RESEARCH TO SUPPORT ALLOCATION OF INDIGENOUS AND NON-INDIGENOUS COMMERCIAL CATCH IN THE TORRES STRAIT LOBSTER FISHERY Darren Dennis 1, Jim Prescott 2, Yimin Ye 1, Tim Skewes 1 February 26 1 CSIRO Marine and Atmospheric Research, 2 AFMA www.csiro.au
Background: The Fishery Jurisdictions and the Torres Strait Treaty 12 14 16 # 1 1 # Coral Sea Australia 3 3 12 14 16 THE SHARED LOBSTER STOCK 1. Queensland EC fishery (QDPI&F) 2. Australian Torres Strait fishery (AFMA) 3. PNG Torres Strait fishery (PNG NFA) 2&3 have obligations under the Torres Strait Treaty (1985) in the TS Protected Zone
Background: The Australian Torres Strait lobster fishery as ornate rock lobsters do not readily enter pots, lobsters are taken exclusively by divers operating from small dinghies using short hand-spears divers either free-dive on shallow reefs or use hookah equipment (surface supplied air supply) to extend their bottom times the commercial diver fishery is comprised of two sectors: Islander (indigenous) fishers and Non-islander fishers Islander fishers (~5 licences) operate from the many island communities and sell to shore-based freezers Non-islander fishers (21 licences) operate from freezer vessels (up to 2 m) long, each supporting 1-7 tenders (~8 tenders) the combined annual catch ranged from 12-8 t (live weight) during the past two decades prior to 1999 catches were exclusively sold as frozen tails; currently 2-3% is sold live
Background: The Ornate Rock Lobster s Rapid & Cross Jurisdiction Life Cycle Recruit to fishery Torres S trait Post-puerulus Gulf of Papua Coral S ea Puerulus Phyllosoma Juvenile Larval Dispersal? 35 28 21 14 7 2 15 1 5 Settlement 1.5 yrs (1+) 2 4 6 8 1 12 14 16 Emigration 2.5 yrs (2+) 2 4 6 8 1 12 14 16 Carapace length (mm) Research Surveys Commercial Catch Breeding Population Reproduction 3 YEAR LIFE CYCLE larval lobsters (.5 years old) settle in Torres Strait in June sub-adult lobsters (2.5 years old) emigrate from Torres Strait in August/September breeding lobsters die after spawning between November and January the fishery targets mainly 1 year-class (2+ lobsters) hence in each year the fishable stock is determined by escapement of 2+ lobsters from the fishery 3 years earlier
Catches of the Fishery Sectors sharing the Lobster Stock 1. Torres Strait Commercial Islander Fishers 2. Torres Strait Commercial Non-Islander Fishers 3. PNG Commercial Fishers 4. Queensland Commercial Fishers (most Torres Strait dual endorsed) The catch of the traditional fishers in Torres Strait and PNG is thought to be negligible TOTAL LOBSTER CATCH (24) = 19 t (live weight) TSIslander 24.9% QLD 15.6% About 7% is taken by Australian Torres Strait fishers TSN-islander 44.7% TSPNG 14.8%
Research to support management of the Torres Strait Islander and non-islander fisheries 1989-25 FISHERY-INDEPENDENT POPULATION SURVEYS status of the recruiting (1+) and fished (2+) year-classes is assessed annually using diver surveys initial stock abundance estimate (51 t live weight ± 2%) suggested exploitation was low and the fishery could support increased effort in both sectors TAC set as the catch of the dive fishery to: maximize the opportunities for traditional inhabitants of both Australia and PNG under the Torres Strait Treaty Importantly expansion was limited to the Islander sector
Annual population monitoring and stock status 1989-25 annual fishery-independent monitoring showed a decline in stock abundance through the 199s concurrent monitoring of the Islander sector catch and effort corroborated the dive survey data fishery modeling suggested fishing mortality was exceeding conservative targets (75% escapement) management regulations including: preventing growth of the non-islander sector, a seasonal ban on hookah diving gear and a minimum size limit (1 mm tail length) were implemented by AFMA to address the treaty objectives 9 Relative abundance 6 3 1988 1989 199 1991 1992 1993 1994 1995 1996 1997 1998 Year 1999 2 21 22 23 24 25 26 1+ years old 2+ years old Relative 2+ abundance 8 6 4 2 1989 199 1991 1992 1993 1994 1995 1996 Year 1997 1998 1999 2 21 22 1 8 6 4 2 2+ lobsters/diver/hr
