Hypoxia during incubation does not affect aerobic performance or haematology of Atlantic salmon ( Salmo salar ) when re-exposed in later life
Hypoxia in aquatic ecosystems is becoming increasingly prevalent, potentially reducing fish performance and survival by limiting the oxygen available for aerobic activities. Hypoxia is a challenge for conserving and managing fish populations and demands a better understanding of the short- and long-...
| Published in: | Conservation Physiology |
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| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Oxford University Press
2019
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| Subjects: | |
| Online Access: | https://doi.org/10.1093/conphys/coz088 http://ecite.utas.edu.au/139792 |
| Summary: | Hypoxia in aquatic ecosystems is becoming increasingly prevalent, potentially reducing fish performance and survival by limiting the oxygen available for aerobic activities. Hypoxia is a challenge for conserving and managing fish populations and demands a better understanding of the short- and long-term impacts of hypoxic environments on fish performance. Fish acclimate to hypoxia via a variety of short- and long-term physiological modifications in an attempt to maintain aerobic performance. In particular, hypoxia exposure during early development may result in enduring cardio-respiratory modifications that affect future hypoxia acclimation capacity, yet this possibility remains poorly investigated. We incubated Atlantic salmon ( Salmo salar ) in normoxia (∼100% dissolved oxygen [DO, as percent air saturation]), moderate hypoxia (∼63% DO) or cyclical hypoxia (100-25% DO daily) from fertilization until 113days post-fertilization prior to rearing all groups in normoxia for a further 8months. At ∼11months of age, subsets of each group were acclimated to hypoxia (50% DO) for up to 44days prior to haematology, aerobic metabolic rate and hypoxia tolerance measurements. Hypoxia exposure during incubation (fertilization to 113days post-fertilization) did not affect the haematology, aerobic performance or hypoxia tolerance of juvenile salmon in later life. Juveniles acclimated to hypoxia increased maximum aerobic metabolic rate and aerobic scope by ∼23 and ∼52%, respectively, when measured at 50% DO but not at 100% DO. Hypoxia-incubated juveniles also increased haematocrit and haemoglobin concentration but did not affect acute hypoxia tolerance (critical oxygen level and DO at LOE). Thus, while Atlantic salmon possess a considerable capacity to physiologically acclimate to hypoxia by improving aerobic performance in low oxygen conditions, we found no evidence that this capacity is influenced by early-life hypoxia exposure. |
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