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Illegal  gillnet  fishing  threatens  endangered  and  endemic  Hovsgol  grayling

 

Chris  Free,  PhD  Student  Institute  of  Marine  and  Coastal  Sciences  Rutgers  University,  New  Brunswick,  NJ,  08901  USA

 

Hovsgol grayling pictureDespite  its  reputation  as  an  arid  country,  Mongolia  contains  a  number  of  large  lakes  and  rivers,  including  Lake  Hovsgol,  the  19th  largest  lake  in  the  world  by  volume,  and  the  Selenge  River,  the  largest  source  of  water  to  Lake  Baikal  in  Russia.  These  lakes  and  rivers  are  home  to  76  native  fish  species  including  6  species  endemic  to  the  country.  Although  Mongolia  has  the  lowest  human  population  density  in  the  world,  its  fish  remain  vulnerable  to  anthropogenic  influences:  climate  change,  mining,  and  overfishing  all  threaten  aquatic  ecosystems  and  14  Mongolian  fish  species  are  considered  endangered  or  threatened  on  the  Mongolian  Red  List.  Although  fishing  is  historically  uncommon  in  Mongolia  and  illegal  throughout  much  of  the  country,  it  may  be  gaining  prevalence  as  a  new  source  of  food,  income,  or  recreation,  and  could  threaten  Mongolian  fish  species  if  left  unmanaged.

 

Hovsgol grayling illegal gillnetDespite  the  closure  of  Lake  Hovsgol  National  Park  to  gillnet  fishing  in  1995,  illegal  fishing  targeting  the  endangered  and  endemic  Hovsgol  grayling  (Thymallus  nigrescens),  the  most  abundant  fish  in  the  lake,  is  known  to  occur.  However,  knowledge  of  fishing  is  largely  anecdotal;  little  is  known  about  the  motivations  for  fishing,  the  frequency  and  methods  of  fishing,  and  the  potential  impact  of  fishing  on  the  globally  unique  Hovsgol  grayling.  The  purpose  of  my  research  is  thus:  (1)  to  gain  a  better  understanding  of  the  motivations  for  fishing  and  the  frequency  and  methods  of  fishing  through  interviews  of  herders  and  rangers;  (2)  to  validate  responses  from  these  interviews  using  surveys  for  derelict  fishing  gear  as  an  indirect  indicator  of  illegal  fishing  activity;  and  (3)  to  evaluate  the  potential  impact  of  illegal  fishing  on  Hovsgol  grayling  using  a  population  dynamics  model.

 

In  Summer  2014,  funded  in  part  by  the  Grayling  Research  Trust,  I  interviewed  4  herding  families  and  1  ranger  to  supplement  interviews  with  6  herding  families  and  7  rangers  from  the  previous  summer.  The  interview  responses  paint  a  bleak  picture:  illegal  gillnet  fishing  for  Hovsgol  grayling  is  rampant  at  river  mouths  during  the  spring  spawning  migration.  For  the  most  part,  this  is  the  only  time  of  year  when  local  people  fish.  It’s  when  the  fish  are  easiest  to  catch,  it’s  before  the  herders  become  busy  with  summertime  milk  production,  it’s  thought  that  grayling  soup  after  a  long  cold  winter  is  good  for  health,  and  it  allows  families  to  delay  the  consumption  of  their  herd  until  the  animals  have  had  time  to  fatten.  There  is  also  a  small  contingent  of  fishermen  who  fish  year-‐round  as  their  primary  source  of  income  and  sell  to  markets  in  the  local  cities.  Despite  these  reports,  park  management  denies  the  occurrence  of  illegal  fishing  and  rangers  rarely  issue  fines  to  illegal  fishermen.

 

Illegal gillnet and fishing equipment mongoliaThe  surveys  for  derelict  fishing  gear  corroborate  the  interview  responses:  fishing  gear,  predominantly  gillnet  material,  was  found  in  10  of  11  transects  distributed  around  the  lake  (covering  12%  of  the  lake  shoreline)  and  was  generally  concentrated  on  accessible  shorelines  near  river  mouths.  Furthermore,  the  most  frequently  observed  gillnet  mesh  size  in  the  surveys  for  derelict  fishing  gear  was  also  the  most  efficient  mesh  size  at  capturing  Hovsgol  grayling  in  our  long-‐term  monitoring  study.  Active  gillnetters  were  observed  near  the  tourists  camps  along  the  developed  southwestern  indicating  that  illegal  fisherman  are  unconcerned  with  nearby  law  enforcement.  Finally,  the  transect  with  the  most  gillnet  material  was  located  at  Har  Us  Spring  where  the  park  management  explicitly  instructs  rangers  to  allow  gillnet  fishing  during  the  spring  migration.  Rangers  report  that  up  to  60  nets,  catching  over  3600  fish  a  day,  will  be  set  everyday  during  the  10  day  migration.  

 

These  results  suggest  that  illegal  gillnet  fishing  on  Lake  Hovsgol  is  very  likely  to  impact  the  endemic  and  already  endangered  Hovsgol  grayling  population.  The  problem  is  unlikely  to  be  resolved  through  top-‐down  control  given  the  reluctance  of  park  management  to  acknowledge  the  problem  and  the  inability  of  rangers  to  prosecute  local  people  (their  neighbors)  or  non-‐local  people  (members  of  a  higher  socioeconomic  status).  Thus,  I  will  focus  my  efforts  on  a  bottom-‐up  approach,  conducting  environmental  outreach  and  education  aimed  to  generate  pride  in  the  lake  and  its  unique  flora  and  fauna.  If  local  people  have  a  vested  interest  in  the  lake  and  its  biodiversity,  they  may  modify  their  fishing  habits  and  empower  the  rangers  in  their  ability  to  enforce  against  non-‐local  fishermen.

 

I  am  grateful  to  the  Grayling  Research  Trust  for  supporting  my  2014  expedition  to  Mongolia.  The  expedition  could  not  have  happened  without  GRT  support  and  I  hope  this  work  will  contribute  towards  the  conservation  of  the  globally  unique  Hovsgol  grayling.

 

 

 


 

 

GS Symposium Speakers

GRT Funded MSc, PhD Studies

Two degree project interim reports were among presentations at the most recent Grayling Society symposium. Both studies are currently funded by the GRT and both operate on a premise that alongside the intrinsic value of grayling as a game fish, their survival challenges provide early indication of problems that are or will likely become problems for other salmonids.

 

Stephen Gregory (Game and Wildlife Conservation Trust) described an MSc study plan for statistical mining of the existing Wylye Study data, questioning the effect of extreme climate events on grayling population dynamics. He emphasized that the GWCT now leads all processing aspects of the 30-year Wylye Grayling Study (WGS) dataset - the longest and most complete in Europe...possibly in the world.

 

Vanessa Huml's (Manchester Metropolitan University) PhD study is titled Assessing adaptive genetic variation for effective management and conservation of European grayling. Read her description of planned work, noting reference to new sequencing technology and reference to the four U.K. genetically distinct groups identified in the earlier genetic census funded by the GRT.

 

The two studies both look at grayling population health/stability under extant environmental conditions but the doctoral work extends inquiry to genetic proclivity for survival ('evolvability').

 

Both investigators will submit detailed results for publication here after review in their respective peer literature.