Too hot to handle? Using movement to alleviate effects of elevated temperatures in a benthic elasmobranch, Hemiscyllium ocellatum

Gervais, Connor R.; Nay, Tiffany J.; Renshaw, Gillian Mary Claire; Johansen, Jacob L.; Steffensen, John F.; Rummer, Jodie L.

doi:10.1007/s00227-018-3427-7

Cited by 33 publications

(46 citation statements)

References 67 publications

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“…Port Jackson sharks (Heterodontus portusjacksoni) exposed to elevated temperatures exhibited an increase in mortality, altered behavior, increased learning performance and feeding, but reduced growth and embryonic development time (Pistevos et al, 2015;Vila et al, 2018Vila et al, , 2019. Conversely, brownbanded bamboo sharks (Chiloscyllium punctatum) showed decreased survival alongside significantly increased embryonic growth and ventilation rates (Rosa et al, 2014), while juvenile epaulet sharks (Hemiscyllium ocellatum) showed significantly decreased growth rates and 100% mortality (Gervais et al, 2018). It is likely that the physiological impacts of increasing ocean temperature will be greater for more active pelagic sharks than for benthic species (Rosa et al, 2014), given their reliance on ram ventilation and continuous movement (Lawson et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

Future Distribution of Suitable Habitat for Pelagic Sharks in Australia Under Climate Change Models

et al. 2020

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Global oceans are absorbing over 90% of the heat trapped in our atmosphere due to accumulated anthropogenic greenhouse gases, resulting in increasing ocean temperatures. Such changes may influence marine ectotherms, such as sharks, as their body temperature concurrently increases toward their upper thermal limits. Sharks are high trophic level predators that play a key role in the regulation of ecosystem structure and health. Because many sharks are already threatened, it is especially important to understand the impact of climate change on these species. We used shark occurrence records collected by commercial fisheries within the Australian continental Exclusive Economic Zone (EEZ) to predict changes in future (2050-2099) relative to current (1956-2005) habitat suitability for pelagic sharks based on an ensemble of climate models and emission scenarios. Our predictive models indicate that future sea temperatures are likely to shift the location of suitable shark habitat within the Australian EEZ. On average, suitable habitat is predicted to decrease within the EEZ for requiem and increase for mackerel sharks, however, the direction and severity of change was highly influenced by the choice of climate model. Our results indicate the need to consider climate change scenarios as part of future shark management and suggest that more broad-scale studies are needed for these pelagic species.

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Section: Discussionmentioning

confidence: 99%

Future Distribution of Suitable Habitat for Pelagic Sharks in Australia Under Climate Change Models

et al. 2020

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“…The epaulette shark ( Hemiscyllium ocellatum ), one such small oviparous shark endemic only to the Great Barrier Reef (GBR), Australia 21 , has been the focus of many climate change related laboratory studies 20 , 22 – 25 because this species thrives in captivity and is considered of least concern in the wild by the International Union for Conservation of Nature (IUCN) Red List Criteria 26 . Additionally, H. ocellatum possess unique morphological and physiological traits that allow them to hunt in isolated tidal pools and survive extreme and repeated hypoxia conditions 27 , 28 .…”

Section: Introductionmentioning

confidence: 99%

Future thermal regimes for epaulette sharks (Hemiscyllium ocellatum): growth and metabolic performance cease to be optimal

Wheeler

Rummer

Bailey

et al. 2021

Sci Rep

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Climate change is affecting thermal regimes globally, and organisms relying on their environment to regulate biological processes face unknown consequences. In ectotherms, temperature affects development rates, body condition, and performance. Embryonic stages may be the most vulnerable life history stages, especially for oviparous species already living at the warm edge of their distribution, as embryos cannot relocate during this developmental window. We reared 27 epaulette shark (Hemiscyllium ocellatum) embryos under average summer conditions (27 °C) or temperatures predicted for the middle and end of the twenty-first century with climate change (i.e., 29 and 31 °C) and tracked growth, development, and metabolic costs both in ovo and upon hatch. Rearing sharks at 31 °C impacted embryonic growth, yolk consumption, and metabolic rates. Upon hatch, 31 °C-reared sharks weighed significantly less than their 27 °C-reared counterparts and exhibited reduced metabolic performance. Many important growth and development traits in this species may peak after 27 °C and start to become negatively impacted nearing 31 °C. We hypothesize that 31 °C approximates the pejus temperature (i.e., temperatures at which performance of a trait begin to decline) for this species, which is alarming, given that this temperature range is well within ocean warming scenarios predicted for this species’ distribution over the next century.

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“…The reallocation of energy towards basic maintenance and away from non-essential processes (e.g. growth, activity, reproduction) is not uncommon (Domenici et al, 2019;Gervais et al, 2018;Marine & Cech Jr, 2004;Munday et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Population variation in the thermal response to climate change reveals differing sensitivity in a benthic shark

Gervais

Huveneers

Rummer

et al. 2020

Global Change Biology

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Many species with broad distributions are exposed to different thermal regimes which often select for varied phenotypes. This intraspecific variation is often overlooked but may be critical in dictating the vulnerability of different populations to environmental change. We reared Port Jackson shark (Heterodontus portusjacksoni) eggs from two thermally discrete populations (i.e. Jervis Bay and Adelaide) under each location's present-day mean temperatures, predicted end-of-century temperatures and under reciprocal-cross conditions to establish intraspecific thermal sensitivity. Rearing temperatures strongly influenced ṀO 2Max and critical thermal limits, regardless of population, indicative of acclimation processes. However, there were significant population-level effects, such that Jervis Bay sharks, regardless of rearing temperature, did not exhibit differences in ṀO 2Rest , but under elevated temperatures exhibited reduced maximum swimming activity with step-wise increases in temperature. In contrast, Adelaide sharks reared under elevated temperatures doubled their ṀO 2Rest , relative to their present-day temperature counterparts; however, maximum swimming activity was not influenced. With respect to reciprocal-cross comparisons, few differences were detected between Jervis Bay and Adelaide sharks reared under ambient Jervis Bay temperatures. Similarly, juveniles (from both populations) reared under Adelaide conditions had similar thermal limits and swimming activity (maximum volitional velocity and distance) to each other, indicative of conserved acclimation capacity. However, under Adelaide temperatures, the ṀO 2Rest of Jervis Bay sharks was greater than that of Adelaide sharks. This indicates that the energetics of cooler water population (Adelaide) is likely more thermally sensitive than that of the warmer population (Jervis Bay). While unique to elasmobranchs, these data provide further support that by treating species as static, homogeneous populations, we ignore the impacts of thermal history and intraspecific variation on thermal sensitivity. With climate change, intraspecific variation will manifest as populations move, demographics change or extirpations occur, starting with the most sensitive populations.

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Too hot to handle? Using movement to alleviate effects of elevated temperatures in a benthic elasmobranch, Hemiscyllium ocellatum

Cited by 33 publications

References 67 publications

Future Distribution of Suitable Habitat for Pelagic Sharks in Australia Under Climate Change Models

Future Distribution of Suitable Habitat for Pelagic Sharks in Australia Under Climate Change Models

Future thermal regimes for epaulette sharks (Hemiscyllium ocellatum): growth and metabolic performance cease to be optimal

Population variation in the thermal response to climate change reveals differing sensitivity in a benthic shark

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