{"id":15053,"date":"2015-06-10T01:56:17","date_gmt":"2015-06-10T01:56:17","guid":{"rendered":"http:\/\/healthmedicinet.com\/news\/longest-ever-tiger-shark-tracking-reveals-remarkable-bird-like-migrations\/"},"modified":"2015-06-10T01:56:17","modified_gmt":"2015-06-10T01:56:17","slug":"longest-ever-tiger-shark-tracking-reveals-remarkable-bird-like-migrations","status":"publish","type":"post","link":"http:\/\/healthmedicinet.com\/news\/longest-ever-tiger-shark-tracking-reveals-remarkable-bird-like-migrations\/","title":{"rendered":"Longest ever tiger shark tracking reveals remarkable, bird-like migrations"},"content":{"rendered":"

<\/p>\n

\n
\n

IMAGE:\u00c2\u00a0<\/strong>This is a tiger shark.
\n view more <\/i><\/p>\n

Credit: Courtesy of Nick Filmalter\/Danah Divers<\/p>\n<\/p>\n<\/figcaption>\n<\/figure>\n

\n<\/p>\n

FORT LAUDERDALE-DAVIE, Fla. \u00e2\u20ac\u201d Tiger sharks are among the largest and most recognizable sharks on the planet, yet many of their habits remain mysterious because they are long-distance travelers that are hard to track. But a new study, reported in the June 9 issue of the journal Scientific Reports<\/em> (http:\/\/www.nature.com\/srep\/2015\/150609\/srep11202\/full\/srep11202.html), has yielded the first ever continuous, two or more-year satellite tagging tracks for the animals. This study reveals remarkable, and previously unknown, migration patterns more similar to birds, turtles and some marine mammals than other fishes. <\/p>\n

Long believed to be mainly a coastal species, the tiger sharks, in fact, made more than 7,500 kilometer, round-trip journeys every year between two vastly different ecosystems \u00e2\u20ac\u201d the coral reefs of the Caribbean and the open waters of the mid-North Atlantic. Furthermore, they returned reliably to the same overwintering areas each year, a discovery with significant conservation implications. <\/p>\n

The study was led by James Lea and Brad Wetherbee, Ph.D., co-first authors, and senior author, Mahmood Shivji, Ph.D., all of whom work out of Nova Southeastern University\u00e2\u20ac\u2122s (NSU) Guy Harvey Research Institute in Florida. Renowned marine artist and conservationist Guy Harvey, a Ph.D. fisheries ecologist, is also an author on the paper and co-led the project\u00e2\u20ac\u2122s tagging work, which took place near Bermuda, in collaboration with the Bermuda Shark Project.<\/p>\n

\u00e2\u20ac\u02dcAs apex predators, the presence of tiger sharks \u00e2\u20ac\u201d and other large sharks \u00e2\u20ac\u201d is vital to maintain the proper health and balance of our oceans,\u00e2\u20ac\u2122 said Dr. Shivji, who is professor at NSU and also the director of NSU\u00e2\u20ac\u2122s GHRI. \u00e2\u20ac\u02dcThat\u00e2\u20ac\u2122s why it\u00e2\u20ac\u2122s so important to conserve them, and understanding their migratory behavior is essential to achieving this goal.\u00e2\u20ac\u2122<\/p>\n

Background<\/strong><\/p>\n

The details of the movements and migrations of tiger sharks and most other large shark species have been a mystery because they are difficult to track for more than a few months because of tag or other logistic limitations. For this project, the tags the team attached to sharks near Bermuda lasted in many cases more than two years, and in some cases more than three years, sending satellite position data each time an animal surfaced.<\/p>\n

One tiger shark, named Harry Lindo, traveled more than 44,000 kilometers (27,000 miles), the longest track distance documented for a tiger shark and possibly the longest ever published for a shark. <\/p>\n

\u00e2\u20ac\u02dcIt is truly remarkable,\u00e2\u20ac\u2122 said Harvey of the animal\u00e2\u20ac\u2122s travels.<\/p>\n

