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THE AWOONGA BARRAMUNDI STORY 1985-‐2014 -...

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THE AWOONGA BARRAMUNDI STORY 19852014
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  •            

         

     THE  AWOONGA  

    BARRAMUNDI  STORY  1985-‐2014  

             

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     THE  AWOONGA  BARRAMUNDI  STORY  1985-‐2014    REPORT    This  report  has  been  prepared  by   Infofish  Australia  for  the  Australian  National  Sportfishing  Association  Qld  Inc  –  March  2015    SCOPE    This   report   provides   a   summary   of   tagging   of   Barramundi   stocked   in   Lake   Awoonga   near  Gladstone,  with  a  focus  on  the  period  from  2010-‐2015  when  the  lake  spilled  each  year  with  stocked  fish  exiting  the  lake.    DATA  SOURCE    Tagging   and   recapture   records   from   1985-‐2014   are  maintained   in   the   Suntag   database   at  http://qld.info-‐fish.net.    Access  to  the  database  is  limited  to  authorised  users.    Data  on  stocking  was  provided  by  the  Gladstone  Area  Water  Board.    Data   on   Boyne   River   flows   from   www.dnrm.qld.gov.au/water/water-‐monitoring-‐and-‐data/portal    for  Station  133005A  to  June  2012.      Tag  grid  maps  and  Google  Earth  maps  are  available  at  www.suntag.org.au.      LOCATION    Lake  Awoonga  is  located  30km  south  of  Gladstone  and  is  covered  by  Suntag  grid  map  GLA.      

     Figure  1:  Suntag  grid  map  of  Lake  Awoonga  

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    SUMMARY  OF  LAKE  AWOONGA  2002-‐2014    A  brief  summary  of  Lake  Awoonga1    

    ! The  dam  wall  was  raised  to  40m  AHD  in  2002  ! The  lake  did  not  spill  from  2002-‐Dec  2010  ! The  lake  reached  it  lowest  level  of  20.84m  in  Feb  2003    ! The  lake  reached  it  second  lowest  level  of  29.11m  in  Feb  2008  ! The  lake  reached  its  highest  level  of  48.30m  in  Jan  2013  ! The   lake   spilled   from  Dec  2010-‐Jun  2011   for   the   first   time  since   the  dam  wall  was  

    raised  in  2002  ! The  lake  spilled  again  in  Jan-‐Feb  2012  ! The  lake  spilled  again  from  Jan-‐Jun  2013  and  reached  its  recorded  highest  level  ! The  lake  just  overtopped  the  spillway  in  Mar  2014  ! The  lake  spilled  again  in  Jan-‐Mar  2015  (currently)  

     SOME  OBSERVATIONS    Some  observations  for  stocked  Barramundi  in  Lake  Awoonga  1985-‐2014:    

    ! From  1996-‐2013   there  were   3,868,432  Barramundi   stocked   in   Lake  Awoonga  with  988,550  stocked  from  2010-‐2014  

    ! From   1985-‐2014   there   were   14,776   Barramundi   tagged   in   Lake   Awoonga   with  14,037  tagged  by  GAWB  as  fingerlings  (150-‐250mm)  

    ! It  was  estimated  that  30,000+  Barramundi  (GAWB  estimate  was  20,000)  spilled  from  the  lake  from  Dec-‐  2010-‐Jun  2011  

    ! Fish  that  spilled  were  in  2  size  ranges  from  400-‐600mm  and  800-‐1,200mm  ! Approximately  1,200  fish  perished,  mainly  due  to  physical  damage  during  the  early  

    stages  of  the  spill  ! Following  the  2011  spill  there  were  1,740  Barramundi  tagged  in  the  area  from  below  

    the  dam  to  Manns  Weir    ! Fish   tagged   in   Lake   Awoonga   and   below   the   dam   were  mostly   recaptured   in   the  

    Gladstone  area  ! One   fish   was   recaptured   760km   to   the   north   in   the   Ross   River   and   another   was  

    recaptured  270km  to  the  south  in  the  Burrum  River    ! Most  fish  that  moved  outside  the  area  moved  to  the  south  with  4  recaptured  in  the  

    Burnett  River,  1  in  the  Kolan  River  and  1  in  the  Burrum  River  ! More   fish   spilled   from   the   lake   in   2012,   2013   and   2015   however   no   estimate   of  

    numbers  was  made  ! Growth   in   the   lake   after   1   year   was   around   320mm,   after   2   years   was   around  

    468mm  and  after  5  years  was  around  784mm.    ! Based  on  growth  a   fish   stocked   in   the   lake  at  216mm  would   reach  1m   in   length  5  

    years  after  release.    

