ANNEX 5 REPORT OF THE WORKING GROUP ON FISH STOCK ASSESSMENT (Hobart, Australia, 9 to 19 October 2000) CONTENTS Page INTRODUCTION ........................................................................................... 283 ORGANISATION OF THE MEETING AND ADOPTION OF THE AGENDA........................ 283 REVIEW OF AVAILABLE INFORMATION .............................................................. 283 Data Requirements Endorsed by the Commission in 1999 ............................................ 283 Data Inventory and Developments in the CCAMLR Database .................................... 283 Database Data Entry and Validation ................................................................. 284 Other .................................................................................................. 285 Fisheries Information .................................................................................... 285 Catch, Effort, Length and Age Data Reported to CCAMLR ...................................... 285 Estimates of Catch and Effort from IUU Fishing .................................................. 286 Landings by all Countries ........................................................................ 286 Estimated Trade in Dissostichus spp. in the 1999/2000 Split-year ............................ 286 Overall Estimates of IUU Catch ................................................................. 287 Indian Ocean Sector .......................................................................... 287 IUU Catches in Assessments .................................................................... 288 IUU and the CDS ................................................................................. 288 Catch and Effort Data for Fisheries for Dissostichus spp. in Waters adjacent to the Convention Area........................................................ 288 Scientific Observer Information..................................................................... 288 Research Survey Data................................................................................ 291 Mesh/Hook Selectivity and related Experiments affecting Catchability........................... 292 Conversion Factors................................................................................... 292 Advice to the Scientific Committee.............................................................. 293 Fish and Squid Biology/Demography/Ecology ......................................................... 293 Dissostichus spp. ..................................................................................... 293 Age Determination Methods ..................................................................... 293 Length to Mass and Natural Mortality Coefficient (D. mawsoni) ............................. 294 Stock Structure................................................................................... 294 Gonad Maturity ................................................................................... 294 Stomach Contents ................................................................................ 295 Tagging Studies ................................................................................... 295 Champsocephalus gunnari ........................................................................... 295 Distribution........................................................................................ 295 Reproduction...................................................................................... 296 Feeding ............................................................................................ 297 Ectoparasites ...................................................................................... 297 Crabs .................................................................................................. 297 Sizes ............................................................................................... 297 Skates ................................................................................................. 298 Fish Identification .................................................................................... 299 Other Species ......................................................................................... 301 Developments in Assessment Methods ................................................................. 301 ASSESSMENTS AND MANAGEMENT ADVICE........................................................ 303 New and Exploratory Fisheries.......................................................................... 303 New and Exploratory Fisheries in 1999/2000 ...................................................... 303 New and Exploratory Fisheries Notified for 2000/01.............................................. 308 General Issues .................................................................................... 308 Review of Individual Notifications .............................................................. 309 Advice to the Scientific Committee ................................................................. 312 277 Assessed Fisheries ....................................................................................... 315 Dissostichus eleginoides.............................................................................. 315 South Georgia (Subarea 48.3) ................................................................... 316 Standardisation of CPUE ..................................................................... 316 Determination of Long-term Annual Yields using the GYM ............................... 318 Growth, Mortality and Fishing Selectivity .................................................. 318 Trends in Selectivity ...................................................................... 319 Recruitment and Natural Mortality........................................................... 320 Assessment.................................................................................... 322 Integration of CPUE into Assessment ....................................................... 323 Management Advice for D. eleginoides (Subarea 48.3) ................................... 323 South Sandwich Islands (Subarea 48.4) ........................................................ 323 Management Advice for D. eleginoides and D. mawsoni (Subarea 48.4) ................ 324 Ob and Lena Banks (Division 58.4.4) ........................................................... 324 Kerguelen Islands (Division 58.5.1) ............................................................. 324 Standardisation of CPUE in the Longline Fishery........................................... 324 Standardisation of CPUE in the Trawl Fishery ............................................. 325 Management Advice for D. eleginoides (Division 58.5.1) ................................. 325 Heard and McDonald Islands (Division 58.5.2) ................................................ 325 Length Frequency............................................................................. 326 Determination of Long-term Annual Yields using the GYM ............................... 326 Assessment.................................................................................... 326 Management Advice for D. eleginoides (Division 58.5.2) ................................. 327 General Advice.................................................................................... 327 Champsocephalus gunnari ........................................................................... 327 South Georgia (Subarea 48.3) ................................................................... 327 Past Assessment .............................................................................. 328 New Information Available in 2000.......................................................... 328 Commercial Fishing........................................................................... 328 Research Surveys ............................................................................. 329 Assessment at this Year’s Meeting .......................................................... 329 Closed Season................................................................................. 332 Management Advice for C. gunnari (Subarea 48.3) ....................................... 332 Kerguelen Islands (Division 58.5.1) ............................................................. 333 Management Advice for C. gunnari (Division 58.5.1) ..................................... 333 Heard and McDonald Islands (Division 58.5.2) ................................................ 333 Commercial Catch ............................................................................ 333 Management Advice for C. gunnari (Division 58.5.2) ..................................... 334 Other Fisheries ........................................................................................... 334 Other Finfish Fisheries ............................................................................... 334 Antarctic Peninsula (Subarea 48.1) and South Orkney Islands (Subarea 48.2).............. 334 Management Advice .......................................................................... 334 South Sandwich Islands (Subarea 48.4) ........................................................ 335 Management Advice .......................................................................... 335 Antarctic Coastal Areas of Divisions 58.4.1 and 58.4.2 ....................................... 335 Pacific Ocean Sector (Subareas 88.2 and 88.3)...............................................