Coral Nursery Project

Georgina Wilcox

The latest CCMI Brochure and the 2012 Research and Education Report says:

The Central Caribbean Marine Institute (CCMI) developed the Little Cayman Research Centre (LCRC) in 2006, and has experienced continuous growth in the use of the facility since then. To date, over 100 visiting scientists have researched at LCRC, and 5 major U.S. universities include an LCRC visit as a permanent part of their curriculum.

CCMI’s purpose in building LCRC was to create an important reference site for international research that will help facilitate an understanding of the current stresses on coral reefs.

Scientists are reporting that coral reefs are now more threatened than tropical rain forests. Nearly 40% of the corals in the Caribbean have died in the past decade. Our scientific mission aims to provide solutions that will reduce human threats to coral reefs. We are partnering with NOAA to install sophisticated instruments on coral reefs to help predict, model, and keep track of environmental changes so that we can better manage our reefs.  In addition, we have provided programmes and scholarships for young people to learn about coral reef conservation, as they are our future leaders and policy makers. Our research projects aim to obtain a better understanding of the threats and impacts affecting our marine environment through long term monitoring. This research is vital to determining how these impacts can be minimized in order to reduce further damage. Each project is therefore strongly linked to conservation and how we can work towards sustainability.

At CCMI we have a strong focus on education and outreach for both the local and international community. Through our efforts we hope to raise awareness and generate more knowledge and interest in our marine environment and the importance of research as a way of working towards improved conservation and sustainable practices.

The invasive Pacific Lionfish– a collaboration supported by Dr. Tom Frazer (University of Florida) and Dr. Carrie Manfrino (CCMI President) has led to a better understanding of how the non­native Lionfish is impacting Little Cayman’s native fish population. This project is also informing us on whether culling can ever be an effective management technique in limited areas. Thanks to this research project we are beginning to learn about the dietary, immigration and reproductive systems of the lionfish, as this invasive species adapts to its new life in the Caribbean. This level of research is required before we can make a convincing statement about the effectiveness of culling in limited areas. The collaboration has resulted in a preliminary publication (Frazer et al., 2012) which explains the need to understand a ‘… relationship between effort and reductions in lionfish abundance, estimates of the rate at which lionfish abundances rebound, rates of prey consumption for different abundances and size of lionfish and ultimately, long­term data that demonstrate beneficial ecological effects from removals. ’

Juvenile Nassau Grouper Mapping – in January 2012, our research team made an exciting discovery… several lagoons around Little Cayman were teaming with young juvenile Nassau groupers. This discovery is significant because Nassau groupers (Epinephelus striatus) are economically and ecologically important to coral reefs. Unfortunately, they are Red Listed as endangered by the International Union for the Conservation of Nature (IUCN). We have surveyed nearly 50% of the potential habitats. Last winter, we incorporated annual juvenile surveys and mapping projects as part of the CCMI LAMP (Long Term Assessment and Monitoring Programme) for the first time, with a goal to fully survey and then map the nearshore areas that are critical to the protection of this important fish.

Coral Nursery – Improving the health of branching corals. This new and exciting conservation project will directly improve the health of the coral reef ecosystem across the region by: enhancing the current wild coral population; and providing high­quality habitats for an abundance of fish and invertebrates. The project strategy includes setting up, developing and maintaining the coral nursery and will result in CCMI becoming the provider for regional training for coral gardening in the future, in association with the Cayman Islands Department of Environment. This conservation project therefore offers a unique opportunity for potential CCMI partners and local stakeholders, who have an interest in being a part of this progressive environmental initiative. The Coral Nursery in Little Cayman will focus on two of the most threatened species in the Caribbean, staghorn coral (Acropora cervicornis) and elkhorn coral (A. palmati)

Research Climate Change & Coral Reef Stress: Ocean Acidification project

The 2012 project included a diverse sampling methodology, to establish a base-line understanding of the chemical properties of various marine habitats. The map of Little Cayman (attached) illustrates the study sites that provide the framework for this and future studies of climate change and coral reef stress.

