Developmental temperature stress and parental identity shape offspring burst swimming performance in sockeye salmon (Oncorhynchus nerka)

Abstract

The persistent effects of embryonic temperature stress and individual parentage on fry swimming performance were examined in a cross-fertilisation experiment using sockeye salmon (Oncorhynchus nerka). A fixedvelocity 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 16°C to hatch and then reared through yolk absorption and exogenous feeding stages in a common posthatch environment (average 6.9°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 12°C prehatch treatment compared to 14 and 16°C, although differences were largely attributable to temperature effects on average fry size. Behavioural observations revealed that fish incubated at 16°C performed more poorly, having a larger proportion of individuals that required stimulation to swim, fatigued more frequently or were classified as 'nonswimmers'. 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 16°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.

Provenance matters: thermal reaction norms for embryo survival among sockeye salmon Oncorhynchus nerka populations

“…Warming in‐river temperatures can negatively affect both the ability of some returning adults to successfully migrate to spawning areas (Macdonald et al ., ; Eliason et al ., ) and alter the maturation of eggs (Jeffries et al ., ), thus increasing the survival cost of maturation and reproduction (Kuparinen et al ., ). Intergenerational temperature effects may also persist from early development and deleteriously affect lifetime success of their offspring (Burt et al ., 2012 a , b ; Salinas & Munch, ). As shown here, a successful spawning event at warm temperatures does not presume offspring survival (Pankhurst & Munday, ).…”

“…Moreover, this study only looked at the sessile embryonic development stage during incubation, the portion of the life history where increasing spawning ground water temperatures may have a direct effect (Healey, ), and did not consider the latent effects of supraoptimal temperature regimes. Carry‐over effects of elevated temperature during incubation have been shown to affect later life stages, even if high temperature is removed (Beacham & Murray, ; Burt et al ., 2012 a , b ). For this reason, it is important to consider these differences in population viability under thermal stress with additional precaution, considering that the effects of temperature on developmental pathways may significantly affect future competitive behaviours, including swimming ability and lifetime fitness.…”

Maternal and environmental influences on egg size and juvenile life‐history traits in Pacific salmon

“…This suggests that for these populations mass at emergence is much more plastic than length and emergence date. The advantages of being at certain length are probably linked to burst swimming ability (Burt et al 2011) and predator avoidance, whereas mass and emergence date likely reflect the ability to survive from emergence to the timing of zooplankton blooms. The increased metabolic cost of higher water temperatures is paid for by a reduction in mass, not length.…”

Does among‐population variation in burst swimming performance of sockeye salmon Oncorhynchus nerka fry reflect early life migrations?

“…Body length (Bams, 1967;Taylor & McPhail, 1985a;Ghalambor et al, 2004;Burt et al, 2012) and mass (Burt et al, 2012; although this was not found by Nadeau et al, 2009) influence burst swimming performance of fishes. Among all fishes (n = 662), log 10 -transformed L T (linear regression, r 2 = 0·13, P < 0·001) and M B (r 2 = 0·07, P < 0·001) were positively related to square-root transformed burst swimming duration.…”

“…Fish from each of the nine populations swam individually (mean number of fish that swam per population, n = 74) after an average of 60 days (range: 59-62 days) post-emergence and transfer to rectangular ponds. Individual fish were randomly selected from a population and transferred without air exposure to a sectioned area (30 cm length × 6·9 cm width × 4 cm depth) of an open-top rectangular flume (230 cm length × 17 cm width × 4 cm depth; Pon et al, 2007;Nadeau et al, 2009;Burt et al, 2012). Only one swim tunnel was used throughout the trials and thus only one fish could be tested at a time.…”