Evidence increasingly suggests that marine environments are stabilised by the role that sharks play as top-predators. In the Cayman Islands this non-use indirect value of sharks may amount to as much as US$37.4 million. More information about the sharks that are found in Cayman, and their importance, is available in the other pages of this section (selectable tabs from the section below).
One of the interesting aspects of the research was how far the sharks moved from Grand Cayman.
The Cayman Island Sharks and Cetaceans Project
Background to the Project
The Cayman Islands receive over 1.6 million visitors a year. With the Cayman Trench along side, the Cayman Islands encompass both shallow and very deep water habitats that provides environments suitable for a wide range of shark and ray (elasmobranch), and whale and dolphin (cetacean) species. Yet there has been little information on what species or the distribution of elasmobranchs or cetaceans in the Cayman territorial seas.
Elasmobranchs and cetaceans are charismatic megafauna that represent keystone species in the marine environment. The project is providing information leading to a greater understanding, both locally and regionally, of the need to conserve both them and the environment on which they depend. This in turn may encourage both a healthier marine environment and sustainable management, including through eco-tourism, of these important species.
The project is addressing some key management issues for Cayman Islands’ elasmobranchs and cetaceans. We are determining the temporal and spatial occurrence of the species in the waters of the Cayman Islands, the threats to the populations especially of scarce or endangered species, and developing recommendations concerning these charismatic species and how best to exploit them sustainably.
The focus is on sharks, which are widely accepted as being in critical global decline, owing to habitat loss and exploitation (see Fowler & Cavanagh, 2005; Stevens et al. 2005). With up to 100 million sharks being caught annually, overall population declines in the region of 90% have been reported for many species, largely as a result of unregulated fishing for shark-fin to meet the demand of the far-eastern restaurant trade (Baum & Myers, 2004; Shepherd & Myers, 2005; Ward & Myers, 2005). In this context the Cayman Islands offer one part of the Caribbean where there is a reasonable prospect not only of conserving shark biodiversity, but using these much misunderstood predators sustainably.
Marine Conservation International is working with the Department of Environment to provide information to assist the Cayman Islands Government in protecting important but threatened shark species to support sustainable, economically beneficial use of these iconic species. The protection of a quality marine environment is key to the islands’ future economic, social and environmental well-being.
The project will contribute to implementation of the UK – Cayman Islands Government Environment Charter, specifically the commitment to ensure the protection and restoration of key habitats, species and landscape features through legislation and appropriate management structures and mechanisms. It will also contribute to meeting commitments and obligations under Multilateral Environmental Agreements including The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES); The Convention on the Conservation of Migratory Species of Wild Animals (Bonn) (CMS); The Convention for the Protection and Development of the Marine Environment of the Wider Caribbean Region (Cartegena); and The Convention on Biological Diversity (CDB).
The methods used to obtain information for the project 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
- maintain a Volunteer Observer Sightings Network in reporting sighting of sharks and rays, and whales and dolphins
- a significant local public awareness and marine environmental education programme.
The main issues being studied can be divided into scientific and management questions.
- How wide or localized are the foraging movements of the main reef shark species in Cayman (Caribbean reef shark, black-tip shark and nurse shark), and the smaller numbers of larger shark species – tiger, great hammerhead and oceanic white-tip sharks? Do individuals have distinct home ranges or territories, or do individuals range freely around a whole island, or even between them?
- Do these species show seasonal movements, either away from the island(s) or between different areas, for mating or for pupping? For example do sharks tend to move away from their normal reef habitats perhaps in autumn to mate and return in spring to give birth in suitable nursery areas? Do the tiger sharks, as evidence from elsewhere suggests, move seasonally between widely disparate parts of the Caribbean?
- Shark-feeding, in order to attract sharks for shark-watching by SCUBA divers, is an important economic activity elsewhere in the Caribbean, estimated to be worth $78 million p.a. in the Bahamas. A ban was placed on this activity in Cayman because of localized concern that the practice may increase shark numbers or make them more aggressive. To address the issue, we are determining whether the provisioning of sharks in a single area results in an increase in either the numbers of sharks appearing at locations at different distances from the feeding area, or in an increase in the tendency of sharks to approach relevant stimuli other locations.
