in 2003 to determine total estimated harvest, contribution of Nile tilapia to the lake's fishery, and impact of angler harvest on Nile tilapia reproduction. Estimates of harvest were corrected for tag loss (1.1%), tag‐induced mortality (1.0%), and nonreporting of tags by anglers (53% reporting rate). Angler‐hours were compared between anglers targeting Nile tilapia and those targeting other species. Anglers harvested an estimated 83% of the stocked Nile tilapia (56% of stocked fish were captured by traditional panfishing techniques; 27% were captured by use of dip nets during the winter die‐off in late November). Anglers targeting primarily Nile tilapia fished significantly longer (5.7 h/angler) than individuals who incidentally caught Nile tilapia while fishing for other species (4.5 h/angler). Analysis of the economic impact of stocking Nile tilapia demonstrated a benefit‐cost ratio of 0.38. Harvest of Nile tilapia did not apparently interfere with the management goal of using the fish as a forage species for game fishes. Tag return data strongly suggested that at midday during the hot summer months, when fishing pressure had traditionally been low, anglers targeted Nile tilapia in favor of the traditional target species (e.g., bluegill Lepomis macrochirus and redear sunfish L. microlophus).

Effects of Increased Nitrogen Fertilization on Water Quality and Yield of Nile Tilapia, Oreochromis niloticus, and Common Carp, Cyprinus carpio, in Earthen Ponds in Egypt

This study investigated the effects of increased nitrogen fertilization on water quality and yield of Nile tilapia, Oreochromis niloticus, and common carp, Cyprinus carpio, in earthen ponds in Egypt. Nine 0.1-ha ponds were filled with water from the Nile River and fertilized once every two weeks with urea and triple super phosphate. Three fertilization regimens were evaluated: (1) no fertilizer (control); (2) low nitrogen treatment in which ponds received 30.9 kg urea/ha plus 30.9 kg triple super phosphate/ha (daily equivalent to 1.0 kgN/ha and 0.4 kg P/ha); and (3) high nitrogen treatment in which ponds received 92.7 kg urea/ha plus 30.9 kg triple super phosphate/ha (daily equivalent to 3.1 kg N/ha and 0.4 kg P/ha). There was a significant increase in total ammonia-nitrogen, nitrate-nitrogen, pH, and chlorophyll awith increased nitrogen in fertilizers; but alkalinity, hardness, total phosphorous, secchi disk visibility, and dissolved oxygen (at 0600 and 1400) were similar. Temperature and secchi disk visibility were the only water quality variables that changed significantly (P<0.05) with season; temperature increased during the summer, but secchi disk visibility decreased. There was no significant difference (P> 0.05) in final body weight, net yield, and reproduction of Nile tilapia among the three treatments. Final body weight and yield of common carp were also similar, regardless of fertilization treatment. It appears that nitrogen did not limit primary production. Low density of tilapia, enhanced turbidity by common carp that affected algal growth and reproduction, and phosphorous limitation may have combined to lower yield in this study.