Tiger Shark Highway<\/strong><\/p>\n

The researchers were able to show that adult male tiger sharks in the Atlantic repeatedly spend their winters in Caribbean island locales including the Bahamas, Turks and Caicos Islands, and Anguilla. Then, during summers, they travel far into the North Atlantic, often more than 3,500 kilometers and as far north as Connecticut, though well offshore in nearly the middle of the ocean. <\/p>\n

\u00e2\u20ac\u02dcThese repeated journeys were very unexpected,\u00e2\u20ac\u2122 said Lea, who also works out of the Marine Biological Association of the United Kingdom, \u00e2\u20ac\u02dcThe tiger shark has traditionally been considered a coastal species, and it is rare among sharks to so easily and habitually switch between the two vastly different environments.\u00e2\u20ac\u2122<\/p>\n

Remarkably, the sharks followed the same pattern each year and returned to almost the same small area in the Caribbean each time. <\/p>\n

\u00e2\u20ac\u02dcEven though they\u00e2\u20ac\u2122ve got a whole range of islands to choose from, it seems like each animal has its favorite winter spot,\u00e2\u20ac\u2122 said Shivji. <\/p>\n

For the tiger sharks, the migrations are something like a \u00e2\u20ac\u02dchighway road trip,\u00e2\u20ac\u2122 on their way to definite destinations. Bermuda is a handy spot for tiger shark tagging because it is the equivalent of a popular highway exit \u00e2\u20ac\u201d lots of animals stop off there for a break while heading north or south. But for the most part the animals travelled directly between their migration destinations, meandering around only after arriving. <\/p>\n

Why They Go<\/strong><\/p>\n

What makes the tiger sharks so committed to particular areas is still an open question. At the south end, the story may be fairly simple. Female tiger sharks are common in the Caribbean in the winter, so the Caribbean may just be the best place for male tiger sharks to find dates, although this is just an educated guess. <\/p>\n

Why they go so far north is more complicated. How far they go seems to be guided by avoidance of colder temperatures \u00e2\u20ac\u201d information that offers one example of how migration research can help to predict the implications of climate change for sharks. <\/p>\n

\u00e2\u20ac\u02dcThere\u00e2\u20ac\u2122s got to be something really good up there to make the sharks undertake such massive, repeated swims, but exactly what is a puzzle,\u00e2\u20ac\u2122 said Shivji. <\/p>\n

One possibility is that they go to feed on young loggerhead turtles that also migrate north \u00e2\u20ac\u201d indeed when the researchers examined stomachs of some tiger sharks killed by long liners in the region, they found turtle remains. But then there are also turtles much farther south. <\/p>\n

Great White Similarities<\/strong><\/p>\n

The only other instance where researchers have found a broadly similar, repeated migration pattern between coastal and distant open water regions is with the warm-bodied, great white and salmon sharks in the Pacific Ocean. White sharks migrate in the winter from the California and Baja coasts to a mid-Pacific open water area dubbed the \u00e2\u20ac\u02dcWhite Shark Caf\u00c3\u00a9.\u00e2\u20ac\u2122<\/p>\n

\u00e2\u20ac\u02dcWe joke that tiger sharks, not being media stars like white sharks, wouldn\u00e2\u20ac\u2122t be comfortable in a \u00e2\u20ac\u02dccaf\u00c3\u00a9\u00e2\u20ac\u2122 and prefer to hang-out in their \u00e2\u20ac\u02dctruck-stop\u00e2\u20ac\u2122 in the mid-Atlantic,\u00e2\u20ac\u2122 says Wetherbee, who is also based at the University of Rhode Island.<\/p>\n

Conservation Implications<\/strong><\/p>\n

Tiger sharks are nearing threatened status, in part because of targeting for the soup fin trade. One of the most important implications of the new research, therefore, is for conservation. <\/p>\n

\u00e2\u20ac\u02dcUnderstanding how these animals use the oceans is the first step toward effective conservation,\u00e2\u20ac\u2122 said Harvey. \u00e2\u20ac\u02dcProtecting migratory species is a great challenge because they can be found in such a wide area. Protecting the areas where animals, such as tiger sharks, spend the most time is a tractable goal once those areas have been identified.\u00e2\u20ac\u2122 <\/p>\n

