I hope everyone enjoyed this week’s livestreams! Yesterday, we were able to take everyone out on the DOE’s boat, called the Sea Keeper, to the Nassau Grouper’s spawning aggregation on the west end of Little Cayman. If you were unable to catch our live broadcast, you can always head over to REEF’s YouTube page where each of our livestreams are archived. Check it out: https://www.youtube.com/live/wdyE69rViIw?feature=share
On Monday, I interviewed Janelle Layton a graduate student at Oregon State University. Janelle is studying the impacts of increasing temperatures on the development of Nassau Grouper. The Grouper Moon team will collected fertilized eggs on spawning nights to bring to a lab. At the lab, Janelle raises these eggs at different temperatures and compares developmental patterns and the genetic make up of the eggs and larvae collected.
Last year, divers collected fertilized eggs from 4 different females that Janelle raised in the lab. Eggs from each female were raised into larvae for 6 days at 4 different temperature treatments. 25°C represented historic temperatures on the aggregation. 27°C represents the current elevated temperature, 29°C and 31°C represent the higher temperatures predicted as a result of climate change. Samples from these experiments were preserved for future analyses in another lab. Pictures were taken of the larvae under a microscope so she could measure growth differences between each sample. Janelle has also started extracting genetic information from different samples to see if different females produce more temperature resilient young.
Janelle’s research was inspired by previous work done by Dr. Alli Candelmo and Dr. Lynn Waterhouse, two other scientists in the Grouper Moon Project. This figure shows the proportion of living larvae over time in different temperature treatments. NG2 and NG3 represent young from two different females. Across all 4 temperature treatments, the proportion of living young declines with time. However, the decline happens much faster at higher temperatures like 29°C and 31°C compared to lower temperatures like 25°C and 27°C. We also noticed that as the temperature increases, larvae began dying at different rates. This means it is possible that certain females are able to produce young that can handle higher temperatures better than other females.
If that is the case, the genetics work Janelle is doing proves why it is critically important to keep the Nassau Grouper spawning aggregation as large as possible. With a large aggregation size, there can be a huge increase in genetic diversity, which can allow populations to have all of the tools necessary to deal with the effects of climate change.
Go Grouper Moon!