What you need to know about juvenile tunas in the Philippines: N. Barut National Fisheries Research & Development Institute, BFAR J. Ingles WWF, Coral Triangle Program Stakeholders Consultation Workshop on Saving the Juvenile Tunas Greenleaf Hotel, General Santos City September 1, 213
Outline of Presentation Some facts about tuna fisheries What is juvenile tuna? How much juvenile tunas do we harvest? Where and When are Juvenile tunas found? Why are juvenile tunas important to us? What needs to be done.
Depletion Ratio Depletion Ratio Total Biomass Adult Biomass 1.2 1.2 1 1.8.8.6.6.4.2 yft bet skj.4.2 yft skj bet 195 196 197 198 199 2 21 195 196 197 198 199 2 21
What is a juvenile tuna Juvenile tuna or immature tunas are those fish that have not reached age of maturity or reached the ability to reproduce. Length/Age at Maturity (Lm) many interpretations the average minimum length or its corresponding age of the fish that is reproductively capable. Minimum length of spawning fish L 5 = length / age where 5% of the new recruits become reproductively capable SKJ = 45 cm; YFT= 1 cm; BET= 15 cm
Quantity ( tons) How much do we harvest? 25 2 15 1 5 Total Tuna Harvest SKJ YFT BET 25 26 27 28 29 21 211 Year Accuracy of estimates improved significantly (2 yrs) Declining trend for all 3 principal species Arguably decline partly due to compliance (high seas closure) Source: WCPFC Yearbook 212
How much juvenile tunas are harvested? 21 Juvenile Tuna catch estimate (mt) Gears SKJ YFT BET TOTAL PS 76679 1461 2166 9296 RN 26365 5363 218 31945 HL large 237 1 246 HL small 2815 4396 132 65213 21 Total Juveniles 192,11 mt HL large HL small RN PS % For 21, 9.8 % of total catch of our tunas are classified as juveniles Both commercial and artisanal gears catch significant quantities; Handline Large harvest predominantly mature individuals Sources: WCPFC Yearbook 212 for total harvest; NSAP database
Frequency Frequency Where are juvenile tunas found? 2 Skj: Lagonoy Gulf (24) 15 1 Juv = 43% Mature = 57 % 5 3 25 19 27 35 43 51 59 69 77 Fork Length (cm) YFT: Lagonoy Gulf (24) 2 15 1 5 2 45 7 95 12 145 Fork Length (cm) Sources: LF from FRMP Project 24; Map redrawn from WWF-PPTST
Frequency Frequency Where are juvenile tunas found? 5 4 Pacific Seaboard (Off Samar) SKJ: HL & TL 3 2 1 1 2 3 4 5 6 7 Fork Length (cm) 3 25 2 YFT: HL&TL Source: WWF FAD report 15 1 5 2.5 27.5 52.5 77.5 12.5 127.5 152.5 177.5 Fork Length (cm) Source: NSAP database
Frequency Frequency Frequency () Where are juveniles found? 2 15 1 BET: Moro Gulf/ Celebes Sea 25 2 15 1 YFT: Moro Gulf/ Celebes Sea 5 5 2.5 27.5 52.5 77.5 12.5 127.5 152.5 177.5 Fork Length (cm) 2.5 27.5 52.5 77.5 12.5 127.5 152.5 177.5 22.5 Fork length (cm) 5 SKJ: Moro Gulf/ Celebes Sea 4 3 2 1 1 7 13 19 25 31 37 43 49 55 61 67 73 Fork Length (cm) Sources: LF from NSAP database, map from WWF FAD report
Frequency Frequency Where are juveniles found? Northwestern Philippine Sea 4 3 SKJ: DLL&TL 2 1 8 6 1 7 13 19 25 31 37 43 49 55 61 67 Fork Length (cm) YFT:DLongline 4 2 2.5 27.5 52.5 77.5 12.5 127.5 152.5 177.5 Fork Length (cm) Sources: LF data from NSAP database, Map from WWF
Where are juvenile tunas found? Philippine EEZ Sources:
FAD deployment evolution in the Philippines Sources WWF 212 FAD tech report
Why are juvenile tunas present all year? Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb NE Monsoon Cohort SPAWNING 15-25 cm 25-35 cm 35-45 cm SW Monsoon Cohort 25-35 cm 35-45 cm 45-6 cm SPAWNING 45-6 cm 15-25 cm Migrates to the Pacific 25-35 cm Yellowfin Tuna Juvenile tunas occur all year; Two cohorts per year; Recruitment to the fishery (~2 cm) occur in April-May and Nov-Dec of each year Smaller individuals in nearshore waters and on upper level of water column; Sizes from 6-1 cm (5-25 kg) disappears from catches and rarely caught in Phil inzone waters; Sources: yamanaka, 1989; www.fishbase.org
How fast do yft grow? YFT = 57.56 cm FL and 3.726 kg in year 1 15-35 cm = 2.5 mm/d; 35-79 cm =.96 cm/d Source: Yamanaka, 1989 Source: Lehodey & Leroy, 1999. Age and growth of yellowfin tuna (T. albacares from the Western and Central Pacific Ocean as indicated by daily growth increments and tagging data
How fast do skj grow? SKJ = up to 27 cm = 1.6 mm/d; 27-71 cm=.8 mm/day Source: Uchima & Struhsaker, 1981
Why are juvenile tunas important to us? Food 192, tons could feed 5.3 million Filipinos Value @ P7/kg, value approximates P13.44 billion Jobs unknown but significant number of direct and indirect beneficiaries that are dependent on juvenile and adult tuna fisheries!! Why are juvenile tunas important to the rest of the world? Ph-born tunas supply undetermined portion of the Western and Central Pacific tuna stocks that are harvested by the DWF that includes Philippine owned companies.
If saving our juvenile tunas is vital to our economy and to our survival... what needs to be done?
We need to: manage the harvest of tunas (both juvenile and adults) by limiting our harvest at a level that we will continue to benefit and allow sufficient numbers to reproduce to replenish the population taken by the fisheries; find a way to compensate our fishers from social and economic cost arising from compliance with conservation measures; Conduct focused research, to provide the decision basis for the policies. Identify innovative solutions to the issue, prototype the solution, pilot test and upscale the feasible ones.
Thank you for your kind attention
PS RN Hand line H&L/ MHL DGN Troll Skipjack 98.9 99.8. 82.6 41.8 9.5 Yellowfin 1. 1. 18. 99.3 no data 1. Bigeye 1. 1. 3.4 93. no data no data 21 SKJ YFT BET TOTAL PS 76679 1461 2166 9296 RN 26365 5363 218 31945 HL large 237 1 246 HL small 2815 4396 132 65213 21 Total Juveniles 19211