Whales are the earth's largest creatures, yet they are incredibly hard to study in the open ocean. For decades scientists have used boats, aircraft and even high cliffs to conduct visual surveys and gather data on whale and dolphin populations. Today, these live surveys form the basis of our knowledge of these marine mammalswhat species live where in the world, which ones tend to live together and how abundantly they are represented.
Now, recent work by paleobiologist Nick Pyenson of the Smithsonian's National Museum of Natural History, has revealed a second, equally valuable resource for information on cetaceansthe record of dead whales and dolphins stranded and washed ashore on beaches around the world
"Some 30 years ago scientists got serious about the conservation of cetaceans, and began keeping records of strandings," Pyenson says. Stranding networks were set up around the world and informationsuch as species type, sex, age, size, cause of deathhave been carefully collected, recorded and archived.
By compiling and comparing long-term data from stranding records and visual sighting records, both taken from nearly every ocean basin in the world, Pyenson verified that stranding records "faithfully reflect the number of species and the relative abundance" found in live surveys.
In fact, Pyenson says, the stranding data in many parts of the world "almost always provides better diversity information about existing cetacean communities than the live surveys. A lot of rare species show up in stranding records that never appear in the live surveys," Pyenson adds.
The stranding record also faithfully reflects the structure of cetacean communities. "There is a strong and significant correlation in relative abundance of species at nearly all taxonomic levels in both the live data and the stranding data."
Pyenson's study, which he refers to as "spreadsheet taphonomy," is the first time the cetacean stranding recor
|Contact: John Gibbons|