Science Questions

Do warmer waters attract more sharks?

I am a high school student who is currently doing some research on sharks and their connection to global warming. Is there any more data available that could further support the theory that warmer waters are bringing sharks into certain areas? Have there been any reports about how humans and other species are being affected by these shark movements? John Yuen

Helen -   I believe that question came from someone who’s been reading our website - there’s a fantastic article there by Bruce Wright from October 2005 about how there are more sharks appearing in inland waters in Alaska.  That’s one particular case that seems to be going on.  On a global scale, last year in fact, there were lots of news stories about shark attacks on the rise being linked to global warming, but really there was no proper science backing that up.  First of all – is there really an increase in shark attacks?  Well, maybe, but not necessarily for any other reason than there’s more people in the water and they were reporting more shark attacks.  There are only 50 to 100 attacks every year but when there’s a peak that occurs, perhaps over the course of a month or two, people get very excited and think “Oh gosh! Something must be going on!”

Yes, sharks do respond to temperature, there are various ways that can affect them and  warming seas are likely to affect sharks.  A recent study has suggested that the Antarctic could become infested with sharks.  There haven’t been any sharks there for 40 million years but as it’s warming up they could start moving back in there.  That could really affect the ecosystems in those areas.  So yes, sharks are affected by warming seas in ways that we’re just starting to understand.

February 2010