Cayman's Marine Environment

By: The Cayman Islands Department of Environment

Impacts
The plight of reefs worldwide has often made international headlines. Stories of wide-scale destruction of these fragile environments through coral bleaching, newly discovered diseases, pollution, sedimentation and over-fishing may seem along way from the tranquil waters of Cayman, but they are in fact very real threats. Over the past four decades the Cayman Islands have seen a tremendous amount of development and while this development has brought with it many rewards, it has not been without a price environmentally.

Perhaps the most far-reaching impacts to the marine environment are those associated with land reclamation, in particular dredging. Low-lying mangrove and wetland areas situated close to the sea make attractive real-estate and need to be 'filled' if they are to create land suitable for development. The 'filling process' most typically involves the mechanical dredging of material, 'marl,' from the sea floor which is pumped ashore to fill these low lying areas. It is estimated that as of 1999 ten million cubic yards of marl has been dredged from the North Sound to fill bordering land. The long term consequences of this activity are very apparent today. Important marine habitats, such as seagrasses and mangroves, and their functions are lost and most will not recover for many decades. Water quality is reduced through fine sediments stirred up during the dredging process and by currents and wave activity on the newly exposed muddy sea floors. The fine sediments are carried onto neighbouring coral reefs where they smother and choke the delicate filter feeding mechanisms of corals and other invertebrates. Reduced water quality may also impact the microscopic animal life that floats in the water column and forms the basis of the coral reef food chain. Poor water clarity means reduced sunlight reaching the sea floor, which in turn impacts the seagrasses and other marine plants that depend on sunlight and clear waters.

The removal of the mangroves means their vital functions are lost and in their place are houses with storm drainage systems, septic tanks and landscaped gardens requiring fertilizers, pesticides and freshwater all of which can find its way into the sea causing problems for an already stressed environment.

Indirectly related to the developmental pressures on reefs are the rising demands placed on reef resources through an increasing population and numbers of visitors. Many more recreational boaters, fishermen, snorkellers and divers can cause any number of problems if they are not managed accordingly. Boat anchors, groundings and pollution, over fishing and the damage inflicted on delicate reefs through careless or thoughtless divers and snorkellers all take their toll on Cayman's reefs.

In addition to the human pressures inflicted on Cayman's marine environment, there is also a background of natural threats that can have or have had a significant influence. Coral bleaching due to high water temperatures during the warmer summer months is occurring on a more frequent basis. This increase in frequency has prompted scientists to link coral bleaching with the current Global Warming trend, which may spell disaster for reefs worldwide. Global warming could also signal a rise in both the frequency and intensity of major storms such as hurricanes, which have a dramatic effect on reefs. Epidemics of coral diseases, fish kills and other harmful outbreaks are also becoming more prevalent.

Marine Parks
Human pressures on our reefs reduce their ability to recover from natural impacts and therefore it is important to limit these impacts wherever possible through responsible management. The 1978 Marine Conservation Law and 1986 Marine Parks Regulations have gone a long way towards protecting the limited and delicate resources of Cayman's marine environment. Perhaps the most important function of the current system of marine protected areas is that of a refuge for marine life. Protecting a portion of the adult breeding population, in particular conchs, lobsters and many species of fish, ensures a continued supply of these culturally important resources by providing areas free from substantial fishing pressures that allow adults to reach the large sizes and maintain the numbers necessary for egg production. Ocean currents then disperse the eggs to settle in fished areas and protected areas alike. Those that settle in protected areas can grow to produce more eggs, whilst the individuals that settle in fished areas will most likely be caught in some form of fishery, however their continued survival remains safeguarded in a marine protected area.

Unlike our terrestrial home the seas around our islands have only limited boundaries and consequently are tightly integrated with areas many thousands of miles away. The oceanic dispersal of eggs means that, in some cases, our coral reefs may rely heavily on other areas of the Caribbean for their continued survival, areas we can not manage. Consequently, until ocean currents and reef recruitment are fully understood, it is vital that a network of marine protected areas are established throughout this region to ensure the continued survival and well being of not just Cayman's marine environments but all of the Caribbean's marine environments.

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