Previous studies suggested that the impacts of ocean acidification will vary depending on the biophysical processes that dominate the different reef habitats, as shown in figure 1. We set up a study to measure the water chemistry across the different major habitats typical of reef systems.

A thorough island wide study was undertaken, to test variability and fluctuations in carbonate chemistry within the different habitats. Components of this study included measuring abiotic factors such as light, temperature and salinity in each reef-zone; the benthic composition for Lagoon habitats on the North side of the island; and diurnal fluctuations in carbonate chemistry, which were quantified for three reef zones. Water samples were taken from 6 sites (almost simultaneously) every 3 hours over several 24 hour periods to precisely measure the diurnal fluctuations in seawater.  In addition, a long-term monitoring site has been established to measure changes in carbonate chemistry over a longer duration of time.

The study identified naturally varying pH environments, that have the potential to act as a refuge against future Ocean Acidification. We also found a wide range of pH values inside the restricted lagoon setting and the narrow range of values in the middle and outer shelf zones. We predicted slightly higher ranges in pH values for the deeper outer shelf sites than we measured because of the upwelling oceanic process which would bring up deeper more acidic (cooler) seawater.

Interestingly, the benthic composition data revealed coral species surviving in marginal reef environments that experience variability in carbonate chemistry. Understanding the mechanisms that allow these corals to survive is important as they may potentially be more resilient to future climate change.

Ultimately this year’s work has quantified the carbonate chemistry of different reef habitats and has identified areas of natural carbonate chemistry variability. Also, coral species have been identified that are able to tolerate these conditions. We will now build on these results to investigate the potential resilience and tolerance of species to carbonate chemistry variability and the importance of this for marine management and conservation.

Coral reefs are damaged by natural disturbances and both local and global anthropogenic stresses. As stresses intensify, so do debates about the efficacy of establishing protected areas on reefs. True headway in this debate requires documented temporal trajectories for coral assemblages subjected to various combinations of stresses; therefore, we report relevant changes at Little Cayman Island. From 1999 to 2004, bleaching and disease caused live coral cover to decrease from 26% to 14%, with full recovery achieved seven years later. We hypothesized that the positive trajectories would vary significantly between marine protected and unprotected areas but we demonstrated a full recovery across this reef system. In addition, juvenile corals achieved similar densities within and outside protected areas, and although not correlated significantly, both densities of juveniles and coral cover increased in recent years. The dominant taxa and size classes that make up the Caribbean reefs persisted. The similarity of recovery within and outside protected areas suggested the relative absence of local anthropogenic stress represented a key influence. Whilst 2012 saw a slight dip in coral cover in comparison to 2011, the trajectory indicates a positive story. Long-term monitoring is key to scientific debate and remains a focus for CCMI.

Conservation:  Cayman Islands Coral Nursery for threatened coral species – pilot project

In September, 2012, we [CCMI] invited coral expert Dr. Diego Lirman from the University of Miami to host our first coral nursery workshop. The workshop introduced a small team of scientists and managers from the Department of Environment and CCMI to coral nursery methodolody and practical solutions to goral gardening. Dr Lirman assisted the team in selecting a nursery site to ensure good water quality, low predation, and workable depths. This site is located due north of the Little Cayman Research Centre which provides easy access for maintenance and oversight.

Following the workshop, we deployed a single structure, multiplying 4 parent colonies of staghorn coral to 58 new individuals as a pilot project. After 3 months of the trial, all colonies have survived and are growing rapidly. These positive results provide the basis for installing additional structures and further developing the nursery.

The Coral Nursery in Little Cayman will focus on the fast growing staghorn coral (Acropora cervicornis). The species experienced massive mortality in the 1980’s which began an ongoing population decline which is still observable today. Branching corals are crucial to reef structure and create essential habitats for fish and invertebrates. The corals from our nursery will be strategically out planted in the surrounding reef area in Little Cayman, to increase the number of healthy and reproductively viable coral colonies in the wild. Coral nurseries provide an excellent opportunity to improve the ability of these coral species to recover naturally and this endeavor will be the first of its kind to take place within the Cayman Islands region. The Little Cayman coral nursery will augment existing populations of staghorn coral, enhance the existing reef structure, and could potentially improve overall coral reef health. The indirect benefits of this conservation project (and a healthier reef ecosystem) will positively impact local tourism and improve local fish stocks, thereby supporting the local economy.

