MSGID: 1:317/3 6279eabe   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    New research pinpoints 'blue corridors' for highly migratory fish    
      
     Date:   
         May 9, 2022   
     Source:   
         University of British Columbia   
     Summary:   
         New research has pinpointed four high-traffic areas in the Pacific   
         Ocean that should be considered of high priority if conservation   
         efforts focused on large pelagic fishes such as tuna, blue marlin   
         and swordfish are to be successful.   
      
      
      
   FULL STORY   
   ==========================================================================   
   New research has pinpointed four high-traffic areas in the Pacific Ocean   
   that should be considered of high priority if conservation efforts focused   
   on large pelagic fishes such as tuna, blue marlin and swordfish are to   
   be successful.   
      
      
   ==========================================================================   
   By studying the tendency of fish to return to their place of birth to   
   reproduce -- a concept known as philopatry that is often, and falsely,   
   thought to apply only to salmon species -- and pairing such knowledge   
   with catch distribution maps and tagging and genetic sequencing studies,   
   researchers at UBC's Sea Around Us initiative identified the tentative   
   migration routes of 11 tuna and other large pelagic fish in the Pacific   
   Ocean and determined that certain areas should be considered as of 'high'   
   and 'very high' priority when it comes to maintaining their populations.   
      
   "We applied the concept of philopatry to the movements extracted from   
   tagging studies of species such as the near-threatened Pacific bluefin   
   tuna and the heavily-fished yellowfin tuna, and we also combined this   
   information with the links between populations inferred from genetic   
   studies. This allowed us to identify tentative annual migration cycles,"   
   said Veronica Relano, a doctoral candidate with the Sea Around Us and   
   lead author of thestudy that presents these findings.   
      
   "The interesting thing is that when we compared our proposed migration   
   routes and the mapped catch data from 1950 to 2016 available on the Sea   
   Around Uswebsite, we found many coincidences. Clearly, the accuracy of   
   these routes is reinforced by considering philopatry, although they are   
   still tentative," she said.   
      
   After analyzing the seasonal migration paths of each of the 11 fish   
   species individually, the researchers superposed them and noticed that   
   several species and populations of these large pelagic fishes use the   
   same migration routes.   
      
   "Those high-traffic areas, two of which are in northeastern and central   
   sections of the Pacific Ocean and two in the southwestern and central   
   sections, should become parts of blue corridors, which are routes where   
   strict fisheries management measures or partial bans of industrial fishing   
   ought to be enforced to allow for increased connectivity of habitats   
   and thus allow populations of marine species to maintain themselves,"   
   said Dr. Daniel Pauly, co-author of the study and the Sea Around Us   
   principal investigator.   
      
   "But before setting up any protected area to support the rebuilding   
   of diminished fish populations, it is important to consider the   
   entire body of knowledge available on the migrations and movements of   
   different species. This is what we set out to do with this study. Our   
   findings suggest in which areas such efforts would be more effective,   
   but as stated in our title, the closed migration cycles we propose are   
   tentative, and thus it would be nice if other researchers set out to   
   test their validity," he said.   
      
      
   ==========================================================================   
   Story Source: Materials provided by University_of_British_Columbia. Note:   
   Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Veronica Relano, Daniel Pauly. Philopatry as a Tool to Define   
      Tentative   
         Closed Migration Cycles and Conservation Areas for Large Pelagic   
         Fishes in the Pacific. Sustainability, 2022; 14 (9): 5577 DOI:   
         10.3390/ su14095577   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2022/05/220509191545.htm   
      
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