The largest living fish, whale sharks, may increasingly be using volcanic islands off the western coast of Europe as a new home as sea surface temperatures rise, researchers say. 
 
 This finding could shed light on how climate change might alter the behavior of fish globally, the scientists added. 
 
 The whale shark is a titan, known to reach up to 41.5 feet (12.65 meters) in length and 47,000 lbs. (21,500 kilograms) in weight, and some anecdotes suggest they can get even larger. Unlike predators such as great white sharks, whale sharks are gentle giants, using rows of their tiny teeth as a filter to strain out tiny creatures in the water for meals, just like the largest whales do. 
 
 "Whale sharks are the largest living fish, yet they are also very elusive," said lead study author Pedro Afonso, a marine and fisheries ecologist at the University of the Azores. 
 
 Whale sharks prefer warm tropical waters that are 79 to 86 degrees Fahrenheit (26.5 to 30 degrees Celsius). However, in recent years, fishermen have increasingly sighted these giant fish around the Azores Islands, nine volcanic isles in the central North Atlantic west of Portugal. These islands lie along the colder northern edge of the waters that whale sharks historically have preferred. [Image Gallery: Mysterious Lives of Whale Sharks] 
 
 To better understand why these gargantuan fish appear more often around the Azores, the scientists analyzed data on whale shark sightings gathered over 16 years, from 1998 to 2013, by observers on tuna fishing boats. Fishermen in the Azores have long detected tuna by looking for whale sharks, locally known as 'pintados' — Portuguese for "spotted," referring to the sharks' spotted skin. 
 
 "They know that a whale shark will almost always carry a school of tuna underneath it," Afonso told Live Science. (It remains a mystery as to why tuna accompany whale sharks, he added.) 
 
 Afonso noted "there was no way we would get to know anything about whale shark occurrences" without observers on these tuna fishing boats. The area in which the whale sharks are seen around the Azores "is 1 million square kilometers [386,000 square miles], easy," Afonso said. 
 
 The researchers used computer models to investigate the patterns of whale shark sightings over time and space, in relation to factors such as food, sea surface temperatures and seafloor features. The scientists found a sharp rise in whale shark sightings in the exceptionally warm year of 2008, and the giant fish became regular visitors to the region afterward. 
 
 The scientists also found that sea surface temperatures helped predict whale shark sightings. For example, higher water temperatures around the southernmost Azores Island of Santa Maria were associated with more sightings of the fish. Observers also spotted the sharks more often in areas with underwater hills and mountains; these seafloor features coincide with large amounts of photosynthetic organisms that feed the creatures that the whale sharks eat. 
 
 These findings are a window into what might happen as climate changes globally, the scientists said. "Large marine animals such as the whale shark can change their oceanic distributions depending on regional conditions," Afonso said. 
 
 Future research could investigate why whale sharks remain in this area during the summer. "Is it only the food around the seamounts, or something else — maybe the presence of other whale sharks to mate with?" Afonso said. 
 
 Afonso and his colleagues Niall McGinty and Miguel Machete detailed their findings online today (July 16) in the journal PLOS ONE. 
 
 Follow us @livescience, Facebook & Google+. Original article on Live Science. ||||| FILE — In this Sept. 13, 2012 file photo, Massachusetts shark expert Greg Skomal pulls the cap off a blood sample taken from an Atlantic great white shark before performing blood gas analysis moments... (Associated Press) 
 
 FILE — In this Sept. 13, 2012 file photo, Massachusetts shark expert Greg Skomal pulls the cap off a blood sample taken from an Atlantic great white shark before performing blood gas analysis moments after the nearly 15-foot, 2,292-pound shark was released from the research vessel Ocearch off the coast... (Associated Press) 
 
 BOSTON (AP) — The movements of great white sharks in the Pacific and Indian oceans have long been the subject of academic study, but new research is just starting to shed light on the behavior of their Atlantic Ocean counterparts. 
 