- The large sharks (tiger sharks, giant hammerheads) are of particular concern, from both conservation and hazard avoidance, and may be attracted to lagoonal areas because they feed on stingrays and turtles. We are tracking the movements of these larger sharks between different coastal zones, around the island and the wider Caribbean region, to understand the behavior and movement patterns of the sharks, and to see whether there are seasonal patterns.
Foraging Movements of Common Shark Species:
Sharks caught during sampling at 17 sites around the three islands are being tagged with conventional (numbered plastic) tags and acoustic tags. There are receivers distributed around the Cayman Islands, already in use to follow movement of Nassau Grouper. These receivers are detecting the presence of individual sharks at key locations around the islands and their movement between. The data will reveal the extent to which, for example, sharks tagged in the south-east of the island visit the northern or western coasts, and vice versa.
Seasonal Movements of Common Shark Species:
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.
Tracking of giant hammerhead and tiger sharks:
Giant Hammerhead and tiger sharks are attracted by the presence of large numbers of stingray, which are one of their preferred food items. Surveys show that there are very few of these large sharks, but a number are tagged both with acoustic tags and satellite tags, in collaboration with the Guy Harvey Research Institute. Acoustic tags and moored acoustic receivers will be used to track the local movements of these sharks. Satellite tags (which send signals via satellite, remotely tracking the longer distance movements of animals) will be used to determine whether these sharks are resident around the island, or as is more likely with the tiger sharks, show seasonal migrations between different parts of the Caribbean. It should be noted that these tags can be detected by similar arrays in other locations in the Caribbean.
Environmental Economic Assessment of Sharks and Cetaceans in Cayman:
An environmental-economic assessment of the potential economic value of sharks and cetaceans in Cayman has been carried out. This is in the context of the conclusion by Anderson (1997) that a single Caribbean Reef Shark will generate an annual revenue is excess of $40,000 per yea. Conclusions from this work should assist in the resolution of relevant issues concerning sharks in particular, which in turn will facilitate both the enactment of the draft conservation legislation, and the implementation of the associated management and enforcement measures.
The Stingrays and Tourist Interaction at Stingray City, Sandbar:
The artificial aggregation of southern stingrays at Sandbar has been protected since 2007 but there has been concern that the numbers of stingrays has declined rapidly over the last few years. The population is currently being monitored for each individual with a visual assessment of their condition.
Surveys of Whales & Dolphin Species:
Boat-based surveys for whales and dolphins around Grand Cayman, Little Cayman and Cayman Brac have been undertaken. The data are supplemented with public sightings data through the Volunteer Observer Sighting Scheme. The public are welcome to assist through the project Facebook site “Sharks & Cetaceans: the Cayman Islands” or by calling Janice Blumenthal at the DoE.
These surveys have revealed that small groups of two species of dolphin, Bottlenose and Spotted, very occasionally visit the islands, while more unusual species, including two small species of whale, Short-finned Pilot and Beaked Whales, are more regularly seen further offshore, around various submarine banks. In addition there is some evidence to suggest that the rare Pygmy Sperm Whale may be associated with the deep slopes of the Cayman trench. More information about these species would be of great value for both conservation and wildlife tourism.
We have identified the presence of 6 dolphin and 4 whale species in Cayman waters, some of which are listed as critically endangered in the Caribbean region:
- Atlantic spotted
- False killer whale
- Killer whale
- Pantropical spotted
- Pilot whale
- Gervais beaked
- Pygmy sperm
Surveys of Shark & Ray Species
Both scientific long lining (involving circle hooks and catch & release) and BRUVS (baited remote underwater video systems) are used to identify the species, location where found and when. These data are then used to assess the abundance and seasonal occurrence of difference species around Cayman.
