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Developmental temperature stress and parental identity shape offspring burst swimming performance in sockeye salmon (Oncorhynchus nerka)
- Burt, Jenn M., Hinch, Scott G., Patterson, David A.
- Ecology of freshwater fish 2012 v.21 no.2 pp. 176-188
- Oncorhynchus nerka, egg incubation, fish, hatching, life history, parentage, processing stages, progeny, rearing, somatotropin, survival rate, swimming, temperature
- â The persistent effects of embryonic temperature stress and individual parentage on fry swimming performance were examined in a crossâfertilisation experiment using sockeye salmon (Oncorhynchus nerka). A fixedâvelocity test of burst swimming was used to assess the endurance capacity and behavioural performance of individual fry from 10 offspring families incubated at 12, 14 or 16âÂ°C to hatch and then reared through yolk absorption and exogenous feeding stages in a common posthatch environment (average 6.9âÂ°C). Fry burst swim time (BST) was influenced by an interaction between incubation temperature and family identity. Average BST was longer for fry from the 12âÂ°C prehatch treatment compared to 14 and 16âÂ°C, although differences were largely attributable to temperature effects on average fry size. Behavioural observations revealed that fish incubated at 16âÂ°C performed more poorly, having a larger proportion of individuals that required stimulation to swim, fatigued more frequently or were classified as ânonswimmersâ. Within all three incubation temperature treatments, mean BST varied significantly among offspring families, independent of fry mass and length. An interesting relationship was observed within the 16âÂ°C treatment, whereby families with higher survivorship were characterised with lower mean BSTs. Collectively, these findings demonstrate that exposure to high temperatures in early sockeye salmon development can result in persistent, parentally mediated effects on fry performance. As such, these results provide important insight into how elevated temperature events during egg incubation may affect early life history selection processes and survival in stages beyond when the stressor is experienced.