Eurekalert has good news from the southeastern Atlantic. Shark populations are getting back to where they should be for a healthy ocean:
Scientists estimate that over-fishing of sharks along the southeast U.S. coast–which began in earnest following the release of Jaws in 1975 and continued through the 1980s–had reduced populations by 60-99% compared to un-fished levels. In response, NOAA’s National Marine Fishery Service in 1993 enacted a management plan for shark fisheries that limited both commercial and recreational landings.
Now, says lead scientist Cassidy Peterson, a graduate student at William & Mary’s Virginia Institute of Marine Science, “We’ve shown that after over two decades of management measures, coastal shark populations are finally starting to recover and reclaim their position as top predators, or regulators of their ecosystem. Our research suggests we can begin to shift away from the era of ‘doom and gloom’ regarding shark status in the United States.”
The researchers say their study–based on modeling of combined data from six different scientific surveys conducted along the US East Coast and in the Gulf of Mexico between 1975 and 2014–provides a more accurate and optimistic outlook than previous studies based on commercial fishery landings or surveys in a single location.
For the current study, the scientists combined data from six different shark surveys: the VIMS Longline Survey, the SouthEast Area Monitoring and Assessment Program’s South Atlantic Coastal Trawl Survey, the South Carolina Coastal Longline Survey, the Georgia Red Drum Longline Survey, the Southeast Fisheries Science Center’s Longline Survey, and the Gulf of Mexico Shark Pupping and Nursery Area Gillnet Survey.
“Our study represents the most comprehensive analysis of patterns in abundance ever conducted for shark species common to our area and the Southeast coast,” says Latour, who directs the longline survey at VIMS. Established in 1973, it is the world’s longest running fishery independent monitoring program for sharks, skates, and rays.
By pooling and modeling data from all six surveys, the researchers were able to estimate population trends for seven of the region’s most common coastal species: the large-bodied sandbar, blacktip, spinner, and tiger sharks, and the smaller Atlantic sharpnose, blacknose, and bonnethead sharks.
The results of the analysis were clear, says Peterson. “All the large-bodied sharks showed similar population trends, with decreasing abundance from the mid-1970s to the early 1990s, then a multi-year period of low abundance, and recent indications of recovery from past exploitation.”
[via Mr. Highfield]