AnAn ecologicalecological riskrisk assessmentassessment forfor thethe effecteffect ofof thethe KoreanKorean tunatuna longlinelongline fisheryfishery inin thethe WesternWestern andand CentralCentral PacificPacific OceanOcean

You Jung Kwon1,2, Doo Hae An2, Chang Ik Zhang1, Dae Yeon Moon2 and Jae Bong Lee2

1Pukyong National University, Korea , 2National Fisheries Research & Development Institute, Korea

EcologicalEcological riskrisk assessmentassessment ScopingScoping ScopingScoping

Comprehensive(qualitative analysis) UncertainLevel 1 Level 1 Time & $$ Qualitative LH LH

(semi-quantitative analysis) Level 2 Level 2

LH LH Focused More certain (quantitative analysis) Level 3 Level 3 Time & $$ Quantitative LH LH Risk Management Response Risk Management Risk Management Response Risk Management

(Smith et al, 2007) LevelLevel 2:2: PSAPSA (Productivity(Productivity andand SusceptibilitySusceptibility Analysis)Analysis)

dB B rB )1( −−= qEB dt K

Productivity, r - recovery rate after potential depletion or damage by the fishing activity

Susceptibility, q - extent of the impact due to fishing activity PurposePurpose

Assessment on the adverse impacts of the Korean tuna longline fishery in the Western and Central Pacific Ocean - target species, non-target species and dependent or associated with the target species

Precautionary approach for the stock or ecosystem management and conservation - identification of non-target species for consideration of future research or management - protect biodiversity in the marine environment

DataData Survey area N 60 o Period: 2005-2008 o 2005 40 Area: Western and Central Pacific Ocean 20 o 2007-2008 2006 Source: 2007 0o 2005 - 20,157 catches in number WCPO 20 o 2006 EPO - 48 species

40 o Collected data by 7 scientific observers

60 o from NFRDI in Korea S EW100 o 120 o 140 o 160 o 180 o 160 o 140 o 120 o 100 o 80 o SpeciesSpecies Group English name Scientific name

Albacore Thunnus alalunga Tunas (5) Bigeye tuna Thunnus obesus Yellowfin tuna Thunnus albacares

Skipjack tuna Katsuwonus pelamis

Bluefin tuna Thunnus thynnus Swordfish Xiphias gladius Billfishes (6) Shortbill spearfish Tetrapturus angustirostris Blue marlin Makaira mazara

Indo-Pacific sailfish Istiophorus platypterus Striped marlin Tetrapturus audax Black marlin Makaira indica Bigeye thresher shark Alopias superciliosus Sharks Blue shark Prionace glauca (13) Galapagos shark Carcharhinus galapagensis Longfin mako Isurus paucus Shortfin mako Isurus oxyrinchus

Oceanic whitetip shark Carcharhinus longimanus

Grey reef shark Carcharhinus amblyrhynchos

Smooth hammerhead Sphyrna zygaena Crocodile shark Pseudocarcharias kamohara i Scalloped hammarhead shark Sphyrna lewini Japanese velvet dogfish Zameus ichiharai

Salmon shark Lamna ditropis Silky shark Carcharhinus falciformis

SpeciesSpecies Group English name Scientific name Turtles Green sea turtle Chelonia mydas (3) Loggerhead sea turtle Caretta caretta Olive ridley sea turtle Lepidochelys olivacea Sickle pomfret Taractichthys steindachneri Other species (21) Black pomfret Taractes rubescens Escolar Lepidocybium flavobrunneum Snake mackerel Gempylus serpens Wahoo Acanthocybium solandr i Longnose lancetfish Alepisaurus ferox Pelagic stingray Dasyatis violacea

Ocean sunfish Mola mola Great barracuda Sphyraena barracuda Opah Lampris guttatus Dolphinfish Coryphaena hippurus Sharptail mola Masturus lanceolatus

Manta ray Mobula japanica

Oilfish Ruvettus pretiosus

Rainbow runner Elagatis bipinnulata

Slender sunfish Ranzania laevis

Suck fish Remora remora

Flyingfish Prognichthys gibbifrons

Crested oarfish Lophotus lacepede

Razorback scabbardfish Assurger anzac Shortnose lancetfish Alepisaurus brevirostris

