Thorsteinson, Lyman

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REVIEWS / 361 PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON KING  AND  TANNER  CRABS.  By ALASKA SEA GRANT COLLEGE PROGRAM. Fairbanks: University of Alaska Fairbanks, 1990. 633 p.,  illus.,  tables.  Softbound. US$14.00. In  November 1989 an  international  symposium  on  the  biology  and management  of  king  and  Tanner  crabs  was  held in  Anchorage, Alaska.  Agency,  university,  and  industry  representatives  from  five nations (U.S., Canada, U.S.S.R., Japan,  and  Argentina)  met  for  three days  to  discuss  the  status  of  fishable  populations,  biological  research, and  management  practices  relative  to  these  crabs.  The  conference was  the  eighth  of  the  Lowell  Wakefield  series,  designed  to  promote technology  transfer  among  various  segments  of  the  fishing  industry. This  was  articulated  in  the  opening  remarks  by Dr. John  Costlow (Duke  University),  who  described  the  societal  benefits  conferred  by such  information  exchanges,  extolling  their  role  in  the  management and  conservation  of  our  coastal  resources.  More  than 50 technical papers  described  various  aspects  of  the  natural  histories,  ecologies, and  fisheries  for  king  and  Tanner  crabs.  The  concluding  session  at  the symposium was an open workshop discussion where participants expressed  their  concerns  for  research  needs  and,  quite  candidly,  their philosophies  regarding  the  management  of  these  lucrative  fisheries. The  symposium  proceedings  is  a  collection  of  most  of  the  techni- cal  papers  presented  at  the  symposium,  including  a  transcript  of  the closing  workshop.  Collectively,  the  papers  provide  a  valuable  single- source  reference  for  all  professionals  participating  in  research  and management  of  these  or  similar  crustacean  resources.  The  document organizes  the  manuscripts  into  five  categories:  life  history,  feeding and  growth,  mortality,  population  structure  and  dynamics,  and  stock assessment  and  management.  The  contents  are  not  meant  to  be  com- prehensive  reviews;  and  individual  contributions vary widely  in  con- tent.  Individually,  the  manuscripts  are  of  an  autonomous  nature,  hav- ing been prepared in standard scientific formats. As such, they provide  excellent  sources  regarding  a  multitude  of  field  and  analyti- cal  techniques  currently  in  use  in  the  study  of  crab  populations. Editorially,  the  papers vary in  writing  quality  and  style.  Some  would benefit  from  additional  peer  review.  However,  considering  the  num- ber  of  papers  involved,  the  international  nature  of  the  meeting,  the relatively  fast  publication  schedule,  and  the  price  of  the  book,  the overall  quality  is  very  good. The meeting was heavily attended by U.S. scientists studying Alaskan  crabs.  As  a  result,  a  majority  of  the  papers  address  king  crab resources  and  issues  pertaining  to  the  Gulf  of  Alaska  and  Bering  Sea. Considering  the  past  and  potential  value  of  this  fishery,  these  papers are  particularly  timely. Several  species  of  commercially  harvested  crabs are included  by the  king  and  Tanner  crab  taxonomic  designations.  Commercial  quan- tities  of  Lithodidae  (king)  and  Majidae  (snow  and  Tanner)  crabs  are widely  distributed  in  temperate  and  higher  latitude  seas  of  the  north- ern  and,  to  a  lesser  extent,  southern  hemispheres.  Major  fisheries  are located  in  inland  waters  of  southeast  Alaska,  on  shelf  areas  of  the Gulf  of  Alaska,  Bering  Sea  and  the  Sea  of  Japan,  and,  in  Canada,  off British  Columbia  and  in  the  Gulf  of  St.  Lawrence.  A  southern  form  of king  crab  (and  two  congeners)  are  harvested  in  sub-Antarctic  waters of  Chile  and  Argentina. Apparently,  few  species  occur  in  sufficient  numbers  or  densities to  support  viable  commercial  fisheries.  The  existing  fisheries  exploit populations  of  four  species  of  king  crab  and  two  species  of  Tanner crabs.  Within  the  king  crab  group,  red  king  crabs re without  question the  most  famous  and  biologically  well  known.  However,  at  least  six other,  lesser  known,  congeners  are  currently  harvested  or are proba- ble  targets  of  expanding  fisheries.  During  the  early  1980s  red  king crab  populations  declined  throughout  Alaska;  they  remain  depressed today.  This  decline  quickly  led  the  fishing  industry  to  shift  to  more abundant  but  less  valuable  Tanner  crab  resources.  This  is  evidenced by the  rapid  economic  growth  in  the  snow  crab  fisheries  that  has occurred  during  the  past  decade.  