This year’s Whale Shark season in Kota Kinabalu has passed with no credible sightings, which leads us to wonder why?
Every year from February to April the waters surrounding the north western coast of Borneo become cooler with temperatures dropping as low as 24 degrees at diving depths. At the same time, Krill begin to appear along with their predator the Whale Shark Rhincodon typus – the only representative of the Rhincodontidae family.
Although the Whale Shark is the largest fish in the ocean, migration patterns are still poorly understood and their absence this season could be attributed to a number of occurrences. For one, last years giant visitors were harassed and injured by locals and tourists, one young male was hit by a boat propeller.
Overfishing and ocean pollution is a rising and constant threat to all marine life within the food chain and will no doubt put pressure on already small numbers of Shark visitors to the region. Unknown to most, fish bombing continues in the surrounding waters of Sabah, although an illegal practice law enforcement appears to be weak in this area and we often hear bombs exploding whilst diving.
This years El Nino could also be a factor, studies at the Australian Institute of Marine Science in Townsville indicate that in strong El Nino years Krill numbers are lower, whereas during La Nina years krill abundance proved to be much higher. So perhaps the El Nino phenomenon somehow negatively affects the whale sharks’ food supply in certain areas, thus less or in our case none are seen.
At Ningaloo reef in Western Australia the Department of Fisheries and Calm have developed strict guidelines for human interaction with Whale Sharks. Perhaps in positive anticipation of them returning next year the local authorities of Sabah should introduce a similar enforcement. For more information on these guidelines please click here.
For more information on Whale Sharks please visit our Marine Biology Sharks section.