Grouper Eggs & Climate Change

Hello Everyone!

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.

Janelle's Lab

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!

Todd

 

Let the Spawning Begin!

Hello Grouper Enthusiasts!

I hope you were all able to join us for today’s third and final livestream from Little Cayman, where we took you for a dive on the Nassau Grouper’s spawning aggregation! The conditions were perfect and we able to see thousands of grouper, a few sharks and much more. If you were unable to join us, you can view all of this year’s livestreams on REEF’s YouTube page. Check out today’s exciting livestream here: https://www.youtube.com/live/wdyE69rViIw?feature=share

On yesterday’s livestream we shared a few video clips from the first night of spawning and I promised to post them here on the blog for all to see. Take a look at this incredible footage! Click the links to see each clip.

GMP Spawning N1-001

GMP Spawning N1-002

GMP Spawning N1-003

GMP Spawning N1-004

GMP Spawning N1-005

Even though today was the last livestream for this year, I will continue to post content here on the blog for the rest of the week. Come back tomorrow and Friday for more videos, photos, and some great behind the scenes glimpses of the research happening here on Little Cayman.

Finally, there had been a student request to see the hammerhead shark we encountered on last year’s Grouper Moon Project, so here you go!

Hammerhead Shark Blog – Large 540p

Go Grouper Moon!

Todd

Counting Nassau Grouper!

Hello Everyone!

Today we had our second livestream from Little Cayman and it was awesome to see all of you who were able to join us! You had such fantastic questions! Today we shared with you some footage of the Nassau spawning, which happened last night. As we discussed, the grouper is able to change its color, very much like an octopus, and it does this for a couple of reasons, such as camouflage. The Nassau can make itself lighter or darker to better blend in with its habitat.  The second purpose of its color changing behavior is for communication. The Nassau will often change its coloration when it encounters other Nassau. Here is a graphic showing the different color phases of the grouper:

Color Phases!

Also on today’s livestream, we also talked about how the Grouper Moon researchers count all those fish, which is no small task. One way that we are estimating the number of fish is by tagging a set number of grouper with brightly colored tags. Once the tags have been placed on the fish, divers start counting fish. Each time, a diver will count 50 fish and then make a notation of how many of those fish have tags on them. We have several divers out there counting those fish, three times a day, collecting as much data as possible. We can then estimate the total number of fish based on the number of tagged fish we count.  Dr. Lynn Waterhouse shared about this process today, but made an error in her math and wanted me to make a correction. Here is a graphic she put together for you explaining the math behind tagging Nassau Grouper:

If you were unable to join us for today’s livestream, do not worry. All of our livestreams are available to watch on REEF’s YouTube page.  Here is the link from today’s livestream:  https://www.youtube.com/live/1yIZuV9sHmc?feature=share

Finally, be sure to tune in for tomorrow’s third and final livestream where we will take you out on the boat and go underwater to see all those magnificent grouper!

Go Grouper Moon!

Todd

Grouper Moon 2023 is here!

Hello Everyone!

It is so amazing to back on Little Cayman for the Grouper Moon Project! We have a wonderful crew of about 20 scientists and researchers from the Cayman Islands Department of the Environment (DOE) and REEF here working hard to monitor and protect the last viable Nassau Grouper aggregation in the Caribbean. I arrived here Sunday after flying over night from Seattle. The sea conditions have been excellent so far and about an hour after I arrived I was able to join the team for the evening dive on the aggregation. It was absolutely stunning. I saw thousands of Nassau Grouper as well as a number of other species, like Tiger Grouper and Bar Jacks.

Today, we had our first Grouper Education livestream! I want to thank all the classrooms that were able to join us. Your support and engagement are a critical aspect to the success the project. Especially, I would like to thank all the teachers for going the extra mile to make this happen. We all appreciate you so much! If you were unable to attend today’s livestream, you can view it anytime on REEF’s YouTube page. Today’s livestream highlighted a number of scientists working on the project and some incredible footage of the growing aggregation on Cayman Brac as well as footage from aggregation here on Little. You can view it here: 

Finally, on today’s livestream, a few of you asked if saw sharks on the aggregation. We definitely see them out there and sometimes they’re able to get ahold of a Nassau, but these are some tough fish. Take a look at this grouper, affectionately known as Lucky, who clearly had a bite taken out of him in the past, but he healed and continues to show up on the aggregation each year! Amazing!

Remember to tune in for our second livestream tomorrow at 11:00am. Go Grouper Moon!

