The American Elasmobranch Society is a non-profit professional society focusing on the scientific study and conservation of sharks, skates, and rays. AES members meet each year in a different North American city, and this meeting is the world’s largest annual gathering of shark scientists. AES recently met in Vancouver, British Columbia for the 2012 meeting, and for the first time the event was live-tweeted by meeting attendees, including myself. I’ve organized the best conference tweets by session using Storify. If anyone has any questions or comments about the research presented below, please feel free to share it in the comments section of this blog post.
Here are selected tweets from the Deepwater Chondrichthyans Symposium.
Continue reading Tweets from the American Elasmobranch Society: Deepwater Chondrichthyans Symposium
Photo credit: study author Pascal Geraghty, New South Wales Department of Primary Industry
Last week, a team of 10 Australian scientists announced that they had found the world’s first “shark hybrids”, offspring of individuals from two different shark species which had interbred. During a routine survey of Australian marine life, 57 sharks were found that physically resembled one species of shark, but had genetic markers inconsistent with that species. Subsequent genetic investigation revealed that these 57 animals were hybrids between common blacktip sharks (Carcharhinus limbatus) and Australian blacktip sharks (C. tilstoni).
Some of these hybrids were “F1″, meaning that one parents was a common blacktip and one was an Australian blacktip. Others were “B+”(backcrossed), which means that one parent was a common blacktip/Australian blacktip hybrid, and the other was a “purebreed” of one of those two species. According to the study’s lead author, Dr. Jess Morgan of the University of Queensland, ”our genetic marker tells us that these hybrids are ‘at least’ F1, and that these animals are reproductively viable and can produce an F2…the hybrids may be generations past F2 but the existing genetic markers can’t distinguish how many generations past the second cross have occurred.”
Continue reading What hybrid sharks mean (and don’t mean) for climate change and evolution: fact-checking the media coverage
“There are known knowns; there are things we know we know. We also know there are known unknowns, that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don’t know we don’t know.” – Former U.S. Secretary of Defense Donald Rumsfeld.
As nature documentary viewers often hear, there is a lot about sharks and rays that scientists don’t know… but what are the most important things that we need to know? A new paper written by Colin Simpfendorfer, Will White, and former Shark Science Monday interview subjects Michelle Heupel and Nick Dulvy attempts to identify these “known unknowns” of shark and ray conservation. “The importance of research and public opinion to conservation management of sharks and rays: a synthesis”, which arose out of the 2010 Sharks International conference, is the most complete record ever created of the research questions that we need to answer in order to better conserve and manage these animals. For young shark researchers eager to work on projects with practical conservation importance, this paper is a great place to start looking for ideas. Additionally, future published work that claims to be important for conservation and management would do well to cite it, and anyone interested in this subject should read it.
Continue reading Shark Science Monday: the Known Unknowns of Shark Conservation