Category Archives: Scientific Research Expeditions

Nassau Grouper Spawning Aggregation, Little Cayman

Nassau grouper (Epinephelus striatus) are endangered predators found on coral reefs in the Caribbean. Around the full moon at the beginning of the year, they gather in thousands to reproduce at a special site on the West end of Little Cayman, Cayman Islands. The Cayman Islands used to be home to five Nassau grouper spawning sites. However, four of these sites are now dormant or depleted.

The Cayman Islands Department of the Environment (DoE) work in collaboration with Reef Environmental Education Foundation (REEF), Scripps Oceanography Institute and Oregon State University to gather data on this aggregation and are responsible for the management and protection of this healthy site. Without their dedication and hard work over the past decade, this spawning aggregation would probably not exist, like many other historic sites in the Caribbean that have been ‘fished to extinction’.

Grouper Moon Project, established in 2002

What has been learned so far?

  1. All Nassau grouper attending the spawning aggregation on the West End of Little Cayman are from Little Cayman (none are traveling from other countries, or even the other two Cayman Islands)
  2. All reproductively-aged Nassau grouper on Little Cayman attend the aggregation each year (and often on multiple months each year)
  3. Larger (older) Nassau grouper arrive earlier and stay longer at the aggregation site.
  4. The fish move back and forth off the site during the aggregation period and often will circumnavigate the island during the day.
Overall the results from Grouper Moon 2017 was very positive. Cayman News

The science!

During the day dives, fish counts are conducted to establish the population of Nassau groupers on the Spawning Aggregation. Lasers are used to assess fish size classes to determine how much of the population are adults or juveniles and what proportion are reproductively active. Hydrophones funded by NOAA International Coral Reef Conservation Program are deployed to record fish sounds during mating and Floy tags are inserted into the fish using spears.


During the spawning, larvae from Nassau and Tiger groupers are collected by swimming up to a ‘spawning burst’ and opening a zip lock bag allowing water and specimens to rush inside. Samples are taken to the Central Caribbean Marine Institute (CCMI) where Alli Candelmo and her team of scientists study the progressive stages of larval growth.


On the night of peak spawning, satellite drifters are released to follow the current and therefore follow the newly released larvae. In doing this, the team hope to establish whether this aggregation repopulates reefs in the Cayman Islands or further afield. This research is funded by the Disney Worldwide Conservation Program. The boat follows the drifters towing the ‘The Acrobat‘ which is able to control depth and take microscopic pictures of the eggs and plankton in the water column. This microscopic camera was developed by Scripps Oceanography Institute and was attached to a plankton net last year for the same purposes.


When the Nassau groupers begin to disappear from the aggregation, approximately after 4 nights of intense spawning, other species of grouper tend to take over this spawning site. This year, Yellowfin grouper were collected using a hand line and brought onto the boat to for surgery. This involves taking length measurements, fin clips, blood samples and inserting a PIT tag so the fish can be followed for  4 years. Like much of the research occurring on this aggregation, this has never been done before and should lead to exciting findings.


Science communication is incredibly important and REEF ensure to include education talks throughout the 2 week period of the Grouper Moon project. Below is an education dive on Bloody Bay Wall where children from local schools in the Cayman Islands can get involved and ask questions about the project.


Last and certainly not least! Sir Richard Branson joined us this year on the Nassau Grouper Spawning Aggregation in the hope to learn previous techniques used by REEF and the DoE to establish spawning aggregations in the British Virgin Islands.

‘Diving the ocean maternity ward’ Richard Branson


A big thank you to the DoE and REEF for involving me in this incredible research!