Lucky was certainly one of the main highlights of the trip!

The Grouper Moon Is Nearly Here!

 

Hello Everyone!

For those of you who are new to the program or just want a refresher, I am
very excited to share with you the Grouper Moon Educator Workshop for
2022. This year’s workshop was prerecorded and is available for you to
stream at your convenience.

A second (shorter) video will be sent out at the end of the month and will walk you
through using StreamYard, the streaming platform we use. It will be quick
and simple and will be followed up with a couple practice “livestreaming”
sessions available for teachers who want to practice using the platform
and to address any technical problems with me.

The workshop is available for you now to stream here:
https://youtu.be/sVo-hJvv1Lc

Link to Grouper Moon educational materials, including lesson plans and
documentary links:
https://www.reef.org/grouper-moon-education-program-resources

Finally, this is our 13th year doing the Grouper Education Project
(yay!) and we are working to update and expand the materials and
resources we have available for students and teachers. To get your
critical feedback, we are asking you to take a survey after viewing the
workshop. The first 15 Cayman educators who complete the survey will
receive a $20 grocery gift card to Fosters!

The Educator Workshop Survey is available to complete online, here:
http://www.reef.org/grouper-moon-edcuator-survey

Thank you for your time and for everything you do as educators. Please do
not hesitate to email me if you have any questions or if you need support
implementing these activities in your classroom.

Go Grouper Moon!

Todd Bohannon
REEF Educator
Grouper Moon Project

Climate Change and Nassau Grouper Larvae

 

One of the members on the Grouper Moon Team is Janelle Layton. She is a masters student in Fisheries Science at Oregon State University and works with Dr. Scott Heppell. Her research focus is concentrated on the impacts of climate change on Nassau grouper by understanding differences in both morphological traits and gene expression. This research will help to predict what might happen to the Nassau grouper due to increasing ocean temperatures as a result of climate change.

Janelle has set up 6 large bins/tanks with sea water in her lab on Little Cayman. She is keeping the different tanks at various temperatures to represent the rising ocean temperatures that scientists are predicting over the next 100 years. The first set of tanks is at 27 ° C, the second is 29° C, and the third is 31° C. She also has control tanks that are set at 25 ° C. The first set of tanks at 27° C represents the current water temperature that we have been recording at the aggregation site. This is already an increase of 2°C from what the researchers first recorded when they began the Grouper Moon Project 20 years ago.

 

After the first evening of spawning on Friday evening, the Grouper Moon Team collected Nassau grouper eggs from four spawning females for Janelle’s research. Friday night the team divided the eggs across four different temperatures. Then we filtered out the unfertilized eggs first using a large funnel and then using pipettes. Every morning and evening we removed dead larvae from the tanks and preserved the dead larvae in RNA Later. The RNA Later is a solution that helps to preserve the genes and protein that a genetic lab will analyze further. The lab will gather data on the heat shock proteins in the larvae. 

Every evening, we also collected living larvae samples from the temperature bins to preserve in RNA Later and formalin. The formalin helps to preserve the structure of the larvae in their various stages of development. They analyzed the larvae for six days after the spawning.

Her hypothesis after examining the initial data is an increase in larvae mortality with increasing temperatures. At higher temperatures, the fish are using more energy to develop in high stress situations that they are possibly completely absorbing their yolk sac too quickly before they can form functional jaws. This causes the fish to be unable to feed themselves when they run out of their yolk sac. However, there is a lot of genetic variability so certain individuals could possibly  be more resilient to the increasing ocean temperatures than others. This is what Janelle expects to see, but we will have to wait for the lab results and her data analysis to find out for certain. 

What do you think will happen? Post your hypothesis in the comments section. 

 

Spawning!

Friday night marked the start of spawning for the Nassau grouper! It was an incredible site to witness. The groupers would shoot upward into the water column as they were spawning, like fireworks.  As the female went up into the water column swimming to release her eggs, several male groupers would follow, swimming in spirals around her. There were several Caribbean reef sharks swimming through the Nassau grouper aggregation site, which was an exciting way to watch the food web in action with the incredible apex predators amongst the groupers.

The day of spawning, the team noticed several things on the morning dive that were clues the spawning might  start later that evening. The female groupers bellies were swollen with eggs, and many more of the fish were in the bi-color or dark phase. There were very few fish in the normal or barred color phase.

