Record Details

Acropora aspera fecundity in colonies experimentally heat-stressed during late stages of gametogenesis (Heron Island, Southern Great Barrier Reef)

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Title Acropora aspera fecundity in colonies experimentally heat-stressed during late stages of gametogenesis (Heron Island, Southern Great Barrier Reef)
 
Creator Morane Le Nohaic
 
Subject Conservation and biodiversity
Marine and estuarine ecology (incl. marine ichthyology)
 
Description The dataset contains information of Acropora aspera coral fecundity in gravid colonies exposed to heat-stress during late stages of gametogenesis. All experimental branches originate from the Wistari Reef slope, in the southern Great Barrier Reef (Capricorn Bunker).
Pilot study/short-term experiment: From September to December 2021, 9x Acropora aspera donor colonies were selected, tagged, and sampled on the Wistari reef slope (~5m depth). From each colony, 9x branches of approximately 20cm length were collected and brought to the Heron Island Research Station. The coral branches were exposed to 3x different temperature treatments:
- Control temperatures for three weeks prior spawning
- +1C above average temperatures for 2 weeks prior spawning
- +1C above average temperatures for 1 week prior spawning
Each of the temperature treatments were replicated in 9x tanks. Each of the x81 sub-colonies were assigned to one treatment with care to have 3x branches of each genotype in each treatment and x3 different genotypes in each tank. Samples (<10cm) were taken before and after the heat-stress period for assessing the treatments impacts on fecundity. The samples for fecundity were collected on the first night of spawning 2021.
Final experiment: From August to November 2022, a longer-term heat-stress experiment was conducted to assess the impacts of heat-stress on late stages of gametogenesis. For this experiment, 9x sub-colonies of approximately 20cm length were collected from each of the 9x donor colonies previously selected and tagged in Wistari Reef (total of 81x experimental branches). The experimental branches were then exposed to 3x different levels of heat-stress intensity and 3x different levels of exposure duration (9x treatments in total):
- Heat-stress intensity levels:
o Control average temperatures
o +1C above average temperatures
o +2C above average temperatures
- Heat-stress exposure duration:
o Short: heat-stress starts ~3 weeks prior spawning
o Medium: heat-stress starts ~6 weeks prior spawning
o Long: heat-stress starts ~9 weeks prior spawning
Samples were collected from the surviving experimental branches on 12/11/2022 and preserved in 5% formalin in sea water.
All fecundity samples that were fixed in formalin and seawater were decalcified in 3-10% hydrochloric acid in May-July 2023. For each decalcified sample, 30 polyps are randomly selected and inspected for presence/absence of eggs to estimate percentages of reproductive polyps within a branch. Among the polyps inspected for each sample, a minimum of 10 gravid polyps were dissected under the microscope to identify, count, and measure ovaries, spermaries, and eggs. Scaled pictures of each polyp were taken with a camera for measurements. For size measurements, the width and length of each element were recorded. Measurements were performed with ImageJ.

Access:
Metadata is fully public. Data files will be made fully public once the research has been published.
For special requests, please directly contact the Data Custodian and CC the Project Leader.
 
Publisher CSIRO
 
Contributor Peter Mumby
Christopher Doropoulos
Selina Ward
 
Date 2023-08-29
 
Type —
 
Format —
 
Identifier csiro:60097
 
Language —
 
Coverage —
 
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