 Researchers in Massachusetts say white sharks appear to venture offshore farther, with more frequency and at greater depths than previously known in the Atlantic. 
 
 Some of the 32 sharks tracked between 2009 and 2014 ended up as far east as the Azores, the Portuguese island chain located more than 2,300 miles (3,701 kilometers) from Cape Cod, where most of the animals were initially outfitted with satellite tags. 
 
 They also were found to make frequent deep dives — as far down as 3,700 feet (1,127 meters) — and spend more time at those dark depths than previous studies in the Atlantic suggest. 
 
 The team, which included scientists from the state Division of Marine Fisheries, the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, had its findings published last week in Marine Ecology Progress Series, a prominent scientific journal. 
 
 "Everything we knew previously indicated that the white shark in the Atlantic is more coastally-oriented, moving north-to-south and remaining on the continental shelf," explained Gregory Skomal, the study's lead author. "So what we're now describing is this other component, this offshore movement into open ocean." 
 
 Skomal says the work has implications for shark conservation efforts since it extends the known habitat for these ancient predators. White sharks are not considered endangered or threatened, but it's illegal to hunt them in U.S. waters. 
 
 "You've got U.S. protection within 200 miles of shore, but you have sharks clearly leaving that protection that are vulnerable to harvest," Skomal said. "We need to engage other countries fishing in these waters to talk about putting similar protections in place." 
 
 The research is exciting because it represents the "first real insights into the movement patterns of white sharks" in the northern part of the Atlantic, says Tobey Curtis, a Massachusetts-based shark researcher for the National Marine Fisheries Service who was not involved with the study. 
 
 "Prior to this, we were only able to piece together information about their distribution from widely scattered reports from fishermen, scientists and the public," he said. "Having tracks of individual sharks really helps fill in the gaps, and provides a more complete picture of white shark movements and migrations." 
 
 The study seems to hew closely to what's been observed of white sharks in other oceans — that juveniles tend to stay in the relatively shallower waters of the continental shelf where food sources abound, while adults are more apt to venture into open ocean, observes Christopher Lowe, a shark researcher at California State University in Long Beach also not involved with the research. 
 
 Indeed, most of the tagged sharks in the Atlantic study generally followed a north-south migration along the Eastern Seaboard. 
 
 They headed to Newfoundland and New England waters in the summer, then down south to the Carolinas and even the Bahamas for the winter. 
 
 Lowe says it remains to be seen what impact continued growth of white shark populations in the Atlantic has on these habits, or whether climate change is playing a role. 
 
 Another key question is finding out what these sharks are actually doing so far offshore. 
 
 Researchers in northern California suggest offshore movements are for mating, a ritual that has never been observed among white sharks. But Skomal and his team believe the animals are more likely foraging — it's just not immediately obvious what they're feeding on. 
 
 "That's the great mystery right now," he said. 
 
 ___ 
 
 Follow Philip Marcelo at twitter.com/philmarcelo. His work can be found at https://www.apnews.com/search/philip%20marcelo
– Those hoping to avoid the world's biggest sharks would do well to stay away from Portugal's Azore Islands. That's where whale sharks—the biggest fish in the sea—are making a new home, likely due to climate change, a study finds. The creatures have a very specific set of temperatures they can tolerate, ranging from 78.8 degrees to 86 degrees Fahrenheit, Discovery notes. The Azores are currently fulfilling the needs of the animals, which, LiveScience notes, can be up to 41.5 feet long and weigh a whopping 47,000 pounds. The temperatures around the Azores, off western Europe, appear to be linked to higher amounts of a favorite whale shark food: chlorophyll-a. Researchers in the area came to their shark population conclusions by assessing 16 years of data from tuna fishermen who've spotted the animals. Indeed, so many sharks have headed there that the region, previously in the northernmost part of the sharks' territory, is experiencing a boom in tourists' "whale shark watching." These tourists, it seems, needn't fear: Whale sharks are by no means ferocious, LiveScience points out. Great whites are a little scarier.