SpeciesSpecies compositioncomposition catchcatch inin weightweight Others 27.9% Escolar 39.3% Bigeye Others thresher shark 9.6% 6.6% Sickle pomfret ShortfinMako shark mako 12.2% 22.9% Blue sharkNon- Opah 60.9% Turtles 20.7%Target target 0.3% Others species species 8.2% 43%Sharks 57%Tunas 28.8% 56.8% Billfishes 5.9%

Striped marlin Skipjack Bluefin Indo-Pacific Black marlin 16.5% 1.3% 0.1% sailfish 0.8% Yellowfin 5.8% 10.6% Albacore 28.5% Swordfish Shortbill 44.5% Bigeye spearfish Blue marlin 59.4% 2.8% 29.6%

Proportion of captured species (weight) by 7 scientific observations from 2005 to 2008 IndicatorsIndicators forfor speciesspecies componentscomponents (Target,(Target, By-catch,By-catch, ProtectedProtected species)species)

Productivity attributes Susceptibility attributes

• Maximum age • Overlap with fishing effort • Age at maturity • Global distribution • Size at maturity • Adult habitat overlap with • Annual fecundity juvenile

• Maximum size • Selectivity

• Reproductive strategy • Post-capture mortality • Trophic level

Attribute SusceptibilitySusceptibility Indicator Overlap with fishing effort

0m 25m Sea surface 25m sp. A 309m 167m sp. B 309m Maximum hook depth sp. C Reference Species A: High risk (2), 100% Species B: Medium risk (1), 50% point Species C: Low risk (0), 0%

bottom AttributesAttributes (CSIRO, 2005) Reference points Attributes Indicators Low (0) Medium (1) High (2) Maximum age (year) < 10 10 – 25 25 < Productivity Age at maturity (year) < 5 5 – 10 10 < Size at maturity (cm) < 40 40 - 200 200 < Maximum size (cm) < 100 100 - 300 300 < Broadcast Demersal Reproductive strategy Live bearer spawners spawners

Trophic level < 2.75 2.75 – 3.25 3.25 < Overlap with fishing 309 < 167 < 25 - 309 Susceptibility effort (m)

Global distribution Worldwide Hemisphere Locality Adult habitat overlap Low rate Medium rate High rate with juvenile Selectivity No selectivity for longline fishery Post-capture mortality Alive Barely alive Dead EcosystemEcosystem riskrisk assessmentassessment TypeⅠ TypeⅡ

2

High risk High risk Ⅱ Ⅱ Medium risk 1 Indicator Attribute Low risk Susceptibility Low risk

Captured mean length Captured mean 0 LengthIndicator at maturity Ⅰ ProductivityAttribute12 Ⅰ TypeTypeⅠⅠ

300 Tunas Sharks

200

100

Billfishes Other speciesOthers

200 Captured mean length (cm) Captured mean

100

0 0 100 200 100 200 300 Length at maturity (cm) TypeTypeⅡⅡ

2.0 2 Tunas Billfishes

1.01 Susceptibility

0.00 1.01 2.02 0.00 1.01 2.02 Productivity TypeTypeⅡⅡ TypeTypeⅡⅡ Galapagos shark 2 Oceanic white-tip Shark Oceanic white-tip Shark sharks

Scalloped hammarhead shark sharks

tunas billfishes tunas Longfin mako 1 Bigeye thresher shark

Susceptibility turtles billfishes turtles Blue shark Shortfin mako

0 12 Productivity ConclusionConclusion

Not only target tuna species were influenced by the tuna longline fishery, but also non-target species were affected by the fishery WCPFC This study

ƒ Blue shark- tunas: medium risk ƒ Galapagos shark ƒ Oceanic white-tip- billfishes: shark medium or highƒ Longfinrisk mako ƒ Shortfin mako - sharks: high risk ƒ Scalloped hammarhead shark ƒ Thresher shark ƒ Oceanic white-tip shark - turtles: : medium or high risk - others: medium or high risk ConclusionConclusion

For reducing non-target species

I. Development and improvement of long-term data collection, monitoring and research programmes

II. Enhancement and development of methodology - more robust assessment III.Identification of captured non-target species by other tuna fisheries such as purse seine or pole-and-line

Provide wider scientific advices to the policy makers and stakeholders