Times of the Islands Summer 2017

More documents

Info

green pages newsletter of the department of environment & coastal resources This Caribbean reef shark is carefully examining a baited hook. The Good Shark Shark research in the Turks & Caicos Islands. By Dr. Aaron C. Henderson and Camilla Smith, School for Field Studies, Center for Marine Resource Studies, South Caicos Photos By Camilla Smith The public perception of sharks has shifted dramatically over the last couple of decades. Whereas they were once portrayed as bloodthirsty monsters, spawning the adage, “The only good shark is a dead shark,” most people now realise that sharks are an extremely important component of the ecosystems in which we find them. As apex predators, sharks have a strong controlling influence on the organisms that they feed upon, and any reduction in shark numbers is counterbalanced by an increase in their prey populations. While this might sound like a good thing, particularly to seafood lovers, the problem is that these increased populations deplete their own food sources much faster than under normal conditions, and so the knock-on effect ripples down through the food chain. 32 www.timespub.tc
green pages newsletter of the department of environment & coastal resources Juvenile lemon sharks are reliant on shallow inshore waters during the early stages of life. The end result of this “trophic cascade” might be a radically altered ecosystem—dead coral skeletons overgrown by algae where once there were healthy coral reefs, for example. Shark populations have already experienced massive declines on a global scale, due mainly to a combination of commercial fishing pressure and habitat loss. So it is extremely important that further serious declines are prevented, not just for the sake of the sharks, but also for the populations of other species that they are connected to, both directly and indirectly. The School for Field Studies Center for Marine Resource Studies on South Caicos has been studying the ecology of local shark populations since 2005, with a view to determining their status and conservation needs. The longest running of these studies has been an investigation into habitat use by juvenile lemon sharks, a species that is classified as “Near Threatened” by the International Union for the Conservation of Nature (IUCN). Its distribution ranges from New Jersey to Brazil, and throughout this range it has experienced heavy fishing pressure, causing a considerable reduction in population size. However, the biggest threat that this species currently faces is habitat loss, as lemon sharks are reliant on shallow inshore waters during the early stages of life. In late spring and early summer, pregnant females move into extremely shallow waters close to mangroves, where they give birth to between 4 and 17 pups, each measuring around 60 cm in length. Having given birth, the females then move straight back out into deeper waters, but the newborn shark pups remain in these shallow areas for the first few years of life. As mangroves support large populations of fish and invertebrates, the shark pups have access to plenty of food as well as being protected from larger predators. Our research on this species has been mainly concerned with identifying areas of particular importance for the shark pups. What we have found is that almost everywhere that you find mangroves, you will find lemon shark pups. But, some areas do seem to be more important than others. As we have recently reported in an article for the scientific journal Aquatic Conservation, the most important area for these pups around South Caicos is the Bell Sound Nature Reserve. Not only is there a greater concentration of the sharks within Bell Sound, relative to other areas around South Caicos, but Bell Sound is also home to the smallest pups. In other words, Bell Sound appears to be an important birthing ground for the pregnant sharks, and the young sharks prefer the sheltered, shallow waters that Bell Sound provides. While our research is ongoing, it seems highly likely that the shark’s main food source is the fish that live around the mangroves in the northeastern corner of the reserve around Iguana Cay, as well as in the western part of the reserve around Man-O-War Bush. Unfortunately, Bell Sound faces an uncertain future, as there have been calls to redraw the boundary of the Nature Reserve and to downgrade it to a National Park. While these proposals would facilitate greater waterbased recreational use of Bell Sound for South Caicos’ growing tourism industry, there can be no denying that any such change will negatively impact the resident lemon shark pups—particularly as there are also plans to remove some of the mangroves from around Iguana Cay. And it’s not just the lemon sharks that rely on these mangroves; most of the fish that live among the mangrove roots are juveniles of species that live out on the reef as adults. The mangroves are an essential nursery habitat for these species, without which populations of reef fish are also likely to decline. More recently, we have started to investigate the ecology of other shark species that live out on the reef and in the deeper sand flats of the Caicos Bank. Our first goal was to determine which species occur locally, in addition to the lemon sharks, and then to assess their movement patterns and habitat preferences. The main techniques that we use for this research are tag and release, and baited remote underwater video stations (BRUVS). Tag and release, as the name suggests, involves capturing, tagging, and releasing the sharks. Captured Times of the Islands Summer 2017 33
Page 1 and 2: TIMES OF THE SAMPLING THE SOUL OF T
Page 3 and 4: The World’s ONLY 5 ★★★★
Page 5 and 6: THE COOL SIDE OF CLASSIC The Palms
Page 7 and 8: Turks And Caicos TurksAndCaicosProp
Page 9 and 10: & Turks Caicos Resort Villages & Sp
Page 11 and 12: VOTED WORLD’S BEST ALL-INCLUSIVE
Page 13 and 14: getting to know Besides being among
Page 15 and 16: known for such songs as “Old Conc
Page 17 and 18: PROVIDENT LIMITED Developing commer
Page 19 and 20: feature Opposite page: South Caicos
Page 21 and 22: The story of the fish vendor demons
Page 23 and 24: The Leading Private Bank in the Tur
Page 25 and 26: green pages newsletter of the depar
Page 31: green pages newsletter of the depar
Page 37 and 38: feature Opposite page: TCI waterspo
Page 39 and 40: As anywhere else, surfing in the TC
Page 41 and 42: Although the global fascination wit
Page 43 and 44: kid with autism from any other chil
Page 45 and 46: feature Opposite page: Everyone is
Page 47 and 48: Provo Golf Club’s stately clubhou
Page 49 and 50: What’s happening at Provo Golf Cl
Page 51 and 52: astrolabe newsletter of the Turks &
Page 63 and 64: Whilst his 31st birthday was spent
Page 65: The Turkana Tribe people of Loiyang
Page 68 and 69: At the community college, Wellingto
Page 70 and 71: faces and places TCI Ministry of To
Page 72 and 73: about the Islands Map provided cour
Page 74 and 75: ing those charged with compressed a
Page 76 and 77: ahamensis). The National Costume co
Page 78 and 79: H H H H H H H H H H H H H H H where
Page 80 and 81: Grace’s Cottage — Point Grace R
Page 82 and 83:
classified ads twr ad Times Summer
Page 84:
Island Living explore the extraordi
show all

Times of the Islands Summer 2017

Create successful ePaper yourself

Delete template?

Save as template?