A monumental shark survey is about to get underway on ocean floors across the globe. Researchers are deploying baited cameras at several hundred underwater locations in order to more accurately tally global shark populations.

Marine predators are on the decline around the world. Some estimates suggest more than 100 million sharks are caught and killed every year. As a number of studies suggest, the loss of top predators can have significant impacts on ocean food chains.

To better understand these worrisome declines, researchers need more accurate data on regional and localized population numbers. Data gaps are particularly glaring in the waters of the Indo-Pacific, tropical western Atlantic, and southern and eastern Africa and Indian Ocean islands.

As part of an international research effort called Global FinPrint, scientists are preparing to use baited remote underwater video to better estimate shark and ray numbers in waters within the data gap regions. The deployed cameras will attract sharks via caged bait over a brief period of time before being retrieved and redeployed in a new location.

As the project's website explains: "Rather than trying to catch sharks to measure their abundance, a new method allows researchers to have the sharks catch themselves -- on camera."

As mentioned, most shark-counting research efforts involve either catching and tagging, or using the number of sharks accidentally caught on fishing lines to estimate totals. These methods are often inaccurate and sporadic. The forthcoming survey will be comprehensive and systematic.

The effort is being led by Demian Chapman of Stony Brook University in New York. It will include input from researchers and marine biologists from all over the world.

"Global FinPrint will help us better understand one of the ocean's great mysteries: What is happening with fragile marine ecosystems when sharks are removed?" Chapman asked in a press release. "Are coral reefs healthier or faster to recover from disturbances like coral bleaching or hurricanes because they have sharks?"

"These are hugely important questions," Chapman concluded. "Many countries rely on healthy coral reefs for food security, tourism and coastal protection."