Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stress
Autor(a) principal: | |
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Data de Publicação: | 2023 |
Outros Autores: | , , , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.1/19644 |
Resumo: | Simple Summary Despite their importance, sharks are among the most endangered ocean species. In addition to overexploitation and the destruction of their natural habitat, climate change is also known to pose a serious threat to them. Among the physico-chemical changes associated with climate change, oxygen loss has been the least studied in terms of its effect on shark physiology and behavior. In this study, we evaluated the impact of deoxygenation (93% air saturation) and hypoxia (26% air saturation) on the anti-predatory behavior and physiology of temperate shark embryos. We found that hypoxia caused a high mortality (44%), significantly increased embryo movement within capsules, and, consequently, reduced the freezing response behavior (a behavior that allows embryos to be unnoticed by predators). Regarding oxidative stress, most biomarkers analyzed were not impacted by the experimental treatments. Overall, our results suggest that the temperate shark's early life stages showed a certain degree of resilience to deoxygenation but not to hypoxia. Climate change is leading to the loss of oxygen content in the oceans and endangering the survival of many marine species. Due to sea surface temperature warming and changing circulation, the ocean has become more stratified and is consequently losing its oxygen content. Oviparous elasmobranchs are particularly vulnerable as they lay their eggs in coastal and shallow areas, where they experience significant oscillations in oxygen levels. Here, we investigated the effects of deoxygenation (93% air saturation) and hypoxia (26% air saturation) during a short-term period (six days) on the anti-predator avoidance behavior and physiology (oxidative stress) of small-spotted catshark (Scyliorhinus canicula) embryos. Their survival rate decreased to 88% and 56% under deoxygenation and hypoxia, respectively. The tail beat rates were significantly enhanced in the embryos under hypoxia compared to those exposed to deoxygenation and control conditions, and the freeze response duration showed a significant opposite trend. Yet, at the physiological level, through the analyses of key biomarkers (SOD, CAT, GPx, and GST activities as well as HSP70, Ubiquitin, and MDA levels), we found no evidence of increased oxidative stress and cell damage under hypoxia. Thus, the present findings show that the projected end-of-the-century deoxygenation levels elicit neglectable biological effects on shark embryos. On the other hand, hypoxia causes a high embryo mortality rate. Additionally, hypoxia makes embryos more vulnerable to predators, because the increased tail beat frequency will enhance the release of chemical and physical cues that can be detected by predators. The shortening of the shark freeze response under hypoxia also makes the embryos more prone to predation. |
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Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stressClimate changeOxygen lossElasmobranchEmbryogenesisPredationSharksSimple Summary Despite their importance, sharks are among the most endangered ocean species. In addition to overexploitation and the destruction of their natural habitat, climate change is also known to pose a serious threat to them. Among the physico-chemical changes associated with climate change, oxygen loss has been the least studied in terms of its effect on shark physiology and behavior. In this study, we evaluated the impact of deoxygenation (93% air saturation) and hypoxia (26% air saturation) on the anti-predatory behavior and physiology of temperate shark embryos. We found that hypoxia caused a high mortality (44%), significantly increased embryo movement within capsules, and, consequently, reduced the freezing response behavior (a behavior that allows embryos to be unnoticed by predators). Regarding oxidative stress, most biomarkers analyzed were not impacted by the experimental treatments. Overall, our results suggest that the temperate shark's early life stages showed a certain degree of resilience to deoxygenation but not to hypoxia. Climate change is leading to the loss of oxygen content in the oceans and endangering the survival of many marine species. Due to sea surface temperature warming and changing circulation, the ocean has become more stratified and is consequently losing its oxygen content. Oviparous elasmobranchs are particularly vulnerable as they lay their eggs in coastal and shallow areas, where they experience significant oscillations in oxygen levels. Here, we investigated the effects of deoxygenation (93% air saturation) and hypoxia (26% air saturation) during a short-term period (six days) on the anti-predator avoidance behavior and physiology (oxidative stress) of small-spotted catshark (Scyliorhinus canicula) embryos. Their survival rate decreased to 88% and 56% under deoxygenation and hypoxia, respectively. The tail beat rates were significantly enhanced in the embryos under hypoxia compared to those exposed to deoxygenation and control conditions, and the freeze response duration showed a significant opposite trend. Yet, at the physiological level, through the analyses of key biomarkers (SOD, CAT, GPx, and GST activities as well as HSP70, Ubiquitin, and MDA levels), we found no evidence of increased oxidative stress and cell damage under hypoxia. Thus, the present findings show that the projected end-of-the-century deoxygenation levels elicit neglectable biological effects on shark embryos. On the other hand, hypoxia causes a high embryo mortality rate. Additionally, hypoxia makes embryos more vulnerable