Quantcast
Environmental News for a Healthier Planet and Life

Help Support EcoWatch

Longest Recorded Whale Shark Migration

Animals
Whale shark at the Georgia Aquarium. Zac Wolf / Wikimedia Commons / CC BY-SA 2.5

A team of scientists has tracked a whale shark (Rhincodon typus) across more than 20,000 kilometers (over 12,000 miles) of ocean, the longest migration ever recorded for the species.

In 2011, the researchers attached a transmitting tag to a shark they named "Anne" in the Pacific Ocean near Panama's Coiba Island. Over the next 841 days, Anne's transmitter would ping the ARGOS satellite whenever she swam near the surface. Those data points allowed the team to follow her movements south to the Galapagos Islands and clear across the Pacific to the Marianas Trench south of Japan and east of the Philippines—a distance of 20,142 kilometers (12,516 miles).


They reported their findings in the journal Marine Biodiversity Records in April.

The discovery solidifies the whale shark's place among the ocean's most widely traveled creatures, alongside leatherback sea turtles, gray whales and Arctic terns. Another whale shark tagged in 1995 held the previous record for the species with a 13,000-kilometer (8,100-mile) swim in 37 months.

But beyond knowing that they're capable of swimming vast distances–females can cover 67 kilometers (42 miles) in a single day—there's still a lot to learn about whale sharks.

"When I first began working on them, their taxonomy was debated, and it still wasn't clear how they reproduced," study co-author and biologist Scott Eckert of Principia College in Illinois said in a statement. "Despite being the world's largest fish, it's amazing to me how little we know about this species."

A whale shark swimming in the Philippines James Heilman, MD / Wikimedia Commons / CC BY-SA 4.0

Part of the reason for those gaps in our knowledge is that whale sharks' movements are difficult to track. In the course of this research, the scientists had to contend with a 235-day period during which they received no transmissions from Anne's tag. She had likely dived too deep—whale sharks can plunge to depths of almost two kilometers, or more than a mile—for the tag to communicate with the satellite.

The team hopes that plotting out the course Anne and other whale sharks take will help to understand what motivates them.

"We have very little information about why whale sharks migrate," Héctor M. Guzmán, a marine biologist at the Smithsonian Tropical Research Institute and the study's lead author, said in the statement. "Are they searching for food, seeking breeding opportunities or driven by some other impulse?"

Evidence has surfaced in previous studies showing that even whale sharks living thousands of kilometers away from each other are still pretty closely related, so reproduction probably has something to do with these long-distance treks.

A more nuanced understanding of their behavior could also help scientists, conservationists and policymakers try to navigate the challenge of protecting such a cosmopolitan animal, especially with all of the threats that whale sharks face. They can ingest plastic as they siphon plankton from the water column, and fishing boats target them for their fins, cartilage and meat.

Even the tourist boats that bring swimmers and divers who want to share the current with a fish that grows as long as 12 meters (40 feet) and weighs up to 19,000 kilograms (21 tons) could be posing problems. Guzmán said researchers have found that the whale sharks around Coiba Island try to stay away from people.

In 2016, the IUCN listed the species as endangered for the first time. And biologists figure that the world's tropical and subtropical seas hold fewer than half the number of whale sharks that they did 75 years ago, increasing the urgency for their protection.

"These studies are critical as we design international policy to protect transboundary species like the whale sharks and other highly migratory marine species," Guzmán said.

Reposted with permission from our media associate Mongabay.

EcoWatch Daily Newsletter

A protest against the name of the Washington Redskins in Minneapolis, Minnesota on Nov. 2, 2014. Fibonacci Blue / CC BY 2.0

The Washington Redskins will retire their controversial name and logo, the National Football League (NFL) team announced Monday.

Read More Show Less
The survival tools northern fish have used for millennia could be a disadvantage as environmental conditions warm and more fast-paced species move in. Istvan Banyai / Wikimedia Commons / CC by 3.0

By Alyssa Murdoch, Chrystal Mantyka-Pringle and Sapna Sharma

Summer has finally arrived in the northern reaches of Canada and Alaska, liberating hundreds of thousands of northern stream fish from their wintering habitats.

Read More Show Less
A mother walks her children through a fountain on a warm summer day on July 12, 2020 in Hoboken, New Jersey. Gary Hershorn / Getty Images

A heat wave that set in over the South and Southwest left much of the U.S. blanketed in record-breaking triple digit temperatures over the weekend. The widespread and intense heat wave will last for weeks, making the magnitude and duration of its heat impressive, according to The Washington Post.

Read More Show Less
If you get a call from a number you don't recognize, don't hit decline — it might be a contact tracer calling to let you know that someone you've been near has tested positive for the coronavirus. blackCAT / Getty Images

By Joni Sweet

If you get a call from a number you don't recognize, don't hit decline — it might be a contact tracer calling to let you know that someone you've been near has tested positive for the coronavirus.

Read More Show Less
Aerial view of burnt areas of the Amazon rainforest, near Porto Velho, Rondonia state, Brazil, on Aug. 24, 2019. CARLOS FABAL / AFP via Getty Images

NASA scientists say that warmer than average surface sea temperatures in the North Atlantic raise the concern for a more active hurricane season, as well as for wildfires in the Amazon thousands of miles away, according to Newsweek.

Read More Show Less
A baby receives limited treatment at a hospital in Yemen on June 27, 2020. Mohammed Hamoud / Anadolu Agency / Getty Images

By Andrea Germanos

Oxfam International warned Thursday that up to 12,000 people could die each day by the end of the year as a result of hunger linked to the coronavirus pandemic—a daily death toll surpassing the daily mortality rate from Covid-19 itself.

Read More Show Less

Trending

The 2006 oil spill was the largest incident in Philippine history and damaged 1,600 acres of mangrove forests. Shubert Ciencia / Flickr / CC BY 2.0

By Jun N. Aguirre

An oil spill on July 3 threatens a mangrove forest on the Philippine island of Guimaras, an area only just recovering from the country's largest spill in 2006.

Read More Show Less