By physically catching the sharks we are able to take basic biological data including measures of length, sex, stage of development, clasper length as well as indications of health or damage. A small tissue sample is also taken to analyze the relatedness of individuals to each other; in wider terms it also allows us to discover if populations in Cayman ever mix with populations from other regions studied such as the Bahamas.
BRUVS are video cameras placed in underwater housings inside a heavy frame; the camera faces a bag with a small amount of fish and is attached to the end of a length of pipe. The camera films anything coming within view for the duration of the tape. The amount of bait used is very small (around 300 grams) and this simulates a natural food fall and attracts from a very small area. This method produces a large amount of data in a largely non-intrusive manner and allows for behavioral monitoring.
We have confirmed the presence of 13 shark and 3 ray species in Cayman waters, some of which are listed as critically endangered in the Caribbean region:
- Caribbean Reef
- Cuban Dogfish
- Great Hammerhead
- Oceanic Whitetip
- Scalloped Hammerhead
- Short Fin Mako
- Six Gill
- Southern Stingray
Public Awareness of Shark and Cetacean Programme
Sharks are often viewed by people as a threat and a danger, not as something that creates balance or as wonderful animals. Awareness of the predicament face by sharks is often limited and fear mongering by media has given rise to a misunderstanding of these creatures. It is important to promote educational awareness and conservational importance for these key animals and a significant local public awareness and marine environmental education programme has been launched. There are a number of activities that we do to raise public awareness and to inform the public of the information gathered from the studies. There are talks to local schools, community groups, business and social groups. Educational leaflets have been designed and distributed, including one on our mascot, Tina the Tiger Shark. Our collaboration with CayBrew Brewery has resulted in a unique shark conservation beer, White Tip Lager. CayBrew have kindly offered to donate 5c on every can of White Tip to the shark conservation fund set up through the DoE.
Work with local residents and visitors has generated a greater understanding of historical populations, looking particularly at occurrences as well as increases or decreases in numbers of observations over time. Collaborating with local fishers, elasmobranch catch or by-catch is monitored and traditional knowledge recorded. The Volunteer Observer Network is hugely supportive and helpful in reporting sighting of sharks and rays, and whales and dolphins
Public participation is of critical importance to the project in the form of reported sightings, if you see or hear of a shark being seen anywhere please report it to us at: TEL: 949 8469.
Marine Conservation International
(MCI) is a partnership formed by marine scientists to enable them to pursue projects with conservation objectives in the most effective way. The Directors (senior partners) are Dr. Rupert Ormond, previously Director of the University of London‘s Marine Biological Station, and Dr. Mauvis Gore, a senior research fellow at the Millport Marine Station, and previously Director of Conservation with the Royal Zoological Society of Scotland. Both Directors have considerable experience of marine biological research and conservation projects stretching back over nearly 40 years and have Adjunct Professorships at Heriot-Watt University.
Save Our Seas Foundation
Founded in 2003 as a non-profit organization with offices in Genève, Jeddah, Dubai, Miami, Cape Town and Edinburgh. It undertakes and supports conservation and research projects concerned with endangered marine species and habitats — notably sharks, marine turtles and coral reefs. It operates two shark centres (for educating and research) one in Kalk Bay near Cape Town and the other in Fort Lauderdale. Shark species which are the subject of research projects include great white shark, common tiger shark, bull shark, basking sharks, silky shark, blue shark, whale shark and grey reef shark, and work on cetaceans ranging in size from the blue whale to the dolphin is also being supported. Conservation, Awareness, Research and Education are the four principals at the heart of the foundations mission. www.saveourseas.com
Overseas Territory Environment Programme
A joint programme of the UK Foreign and Commonwealth Office and the Department for International Development; its aim is to support country governments in the implementation of their Environmental Charters, as well as more generally address environmental management issues. In particular OTEP supplies funding for projects concerned with the conservation of terrestrial and marine biodiversity, and the mitigation of pollution and waste problems. www.ukotcf.org