Enhancing Coral Settlement Through a Novel Larval Feeding Protocol

Intensifying anthropogenic stressors have contributed to declines in reef-building corals in many regions. These disturbances result in reduced live coral cover, impacting key population-level processes such as coral larval settlement and recruitment that are essential for reef recovery. Reef restor...

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Main Authors: Colleen Rodd, Steve Whalan, Craig Humphrey, Peter L. Harrison
Format: Article
Language:English
Published: Frontiers Media S.A. 2022-07-01
Series:Frontiers in Marine Science
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2022.918232/full
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author Colleen Rodd
Colleen Rodd
Steve Whalan
Steve Whalan
Craig Humphrey
Peter L. Harrison
Peter L. Harrison
author_facet Colleen Rodd
Colleen Rodd
Steve Whalan
Steve Whalan
Craig Humphrey
Peter L. Harrison
Peter L. Harrison
author_sort Colleen Rodd
collection DOAJ
description Intensifying anthropogenic stressors have contributed to declines in reef-building corals in many regions. These disturbances result in reduced live coral cover, impacting key population-level processes such as coral larval settlement and recruitment that are essential for reef recovery. Reef restoration efforts that rely on enhanced larval supply provide a pathway for the recovery of degraded reefs. However, corals at very early life stages experience high post-settlement mortality bottlenecks, which impede stock-recruitment processes. Overcoming these bottlenecks is a high priority goal in coral restoration. Some coral larvae are known to be capable of gaining exogenous nutrients. Therefore, we hypothesised that the capacity to access exogenous nutrients may confer advantages to larval survival, settlement and post-settlement success. The present study aimed to quantify the effect of larval feeding on coral larvae settlement and early post-settlement survival. We completed an ex-situ experiment using aposymbiotic larvae of two broadcast spawning reef-building coral species - Acropora tenuis and Acropora millepora. Larvae were randomly assigned to either fed or unfed treatment groups for each species. Fed larvae received homogenised Artemia once a day, for three days. Results show that for both species, feeding significantly increased larval settlement. Feeding A. millepora larvae more than doubled mean settlement (13.0 ± 1.17 SE vs 31.4 ± 2.88 SE; p <0.001). Similarly, feeding A. tenuis larvae increased mean settlement from 18.2 ( ± 1.85 SE) to 29.9 ( ± 2.22 SE; p <0.001). Larval feeding had an immediate positive effect on spat survival, such that A. millepora and A. tenuis spat from fed treatments had increased survival three days post-settlement (89.5% ± 3.75 SE vs 70.6% ± 2.59 SE, p <0.001; 88.8% ± 2.21 SE vs 71.4% ± 3.80 SE, p <0.001, respectively). Therefore, enhancing settlement and early post-settlement survival by feeding larvae homogenised Artemia has the potential to improve the effectiveness of larval rearing protocols and coral restoration efforts.
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spelling doaj.art-5bcfd69f70b348538055710d92fd9bc82022-12-22T02:59:56ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452022-07-01910.3389/fmars.2022.918232918232Enhancing Coral Settlement Through a Novel Larval Feeding ProtocolColleen Rodd0Colleen Rodd1Steve Whalan2Steve Whalan3Craig Humphrey4Peter L. Harrison5Peter L. Harrison6Marine Ecology Research Centre, Southern Cross University, Lismore, NSW, AustraliaFaculty of Science and Engineering, Southern Cross University, Lismore, NSW, AustraliaMarine Ecology Research Centre, Southern Cross University, Lismore, NSW, AustraliaFaculty of Science and Engineering, Southern Cross University, Lismore, NSW, AustraliaThe National Sea Simulator, Australian Institute of Marine Science, Townsville, QLD, AustraliaMarine Ecology Research Centre, Southern Cross University, Lismore, NSW, AustraliaFaculty of Science and Engineering, Southern Cross University, Lismore, NSW, AustraliaIntensifying anthropogenic stressors have contributed to declines in reef-building corals in many regions. These disturbances result in reduced live coral cover, impacting key population-level processes such as coral larval settlement and recruitment that are essential for reef recovery. Reef restoration efforts that rely on enhanced larval supply provide a pathway for the recovery of degraded reefs. However, corals at very early life stages experience high post-settlement mortality bottlenecks, which impede stock-recruitment processes. Overcoming these bottlenecks is a high priority goal in coral restoration. Some coral larvae are known to be capable of gaining exogenous nutrients. Therefore, we hypothesised that the capacity to access exogenous nutrients may confer advantages to larval survival, settlement and post-settlement success. The present study aimed to quantify the effect of larval feeding on coral larvae settlement and early post-settlement survival. We completed an ex-situ experiment using aposymbiotic larvae of two broadcast spawning reef-building coral species - Acropora tenuis and Acropora millepora. Larvae were randomly assigned to either fed or unfed treatment groups for each species. Fed larvae received homogenised Artemia once a day, for three days. Results show that for both species, feeding significantly increased larval settlement. Feeding A. millepora larvae more than doubled mean settlement (13.0 ± 1.17 SE vs 31.4 ± 2.88 SE; p <0.001). Similarly, feeding A. tenuis larvae increased mean settlement from 18.2 ( ± 1.85 SE) to 29.9 ( ± 2.22 SE; p <0.001). Larval feeding had an immediate positive effect on spat survival, such that A. millepora and A. tenuis spat from fed treatments had increased survival three days post-settlement (89.5% ± 3.75 SE vs 70.6% ± 2.59 SE, p <0.001; 88.8% ± 2.21 SE vs 71.4% ± 3.80 SE, p <0.001, respectively). Therefore, enhancing settlement and early post-settlement survival by feeding larvae homogenised Artemia has the potential to improve the effectiveness of larval rearing protocols and coral restoration efforts.https://www.frontiersin.org/articles/10.3389/fmars.2022.918232/fullrecruitmentpost-settlement survivalcoral restorationreef restorationfacultative planktotrophylarval energetics
spellingShingle Colleen Rodd
Colleen Rodd
Steve Whalan
Steve Whalan
Craig Humphrey
Peter L. Harrison
Peter L. Harrison
Enhancing Coral Settlement Through a Novel Larval Feeding Protocol
Frontiers in Marine Science
recruitment
post-settlement survival
coral restoration
reef restoration
facultative planktotrophy
larval energetics
title Enhancing Coral Settlement Through a Novel Larval Feeding Protocol
title_full Enhancing Coral Settlement Through a Novel Larval Feeding Protocol
title_fullStr Enhancing Coral Settlement Through a Novel Larval Feeding Protocol
title_full_unstemmed Enhancing Coral Settlement Through a Novel Larval Feeding Protocol
title_short Enhancing Coral Settlement Through a Novel Larval Feeding Protocol
title_sort enhancing coral settlement through a novel larval feeding protocol
topic recruitment
post-settlement survival
coral restoration
reef restoration
facultative planktotrophy
larval energetics
url https://www.frontiersin.org/articles/10.3389/fmars.2022.918232/full
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