to predators, because the increased tail beat frequency will enhance the release of chemical and physical cues that can be detected by predators. The shortening of the shark freeze response under hypoxia also makes the embryos more prone to predation.FCT AGA-KHAN/541746579/2019; LISBOA-01-0145-FEDER-028609; DL57/2016/CP1479/CT0023; LA/P/0069/2020; 2021.01030.CEECINDMDPISapientiaVarela, JaquelinoMartins Rebocho, SandraCourt, MelanieSantos, Catarina PereiraPaula, José RicardoFerreira, Inês JoãoDiniz, MárioRepolho, TiagoRosa, Rui2023-05-30T14:04:18Z20232023-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10400.1/19644eng10.3390/biology120405772079-7737info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-07-24T10:32:07Zoai:sapientia.ualg.pt:10400.1/19644Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:09:13.804855Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stress |
title |
Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stress |
spellingShingle |
Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stress Varela, Jaquelino Climate change Oxygen loss Elasmobranch Embryogenesis Predation Sharks |
title_short |
Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stress |
title_full |
Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stress |
title_fullStr |
Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stress |
title_full_unstemmed |
Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stress |
title_sort |
Impacts of deoxygenation and hypoxia on shark embryos anti-predator behavior and oxidative stress |
author |
Varela, Jaquelino |
author_facet |
Varela, Jaquelino Martins Rebocho, Sandra Court, Melanie Santos, Catarina Pereira Paula, José Ricardo Ferreira, Inês João Diniz, Mário Repolho, Tiago Rosa, Rui |
author_role |
author |
author2 |
Martins Rebocho, Sandra Court, Melanie Santos, Catarina Pereira Paula, José Ricardo Ferreira, Inês João Diniz, Mário Repolho, Tiago Rosa, Rui |
author2_role |
author author author author author author author author |
dc.contributor.none.fl_str_mv |
Sapientia |
dc.contributor.author.fl_str_mv |
Varela, Jaquelino Martins Rebocho, Sandra Court, Melanie Santos, Catarina Pereira Paula, José Ricardo Ferreira, Inês João Diniz, Mário Repolho, Tiago Rosa, Rui |
dc.subject.por.fl_str_mv |
Climate change Oxygen loss Elasmobranch Embryogenesis Predation Sharks |
topic |
Climate change Oxygen loss Elasmobranch Embryogenesis Predation Sharks |
description |
Simple Summary Despite their importance, sharks are among the most endangered ocean species. In addition to overexploitation and the destruction of their natural habitat, climate change is also known to pose a serious threat to them. Among the physico-chemical changes associated with climate change, oxygen loss has been the least studied in terms of its effect on shark physiology and behavior. In this study, we evaluated the impact of deoxygenation (93% air saturation) and hypoxia (26% air saturation) on the anti-predatory behavior and physiology of temperate shark embryos. We found that hypoxia caused a high mortality (44%), significantly increased embryo movement within capsules, and, consequently, reduced the freezing response behavior (a behavior that allows embryos to be unnoticed by predators). Regarding oxidative stress, most biomarkers analyzed were not impacted by the experimental treatments. Overall, our results suggest that the temperate shark's early life stages showed a certain degree of resilience to deoxygenation but not to hypoxia. Climate change is leading to the loss of oxygen content in the oceans and endangering the survival of many marine species. Due to sea surface temperature warming and changing circulation, the ocean has become more stratified and is consequently losing its oxygen content. Oviparous elasmobranchs are particularly vulnerable as they lay their eggs in coastal and shallow areas, where they experience significant oscillations in oxygen levels. Here, we investigated the effects of deoxygenation (93% air saturation) and hypoxia (26% air saturation) during a short-term period (six days) on the anti-predator avoidance behavior and physiology (oxidative stress) of small-spotted catshark (Scyliorhinus canicula) embryos. Their survival rate decreased to 88% and 56% under deoxygenation and hypoxia, respectively. The tail beat rates were significantly enhanced in the embryos under hypoxia compared to those exposed to deoxygenation and control conditions, and the freeze response duration showed a significant opposite trend. Yet, at the physiological level, through the analyses of key biomarkers (SOD, CAT, GPx, and GST activities as well as HSP70, Ubiquitin, and MDA levels), we found no evidence of increased oxidative stress and cell damage under hypoxia. Thus, the present findings show that the projected end-of-the-century deoxygenation levels elicit neglectable biological effects on shark embryos. On the other hand, hypoxia causes a high embryo mortality rate. Additionally, hypoxia makes embryos more vulnerable to predators, because the increased tail beat frequency will enhance the release of chemical and physical cues that can be detected by predators. The shortening of the shark freeze response under hypoxia also makes the embryos more prone to predation. |
publishDate |
2023 |
dc.date.none.fl_str_mv |
2023-05-30T14:04:18Z 2023 2023-01-01T00:00:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10400.1/19644 |
url |
http://hdl.handle.net/10400.1/19644 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.3390/biology12040577 2079-7737 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
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MDPI |
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MDPI |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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