2017 Project Scientists

Croy McCoy, Cody Panton, Paul Chin, Ivan Montieth , Chris Dixon, Keith Neale, Kevin Jackson 
Brice Semmens, Christy Semmens, Scott Heppal, Steve Gittings, Hal Peterson, Brian Stock, Lynn Waterhouse, Todd Bohannon, Alli Candelmo

Additional Support

Dr Guy Harvey, George Schellenger, Jessica Harvey, Louisa Gibbon  
Peter Hillenbrand,  Little Cayman Beach Resort/Reef Divers &  Southern Cross Club

February 2017
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Cayman Islands Research 2017

Red-Footed Boobies,
Little Cayman

First impressions at the National Trust’s Booby Pond Nature Reserve may suggest a desolate, guano smelling, muddy swamp. However, if you can look past this unpleasant aroma, a beautiful ecosystem filled with seabirds emerges.

Booby Pond is home to the largest colony of red-footed boobies (sula sula) in the Caribbean; approximately 3500 breeding pairs. The species is present in two colour morphs (90% brown & 10% white) and their beautiful beaks can change colour throughout the year, being particularly bright during breeding season. Rhiannon Meier and the Department of Environment are conducting research on the seabirds involving camera monitoring, population genetics, spatial ecology and behaviour.

The Magnificent Frigate bird (Fregata magnificens) can also be found at Booby Pond, often competing with the boobies for resources. When boobies return to land after a long day out at sea, both can be found squabbling in mid-air as the Frigate bird maliciously tries to hijack their catch. This is known as kleptoparasitism and the frigates often win due to their strength and speed. The male Frigate bird is jet black with a striking red gular sac which it inflates to attract females. The females are slightly bigger with a white chest.

Both species do managed to coexist at Little Cayman’s Booby Pond, nesting amongst the branches of mangroves and forest trees in the nature reserve. February is peak nesting time for Red-footed Boobies with both parents taking turns to incubate the egg.

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· 13/JAN/2017 ·

Botanic Park, Family Fun Day

We attended the Family Fun Day at the Queen Elizabeth II Botanic Park and played a game with the children (and adults!) in which they had to match up the names of certain species to the pictures displayed on our desk. All species can be found in Cayman and it was a great opportunity to talk about invasive species such as the green iguana and endemic species such as the blue iguana. I thoroughly enjoyed returning to my terrestrial routes today!

The Botanic Park is located in the district of North Side on Frank Sound Road and was opened in 1994 by Queen Elizabeth II. It is home to the native and endangered blue iguana (Cyclura lewisi). The blue iguana is one of the longest-living species of lizard, with a known record of 67 years! Habitat destruction is the main factor threatening the survival of this beautiful reptile in conjunction with possible threats from the common green iguana, (Iguana iguana), an invasive species from Central America which have become well-established in Grand Cayman since the 1980s. An ‘Invasive Species’ is a non-native plant or animal, which adversely affects the habitat it invades, ecologically or economically. Green iguanas far outnumber the endemic blue iguana and the Department of Environment (DoE), Terrestrial Ecology Unit, has been trying to reduce the green iguana population by initiating a cull in 2015. The DoE fears the iguanas could massively invade Little Cayman and Cayman Brac, where so far only a few of the greens have been spotted. A further eradication program takes place on the sister islands.

The Blue Iguana Recovery Program is a partnership, linking the National Trust for the Cayman Islands with the Cayman Islands Department of Environment, the QE II Botanic Park, and two overseas Partners, the International Reptile Conservation Foundation and the Durrell Wildlife Conservation Trust. The objective of this project is to save the blue iguana from extinction and restore its population to natural numbers. This requires extensive conservation effort, spanning habitat protection, captive breeding and release, research and monitoring, education and outreach, and all the planning, management and fund raising that is needed to keep this urgent work moving forward.

· 22/JAN/2017 ·

Stingray Conservation and Ecology Research

Sandbar in Grand Cayman is home to an aggregation of southern stingrays (Dasyatis americana). They are attracted to the shallow water by tour operators which feed them squid, providing close tourist encounters with the beautiful creatures. The socio-economic value of the rays to the Cayman Islands economy is enormous, however, it is important to monitor the impact this interaction has on the population and health of the stingrays.

