Sea Turtle Recovery Action Plan for Barbados - WIDECAST

Barbados Sea Turtles …
to large amounts of herbicides. The relative bareness of the soil under vegetable cultivation
compared to that under cane cultivation means that more soil is eroded by wind and rain. In
addition, the soil is heavily fertilized (nitrates and phosphates) to allow several vegetable crops
to be grown on each field per season. The increasingly heavy use of herbicides, pesticides, and
fertilizers increases the pollutant composition of run-off. Changing agricultural practises may
also cause an increase in the suspended particulate matter (SPM) load, as well as the amount of
nitrates and phosphates in coastal marine waters.
SPM stresses marine organisms in a number of ways, such as by decreasing light
penetration and reducing the growth rate of corals, by physically smothering corals, and by
impairing fish respiration. Sediment-covered surfaces restrict larval settlement, and large
quantities of SPM settling and decomposing on a reef cause an increase in bacterial activity. In
small quantities, nitrates and phosphates are important nutrients needed for the metabolic
processes of living organisms. In excessive quantities, however, they cause phytoplankton
blooms blocking light and decreasing the rate of coral growth. Sewage is another source of
SPM, and of inorganic nutrients as well. With the exception of one major sewage treatment
system in Bridgetown, sewage is disposed into septic tanks or pits. These are either
'soak-aways', or the contents are piped a short distance offshore and released. A sewage
treatment system will be constructed to serve the needs of the south coast in the near future, and
one is also planned for the west coast. One option is that lightly treated sewage will be deposited
offshore beyond the bank reef and in-to currents which will carry the sewage away from the
island. Such a system is preferable to heavy chemical treatment and deposition closer to shore.
Some of the chemicals used in sewage treatment (e.g., chlorine) may be more lethal to corals
than the sewage itself, and treatment to remove nitrates and phosphates is too costly.
The effects of pesticides and herbicides on nearshore marine communities in Barbados
are unknown, but east coast fishermen partially attribute the decline in sea eggs (Tripnuestes
ventricosus) to the effects of pesticides on nearshore sea grass communities. Attempts to
investigate this problem quantitatively are currently underway. Since a variety of nearshore
marine communities, most notably sea grass beds and coral reefs, are essential for the survival of
depleted sea turtle stocks in Barbados, this information will also be useful in implementing a
national recovery strategy for sea turtles.
4.147 Others
Careless anchoring of boats on coral reefs and the dragging of anchors and anchor chains
causes an unquantified amount of damage, particularly to coral reefs situated off the west coast.
Mooring facilities are greatly needed, particularly on the west coast, to accommodate visitation
to coral reef areas. The Barbados Marine Reserve is protected by legislation (section 4.21) that
prohibits damaging anchoring and fishing practices within a small designated area of the west
coast nearshore waters. Elsewhere, inexpensive and effective mooring technologies, such as
those designed by Halas (1985), should be installed in Barbados as soon as possible. Land has
recently been reclaimed and the sea floor dredged for the construction of fish markets at Oistins
and in Bridgetown. The effects of these constructions on current movements are unknown, but a
short-term effect has been a substantial lowering of the clarity of water in the area. Hotels and
houses on the west and south coasts often dispose of kitchen waste water through short drainage
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