Great White shark Lydia continues crossing the mid-Atlantic. First caught and tagged with a tracking device off the coast of Jacksonville, Florida, in March 2013 a great white shark nicknamed Lydia has traveled more than half way across the Atlantic. Her last satellite check-in had her 745 miles off the Irish coast. It is unclear if the 14 foot fish will continue swimming toward Ireland or change direction.
Heidi Dewar, a National Marine Fishery Service biologist from La Jolla, CA has theorized that other great white sharks may have made similar journeys. Lydia was the first tracked by researchers. The tracking of such a predator has help researchers understand the migration patterns of great white sharks and can demonstrate how the fish interacts with other species.
Based on Lydia’s travel patterns, researchers have learned that the North Atlantic Ocean is not too cold to support her. The Great White Shark Lydia has meandered up the U.S. East Coast to Nova Scotia, Canada following a rich chain of aquatic life that includes sea lions before turning east for Europe.
To date, Lydia has swum more than 19,400 miles. The previous Great White shark record holder was a female who crossed the Indian Ocean twice in 2004 and swam 12,427 miles before her tracking stopped.
Great White shark Lydia continues crossing the mid-Atlantic with the data indicating her she did not dive deep down into the ocean’s depths during her journey. Instead, she swam closer to the surface making researchers wonder if such behavior was normal. Her senses can perceive magnetic anomalies that may have kept her closer to the surface. She could have also hunted various schools of fish that traversed the area.
Greg Skomal, a Massachusetts Marine Fisheries researcher who tagged Lydia, thinks people are only now starting to learn about the great white sharks. Until recent advances in technology, tracking a predator such as Lydia was not possible. Previous archival tags attached to sharks stored information until they detached from the fish and could be later retrieved by researchers. Now, whenever Lydia’s dorsal fin rises above the ocean surface, her tag transmits data such as her location and how deep she has swam to a satellite.
Lydia is one of the few female great white sharks to be tagged. She is thought to be in her early twenties and may be pregnant. If she enters the Mediterranean, she may swim to a known shark birthing area near Turkey. Researchers will certainly take note. It has long been thought there are distinct populations of great white sharks around the world. The current theory is that a shark such as Lydia travels a typical pattern. She will give birth and then trek great distances foraging for two years before migrating back to where she started.
The goal is to attach more tracking devices to Great White sharks such as Lydia to gather preliminary information on their travel habits. Until researchers understand how a shark like Lydia traverses the oceans, it will be difficult to develop conservation policies to protect them. Great White shark Lydia continues crossing the mid-Atlantic making her the current record holder for her species.
By Brian T. Yates