Although  several  species  are cap tured, C. bairdi and C. opilio crabs  constitute  the  bulk  of  all  landings. The  unifying  theme  of  the  symposium  was  the  socioeconomic  and biological  information  needed  to  bring  stability  to  the  seafood  indus- try. High  interannual  variation  in  resource  abundance  typifies  the king  and  Tanner  crab  fisheries  of  the  world.  They  have  historically followed  economic  cycles  of  “boom  or  bust,”  and  it  is  during  periods of  diminished  resource  abundance  that  fishery  effects  become  most profound.  The  stock  fluctuations are pervasive  in  the  seafood  indus- tries,  affecting  individual  and  corporate  incomes,  capitalization,  and the  marketplace.  In  a  sense  these  fluctuations  are  reflective  of  the dynamic  nature  of  marine  ecosystems,  where  shifts  in  abundance  fol- low  the  complex  interplay  of  abiotic  and  biotic  factors  responsible  for exceptional  year  class  successes or failures.  At  the  species  level,  the growth  and  decline  of  populations  underlie  the  biological  and  eco- nomical  instability  that  pervades  both  the  management  and  harvest sectors  of  the  fishing  industry. Achievement  of  increased  economic  and  regulatory  stability  may be  possible  with  improved  knowledge  of  the  causes,  magnitudes,  and periodicities  in  recruitment  and  with  foresight  of  the  economic  effects of resource  management.  The  management  of  crab  stocks  requires, among  other  things,  reliable  information  about  the  magnitude  and condition of the  resource  at  any  given  time.  This  has  traditionally been  accomplished by means  of  broad-scale  resource  surveys designed  to  provide  data  on  the  size,  sex,  and  relative  abundance  of fishable  stocks.  Landing  statistics as a  surrogate  for  stock  abundance should  also be monitored  to  examine  trends  within  exploited  popula- tions.  Since  variability  is  pervasive  in  the  marine  environment,  long- term  records  of  biological  and  oceanographic  data  are  necessary  to document  change and assess  the  significance  of  fishery  activities. A  shared  goal  of  management  and  industry  alike  is  for  biological stability  within  the  king  and  Tanner  crab  populations.  If  realized, exploited  populations  would  be  able  to  maintain  and  perpetuate  them- selves  while  annual  harvests  remain  relatively  constant  in  the  face  of variable  recruitment.  Various  strategies  are  employed to protect stocks;  and  most  commonly,  a  quota  system  limiting  catches  of  cer- tain  sizes  is  employed.  The  size  restriction  generally  applies to male crabs  old  enough  to  have  mated  at  least  once  prior  to  recruitment  into the  fishery.  However,  the  determination  of  age  in  crabs  is  imprecise. Further,  field  and  laboratory  observations  provide  conflicting  results as  to  the  effective  size  male  crabs  must  be  in  the  wild  for  successful first  mating.  The  determination  of  morphometric  maturity  in  male C. opilio crabs  is  also  uncertain  and  may  be  better  indicated  by  claw  size than  by  conventional  measures  of  carapace  width.  In  each  instance, these  problems  have  direct  bearing  on  the  determination  of  the  repro- ductive  potential  of  these  populations.  Since  there  is  a  tendency  to overfish,  questions  persist  about  possible  fishery  effects  on  declining or  depressed  stocks. A number  of  numerical  models  are  used  to  describe  relationships between  age  and  growth  and  stock  abundance  in  crabs.  The  effects  of temperature-dependent  growth,  varying  size,  and  sex  restrictions  on the  management  strategies  for  red  king  crab  as  explored  in  modeling efforts  are  described  in  a  number  of  papers.  A  comparison  of  the  pre- dictive  capabilities  of  traditional  spawner-recruit  and  cohort  analysis models  used  to  forecast  year  class  strengths  in  red  king  crab  suggests biological  and  statistical  advantages  to  the  latter  approach.  Evidently, cohort  analysis  more  accurately  describes  the  parent-recruitment  rela- tionship  over  the  lifetime  of  the  crab. Crabs  have  interannual  variations  in  abundance  that  range  over  an order  of  magnitude  at  the  exploited  stage.  These  variations  have  led biologists  to  seek  explanations  for  cycles  within  the  dynamics  of local  crab  populations  and  in  their  relationships  to  habitat  attributes. The  book  contains  numerous  examples  of  recent  studies  investigating various  determinants  of  year  class  success.  