Some sharks return to the same sites to breed for decades

Dec 15, 2022, 6:01 PM | Updated: Dec 16, 2022, 8:57 am
In this photo provided by Connor F. White, scientists Wes Pratt, left, and Nick Whitney, measure an...

In this photo provided by Connor F. White, scientists Wes Pratt, left, and Nick Whitney, measure an adult nurse shark on the nurse shark courtship and mating ground in the Dry Tortugas, Fla., on June 24, 2022. Scientists say some species of shark return to the same breeding grounds for decades at a time, and live longer than previously thought. (Connor F. White via AP)

(Connor F. White via AP)

Some species of shark return to the same breeding grounds for decades at a time, and live longer than previously thought, scientists studying the animals off Florida say.

Scientists with the New England Aquarium found that nurse sharks returned to the waters off the Dry Tortugas, 70 miles (113 kilometers) from Key West, to mate for up to 28 years. They also found that the sharks’ life span appears to extend at least into their 40s, rather than about 24 years as previously believed.

The researchers published their findings in October in the journal PLOS ONE as part of the world’s longest running study of shark mating behavior. The research sheds new light on the way sharks breed and the role their environments play in their reproduction, said Nick Whitney, a senior scientist with the aquarium and a co-author of the study.

“This is the first example that has shown long-term use of a mating ground,” Whitney said. “To observe natural shark behavior in the wild is incredibly rare to begin with and to observe mating behavior is really unusual.”

Scientists have known nurse sharks have used the waters off the Tortugas as a breeding ground since at least the late 19th century, but the question of whether the sharks returned to the area lingered. The researchers with the aquarium tagged 118 sharks from 1993 to 2014 and found that more than two-thirds returned to the breeding grounds in subsequent mating seasons.

The scientists wrote that this evidence of long-term fidelity to one site “reveals the importance of identifying and protecting mating sites for this and other” species.

Members of the research team said they did not guess the same animals would continue mating at the site for years at a time. Of all the sharks returning to the site, nearly 60% were monitored for more than 10 years and 13% were monitored for more than 20 years.

David Shiffman, a marine biologist at Arizona State University who was not involved in the study, said the work could open up new perspectives on sharks and how they migrate and make use of habitat.

That could be a key to helping conserve them, he said.

“Some of the better-known shark species are highly migratory, regularly crossing oceans. So to learn that other species are homebodies that use the exact same habitat year after year is fascinating,” Shiffman said.

The Dry Tortugas is a remote group of islands in the Gulf of Mexico that is beloved by divers and birdwatchers. The area’s status as a breeding ground for nurse sharks could be jeopardized by a direct hit it suffered during Hurricane Ian in September, Whitney said.

The scientists have not yet been able to find out if their underwater monitoring stations held up through the storm, they said. They also don’t yet know if sharks have come back. Female sharks come into the shallows in the area to get ready to give birth in September and October, said Ryan Knotek, an associate scientist with the aquarium and study co-author.

The site’s vulnerability is a good reason to protect both the sharks and their breeding grounds, Whitney said.

“These sharks clearly have a strong interest to return to this state,” he said. “This was a shark that was once thought to be a sedentary couch potato of a shark. It turns out they are much more active.”

Copyright © The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.


Associated Press

TV anchors T.J. Holmes, Amy Robach leave ABC amid romance

NEW YORK (AP) — T.J. Holmes and Amy Robach, anchors at the afternoon extension of ABC’s “Good Morning America,” are leaving the network after their romance was reported in November. The pair were taken off the air and placed on temporary hiatus after photos surfaced of them holding hands and spending time together. Both were […]
2 days ago
From left, Sweden's Defense Minister Pal Jonson, Prime Minister Ulf Kristersson and Foreign Ministe...
Associated Press

Finnish, Swedish FMs: NATO membership process hasn’t stopped

HELSINKI (AP) — The foreign ministers of Sweden and Finland reiterated in separate interviews published Saturday that the process for the two Nordic nations to join NATO is continuing despite Turkey’s president saying Sweden shouldn’t expect his country to approve its membership. Swedish Foreign Minister Tobias Billström acknowledged in an interview with Swedish newspaper Expressen […]
2 days ago
Associated Press

Gregory Allen Howard who wrote ‘Remember the Titans’ dies

NEW YORK (AP) — Screenwriter Gregory Allen Howard, who skillfully adapted stories of historical Black figures in “Remember the Titans” starring Denzel Washington, “Ali” with Will Smith and “Harriet” with Cynthia Erivo, has died. He was 70. Howard died Friday at his home in Miami after a brief illness, according to a statement from publicist […]
2 days ago
Associated Press

Delaware Gov. John Carney tests positive for COVID-19

WILMINGTON, Del. (AP) — Delaware Gov. John Carney has tested positive for COVID-19, the governor’s office announced on Saturday. Carney tested positive late Friday using an at-home antigen test after experiencing mild symptoms, according to a news release. Carney, 66, said he’s “feeling fine” and is isolating himself — following U.S. Centers for Disease Control […]
2 days ago
Associated Press

Man accused in substation vandalism is released from custody

TACOMA, Wash. (AP) — One of the two men charged with vandalizing electrical substations in Washington state over the holidays to cover a burglary was ordered released from federal custody Friday to seek substance abuse help. A federal judge issued the order for Matthew Greenwood, 32, after renewed efforts by his attorney to get Greenwood […]
2 days ago
Associated Press

Dismissal of lawsuit over Columbus Day name change upheld

PHILADELPHIA (AP) — A federal appeals court has upheld a lower court’s dismissal of a lawsuit alleging that the mayor of Philadelphia discriminated against Italian Americans in renaming the city’s Columbus Day holiday to Indigenous Peoples’ Day. A U.S. District judge ruled a year ago that the plaintiffs, a council member and three Italian American […]
2 days ago

Sponsored Articles

safety from crime...

As crime increases, our safety measures must too

It's easy to be accused of fearmongering regarding crime, but Seattle residents might have good reason to be concerned for their safety.
Comcast Ready for Business Fund...
Ilona Lohrey | President and CEO, GSBA

GSBA is closing the disparity gap with Ready for Business Fund

GSBA, Comcast, and other partners are working to address disparities in access to financial resources with the Ready for Business fund.

Medicare open enrollment is here and SHIBA can help!

The SHIBA program – part of the Office of the Insurance Commissioner – is ready to help with your Medicare open enrollment decisions.
Lake Washington Windows...

Choosing Best Windows for Your Home

Lake Washington Windows and Doors is a local window dealer offering the exclusive Leak Armor installation.
Anacortes Christmas Tree...

Come one, come all! Food, Drink, and Coastal Christmas – Anacortes has it all!

Come celebrate Anacortes’ 11th annual Bier on the Pier! Bier on the Pier takes place on October 7th and 8th and features local ciders, food trucks and live music - not to mention the beautiful views of the Guemes Channel and backdrop of downtown Anacortes.
Swedish Cyberknife Treatment...

The revolutionary treatment of Swedish CyberKnife provides better quality of life for majority of patients

There are a wide variety of treatments options available for men with prostate cancer. One of the most technologically advanced treatment options in the Pacific Northwest is Stereotactic Body Radiation Therapy using the CyberKnife platform at Swedish Medical Center.
Some sharks return to the same sites to breed for decades