In 2023, CCMI will mark 25 years of operations in the Cayman Islands. One of our most important efforts in this time has been our long-term coral monitoring project, which has taken place annually since 1998 on Little Cayman reefs. Through this regular effort, scientists have been able to observe the health and status of these reefs over time, identifying trends in reef health and noticing that Little Cayman reefs demonstrate their resiliency and ability to bounce back to a healthy state after a period of stress.
This work has shown us there is hope for coral reefs for the future, and it has highlighted the urgent need for our ongoing research to understand this resiliency to disease, warming temperatures, changes in the ecosystem composition, and other outside factors that continue to put pressure on local reefs, jeopardizing their long-term survival.
CCMI’s 2023 ‘Healthy Reefs for the Future’ emphasizes the need for swift action that ensures coral reefs can survive beyond the challenges of today.
We have many exciting plans in place for the Healthy Reefs campaign including:
continuing annual AGRRA survey of coral reefs to add to our 24-years of knowledge of the status of Little Cayman’s reefs – one of the longest running efforts of its kind in the region!
increased coral reef monitoring in response to disease and changes in ocean activity
producing our fourth annual Reef Report Card for an update on the Little Cayman reefs
sharing latest research and findings from the Little Cayman Research Centre with the public through the annual Grand Cayman Reef Lecture Series, Reefs Go Live programmes, educational materials, and fun events that get everyone involved!
WHAT IS A HEALTHY REEF?
Coral reefs are often referred to as ‘rainforests of the sea’ because of their tremendous diversity of species, vibrant colours and tremendous levels of productivity and interconnectedness. Unfortunately, due to changing environmental conditions and increased human activity near tropical coastlines, once vibrant reefs that teemed with dozens of species of fish are in decline. This is a worldwide occurrence where more than 70% of all coral reefs are under threat, and it is time to help our reefs stabilize and return to a healthy state.
But what does that look like? If a reef was healthy, you would expect to see:
high percentage of coral cover
low levels of macroalgae
high diversity of reef fishes and invertebrates
high density of reef fishes and invertebrates
clear waters (low levels of sedimentation)
no coral disease or bleaching
3D reef structures that provide crevices for reef inhabitants to hide
Long Term Records to Strengthen Our Understanding of Coral Resilience
Coral reefs are the largest mass of construction workers on the face of the earth. They are natural architects in the shallow sea but only remain productive when juvenile corals are able to survive after recruitment onto the reef. At every dive location on the reef around Little Cayman, we see evidence of recruitment. This is a good sign for the future.
Using the AGRRA, Atlantic Gulf Rapid Reef Assessment protocol and collecting additional recruitment data, this project investigates the potential for juvenile corals to survive and replenish the local reefs. Results from this work will help generate an understanding of the mechanisms that are driving reef resilience.
AGRRA data on the benthic habitat and fish populations surrounding Little Cayman has been collected regularly since 1999. As CCMI researchers continue to collect this data annually, notes, reports, and peer reviewed journal articles are available online to scientists, policy-makers, and the general public. These surveys document patterns of local change over the last two decades and enable regional comparisons through the Healthy Reef Framework developed for evaluating the Mesoamerican Barrier Reef.
WHY SHOULD I CARE?
In the Cayman Islands, coral reefs are not only beautiful, but they provide a lot of value and support for our islands.
Coral reefs cover less than 1% of the ocean but are home to more than 25% of all marine species. This biodiversity is truly vital to healthy ocean ecosystems.
The marine environment generates $69 million USD from tourism every year in the Cayman Islands (Wolfs Company 2017)
The reef is responsible for $5 million USD protection to infrastructure in the Cayman Islands from storms and wave erosion each year (Wolfs Company 2017)
Annual Reef Report Card for Little Cayman’s Reefs
CCMI launched the Reef Report Card following the 2019 AGRRA surveys to share the status of Little Cayman’s coral reefs, important observations, and long-terms trends from the aggregation of data of our annual surveys in an easy to use, concise tool.
Of the reefs surveyed, 10% were in “very good” health in 2020, 40% were “good +”, and 40% were “good”.
At the bottom end of the health spectrum, we had no surveyed reefs listed as in “poor” health and only 10% classed as “fair”.
Composition of the coral community on the reef has shifted over time, from reefs dominated by massive boulder corals, such as Orbicella spp., to smaller corals such as Agaricia spp. and Porites spp.
The size of corals surveyed has decreased by 60% overall, which may indicate that the reefs are less structurally robust and capable of providing some of the important services we depend upon them for, such as storm protection and complex habitats for a variety of marine life.
There was a decline of 13% in the cover of algae on the reefs in Little Cayman from 1999 to 2021.
New coral recruits, or baby corals, have declined by 83% from 2006 to 2021. Within that, researchers also see that of the species of recruits recorded, there are almost no Orbicellaspp recruits and no Montastreaspp recruits after 2017, both of which are important boulder corals.
Fish abundance (density), biomass and species richness have all increased overall since 1999, indicating a rebounding fish population.
Fish biomass has been higher inside of Marine Protected Areas (MPAs) compared to outside throughout the 23 years of surveys; in 2021, this was 40% higher inside MPAs than outside.
Parrotfish density has increased by 47% since 1999.
Grouper density has rebounded following protections enacted in 2016.
Shifts in species contributions, colony size and recruitment indicate that while coral cover remains high, coral populations are vulnerable.
Local protections and low human impact have undoubtedly shielded Little Cayman from the extremity of global pressures that are heavily impacting reefs around the globe; however, changes are still occurring that put the reefs increasingly at risk.
The 2020 AGRRA surveys reveal that Little Cayman’s coral reefs show positive traits of resiliency, with continued high coral and fish abundances. However, shifts in species contributions and colony size indicate that while coral cover remains high, Little Cayman is not immune to human impacts and global climate change.
In summary, there has been a gradual decline in coral cover over the last 20 years, going from roughly 24% to 20% average coral cover. However, this change is not statistically significant. The slow rate of decline indicates that the reefs of Little Cayman are more resilient than reefs in other parts of the Caribbean where declines were rapid and have not rebounded.
In 2018, CCMI started something. We got people involved in learning about and taking action for coral reefs during the third International Year of the Reef! Based on the high level of interest in events and experiences offered by CCMI, we are motivated to continue outreach opportunities across the Cayman Islands. We hope you will join us in promoting Healthy Reefs!
Check back for upcoming events at CCMI!
Healthy Reefs Virtual Art Gallery
For the third year, Ms. McDougall’s art class at the Cayman Islands Further Education Centre (CIFEC) were tasked with designing a poster in support of CCMI’s Healthy Reefs awareness campaign.