Research to address potential conflict between the Islander and Non-islander sectors (1) Traditional free-diver versus hookah diver catch rate concern was raised that hookah fishing may be impacting the catch rates of freedivers independent monitoring of catch rates allowed a comparison of both methods during 1989-21 Kgs/diver/hour 6 1987 1988 Method Hookah Free 1989 199 1991 1992 1993 1994 1995 Year ANOVA: Years P<.1 Method P<.1 1996 1997 1998 1999 2 21 22 the hookah diver catch rate was on average 48% higher than that of free divers however, there was no widening of the gap between the methods over time it was concluded that hookah divers were not adversely affecting catch rates of free divers
Research to address potential conflict between the Islander and Non-islander sectors No. lobsters (thousands) Warraber Island 4 3 2 1 March 1994 August 1994 1.5 1.5 Tail weight (tonnes) (2) Local depletion of traditional home reefs by hookah divers concern was raised that non-islander hookah divers fishing near home reefs may deplete the shallow reef-edge population a research project, based at Warraber Island in central Torres Strait, was undertaken to address this concern diver surveys of the reef-edge and off-reef (within 2 km of the reef-edge) populations were conducted at the start (March) and end of the fishing season (August) the decline in numbers on the reef-edge was explained by the local catch and natural mortality, suggesting movement onto the reef-edge during the fishing season was negligible
Research to address potential conflict between the Islander and Non-islander sectors Number of lobsters 6 8 14 Habitat Off reef 2 1.3:1 45 1:1.1 113 1:1.1 3 9 15 6 8 8 Carapace length (mm) Reef edge 19 1.4:1 44 1.9:1 32 1.7:1 August 1993 March 1994 August 1994 3 9 15 Stock estimate (# lobsters) and 95% CI Pilot (August 1993) Off-reef 39618 ± 1862 1 st survey (March 1994) 32839 ± 11645 2 nd survey (August 1994) 36884 ± 11518 Reef edge 3719 ± 163 277 ± 167 962 ± 4 only large (2+) lobsters were found on the reef-edge cf. off-reef suggesting movement onto the reef must occur after 2+ lobsters leave on the breeding migration (August/September) with minimum size limits and a seasonal closure (Oct/Nov) in place the off-reef recruits (1+) were protected and hence hookah fishing would have little impact on the reef-edge population the off-reef population comprised 1 times the number of recruits (1+) required to replenish the reef-edge it was concluded that hookah fishing should be excluded within 2 km of the Warraber Island home reef to conserve the traditionally fished population
Recent Islander and Non-islander catch Year Lobster catch (tonnes whole) Nonislander sector Islander sector 21 62 59 121 22 132 79 211 23 325 144 469 24 488 272 76 25* 396 24 6 Total % Islander sector 49 37 31 36 34 recent recovery of catch data from processing companies by AFMA has allowed an assessment of trends in Islander and Non-islander catch increased stock abundance since 21 saw an 8 fold increase in the Non-islander catch whilst the increase was only 3 fold for the Islander catch whilst the 21 stock was anomalous these trends highlight an increased ability to compensate for stock abundance in the Nonislander sector to compensate AFMA has implemented effort cuts (2-3% reduction in tender numbers) in the Non-islander sector since 23
Future research to support sector allocations under the new quota managed system in July 25 the Torres Strait Protected Zone Joint Authority (PZJA) decided to move to a 5/5 share of entitlements between the Islander and Non-islander sectors these allocations will rely on accurate estimates of pre-season recruit (1+) abundance and projected mortality and the first pre-season survey was undertaken in November 25 most importantly the success of the QMS will rely on effective, timely and validated monitoring of catch in both sectors of the fishery the 5% share for the Islander sector addresses the need to maximize the opportunities for traditional inhabitants under the Torres Strait Treaty TSIslander 35.8% The future challenge will be to ensure the Islander sector increases its share of the pie; particularly during years of high stock abundance TSN-islander 64.2%
Contact, Darren Dennis Name: Darren Dennis Title: Experimental Scientist Phone: (+61 7 38267248) Email:darren.dennis@csiro.au Web: www.marine.csiro.au Thank You Contact CSIRO Phone: 13 363 4 +61 3 9545 2176 Email: enquiries@csiro.au Web: www.csiro.au www.csiro.au