During more than 400 million years of their evolution, sharks had practically only two enemies – larger sharks and illnesses. Small and newborn sharks are especially threatened. In order to prevent their pups from becoming victims of larger sharks, most female sharks bear their young in protected shallow waters. These shark "nurseries" are not easily accessible to larger sharks and thus represent a safe haven for shark pups as well as other, smaller shark species.
Unfortunately, these shark "nurseries" are becoming rare due to environmental destruction.
Additionally, more than 80% of all shark species live in coastal areas and are thus directly exposed to the many harmful chemicals which are transported from our rivers directly into the ocean.
A current example (2005) of this destruction of shark nurseries due to profit greed is the internationally famous shark research station in Bimini on the Bahamas, headed by Professor Samuel Gruber, also known as "Doc Shark". Professor Gruber has been researching the Bimini lagoon for years, a shark nursery frequented in particular by lemon sharks.
An investor now wants to build a hotel complex, including casino and golf course, immediately adjacent to the lagoon. For this purpose the mangroves in the lagoon are to be cleared, i.e. especially for the golf course. Should this golf course be built despite the massive protests of various scientists and interventions on the part of the Bahamian Government, then lawn fertilizer will run unpurified directly into the lagoon, permanently destroying the habitat of young sharks.
In the Philippines, the mangrove forests have shrunk from 5,000 to 350 square kilometers between 1920 and today.
Each year Indonesia exports 250,000 cubic meters of wood shavings to Japan.
On Java a vicious circle began with the clearing of the mangroves which used to edge the entire northern coastline. The mangroves were cleared to make room for fish farms. But mangroves are also used by many bony fish as a protective harbor for their young. The result was a continuous decline in fishing yields. More and more mangroves were cleared and even more fish farms were established in their place so that finally, next to the decrease in the number of fish caught, it also led to increased erosion of the coastal areas. The protection from erosion once provided by the branching out of the mangrove roots was extinguished. The latest example of the havoc caused by clearing mangrove forests is seen in Aceh which was severely hit by a tsunami in December 2004.
Aquacultures (e.g. shrimp and fish farms) are a serious threat to numerous tropical and subtropical coastal areas. By maintaining these cultures in shallow ponds which do not conform to the animals' needs, large amounts of antibiotics are often needed to protect them from infections. In order for the animals to grow quickly, more food is given than necessary. Antibiotics, excrements and surplus food are all diverted in unpurified form directly into the ocean. Depending on the current, a large section covering many square kilometers of coastline are thus also poisoned each year.
The year 2002 saw the clearing of 765,500 hectares of mangrove forests worldwide for aquacultures, 639,000 alone solely for shrimp farms.