Every 6 months the southern stingrays at Sandbar, Grand Cayman are surveyed by the Guy Harvey Research Institute and the Cayman Islands, Department of Environment. This research involves a skilled pair of hands to initially catch the stingray, a technique that Guy Harvey has mastered over the years. Once the ray has been caught it is placed in a large net and lifted into a paddling pool filled with seawater on the deck of the boat. A cloth and clamp is then placed over the barb on the stingrays tail to avoid getting stung during the survey. Length between wing tips is measured and a scanner is used to check whether the animal is a recapture from previous studies. If the ray has previously been caught, it is marked at the base of the right wing to ensure it will not be captured again during this survey and then returned to the water. If it is a new specimen a PIT (passive integrated transponder) tag is inserted at the base of the tail where it meets the disk on the left side of the animal. This research has been conducted since 2002.

Everyone in the Cayman Islands benefits from the presence of this unique marine interactive site and it is important the population status and wellbeing of the stingrays continues to be monitored.

· 25/JAN/2017 ·

The Reef Rover

Steve Schill from The Nature Conservancy and George Raber from The University of Southern Mississippi hope to used an autonomous boat drone to map of coral reefs in the Cayman Islands. This innovative research will hopefully be used in the future by the Department of Environment to rapidly assess coral reefs at low cost.

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The training took place in George Town harbour, where the coral reef at Eden Rock was recently damaged by a cargo vessel. The equipment is initially set up on the boat and then placed into the water. The drone follows a manually imported route through an android app and takes one picture per metre from the surface. The photos can then be post-processed to create a 3D mosaic of the reef structure to assist coral reef monitoring techniques.

· 27/JAN/2017 ·

Photogrammetry

Photogrammetry is a method used to survey and measure complex areas/structures using images. Much like the drone method above, divers can swim with a camera and map an area of the sea floor. Multiple overlapping images can be processed in a stereo-plotter (photoscan/Pix4D) to make a topographic, 3-dimensional mosaic. This is done by measuring conjugated points appearing in different images. Unlike invasive mechanisms used to measure surface area of coral reefs, photogrammetry is accomplished without physical contact with the structure.

To be continued..

· 01/FEB/2017 ·

Reef Restoration

Over the past 30 years, coral reefs have faced major global decline from natural disasters and human induced stressors. Some scientists believe that restoration efforts “put a bandage” on the problem. Meaning  that it will not address the major issue of coral reef decline, but instead slow down the inevitable.

To be continued..

· 01/FEB/2017 ·

Mangroves: Guardians of the Coast

Mangroves are found globally, are one of the most important ecosystems on our planet and may be one of nature’s best defences against global changing climate. They are highly adapted to their environment and can be found in the transitional zone between the land and the sea, capable of expelling salt from their routes, allowing them to thrive in highly saline waters and soils.

They provide barriers against erosion and hurricanes, effectively safe guarding our coasts. As well as helping to provide the oxygen we breathe, mangroves play a vital role in sequestering carbon dioxide which can be used as a tool to fight global climate change.

They protect coral reefs from sedimentation and are nurseries for thousands of reef species, some of which are important food sources. They also provide a critical habitat for endemic terrestrial species and sea birds.

Although these forests have high ecosystem value, mangroves are under threat primarily from anthropogenic impacts. For example in Asia ~40% of mangroves have been destroyed for shrimp fisheries, which are much less productive and often leave the land unusable from pollution. However, realisation of the ecosystem services our coastal ecosystems provide, has initiated a response from NGOs around the world to restore these important habitats. E.g. The Mangrove Action Project. The Department of Environment, Cayman Islands has completed similar projects after severe storm damage such as Hurricane Ivan in 2004.

· 05/FEB/2017 ·

Nassau Grouper Spawning Aggregation, Little Cayman

Check out Changing Seas – Grouper Moon Project 2012

Click here to find out more about exciting research from Grouper Moon 2017 project with the Cayman Islands Department of the Environment (DoE) and Reef Environmental Education Foundation (REEF).

