Posts Tagged Krill
My family and I have just returned from a fantastic trip to the Philippines. While the scuba diving was superb everyone’s highlight was the 30 minutes we spent swimming with whale sharks. Whale sharks are the world’s largest fish. They can grow up to 40 feet long and weigh as much as 20 tons. Despite these impressive statistics they pose no danger to humans, being filter feeders that consume things like plankton, krill and fish eggs.
The small town of Oslob, on the island of Cebu, is where our amazing interaction took place (http://www.oslobwhalesharks.com). Whale sharks used to be regarded as pests, and were even killed by locals, as their presence interfered with their fishing activities. This has now changed with these massive fish pumping significant ecotourism dollars into the local economy. However, in order to ensure that the steady stream of tourists has something to snorkel with, the locals have begun feeding krill to the whale sharks. At this point the activity is regulated so that feeding and swimming only occur between 6 am and midday.
Ordinarily I am completely against the feeding of wildlife but, in this case, I might have to make an exception. One criticism that has been levelled at the activity is that it changes the whale shark’s behaviour inducing them to stay for the free food, instead of foraging far and wide, as they normally would. Up to 50 whale sharks have been identified by local researchers, but there were only three swimming about while we were there. A whale shark consumes between 0.5 and 3.0% of its bodyweight every two to three days. An adult whale shark needs to eat about 400 kg to fill its massive stomach (http://wiki.answers.com/Q/How_much_do_whale_sharks_eat). The ones we interacted with were possibly half grown, which still translates into 200 kg of food. I cannot see it being economically viable or physically possible to tip this much krill down their throats, which means that the whale sharks still need to forage to satiate themselves, and possibly come in for a free feed when they feel like a top up. The fact that the water was not boiling with whale sharks would seem to bear this out.
Unlike the junk food that is put out in bird feeders whale sharks are at least fed a natural diet, so there should hopefully not be any nutritional issues.
A recent Australian study found that tourism had no negative effects on the whale sharks’ behaviour (http://au.news.yahoo.com/thewest/a/-/breaking/15561889/whale-shark-tourism-harmless-report). Admittedly these whale sharks were not being fed.
However, if the alternative to feeding and ecotourism is spearing, then it is difficult not to endorse the current activities which, at the moment, appear to be reasonably well regulated. When I say we interacted with the whale sharks this is not strictly true as they appeared to completely ignore us, swimming where they wanted, and doing what they wanted when they wanted, as is your prerogative when you weigh several tons.
The locals’ view of whale sharks has certainly changed since this tourism venture began in December 2011. This is probably motivated more by self-interest than any inherent concern for the whale sharks or their conservation. It has certainly become very trendy for zoos in particular to promote their animal encounters as a way of encouraging conservation. An interaction with a whale shark (or koala, or gorilla, or seal) will make people more likely to care about their conservation, or so the rhetoric goes. But does it? Is there any real evidence to support the statement that animal interactions foster greater conservation outcomes? Or are the people who seek animal interactions more likely to join conservation organisations, donate money and plant trees anyway? I suspect the latter is more likely to be the case.
The fact that we are prepared to spend a considerable amount of money to swim with a large fish (or cuddle a koala, or see a gorilla, or kiss a seal) shows how isolated from the natural world we have become, and how we still see nature as entertainment, instead of a vital part of our existence. Not that I am any different because I got just as much of a buzz from my up close and personal experience as everyone else did.
Dr. F. Bunny