The Grouper Moon Team collected some eggs for  a research study being conducted by Janelle Layton and Dr. Scott Heppell from Oregon State University. The research focus is concentrated on the impacts of climate change on Nassau grouper by understanding differences in both morphological traits and gene expression. To collect the eggs, the team used bags to collect samples from various spawning females.

The spawning continued both Saturday and Sunday evenings making for an exciting weekend for both the groupers and the team!

There are many questions about the Nassau grouper that the Grouper Moon Project team have and are researching. This is yet another reason why it’s important to stay curious and always ask questions about the world around you. Do you have any questions for the Grouper Moon Project team? If so, post them as a comment on the blog, and the team will try to answer them for you.

Is love in the water for the Nassau Grouper this Valentine’s Day?

This year is unique in that it is what Grouper Moon researchers consider a ‘Split Moon.’ This means the full moon falls in the middle of the month. The Grouper Moon team didn’t see any spawning activity during the January full moon, so we are anticipating spawning activity in the days after the February full moon.

The Grouper Moon Team made their way back to Little Cayman today so stay tuned for more updates from in the field and to see what the February full moon brings.

To learn more about the Grouper Moon Project, including links to documentaries, published papers, and the education program, visit www.REEF.org/groupermoonproject.

What do you think? Will the Grouper Moon team see the Nassau grouper spawning this week? Post your predications in the comments.

 

Climate Change and the Nassau Grouper

One of the members on the Grouper Moon Team this year is Janelle Layton. She is a masters student in Fisheries Science at Oregon State University and works with Dr. Scott Heppell. Her research focus is concentrated on the impacts of climate change on Nassau grouper by understanding differences in both morphological traits and gene expression.

This research will help to predict what might happen to the Nassau grouper due to increasing ocean temperatures as a result of climate change.

Earlier today, I got a tour of Janelle and Scott’s lab that has been set up in one of the bedrooms at our rental house on Little Cayman.

Janelle has set up 6 large bins/tanks with sea water. She is keeping the different tanks at various temperatures to represent the rising ocean temperatures that scientists are predicting over the next 100 years. The first set of tanks is at 27 ° C, the second is 29° C, and the third is 31° C. She also has control tanks that are set at 25 ° C. The first set of tanks at 27° C represents the current water temperature that we have been recording at the aggregation site. This is already an increase of 2°C from what the researchers first recorded when they began the Grouper Moon Project 20 years ago.

This evening we hope to collect some eggs from the spawning Nassau groupers! Janelle and Scott will then put the eggs in the various tanks and look at the impacts of the higher ocean temperatures on the larvae. They will examine the gene expression of heat shock proteins.

Stay tuned to see if we have spawning on this evening’s dive! Make your predictions on whether or not the team will see the Nassau grouper spawn in the comments.

Sharks!

Hammerhead Shark Video – Click Here

Yesterday at the Spawning Aggregation Site (SPAG) the team saw a hammerhead shark! This is the first documented sighting of a hammerhead at the SPAG in the 20 years that the Grouper Moon Project Team has been researching the site.

In the Cayman Islands, long term surveying of shark populations to monitor shark populations in underway. Education about the critical role that sharks play in maintaining a healthy marine environment and the need for a healthy respect for sharks is key in changing public perception to a positive attitude.

With the help of acoustic tags, baited remote underwater video (BRUV) surveys, diving surveys and satellite tags, the Department of Environment together with Marine Conservation International, supported by the Cayman Islands Brewery’s White Tip Shark Conservation Fund, have been studying, monitoring and working to protect local shark populations in the Cayman Islands since 2009.

All sharks are protected species in the Cayman Islands. Their population is fragile and small, making their protection and research key elements for conservation.

On the afternoon and evening dives each day, the Grouper Moon team has been treated to several Caribbean reef shark sightings in addition to the hammerhead sighting when they swam through the Nassau grouper aggregation site, which was an exciting way to watch the food web in action with the incredible apex predators amongst the groupers.

As an added treat, this morning while walking down the dock to the boat, we saw 4 blacktip sharks, 2 lemon sharks, and a juvenile Caribbean reef shark swimming around the dock as a divemaster was cleaning lionfish.

It’s always a highlight of the dive to see a shark and we have been very lucky so far this trip with 20 shark sightings total!

“Sharks are beautiful animals, and if you’re lucky enough to see lots of them, that means that you’re in a healthy ocean. You should be afraid if you are in the ocean and don’t see sharks.” – Dr. Sylvia Earle