Sea Turtle Recovery Action Plan for St. Kitts and Nevis - WIDECAST

CEP Technical Report No. 17
2) Artificial lighting: Sea turtles, especially hatchlings, are profoundly influenced by
light. Baby sea turtles, freshly emerged from the nest, depend largely on a visual response to
natural seaward light to guide them to the ocean. In zones of coastal development, sources of
artificial light distract hatchlings so that they turn away from the sea and crawl landward. It is
essential that artificial light sources be positioned so that the source of light is not directly visible
from the beach and does not directly illuminate areas of the beach; if lighting must be seen from
the beach, it should emit wavelengths (560-620 nm) which are least attractive to sea turtles. Low
pressure sodium lights should be used to the maximum extent possible. Low intensity,
ground-level lighting is encouraged. Nighttime and security lighting should be mounted not
more than 5 m above the ground and should not directly illuminate areas seaward of the primary
dune or line of permanent vegetation. No lighting, regardless of wavelength, should be placed
between turtle nests and the sea.
Natural or artificial structures rising above the ground should be used to the maximum
extent possible to prevent lighting from directly illuminating the beach/dune system and to buffer
noise and conceal human activity from the beach. Improving dune height in areas of low dune
profile, planting native or ornamental vegetation, or using hedges and/or privacy fences is
encouraged. Barriers between 76-85 cm high are generally sufficient to block visual cues from
artificial lights (Ehrenfeld, 1968; Mrosovsky, 1970). Ferris (1986) showed that a simple "fence"
of black polyester material stretched between three posts and positioned between the nest and a
lighthouse resulted in the hatchlings orienting correctly to the sea. Balcony lights should be
shielded from the beach, decorative lighting (especially spotlights or floodlights) within
line-of-sight of the beach should be prohibited, and safety/security lights should be limited to the
minimum number required to achieve their functional roles (section 4.132).
3) Beach stabilisation structures: Hard engineering options to beach protection,
including impermeable breakwaters, jetties, groynes and seawalls positioned on the beach or in
the nearshore zone, should be considered only as a last resort. There are already cases of
beaches lost, rather than secured, as a result of armouring in St. Kitts and Nevis (section 4.133).
Sandy beaches are naturally dynamic. The physical characteristics of the coastline should be
taken into account prior to coastal construction so that adequate setbacks, rather than expensive
and often counter-productive armouring, can be used to provide for the long-term conservation
of the beach resource. With regard to the possible development of a marina on the Southeast
Peninsula or elsewhere, Orme (1989) notes that it can be engineered "without recourse to
entrance jetties that significantly impact littoral drift and beach stability."
4) Design setbacks: If development of land adjoining a sandy beach is planned, setback
limits should be defined that reflect the damage likely to be caused to the beach and backshore
environment during a major storm, and that take into consideration beach and backshore
characteristics. Setbacks should provide for vegetated areas including lawns and dunes between
hotels, homes and similar structures, and the beach proper. Setbacks of 30-40 m and 80-120 m
from the line of permanent vegetation are reasonable guidelines for upland coast development
and lowland beach coast development, respectively (section 4.133). Setbacks not only help to
protect coastal properties from storm damage, but also reduce overcrowding of the shorezone,
lessen the likelihood that local residents will be excluded from the beach, and enhance the
probability that artificial lighting will not shine directly on the beach.
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