One Stock or Two:
   Studying 
     the Movements and Biology of Atlantic Bluefin Tuna with Electronic Tags
   
   Barbara Block
            - Charles & Elizabeth Prothro Professor in Marine Sciences, 
 Stanford     University
   
     
   
 Seminar     Abstract:
  
  The deployment of electronic
data  storage tags that are surgically implanted or satellite-linked provides
marine  researchers with new ways to examine the movements, environmental
preferences,  and physiology of pelagic vertebrates.  We report the
results obtained  from tagging of Atlantic bluefin tuna with implantable
archival and pop-up  satellite archival tags.  The electronic tagging
data provide insights  into the seasonal movements and environmental preferences
of this species.   Bluefin tuna dive to depths of >1000 meters and
maintain warm body temperature.   Western-tagged bluefin tuna make trans-Atlantic
migrations and they frequent  spawning grounds in the Gulf of Mexico and
eastern Mediterranean.  These  data are critical for the future management
and conservation of bluefin tuna  in the Atlantic.  
   
   
   
   
 Speaker     Bio:
   
   Barbara A. Block received her
 Ph.D.     from Duke University. Her research is focused on how large pelagic
 fishes     utilize the open ocean environment. Investigations center upon
 under-standing     the evolution of endothermic strategies in tunas, billfishes
 and sharks.    Block and her colleagues investigate the cellular  mechanisms
 underlying    heat generation and force production in skeletal muscle, the
 evolution of   endothermy, and the physiological ecology of tunas and billfishes.
 The research   in the lab is interdisciplinary, combining physiology, ecology
 and genetics   with oceanography and engineering. 
   
          Professor Block and colleagues at the Monterey Bay Aquarium have
 also   established  the Tuna Research and Conservation Center, a unique
facility    that permits  physiological research on tunas. They are employing
new techniques    in wildlife  telemetry and molecular genetics to directly
examine the short-    and long-term  move-ment patterns, stock structure
and behavior of tunas   and billfishes.  The fish are highly exploited in
international fisheries,   and effective management  of existing biodiversity
requires an under-standing    of their biology and population structure.
The Block lab actively engages    in research at sea to understand the movements
and physiological ecology   of tunas and billfishes and to gain insight into 
the selective advantage  
          of endothermy in fishes. 
   
          Block and her colleagues are conducting research with a new type
 of  remote   telemetry device, called pop-up satellite archival tags. The
 tags  are essentially   computers that record navigational information,
body  temperature,  depth and  ambient temperature data. The information
gained  with these tags  will improve  our understanding of the biology of
these species and increase  our knowledge  of stock structure. The successful
implementation  of the novel  satellite archival tag technology has provided
marine researchers  with new  tools for studying inaccessible marine vertebrates.
   
   
   Readings:
              
   
         Block, Barbara et al.
         ,  2001.  Science  293,  p.  1310-1314.
   
   
        Block, Barabara et al.
       , 2001.  Electronic Tagging and Tracking in Marine Fisheries, 
     p. 65-88.
   
   
      Block, Barabara et al.
       ,  1998.  Proc. of Nat. Acad. of Sci.  95,  p. 
9384-9389.
   
   
   Powell, Chris, 2001.    Wildlife in North Carolina - Tuna Online.
 
 
 
  
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