They  include  field  studies concerning  the 1) migration  and  movement  behaviors  of  crabs, 2) the role  of  ocean  temperatures  and  currents  on  ontogenic  development and  larval  drift,  and 3) food  habits  and  growth  in  crabs. In the  labora- tory,  experiments  concerning  the  effects  of 1) temperature  and  salin- ity  on  the  growth  of  larval  and  juvenile  crabs  and 2) diet  on  growth  in crabs  have  been  recently  conducted  to  explore  environmental  influ- 362 J REVIEWS ences  in  a  broader  sense.  The  nearly  synchronous  decline  of  Alaskan king crab populations in the early 1980s has sparked scientific inquiry  about  disease  and  parasitism  in  crabs.  Three  extended abstracts  provide  preliminary  information  about  potentially  wide- spread  role  of  epizootics  as  a  factor  influencing  stock  abundance. New  advances  in  genetic  stock  identification  techniques  and  protec- tion  of  nursery  areas  of  young  crabs  may  aid  in  the  rebuilding  of depressed  stocks. Habitat  protection,  particularly  for  that  of  young  crabs,  while  uni- versally  recognized  as  being  important,  is  not  always  practiced.  It  is disappointing  that  this  issue  and  others  pertaining  to  the  protection  of stocks  were  not  fully  explored  at  the  meeting.  Without  exception, information  is  lacking  about  juvenile  crabs  (of  all  species)  and  their habitat  requirements.  With  few  exceptions  little  has  been  done  to ensure  environmental  quality  or  well-being  of  young  crabs  distributed in these areas. In the western Bering Sea, the U.S.S.R. prohibits trawling  in  nearshore  environments  important to reproducing  and rearing  king  crabs.  Similarly,  the  Japanese  have  identified  a  nursery for C.  opilio crabs  and  have  taken  appropriate  protective  measures. The  policies  of  other  nations  regarding  the  size  and  seasonal  catch restrictions  prescribed  for  industry  often  represent  the  extent  of  bio- logical  protection.  Groundfishery  effects  on  benthic  habitats  and  popu- lations  may be substantial. In the U.S. and  other  nations,  bycatch - the  number  of  crabs  captured  in  bottom-sweeping  trawls -is  capped by  management  but  continues to be  a  major  source of mortality. Perhaps  such  issues  will be addressed  in  future  symposia. Lyman  Thorsteinson Arctic Environmental Assessment  Center Grace  Hall, Suite 300 4230 University  Drive Anchorage,  Alaska 99508 USA. THE SOUTHERN ICE-CONTINENT. By ERICH V. DRYGALSKI. Bluntisham, Huntingdon, UK. Bluntisham Books, 1989. E49.95; US$95.00. About  a  century  ago,  when  the  Deutsche  Siidpolarexpedition  was planned  and  finally  carried  out,  the polar regions of our  earth  were still  terra  incognita.  Drygalski’s  narrative  of  this  German  South  Polar Expedition  from  1901  to  1903  on  board  the  research  ship Gauss gives an expansive  account  of  the  plentiful  discoveries  that  were  still  to be made  in  the  Southern  Ocean  and  on  the  Continent.  Although  a  com- prehensive  synopsis  (20  volumes)  of  the  results  of  the Gauss expedi- tion  has  been  published,  the  cruise  report  by  Drygalski,  the  expedi- tion  leader,  is  still  fascinating  to  read. The  first  three  chapters  give  an  insight  into  the  scientific  planning, funding,  selection  of  the  expedition  members  and  fitting  out  of  the ship. There was some cooperative planning with Scott’s Discovery expedition,  which  was  bound  for  the  Pacific  sector,  whereas  the Gauss was  to  approach  the  ice  from  the  Indian  Ocean.  There  had  been  some preceeding  reconnaissance  cruises  to  the  Kerguelen  in  1874  to  set  up a  meteorological  and  magnetic  station.  The Valdivia’s German  Deep Sea  Expedition  in  1888/89 from Cape  Town  went  close  to  Enderby Land  and  was  regarded  as  very  successful.  The  cruise  plans  of  the Gauss were strongly influenced by G.v. Neumeyer, who favoured magnetic  measurements  on  the  Kerguelen  and  proposed  a  warm water  current  flowing  southward  across  Antarctica to join the Weddell  Sea. The  cost  of  the  expedition  could  not  be  met  by  private  subscrip- tions,  but  was  finally  secured  by  the  Reichstag,  as  the  dispatch  of  a Siidpolarexpedition  had  become  a  matter  of  national  honour  in  many European  nations. Is there  a  parallel  to be seen  in  the  present?  The Gauss was  finally  built  at  the  Howaldt  shipyard  in  Kiel  to  the  appar- ent  satisfaction  of  the  expedition  members. For  a  quarter  of  the book there  follows  a  detailed  description  of the  cruise,  starting  with  its  departure  from  Kiel  (August  1901)  to  the day  when  the Gauss was  beset  in  the  ice  (February  1902).  The  expe- dition  started  with  the  disclosure  of  serious  shortcomings  in  the  ship and  its  equipment.  