Our Valuable Biodiversity
The immense value of species as goods used by humans (e.g. food, timber, medicines, etc.) is one of the strongest arguments for biodiversity conservation. One of the primary objectives of biodiversity management is management of exploited species for a sustained yield. This means that we must aim to control how much we harvest species from the wild to ensure that we can continue to use these resources into the future.
Game species in forests, marine fish, wildlife pets, timber and other forest products (herbal medicines, handicraft materials, organic pesticides, dyes, horticultural plants) are all important groups of biodiversity that are used in T&T. Unfortunately, all of these are being over-exploited and this jeopardises their potential to be used as a naturally renewable resource that can be sustainably used.
Over-use of biodiversity
Last week’s article highlighted how our game species are being over-hunted and the populations have declined to such low levels that they cannot support continued high levels of hunting. This pattern holds for all of the other biodiversity goods.
Studies by the Fisheries Division have shown that most of the traditional coastal fish species are close to fully, fully, or over-exploited. This means that our marine fish stocks are declining.
Similarly, over-collection of birds for the pet trade is commonplace. This has already caused the disappearance of the Blue and Gold Macaw from the wild. Other popular cagebirds, which can now be legally hunted under the Conservation of Wildlife Act, may be facing a similar fate.
Biodiversity: A Rich Resource
The value of biodiversity resources that are exploited as goods is considerable and usually unappreciated. A comprehensive study of the economic value of T&T’s biodiversity has never been done. The Environmental Management Authority (EMA) is planning to undertake such a study in the near future. Nevertheless, some data is available to hint at how considerable these figures would be.
• The value of the game harvest in T&T was estimated at over TT $25 million from 1990 to 1995. Over six thousand registered hunters used this resource.
• The T&T fishing industry includes coastal demersal soft bottom species (e.g. shrimp), coastal demersal rocky or coraline bottom (e.g. snappers, groupers, grunts, lobsters), coastal pelagic species (e.g. flying fish, carite, sharks, cavalli), oceanic highly migratory species (e.g. tunas, swordfish, sharks, kingfish), and deep water demersal species (e.g. snappers, groupers, shrimp). This industry is worth an estimated TT $100 million annually, representing 13% of the agricultural contribution to Gross Domestic Product (GDP). Estimates of the number of fishermen in this industry range from eight to thirteen thousand.
• Timber resources in T&T were valued at TT $4.1 billion. The Forestry Division collected about TT $30 million in revenues from natural forests and plantations from 1980 to 1997. Approximately twenty-five percent of the total land area of T&T is managed by the State for the production of timber, and an additional ten percent managed as private forests, with some timber harvesting taking place. In T&T there are over sixty sawmills which employ several hundred people and contribute about 0.2% of the GDP.
• Three hundred and forty six cagebirds were reportedly caught between 1990 and 1995, at an estimated value of over TT $53,000.
Principles for Managing Exploited Species
Management of these exploited species is absolutely essential if we are to stem the destructive and uncontrolled over-exploitation that is currently taking place. Some key principles can be elucidated.
(1) Data needs to be collected on the catch being harvested and on the biology, ecology and population sizes of the species concerned. This is used to calculate a sustained yield that can be taken each season.
(2) Controls need to be put in place to limit the degree of hunting. This may be through the institution of permit systems, bag limits, catch restrictions, etc. The catch must be limited to the maximum sustained yield.
(3) Harvesting must not damage the reproductive potential of the population, which would reduce population growth and reduce the potential sustained yield. Young and pregnant individuals must not be taken. Limits on size, restrictions on pregnant animals, and a closed season during the reproductive months must be used.
(4) There must be strict monitoring and enforcement so that there is no illegal harvesting and legal harvesting is within the controls established.
(5) Protection of the habitats of exploited species is an integral component of any management plan. Wetlands (as nurseries for marine species) and coastal areas are critical habitats for many marine fish. Management of large areas of good quality forest is necessary for protection of game and other forest species.
(6) Harvesting methods used must specifically target the species desired. Methods that capture “undesired species” that are then lost are destructive to the ecosystem. Drift fisheries and trawling are examples of methods that have a large “incidental catch” of species (for example turtles).
T&T is still awaiting the passage of new legislation for wildlife management, including the Wildlife Bill, which needs to be reintroduced. Similarly, the National Biodiversity Strategy and Action Plan (NBSAP) is awaiting debate and formal adoption as a Government policy. After adoption of legislation and policy, rules and regulations must be developed and institutional systems put in place for management (including data collection, regulation and enforcement).
T&T clearly has a long way to go to address the over-exploitation of biodiversity that is taking place. This is threatening to deplete populations below levels that can produce sustained yields, thereby destroying a very valuable resource for T&T’s economy... a resource that, with proper management, will be renewable. - Nicole Leotaud, Education Centre Director - 26th March 2001