About Whale Sharks
Habits
Whale sharks are fish,and therefore they have no obvious physiological requirement to swim at the surface (i.e. to breathe
air) even though they are most often observed there during ‘seasonal’ aggregations. Tracking studies indicate that whale sharks can dive to great depths (>1500m). They can remain away from the surface for long periods and this makes their movements
difficult to study.
Feeding
Whale sharks generally feed on very small planktonic prey (e.g. krill, copepods, small fish etc.)that they ‘filter ’ from the water using the fine mesh of their gill-rakers. Whale sharks are often found in areas where large concentrations of this food source are found.
The predictable annual whale shark aggregation at Ningaloo Marine Park is closely linked with an increase in productivity of the region associated with the mass coral spawn around March/ April each year. Similarly, their appearance at Christmas Island appears linked to the red crab spawns in December/January.
Migration
Whale sharks are regarded as highly migratory -although their migration patterns are poorly understood. Research at Ningaloo Marine Park suggests that some sharks undertake a northerly migration when leaving the area. Limited satellite tracking data combined with their seasonal appearance at Christmas Island provides support for this theory.
Satellite tracking of whale sharks in US waters and also in the South China Sea have revealed that whale sharks can travel great distances (1,000s of kilometres). These migrations may take years to complete. A far greater understanding of whale shark movements will be possible with global ‘photo-tagging ’ via the ECOCEAN Library in combination with limited satellite tracking studies throughout the world.
As a giant filter-feeder,reliant upon large quantities of food from seasonal ‘food pulses ’,the whale shark is potentially susceptible to declines in productivity at its feeding locations. It is therefore essential that migratory paths are confirmed and we more fully understand which whale shark sighting locations are critical to their survival.
Dangerous?
Whale sharks are filter-feeders and pose no immediate threat to humans.Whale sharks are very large and powerful animals and should be treated with the utmost respect.Their tail in particular has the potential to harm. (taking from EcoOcean Brochure - so see full brochure click here)
