Biological passports help researchers track the worlds biggest fish

first_img ‘Biological passports’ help researchers track the world’s biggest fish They also measured isotopes—or forms—of nitrogen and oxygen present in tiny patches of skin taken from sharks living in the three areas. Each region has its own signature ratio of the two isotopes, which is reflected in the plants and animals that live there. So the skin patches essentially became “biological passports,” the researchers note, recording where the sharks had traveled.Combined, the two sets of information show the sharks—many of which were young males—didn’t travel far: Most swam just a few hundred kilometers from their feeding grounds. Just two made the 2000-kilometer journey from one territory off the coast of Mozambique to another off Tanzania.The results highlight the need to protect specific shark populations, the researchers write, and not assume that sharks from healthy groups will repopulate lost groups. And shark conservation could have economic benefits, they add, because the chance to see a whale shark has become a big tourist draw in many coastal regions. Nuno Sa/Minden Pictures Click to view the privacy policy. Required fields are indicated by an asterisk (*) Sign up for our daily newsletter Get more great content like this delivered right to you! Country Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe Email By David MalakoffAug. 9, 2018 , 7:00 AM The world’s largest fish is something of a homebody, rarely wandering far from its favorite feeding waters, a new study reveals. And that has big implications for efforts to protect endangered whale sharks (Rhincodon typus), which have seen their numbers fall by half over the past 3 decades.The behemoths typically glide slowly through the world’s oceans, grazing on plankton. They grow to 20 meters long and 40 tons. Previous research revealed they can swim more than 10,000 kilometers in a year, and dive to 2000 meters beneath the surface. And genetic studies suggested the sharks are divided into distinct regional populations.Those groups appear to be even more distinct than previously realized, researchers report today in Marine Ecology Progress Series. To trace how far whale sharks moved, scientists sifted through nearly 4200 photographs of some 1200 whale sharks taken in three areas in the western Indian Ocean and the Persian Gulf. Each shark has distinctive markings that allow researchers to identify individuals, so they were able to see whether the fish were moving between the three areas.last_img

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