Reproduction and embryo viability of a range-limited tropical freshwater fish exposed to fluctuating hypoxia

2018 ◽  
Vol 69 (2) ◽  
pp. 267 ◽  
Author(s):  
Nicole Flint ◽  
Richard G. Pearson ◽  
Michael R. Crossland

Hypoxia can profoundly affect fish reproduction and larval development, but its effects on fish from tropical Australia are not well understood. In the present study, the effects of diel fluctuating hypoxia on reproduction and embryo viability were investigated for a range-limited tropical freshwater fish, namely the Utchee Creek rainbowfish (Melanotaenia utcheensis). The lethal level for adult rainbowfish after gradual oxygen depletion was ~7% dissolved oxygen (DO) saturation. After 28 days, the reproductive success of adult fish exposed to fluctuating hypoxia treatments was measured by fecundity, gonad health, egg incubation time, egg and larval mortality, viability and size of hatching larvae. Reproduction was impaired in the lowest sublethal treatment (minimum 10% DO saturation each day). No ill effects of parental exposure to diel fluctuating hypoxia on embryos were identified, and minor differences in temperature between aquaria had a greater effect on embryos than parental hypoxia treatments. Similarly, no effects of embryonic exposure to diel fluctuating hypoxia were identified. Utchee Creek rainbowfish appear to be more hypoxia tolerant than temperate species, in keeping with their habitat in warm lowland streams, but they are still susceptible to the increasing frequency and intensity of hypoxia possible with increasing temperature and reduced flow as a result of climate change.

2021 ◽  
Vol 335 (9-10) ◽  
pp. 721-722
Author(s):  
Bernd Pelster ◽  
Adalberto L. Val ◽  
Reinhard Dallinger

2018 ◽  
Vol 69 (6) ◽  
pp. 987
Author(s):  
N. Flint ◽  
R. G. Pearson ◽  
M. R. Crossland

Hypoxia can have profound sublethal effects on reproduction and embryonic development of some freshwater fish. In the present study, the effects of diel fluctuating hypoxia on embryo viability were investigated for the eastern rainbowfish Melanotaenia splendida splendida, a small-bodied species common in wetlands of tropical Queensland. After daily hypoxic exposure (minimum 5% saturation) from fertilisation until hatch, no effects were found on egg incubation time, egg and larval mortality, and viability and size of hatching larvae. Older life history stages of the species are vulnerable to this level of hypoxia. Embryos of phytolithophilic species are likely exposed to fluctuating dissolved oxygen saturations in their natural habitat, and hypoxia tolerance may be a requirement for fish species that spawn predominantly on submerged plant material.


2007 ◽  
Vol 57 (3) ◽  
pp. 293-300 ◽  
Author(s):  
Tanusree Dutta ◽  
Subhendu Acharya

AbstractA new species of myxozoan (Myxozoa: Bivalvulida) Thelohanellus habibpuri sp. n. parasitic in tropical freshwater fish collected from the Habibpur, West Bengal, India is described in this paper. T. habibpuri was found in the Pectoral fin of Labeo rohita (Hamilton-Buchanan, 1882). The diagnostic characters of T. habibpuri are: generally oval milky-whitish plasmodia attached in the pectoral fin of host fishes; spore egg-shaped to ovoid with slightly tapering anterior and rounded posterior end, averaging 13.9 × 8.5 μm in size; a single oval-round polar capsule 6.0 × 4.9 μm in diameter, with polar filament wound in 3-4 coils. Finely granular sporoplasm containing two slightly oval nuclei (1.4 μm in diameter) and a small iodinophilous vacuole (3.0 μm in diameter) present in the spore.SEM study of this myxozoan reveals the anterior extremity of spore is truncated. The Cnidocyst discharge channel appear as a dark area. The longitudinal wavy surface are visible on the spore.


Hydrobiologia ◽  
1970 ◽  
Vol 35 (2) ◽  
pp. 297-304 ◽  
Author(s):  
Asif A. Khan ◽  
A. Qayyum Siddiqui ◽  
M. Nazir

2010 ◽  
Vol 36 (3) ◽  
pp. 411-417 ◽  
Author(s):  
Prakash Sharma ◽  
Vikas Kumar ◽  
Amit Kumar Sinha ◽  
Jayant Ranjan ◽  
H. M. P. Kithsiri ◽  
...  

HortScience ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. 562-566 ◽  
Author(s):  
Jorge M. Fonseca ◽  
James W. Rushing ◽  
Robert F. Testin

The influence of temperature and O2 concentration on respiration and shelf life of fresh-cut watermelon was investigated. Product stored at selected temperatures from 1 to 30 °C showed increasing respiration and reduced shelf life with increasing temperature. Oxygen depletion and CO2 evolution were measured using a closed system method and rates of O2 consumption and CO2 production were computed. A mathematical model found to predict the CO2 production as function of temperature and O2 showed an elevated rate of CO2 production at about 14% O2 or lower. A modified atmosphere trial that compared product stored at 7 to 9 °C in air with product at either 14% or 8% O2 revealed increased respiration in the latter treatments, suggesting a relatively high anaerobic compensation point (ACP) at >14% O2. Our results suggest limited applicability of modified atmosphere packaging (MAP) for this product. Fresh-cut watermelon had extended shelf life and reduced respiration rate when stored at 1 to 3 °C and in >14% O2 atmospheres.


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