WHALE SHARKS

The whale shark is the largest living shark. It is one of the three filter-feeding species of shark, with a broad, flattened head and minute teeth. It also has a distinctive patterning of light spots and stripes over a dark background, fading to a light colour on the underside. This natural camouflage allows it to ‘blend’ into its surroundings when viewed from any angle.

It is believed to sieve zooplankton as small as 1mm in diameter through the fine mesh of their gill-rakers. However, unlike the megamouth and basking sharks, the whale shark does not rely on forward motion but can hang vertically in the water and ‘suck’ food.

Whale sharks are found in all tropical and warm temperate seas except the Mediterranean, with a range typically between latitudes 30°N and 35°S. They are known to inhabit both deep and shallow coastal waters and the lagoons of coral atolls and reefs, frequently in surface sea-water between 21 and 25°C.

They regularly visit Gladden Spit in Belize from February to May.

After feeding on cubera and dog snapper spawn at Gladden Spit, several miles north of The Silk Cayes, it was found that sharks dispersed throughout the Belize Barrier Reef with directed movements of over 550 km recorded to the tip of the Yucatan Peninsula and east of the Bay Islands in Honduras.

Rachel Graham, who was studying the whale shark in Belize writes that the "patterns of whale shark movement and feeding behaviour indicated that the marine reserve boundaries encompassed the main spawning aggregation and whale shark feeding zones."

"Increased visitor and boat numbers to the marine reserve coincided with alterations in the spawning behaviour of aggregating snappers and consequently the visitation of whale sharks at Gladden Spit. Strong management directives and enforcement are needed at the marine reserve to check unregulated growth of tourism and thus minimize its impacts on the fish spawning aggregations and visiting whale sharks."

She is entirely right. During my years of leading groups to Gladden Spit, there were occasions where there were so many boats in the area diving and fishing at the same time that there was a real danger to visitors being snagged by a fishing line or simply getting confused and losing their dive group.

The efforts of people like Rachel Graham will be the deciding point for places like Gladden Spit. Read more on her research here.