           

    1  From  GAWB  website  http://www.gawb.qld.gov.au/dam-‐levels    

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    FISH  STOCKED  INTO  LAKE  AWOONGA    Fish   have   been   stocked   into   Lake   Awoonga   since   the   1980s.   The   Gladstone   Area   Water  Board  (GAWB)  established  a  fish  hatchery  in  the  1990s  and  has  stocked  the  lake  since  then.  Table  1  shows  the  numbers  of  fish  stocked  from  1996-‐Jun  2013.2  Table  2  shows  the  numbers  of  Barramundi  stocked  from  2010-‐2015.3    Species   Numbers  stocked   Av  size  Barramundi   3,868,  432   40.6mm  Sea  Mullet   526,718   52.8mm  Yellowfin  Bream   78,003   No  record  Mangrove  Jack   70,942   70.9mm  Silver  Perch   100,625   No  record  Golden  Perch   105,825   No  record  Sooty  Grunter   25,500   No  record  Sleepy  Cod   2,000   No  record  Southern  Saratoga   72   No  record  Pikey  Bream   14   No  record  Barred  Javelin   4   No  record  Total   4,778,135    

     Table  1:  Fish  stocked  into  Lake  Awoonga  by  GAWB  from  1996-‐2013    Barramundi   Numbers  stocked  2010-‐11   207,000  2011-‐12   344,000  2012-‐13   220,550  2013-‐14   198,000  2014-‐15   315,500  (350  tagged)  Total   2,271,600  

     Table  2:  Barramundi  stocked  into  Lake  Awoonga  by  GAWB  from  2010-‐2015    FISH  SPILLING  FROM  LAKE  AWOONGA     The  dam  wall  was  raised  in  2002  to  40m  AHD.  In  Dec  2010  the  lake  spilled  for  the  first  time  since  the  wall  was  raised.  The  dam  spilled  from  Dec  2010-‐Jun  2011  and  it  was  estimated  by  GAWB   that   20,000   Barramundi   spilled   from   the   lake.   In   2011   the   Gladstone   commercial  catch  was  249.0t  and  that  was  up  1,600%  on  2010.  The  average   length  of   fish   in   the  2011  catch  was  927mm  and  9.15kg  in  weight.  That  equates  to  27,700  fish  and  when  1,204  tagged  fish  (average  length  790mm),  an  unknown  recreational  catch  and  unknown  fish  not  caught  is  added  it  suggests  the  number  of  fish  that  spilled  from  Awoonga  was  likely  to  be  higher  than  the   GAWB   estimate.   Approximately   1,200   fish   perished,   mainly   due   to   physical   damage  during   the   initial   stages  of   the   spill.     There  were  2   size   ranges  of   fish   in   the   spill  with   fish  from   400-‐600mm   and   800-‐1,200mm.   Figure   2   shows   3   Barramundi   at   the   top   of   the  Awoonga  spillway  in  2011.    

    2  From  GAWB  website  http://www.gawb.qld.gov.au/fish-‐hatchery    3  From  GAWB  Hatchery  

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    The  dam  spilled  again  from  Jan-‐Feb  2012,  Jan-‐Jun  2013,  a  minor  spill  in  Mar  2014  and  again  from  Jan  2015.    Fish  spilled  from  the  lake  in  2012,  2013  and  2015  and  were  mostly  in  the  size  range  500-‐600mm.  There  were  no  estimates  of  the  numbers  of  fish  that  spilled.    The   spilled   of   stocked   fish   from   impoundments   is   not   limited   to   Lake   Awoonga   or  Barramundi.  Barramundi  and  Bass  leave  most  impoundments  where  they  are  stocked  when  the  dam  spills  eg  Barramundi  from  Lake  Monduran  and  Bass  from  Lake  Somerset.    

     Figure  2:  Barramundi  at  the  top  of  the  Awoonga  spillway  in  2011  

     TAGGED  BARRAMUNDI    From  1985-‐2015  there  were  14,776  Barramundi  tagged  in  Lake  Awoonga  with  14,037  tagged  by  GAWB  as  fingerlings  (150-‐250mm).  Of  those  13,553  were  tagged  from  1995-‐2000.  There  were  more  fingerlings  tagged  from  2005-‐2010  however  the  records  were  lost.    Over  the  same  period  there  were  6,372  Barramundi  tagged  in  the  Gladstone  area  in  Suntag  grid  maps  BRG,  GLD,  CR02  and  CISG  with  4,691  tagged  from  2010-‐2015.  Figure  3  shows  the  tagging  each  5  years.      The   tagging   in  2010-‐2015  accounts   for  73.6%  of   the   tagging  effort  over   the  past  30  years.  This  increase  is  largely  due  to  fish  spilling  from  Lake  Awoonga  and  then  being  tagged,  mostly  In  the  area  below  the  dam  to  Manns  Weir  downstream,  a  distance  of  about  5km.  This   is  a  freshwater  section  of  the  river.  In  the  25  years  prior  to  2010  there  were  only  30  Barramundi  tagged  in  that  section  for  the  river.  From  2010-‐2015  there  have  been  1,740  fish  tagged  being  mostly  fish  that  spilled  from  Lake  Awoonga.      