· 10/FEB/2017 ·

Shark Ecology

Sharks are in critical global decline, threatened mainly by habitat loss and over exploitation. There is  13 shark and 3 ray species in Cayman waters: Nurse Shark (Ginglymostoma cirratum) and Caribbean Reef Shark (Carcharhinus perezi) are the most common. Marine Conservation International and the Department of Environment work together to provide important information to the Government to enforce the protection of this important but threatened shark species, in the hope to support sustainable, economically beneficial use of these iconic predator.

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Methods used include:

  • Boat surveys for cetaceans using established visual transect methods
  • Baited Remote Underwater Videos (BRUVs), supplemented by SCUBA diving, to assess shark and ray populations
  • Collaboration with local fishers to monitor elasmobranch catch or by-catch, and record traditional knowledge
  • Maintaining a Volunteer Observer Sightings Network for reporting sightings of sharks and rays, and whales and dolphins
  • Local public awareness and marine environmental education programme.

Receivers have been placed around the three islands to monitor the movements of tagged sharks. This month we collected and re-deployed the receivers at the different sites to ensure they are working efficiently. The data will reveal the extent to which sharks move between islands and at what time they are most abundant in certain areas. The receivers will also record whether individual sharks change their preferred locations around the islands or move away on a seasonal basis. Such movement may be related to breeding or reflect the use of alternative foraging grounds either offshore or in deeper water. To provide a more complete understanding of the life cycle of these species, sharks are caught and tagged at a number of supplementary sites which are suspected of being pupping or nursery grounds for one or more species. This will provide additional data indicative of the role of these areas, and allow tagging of juveniles whose life history may be followed over successive years by Department of Environment staff. For more information please click here.

· 14/MAR/2017 ·

Deep Sea 7-gill Shark

Caught accidentally off the west end of Grand Cayman approx. 1500 ft/ 500 m water.

Johanna Kohler, Shark Project Coordinator at the DoE dissected the shark and gathered the information below about the species:

  • Species: Sharpnose Sevengill Shark (Heptranchias perlo)
  • Size at birth: 26 – 27 cm TL
  • Size at maturity: Male ~80 cm, Female ~100 cm
  • Max TL: 139 cm
  • Like typical for its family the Sharpnose Sevengill shark has 7 gill slits and only one dorsal fin which is far back on its body.
  • Teeth: comb-shaped
  • Distribution: patchy but wide-ranging. Tropical and temperate seas, not northeast Pacific
  • Habitat: Mainly deep water (27-720m; max 1000 m). Benthic and epibenthic
  • Reproduction: Ovoviviparous (young are nurtured by yolk sack in uterus only (not placenta) and born alive,6-20 pups per litter.
  • Behaviour: Poorly known. May be a strong active swimmer feeding on small to moderate large demersal and pelagic fishes, small sharks, crustaceans and cephalopods. Bites when captured.
  • IUCN status: Near threatened.
  • They are relatively uncommon and caught as bycatch in bottom trawl and longline fisheries.
· 26/MAR/2017 ·

Palmyra Atoll

An unimaginable and unforgettable experience

This year I was given an invaluable experience to travel to a small remote island in the central Pacific Ocean with Scripps Research Institute and Bigelow Laboratory for Ocean Sciences. This unique expedition introduced me not only to the Earth’s largest oceanic division, but to a new world where human influence on the marine environment is minimal.

image Continue reading Palmyra Atoll

Cayman Islands Research 2016

Cayman Islands – My second home

At the beginning of this year I travelled back to the Cayman Islands to work with the Department of Environment for a 6 month period as a coral reef ecology intern to gain further experience with coral reef ecosystems, conservation and science communication.

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screen-shot-2016-09-26-at-11-16-34screen-shot-2016-09-26-at-11-16-41 Continue reading Cayman Islands Research 2016