Fock, Heino O.

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  Institutsleiter: Dr. Gerd Kraus Palmaille 9 22767 Hamburg Fon  040 38905 177 Fax     040 38905 263 www.thuenen.de  sf@thuenen.de  Thünen-Institut  für Seefischerei Federal	  Research	  Institute	  for	  Rural	  Areas,	  	  Forestry	  and	  Fisheries	  	  Thünen-­‐Institute	  of	  Sea	  Fisheries	      	  	  	  	  	  Palmaille	  9,	  22767	  Hamburg	   	  	  	  	  	  	  	  	  	  	  Telephone	  +4940	  38905-­‐169	   	  	  	  	  	  	  	  	  	  	  	  	  	  Telefax	  +4940	  38905-­‐263	   	   Az.:Dr.Fo./vS./	  4105	     Report	  of	  the	  	  Trinational	  Doggerbank	  Survey	  2016,	  cruise	  WH	  396	  of	  the	  FRV	  Walther	  Herwig	  III	  	  July	  04	  -­‐	  15,	  2016	  	  Scientist	  in	  charge:	  Dr.	  Heino	  O.	  Fock	  	     Summary	  An	  international	  team	  comprising	  scientists	  from	  UK	  (2),	  The	  Netherlands	  (1)	  and	  Germany	  (6)	  took	  part	  in	  a	  fisheries	  survey	  in	  the	  Doggerbank	  area	  in	  the	  North	  Sea	  covering	  the	  trinational	  Doggerbank	  Natura	  2000	  MPA	  as	  well	  as	  a	  small	  section	  of	  the	  Danish	  EEZ.	  34	  hauls	  were	  sampled	  during	  WH396.	  20	  hauls	  were	  sampled	  in	  the	  UK	  part	  of	  the	  Doggerbank,	  9	  hauls	  in	  the	  Dutch,	  4	  in	  the	  German	  part	  and	  1	  in	  the	  Danish	  sector,	  respectively.	  41	  CTD	  casts	  were	  deployed,	  7	  extra	  stations	  and	  34	  casts	  in	  combination	  with	  the	  hauls.	  The	  video	  test	  was	  run	  in	  the	  German	  sector.	  Small	  fish	  sampling	  by	  means	  of	  dredge	  sampling	  and	  beam	  trawls	  was	  not	  undertaken	  due	  to	  time	  constraints.	  	  	  	    Verteiler: TI - Institut für Seefischerei Saßnitzer Seefischerei e. G.   per  e-mail: Bundesanstalt für Landwirtschaft und Ernährung, Hamburg BMEL, Ref. 614 BMEL, Ref. 613 Schiffsführung FFS “Walther Herwig III “ TI – Präsidialbüro (Michael Welling) TI – Verwaltung Hamburg TI - Institut für Fischereiökologie TI - Institut für Ostseefischerei Rostock TI – FIZ-Fischerei TI - PR MRI - BFEL HH, FB Fischqualität Dr. N. Rohlf/SF - Reiseplanung Forschungsschiffe Fahrtteilnehmer       Bundesamt für Seeschifffahrt und Hydrographie, Hamburg Mecklenburger Hochseefischerei GmbH, Rostock Doggerbank Seefischerei GmbH, Bremerhaven Deutscher Fischerei - Verband e. V., Hamburg Leibniz-Institut für Meereswissenschaften IFM-GEOMAR Deutscher Hochseefischerei-Verband e.V. H. Cammann-Oehne, BSH DFFU   Aim	  Cruise	  WH396	  pursued	  three	  objectives:	  • To	   collect	   fish	   samples	   on	   the	   Dogger	   Bank	   in	   addition	   to	   the	   IBTS	   sampling	   based	   on	   IBTS	  methodology	   and	   in	   accordance	   to	   the	   high-­‐resolution	   scheme	   applied	   during	   the	   German	  DOGS	   survey	  May	   2006	   in	   support	   of	   evaluating	   the	   state	   of	   the	  Dogger	   Bank	  Natura	   2000	  MPA,	  here:	  creating	  base-­‐line	  data	  before	  management	  measures	  are	  implemented.	  • To	   conduct	   comparative	   studies	   on	   the	   performances	   of	   3	   m-­‐,	   2	   m-­‐	   beam	   trawls	   and	   1	   m	  dredges	  in	  sampling	  small	  sized	  bottom	  fishes.	  	  	  • To	   conduct	   nighttime	   video	   sampling	   along	   transects	   in	   order	   to	   evaluate	   the	   efficacy	   of	  proposed	  management	  measures,	  here:	  designated	  closures	  of	  bottom	  fisheries.	  	  	  	  Cruise	  narrative	  The	  scientific	  staff	  consisted	  of	  9	  scientist,	  2	  from	  UK	  (CEAFS	  and	  JNCC),	  RWS	  from	  The	  Netherlands	  (1),	  and	  6	  scientist	  from	  the	  Thünen	  Insitute.	  The	  cruise	  started	  on	  July	  5	  with	  one	  day	  delay	  in	  Bremerhaven/Germany.	  Weather	  conditions	  were	  good	  during	  the	  cruise,	  so	  that	  the	  complete	  trawling	  program	  according	  to	  the	  first	  objective	  could	  be	  fulfilled	  (Fig.	  1	  as	  plan	  overview	  and	  as	  realized	  working	  stations).	  	  The	  delay	  caused	  a	  shortage	  of	  the	  program,	  so	  that	  the	  experimental	  comparative	  studies	  on	  the	  performance	  of	  beam	  trawls	  and	  dredges	  to	  catch	  small	  fishes	  was	  skipped.	  Technical	  problems	  further	  reduced	  worktime	  at	  the	  end	  of	  the	  cruise,	  so	  that	  only	  a	  short	  test	  run	  for	  the	  video	  device	  was	  undertaken.	  	  	  	  Trawl	  sampling	  according	  to	  first	  objective	  was	  undertaken	  according	  to	  following	  country	  and	  Natura	  category	  split	  (table	  1).	  	  Table1	  Sampling	  design	  by	  country	  (within	  /	  outside	  refer	  to	  zoning	  scheme	  inside	  the	  MPA	  proper	  incl.	  Danish	  part	  indicating	  fisheries	  closures	  (within)	  and	  unrestricted	  areas	  (outside)).	  	  N2000	  area	  category	   Germany	   Denmark	   UK	   The	  Netherlands	  Within	   3	  	  9	   3	  Outside	   1	   1	   11	   6	  	  Sampling	  /	  Results	  	  CTD	  casts	  	  41	  stations	  with	  CTD	  casts	  were	  sampled,	  accompanied	  by	  bottle	  samples	  to	  calibrate	  salinity.	  Extra	  stations	  were	  placed	  into	  areas	  which	  firstly	  due	  to	  projected	  wind	  farming	  will	  likely	  be	  unavailable	  to	  trawling	  operations	  in	  the	  future	  and	  secondly	  outside	  the	  MPA	  proper	  to	  obtain	  a	  better	  description	  of	  bank	  hydrography.	  Fig	  2	  shows	  a	  clear	  gradient	  in	  bottom	  temperature	  observed	  during	  the	  cruise,	  partly	  reflecting	  the	  gradiuent	  in	  summit	  depth	  of	  the	  bank,	  i.e.	  the	  southern	  part	  is	  more	  shallow	  than	  the	  	  northeastern	  section.	  	  	  	  IBTS-­‐standard	  hauls	  Sampling	  at	  34	  stations	  (see	  Table	  1)	  was	  carried	  according	  to	  the	  International	  Bottom	  Trawl	  Survey	  standard	  protocol	  in	  order	  to	  obtain	  full	  comparability	  with	  Q3-­‐IBTS	  sampling	  in	  the	  area.	  	  Catch	  composition	  varied	  between	  stations	  (Fig.	  3).	  