This  part  of  the  book  also  contains  exhaustive descriptions  of  the  different  port  calls,  including  biological,  geologi- cal  and  political  considerations  (the Boer War  raged  in  South  Africa). The  scientific  highlights  were  the  confirmation  of  the  Romanche Deep  and  the  discovery  of  the  Crozet-Kerguelen  trench,  with  cold Antarctic  water  at  depth. The  central  part  of  the  book  deals  with  the  real  Antarctic  adven- ture. The seizure of the ship in the ice was followed by intensive activities  to  set  up  a  winter  station  and  consequent  collection  of  mete- orological, magnetic, astronomic, geodetic, glaciological, oceano- graphic and biological  data from various  huts and the  ship. Continuous  loss  and  failure of equipment was met with ingenious inventions:  construction  of  a  tide  gauge;  the  building  of  lamps  for burning oil from seal blubber according to Meyers Konserva- tionslexikon;  setting  up  a  windmill  for  generation f electricity;  “hir- ing”  an  emperor  penguin  to  carry  a  line  under  water  from  bow  to stem of  the  ship. Several  expeditions  on  sledges  were  carried  out  to  the  coast, 90 km away  from  the  ship,  and  farther  inland  to  the  Gaussberg.  The  dogs were  taken  over  from  the  Kerguelen  Station,  to  which  they  had  been shipped  from  Kamchatka  via  Australia.  One  sledge  party  almost  got lost  in  a  blizzard  when  returning  to  the  ship.  Drygalski  describes  all these  activities,  sometimes  exhaustively  and  sometimes  only  briefly, in  a  light-hearted,  matter-of-fact  style  but  also  with  some  sense of irony  and  humour.  From  his  account  spirits  were  high  throughout among  the  expedition  members.  Only  in  November/December  1902, when  no  hope  of  getting  out  of  the  ice  was  in  sight,  did  the  excite- ment  about  the  new  discoveries  subside;  the  prospect  of  staying  a second  winter  in  the  ice  dampened  the  mood.  Many  plans  were  made about  how  to  get  the  ship  out  of  the  ice  (e.g.,  blasting  icebergs  until they  capsize  to  make  it  out  of  the  ice  in  their  wake) or to  set  out  to Knox  Land,  900 km away,  for  a  rendezvous  with  a  relief  party  in  the austral  summer  of  1903/04. However,  in  February  1903  the  ice  broke  and Gauss drifted  help- lessly  in  the  pack  in  a  westerly  direction  before  it  was  completely  free in April 1903. The scientific work went on and the reader, waiting excitedly  for  the  ship  to  get  free,  has  to  put  up  with  intermingled remarks  about  phytoplankton  and  benthos  populations or about  the role  of  nitrifying  and  denitrifying  bacteria  in  relation  to  Karl  Brandt’s theories - business  as  usual.  Drygalski  had  seriously  planned  a  sec- ond  winter  station  and  found  it  the  hardest  decision  not  to  carry  this out  and  to  sail  to  the  Kerguelen  for  safety  reasons. The  journey  back  to  Kiel  is  described  similarly  as  the  journey down  south  at  the  beginning  (full  of  details  about  South  Africa, where  the  Boer  War  had  just  ended),  as  are  the  reports  about  the island  where  the  ship  called  into port (e.g.,  a  photograph  of  the  grave of  Bonaparte  on  St.  Helena). Drygalski  was  deeply  disappointed  by  the  rejection  of  his  pro- posal  to  set  out  for  Antarctica  again  from  Cape  Town  and  his  instruc- tions  to  sail  back  to  Germany  as soon as  possible.  The Gauss expedi- tion  was  regarded  as  a  failure.  News of the  exploits  and  surveys  of Scott’s Discovery expedition  had  broken  in  Germany. In comparison the Gauss had  broken  no  record; Discovery had  finally  reached 82”s in  the  Ross  Sea,  whereas Gauss was  beset  just  north  of  the  polar  cir- cle.  Drygalski  regarded  his  expedition  as  part  of  an  international  plan, and  he  had  worked  in  his  area  as  effectively  as  other  expeditions  in different  regions,  but  “the  fact  that  the  coast  lay  where  we  found  it was  noted  with  regret  by  some  critics,  because  it  was  situated  at an insufficient  high  latitude.”  How  do  we  measure  the  success of an expedition  today? The  tasks of the Gauss were  plentiful.  It  had to explore  an unknown  coast,  it  had  to  carry  out  magnetic  measurements  for  the sake  of  safer  navigation  in  the  Southern  Ocean,  and  it  conducted an impressive  sampling  program  for a variety  of  parameters,  despite  a long  list  of  minor  mishaps. It was  the  second  ship,  after  the Belgica, captured in the  ice for an entire  year.  On  reading  this book on a warm 

Proceedings of the International Symposium on King and Tanner Crabs, by Alaska Sea Grant College Program

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Proceedings of the International Symposium on King and Tanner Crabs, by Alaska Sea Grant College Program

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