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Stakeholders Consultation Workshop on Saving the Juvenile Tunas
Greenleaf Hotel, General Santos City
September 10, 2013
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
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.
0
0.2
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0.6
0.8
1
1.2
1950 1960 1970 1980 1990 2000 2010
Dep
leti
on
Rat
io
yft
skj
bet
0
0.2
0.4
0.6
0.8
1
1.2
1950 1960 1970 1980 1990 2000 2010
De
ple
tio
n R
atio
yft
bet
skj
Adult Biomass Total Biomass
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 • L50= length / age where 50% of the new recruits
become reproductively capable
SKJ = 45 cm; YFT= 100 cm; BET= 105 cm
How much do we harvest?
0
50
100
150
200
250
2005 2006 2007 2008 2009 2010 2011
Qu
anti
ty (
00
0 t
on
s)
Year
SKJ
YFT
BET
• Accuracy of estimates improved significantly (2 yrs) • Declining trend for all 3 principal species • Arguably decline partly due to compliance (high
seas closure)
Total Tuna Harvest
Source: WCPFC Yearbook 2012
How much juvenile tunas are harvested?
2010 Juvenile Tuna catch estimate (mt)
Sources: WCPFC Yearbook 2012 for total harvest; NSAP database
Gears SKJ YFT BET TOTAL PS 76679 14061 2166 92906 RN 26365 5363 218 31945 HL large 0 2037 10 2046 HL small 20815 43096 1302 65213 2010 Total Juveniles
%
PS
RN
HL
small
HL
large
• For 2010, 90.8 % of total catch of our tunas are classified as juveniles
• Both commercial and artisanal gears catch significant quantities;
• “Handline Large” harvest predominantly mature individuals
192,110 mt
Where are juvenile tunas found?
Sources: LF from FRMP Project 2004; Map redrawn from WWF-PPTST
0
50
100
150
200
19 27 35 43 51 59 69 77
Fre
qu
en
cy
Fork Length (cm)
Skj: Lagonoy Gulf (2004)
Mature = 57 % Juv = 43%
0
50
100
150
200
250
300
20 45 70 95 120 145
Freq
uen
cy
Fork Length (cm)
YFT: Lagonoy Gulf (2004)
Where are juvenile tunas found?
Source: WWF FAD report
0
100
200
300
400
500
0 10 20 30 40 50 60 70
Freq
ue
ncy
Fork Length (cm)
SKJ: HL & TL
0
500
1000
1500
2000
2500
3000
2.5 27.5 52.5 77.5 102.5 127.5 152.5 177.5
Freq
uen
cy
Fork Length (cm)
YFT: HL&TL
Pacific Seaboard (Off Samar)
Source: NSAP database
Where are juveniles found?
Sources: LF from NSAP database , map from WWF FAD report
0
5
10
15
20
25
2.5 27.5 52.5 77.5 102.5 127.5 152.5 177.5 202.5
Freq
uen
cy (
000)
Fork length (cm)
YFT: Moro Gulf/ Celebes Sea
0
1000
2000
3000
4000
5000
1 7 13 19 25 31 37 43 49 55 61 67 73
Freq
uen
cy
Fork Length (cm)
SKJ: Moro Gulf/ Celebes Sea
0
50
100
150
200
2.5 27.5 52.5 77.5 102.5 127.5 152.5 177.5
Freq
uen
cy
Fork Length (cm)
BET: Moro Gulf/ Celebes Sea
Where are juveniles found?
Sources: LF data from NSAP database , Map from WWF
0
100
200
300
400
1 7 13 19 25 31 37 43 49 55 61 67
Freq
uen
cy
Fork Length (cm)
SKJ: DLL&TL
0
200
400
600
800
2.5 27.5 52.5 77.5 102.5 127.5 152.5 177.5
Freq
uen
cy
Fork Length (cm)
YFT:DLongline
Northwestern Philippine Sea
Where are juvenile tunas found?
Sources:
Philippine EEZ
FAD deployment evolution in the
Philippines
Sources WWF 2012 FAD tech report
Why are juvenile tunas present all year?
Sources: yamanaka, 1989; www.fishbase.org
Month NE Monsoon
Cohort
SW Monsoon
Cohort
Jan 25 -35 cm
Feb SPAWNING
Mar
35 - 45 cm Apr 15-25 cm
May
Jun 25 -35 cm
45 - 60 cm Jul
Aug 35 - 45 cm
Sep SPAWNING
Oct
Nov 45-60 cm 15-25 cm
Dec
Jan Migrates to the 25 -35 cm
Feb Pacific
• Juvenile tunas occur all year; • Two cohorts per year; • Recruitment to the fishery
(~20 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 60-100 cm (5-25 kg) disappears from catches and rarely caught in Phil in- zone waters;
Yellowfin Tuna
How fast do yft grow?
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
YFT = 57.56 cm FL and 3.726 kg in year 1 15-35 cm = 2.5 mm/d; 35-79 cm = 0.96 cm/d Source: Yamanaka, 1989
How fast do skj grow?
SKJ = up to 27 cm = 1.60 mm/d; 27-71 cm= 0.8 mm/day Source: Uchima & Struhsaker, 1981
Why are juvenile tunas important to us?
Food – 192,000 tons could feed 5.3 million Filipinos Value – @ P70/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?
• 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.
We need to:
Thank you for your kind attention
PS RN
Hand line
H&L/ MHL
DGN Troll
Skipjack 98.9 99.8 0.00 82.6 41.8 90.5
Yellowfin 100.0 100.0 18.0 99.3 no data 100.0
Bigeye 100.0 100.0 3.40 93.0 no data no data
2010 SKJ YFT BET TOTAL PS 76679 14061 2166 92906 RN 26365 5363 218 31945 HL large 0 2037 10 2046 HL small 20815 43096 1302 65213 2010 Total Juveniles 192110