Assisted gene flow using cryopreserved sperm in critically endangered coral

Area of Science:

• Marine Biology
• Conservation Genetics
• Climate Change Adaptation

Background:

• Coral populations face decline and reproductive failure, hindering adaptation to climate change.
• Assisted gene flow (AGF) is a conservation strategy to enhance genetic diversity in at-risk populations.
• Technical challenges in coral conservation include difficulties in moving adults and short gamete viability.

Purpose of the Study:

• To demonstrate the feasibility of AGF in corals using cryopreserved sperm.
• To assess the reproductive compatibility and survival of AGF-derived coral offspring.
• To establish a viable conservation tool for increasing genetic diversity in threatened coral species.

Main Methods:

• Utilized cryopreserved sperm from distinct Caribbean coral populations (Florida, Puerto Rico) to fertilize eggs (Curaçao).
• Employed 19,696 single-nucleotide polymorphism markers to confirm interpopulation parentage in offspring.
• Monitored the 6-month survival rate of the assisted gene flow offspring.

Main Results:

• Successfully demonstrated AGF in Acropora palmata using cryopreserved sperm aged 2-10 years.
• Confirmed reproductive compatibility across a significant Caribbean gene flow barrier.
• Achieved a 42% 6-month survival rate for AGF offspring, the highest recorded for this species.

Conclusions:

• AGF using cryopreserved sperm is a viable conservation strategy for threatened marine populations.
• This method enables the introduction of genetic diversity without relocating adult corals.
• The study produced the largest wildlife population to date from cryopreserved material, offering hope for coral reef restoration.