Other studies were Nassau Grouper Recruitment & grouper Habitat Mapping and Lionfish.

Populations of the economically and ecologically important Nassau grouper (Epinephelus striatus, Bloch, 1792) have declined to the point of being declared Endangered by the International Union for the Conservation of Nature (IUCN). Beyond existing efforts to reduce top-down pressure from overfishing, especially on spawning aggregations, recovery of Nassau grouper could be enhanced by preventing bottom-up pressures created by degradation of essential habitats. The most robust Nassau grouper aggregation site of Little Cayman is located on the west end of the island. Aggregation sites have been protected around all three islands for the past 8 years but juvenile fish have not been seen until January 2012.

CCMI scientists, working on the north side of Little Cayman discovered numerous small juvenile Nassau grouper which provided the impetus for this study to document the microhabitat associations for grouper in shallow, nearshore lagoons. Our results showed that in total, 82% of juvenile grouper that were 12–26 cm in total length and approximately one year old associated with hardbottom rather than other equally or more widespread microhabitats, i.e., sand, seagrass and algae. Hardbottom provided crevices, holes, ledges and other shelters. Approximately 96% of shelters contained a single juvenile grouper, and 10–66% of these shelters also contained one or more cleaning organisms. The mapped habitat is almost entirely located within the current marine replenishment zones around Little Cayman.

Over the course of 2012, several types of data were collected for the CCMI-University of Florida collaborative lionfish project, which aims to determine whether focused lionfish removal efforts have an effect on native fish communities. Field surveys of native fish and lionfish density were conducted at each of six study sites. Quarterly culls were also conducted at culled sites. In addition to field work, lab analysis of stomach contents was performed on lionfish collected from quarterly culls and weekly community culls.

Three experimental sites, where regular lionfish culls occur, were established at the following dive sites: Blacktip Boulevard, Joy’s Joy, and Penguin’s Leap. In addition, three control sites, where no lionfish culling occurred, were established at Rock Bottom, Crystal Palace, and “Fins” (anchor drop). Three of the six sites were located within the marine park, and three were located outside the marine park.

Average native fish abundance was higher in experimental (culled) sites than control (non-culled) sites for all quarters. Significant differences in average native fish abundance between control and experimental sites were found for the 3rd and 4th quarter (p = 0.04 and p = 0.03, respectively).

Lionfish density was determined for quarters 2, 3, and 4 by counting every lionfish encountered along each of six 50 meter long belt transects per site. Lionfish density was found to be higher at non-culled sites compared to culled sites for each of the three quarters studied (Figure 2). Lionfish density at non- culled sites was significantly higher than culled sites for the third quarter (p=0.03).

Trend lines indicate that over the course of the latter three quarters of study, lionfish density has, on average, been increasing over time at both non-culled and culled sites.

Over 1,519 lionfish were removed from the waters surrounding Little Cayman over the course of 2012. Quarterly culls of study sites were completed in addition to community culls, which generally occurred weekly, depending on weather and availability of resources. Community culls were scheduled sporadically during the fourth quarter as a result of poor weather conditions and an absence of volunteers.

A total of 1344 diet analyses were performed in 2012. 77 different diet codes were recorded over the course of the year. “Fish” was the most common category of diet item recorded, identified 57.30% of the time. Unknown fish and unknown shrimp were the most commonly found prey items in lionfish stomachs. Of all identifiable prey items (i.e. excluding unknown fish, shrimp, etc.), the most common was the redband parrotfish (Sparisoma aurofrenatum).

You can download the two reports at the following places:

CCMI Brochure: http://reefresearch.org/files/uploads/Research_and_Education_FINAL_LO_RES_for_web.pdf

CCMI Research & Education Report:

http://reefresearch.org/files/uploads/Research_and_Education_FINAL_LO_RES_for_web.pdf

To find out more about the CCMI please go to: http://reefresearch.org/