The	  southern	  part	  was	  characterized	  by	  a	  higher	  proportion	  of	  mackerel	  (Scomber	  scombrus)	  and	  sprat	  (Sprattus	  sprattus).	  Other	  dominating	  species	  were	  dab	  (Limanda	  limanda)	  and	  grey	  gurnard	  (Eutrigla	  gurnardus).	  	  	  3  Video	  sampling	  Technical	  problems	  caused	  a	  reduction	  of	  the	  video	  program.	  A	  short	  test	  run	  was	  done	  on	  the	  Weisse	  Bank	  to	  check	  functionality	  of	  equipment	  (Fig.	  1	  lower	  panel).	  	  	  	  	  Dissemination	  within	  the	  Doggerbank	  Monitoring	  Group	  (DBMG)	  The	  Doggerbank	  Monitoring	  Group	  as	  subgroup	  assigned	  to	  the	  Doggerbank	  Steering	  Group	  as	  well	  as	  cruise	  participants	  from	  JNCC,	  CEFAS	  and	  RWS	  will	  evaluate	  the	  results	  of	  this	  survey	  in	  combination	  with	  IBTS	  2016	  results,	  evaluate	  potential	  indicators	  and	  give	  recommendations	  concerning	  future	  survey	  design	  and	  survey	  frequency.	  	  	  	  A	  workshop	  will	  be	  held	  in	  January	  2017	  in	  Hamburg	  	  to	  achieve	  these	  goals.	  	  	  Acknowledgements	  The	  Thünen	  Institute	  is	  grateful	  to	  all	  who	  have	  contributed	  to	  this	  successful	  cruise:	  fisheries	  departments	  and	  authorities	  in	  The	  Netherlands,	  UK;	  Denmark	  and	  Germany	  as	  well	  as	  crew	  and	  management	  of	  the	  FRV	  Walther	  Herwig	  III	  for	  their	  excellent	  support	  during	  the	  cruise.	  	  	  	  Cruise	  participants	  Name	  and	  	  affiliation	   	   Name	   Function	   Institution	  1	   Heino	  Fock	   Cruise	  leader	   TI_SF,	  Hamburg	  2	   Katharina	  Baumhoefener	   Scientist	   TI_SF,	  Hamburg	  3	   Hanna	  Heidemann	   Scientist	   TI_SF,	  Hamburg	  4	   Joel	  Cuperus	   Scientist	   RWS	  	  ,	  NL	  5	   Suzanne	  Ware	   Scientist	   CEFAS,	  UK	  6	   Tammy	  Noble-­‐Jones	   Scientist	   JNCC,	  UK	  7	   Felix	  Müller	   Scientist	   TI_SF,	  Hamburg	  8	   Finn	  Werner	   Scientist	   TI_SF,	  Hamburg	  9	   Ismael	  Nunez-­‐Riboni	   Scientist	   TI_SF,	  Hamburg	      TI_SF	  	   Thünen-­‐Institute	  of	  Sea	  Fisheries	  RWS	   Rijkswaterstaat	  JNCC	   Joint	  Nature	  Conservation	  Committee	  CEFAS	  	   Centre	  for	  Environment,	  Fisheries	  and	  Aquaculture	  Science	  	  	  	  	  	  Dr.	  Heino	  O.	  Fock	  	        4  Figures	  	  Fig.	  1:	  WH396	  station	  plot	  –	  plan	  overview	  (top	  panel)	  and	  after	  completion	  of	  survey	  activities	  on	  	  July	  13,	  2016	  (lower	  panel)	     5  Fig.	  2:	  WH396	  bottom	  temperature  6  Figure	  3	  :	  Biomass	  per	  haul	  by	  main	  fish	  species.	  	  Empty	  bars	  indicate	  extra	  CTD-­‐casts	  without	  trawling.	  Unit	  kg/30	  haul.	  Other	  includes	  jellyfish,	  which	  partly	  explains	  the	  high	  values.	         

Report of the Trinational Doggerbank Survey 2016, cruise WH 396 of the FRV Walther Herwig III July 04 - 15, 2016

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