Guided in part by early access to the GHRI team\u00e2\u20ac\u2122s data about the importance of the Bahamas habitat to the tiger shark\u00e2\u20ac\u2122s annual migratory pathways, The Bahamas government established a shark sanctuary in 2011 prohibiting commercial shark fishing in their territorial waters. <\/p>\n

How to Follow Sharks<\/strong><\/p>\n

All of the satellite tracks for tiger sharks in this study, as well as ongoing tracks for other species including mako sharks, oceanic whitetip sharks and marlins, can be found online at http:\/\/www.ghritracking.org <\/p>\n

###<\/p>\n

About Nova Southeastern University (NSU)<\/strong><\/p>\n

\tLocated in beautiful Fort Lauderdale, Florida, NSU is a dynamic research institution dedicated to providing high-quality educational programs at the undergraduate, graduate and first-professional degrees levels. An independent, not-for-profit institution with approximately 25,000 students, NSU has campuses in Fort Lauderdale, Fort Myers, Jacksonville, Miami, Miramar, Orlando, Palm Beach and Tampa, Florida as well as San Juan, Puerto Rico and online globally. For more than 50 years, NSU has been awarding degrees in a wide range of fields, while fostering groundbreaking research and an impactful commitment to community. Classified as a research university with \u00e2\u20ac\u02dchigh research activity\u00e2\u20ac\u2122 by the Carnegie Foundation for the Advancement of Teaching, NSU is one of only 37 universities nationwide to also be awarded Carnegie\u00e2\u20ac\u2122s Community Engagement Classification. For more information, please visit http:\/\/www.nova.edu <\/p>\n

About NSU\u00e2\u20ac\u2122s Halmos College of Natural Sciences and Oceanography<\/strong><\/p>\n

\tLocated on two campuses, one at the entrance to Port Everglades with immediate access to the Atlantic Ocean and the other at NSU\u00e2\u20ac\u2122s main campus in Fort Lauderdale, the college provides high-quality undergraduate and graduate education programs in a broad range of disciplines, including natural sciences, marine sciences, mathematics, biology (pre-medical, pre-health profession) and chemistry. Research is done by faculty and students in a number of areas, including coral reefs, physics, genomics, sharks, fisheries, biology, chemistry, and mathematics. One of the college\u00e2\u20ac\u2122s locations is home to the the state-of-the-art NSU Guy Harvey Oceanographic Center, an 86,000 square-foot Silver LEED Certified structure that contains laboratories, offices, seminar rooms, an auditorium and indoor and outdoor running sea water facilities. For more information, please visit http:\/\/www.nova.edu\/ocean<\/p>\n

About NSU\u00e2\u20ac\u2122s Guy Harvey Research Institute<\/strong><\/p>\n

\tEstablished in 1999, the Guy Harvey Research Institute (GHRI) is a collaboration between the renowned marine artist, scientist and explorer, Dr. Guy Harvey, and Nova Southeastern University\u00e2\u20ac\u2122s Halmos College of Natural Sciences and Oceanography. The mission of the GHRI is to provide the scientific information necessary to understand, conserve and effectively manage the world\u00e2\u20ac\u2122s marine fishes and their ecosystems. It is one of only a handful of private organizations dedicated exclusively to the science-based conservation of marine fish populations and biodiversity. For more information, please visit http:\/\/www.nova.edu\/ocean\/ghri\/index.html<\/p>\n","protected":false},"excerpt":{"rendered":"

IMAGE:\u00c2\u00a0This is a tiger shark. view more Credit: Courtesy of Nick Filmalter\/Danah Divers FORT LAUDERDALE-DAVIE, Fla. \u00e2\u20ac\u201d Tiger sharks are among the largest and most recognizable sharks on the planet, yet many of their habits remain mysterious because they are long-distance travelers that are hard to track. But a new study, reported in the June […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-15053","post","type-post","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/posts\/15053","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/comments?post=15053"}],"version-history":[{"count":0,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/posts\/15053\/revisions"}],"wp:attachment":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/media?parent=15053"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/categories?post=15053"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/tags?post=15053"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}