Students planning to spend their winter break on the Oregon coast should keep a lookout for some shark species with unexpectedly long lifespans swimming near the beach.
New research suggests that sharks can live much longer than scientists originally believed. Four shark species analyzed in a recent study published in the journal “Fish and Fisheries” (Great White, Common Thresher, Soupfin and Tiger) often swim in Oregon’s coastal waters.
But don’t worry, the odds of becoming a shark attack victim are minuscule. There have only been 29 shark attacks off the Oregon coast since 1974, and only one has been fatal.
Earlier this month, the Tillamook County Sheriff’s office issued a warning to swimmers, surfers and fishermen, which said that multiple people reported seeing several large sharks near Cape Kiwanda, about 50 miles northwest of Salem. There were also multiple shark sightings off Cannon Beach last July.
While shark sightings can instill fear in Oregon beachgoers, the intrigue surrounding sharks has escalated in recent years, as scientists begin to understand their lifespans more accurately. Last year, researchers in Denmark determined that the Greenland shark — a species that can grow as large as a Great White shark — can live at least 272 years. The study also found that they don’t reproduce until they’re about 150-years-old.
“We had an expectation that they would be very long-lived animals, but I was surprised that they turned out to be as old as they did,” the leader of the Greenland shark study, Julius Nielsen, told National Geographic magazine.
The old method of determining the age of a shark relied on researchers counting calcified growth bands on a shark’s vertebrae. In many cases, counting a band is up to the judgment of the researcher, which has led to counting discrepancies between scientists looking at the same bands.
The new method of determining a shark’s age is based on radioisotope dating from carbon released into the atmosphere by nuclear bomb tests in the 1950s and 60s. This method is much more accurate, and it has substantial implications for how people research and treat sharks in the wild.
Shark conservation decisions are largely based on the lifespan of sharks. And although no shark species are currently listed as “endangered” under the Endangered Species Act, many species are vulnerable to becoming endangered as a result of overfishing and human ecological impact.
According to the National Oceanic and Atmospheric Administration, data about sharks’ lifespans can inform scientists about their ecological role, feeding habits and reproductive tendencies. This information is crucial to improving regulations intended to ensure sustainable shark populations for years to come. Further shark research like these studies will better inform about how to address their declining numbers in the future.