Although relatively
common throughout the Caribbean and beyond, the southern stingray is something
of a Cayman Islands icon.
Around 100 of the
friendly rays entertain visitors on a daily basis at Stingray City and the
Sandbar, two of the top attractions for visitors to Grand Cayman. Despite being such star players in Cayman’s
tourism industry – the Department of Environment has recently given the
stingrays at these sites a daily economic value, based on the revenue they
generate - surprisingly little was known
about this particular group of rays until the last decade.
Marine artist,
conservationist, scientist and diver, Guy Harvey, approached the Department of
Environment in the early 2000s, with a proposal to carry out a two year study
of the stingray population, to which they readily agreed.
Stingrays are
typically solitary animals that inhabit inshore waters, and tend to feed at
night on clams, crabs, shrimp, worms and even small fish. The world famous rays
at Stingray City, however, congregate in schools of up to 100 individuals and
feast during the daytime on squid fed to them by tour guides. Guy Harvey was interested in examining the
effect of their ‘taming’ on numbers, feeding and breeding habits, ratio of
males to females, etc .
Over 200 stingrays,
most of which were Stingray City regulars, were tagged with Passive Integrative
Transponders. A smaller number of ‘wild’ rays from other areas were tagged and used
as a control group.
The study found that the
Southern Stingrays from Stingray City and the Sandbar demonstrated remarkable
fidelity to their chosen sites, with only one ray moving between the two. It
was also found that while the larger females – they can weigh three times more
than the males – tended to feed only by day, males and smaller females
continued to forage at night and were not dependent on being fed by humans. The
study also revealed that feeding was having no effect on numbers, and no
population explosion had occurred.
When hurricane Ivan
hit in 2004, it was catastrophic for Grand Cayman. In the aftermath of the storm, the stingrays
were not fed regularly for around three months. In 2008 Guy Harvey’s Research
Institute returned to examine the effects the storm and the subsequent lack of
regular feeding might have had on the stingray population.
The study found that
the majority of the stingrays they captured (74%) were the same ones that had
been tagged in the previous study.
Although some were newcomers to the site, the overall numbers of
resident stingrays remain unchanged.
Southern Stingrays are
not considered a protected species, but in Cayman at least, their importance
for the tourism industry is undeniable.