    Barramund   Barramund

     

    Barramundi  

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    Figure  4  shows  the  locations  where  tagged  fish  were  released  or  fish  were  tagged  in  the  lake  and  in  the  area  downstream  to  Manns  Weir.    

     Figure  3:  Barramundi  tagged  in  Lake  Awoonga  and  in  the  Gladstone  area  from  1985-‐2015  

     Figure  4:  Fish  tagged  in  Lake  Awoonga  and  below  the  dam  to  Manns  Weir  

     Figure  5  shows  the  timeline  of  Barramundi  tagged  in  the  Boyne  River  from  below  the  dam  from  1985-‐2015.  This  shows  the  low  numbers  of  fish  from  1985-‐2010  and  then  the  fish  that  spilled  from  Lake  Awoonga.  It  shows  the  2  size  classes  of  fish  that  spilled  

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    from  the  lake  in  2011  being  400-‐600mm  and  800-‐1200mm.  Figure  6  shows  the  same  timeline   for   the  Calliope  River   that  also   shows  an   influx  of   fish   similar   to   the  ones  that  spilled  from  Awoonga  not  long  after  they  spilled.  This  indicates  that  the  fish  that  spilled   from   the   lake  moved   throughout   the   Gladstone   area   and   into   the   Calliope  River.    

     Figure  5:  Timeline  of  Barramundi  tagged  in  the  Boyne  River  below  Lake  Awoonga  1985-‐2015    

     Figure  6:  Timeline  of  Barramundi  tagged  in  the  Calliope  River  1985-‐2015  

     BARRAMUNDI  RECAPTURES    From  1985-‐2010   there  were   14,773   Barramundi   tagged   in   Lake  Awoonga  with   229   (1.6%)  recaptures.  All  except  1  fish  were  recaptured  in  the  lake.  That  fish  was  a  tagged  fish  released  into  the  lake  in  Jan  1996  and  recaptured  in  Jun  1997  in  the  Boyne  River  after  going  over  the  dam  wall.  

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    Following   the   spilling  of   the   lake   in  2011  a   further  49   (0.3%)   fish  were   recaptured  with  all  being  recaptured  outside  the  lake.  Of  those  4  were  recaptured  twice.  While  most  fish  were  recaptured   in  the  Gladstone  area  there  were  2  fish  recaptured   in  the  Burnett  River  180km  south  and  1  fish  recaptured  in  the  Fitzroy  River  100km  north.    

     Figure  7:  Locations  where  Barramundi  tagged  in  Lake  Awoonga  were  recaptured  

     

       

    Figure  8:  Locations  where  Barramundi  tagged  in  Lake  Awoonga  were  recaptured  in  the  Gladstone  area  

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     Figure  9:  Recaptures  of  Barramundi  tagged  below  Awoonga  dam  wall  to  Manns  Weir    

     

       

    Figure  10:  Recaptures    in  the  Gladstone  area  of  Barramundi  tagged  below  Awoonga  dam  wall  to  Manns  Weir    

     

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    From  2010-‐2015  there  were  1,740  fish  tagged  below  the  dam  wall  to  Manns  Weir  with  244  (14.0%)   recaptured  with   20   recaptured   twice,   2   recaptured  3   times   and  one   recaptured  4  times.  Of  those  157  (64.3%)  were  recaptured  in  the  area  from  the  dam  wall  to  Manns  Weir.      The   remaining   fish   were   recaptured   as   far   away   as   760km   north   in   the   Ross   River   at  Townsville   and   270km   south   in   the   Burrum   River   at   Hervey   Bay.   There   were   also   4   fish  recaptured  in  the  Burnett  River  and  1  fish  in  the  Kolan  River.    Figure   7   shows   where   fish   tagged   in   Lake   Awoonga   were   recaptured   and   figure   8   shows  where  they  were  recaptured  in  the  Gladstone  area.  Figure  9  shows  where  fish  tagged  below  the   dam   wall   to   Manns   Weir   were   recaptured   and   figure   10   shows   where   they   were  recaptured  in  the  Gladstone  area.    BARRAMUNDI  GROWTH    There  were  198  recaptures  where  growth  was  assessed.  This  was  for  fish  tagged  from  150-‐300mm  when  stocked  and  recaptured   in   the   lake.  Growth  was  assessed   for   fish   that  were  out   for   90   days   or   more   and   had   positive   growth.   Figure   11   shows   the   growth   of   fish  compared  with  days  out  between  tagging  and  recapture.    Growth  after  1  year  was  around  320mm,  after  2  years  was  around  468mm  and  after  5  years  was  around  784mm.  Based  on  that  growth  a  fish  stocked  at  216mm  would  reach  1m  in  length  5  years  after  release.  

     Figure  11:  Growth  of  Barramundi  in  Lake  Awoonga


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