BFT-Table 1. Estimated size, weight and weight at size conversion factors for Atlantic bluefin tuna stocks. Highlighted weight - size functions correspond to the annual equations representing overall mean forthe population. Size measures are straight fork length (SFL), curved fork length (CFL), length 1st dorsal spine (LD1), head length straight line from snout to operculum (HeadL), preopercular length straightline from the snout to preoperculum (PreOP). Weight measures are round weight: weight of the whole fish (RWT); gutted weight: weight without guts and gonads (GWT); gutted and gilled: weight withoutguts, gonads and gills (GGWT); gutted gilled and tailed: weight without guts, gonads, gills and tail (GGTWT); and dressed weight: weight of fish gutted, head and tail off (DWT). All size units are centimeters(cm) and weight in kilograms (kg).

Function relationship by stock unit

XYX range

Y rangenSize conversion factors
SFL = alpha + beta*CFL
CFL = alpha + beta*SFL

CFL cm
SFL cm

SFL cm
CFL cm55 ‐ 275
53 ‐265

53 ‐ 265
55 ‐27410351035

Weight conversion factors
RWT = alpha + beta*DWT
DWT = alpha + beta*RWT

DWT kgRWT kgRWT kg
DWT kg93 ‐ 637
70 ‐ 514

70 ‐ 514
93 ‐ 637

1960
1960

Wgt size relations
RWT_std = alpha*SFL_std^beta

SFL cmRWT kg53 ‐353

4 ‐637RWT = alpha*CFL^beta
DWT = alpha*CFL^beta
GGTWT = alpha*SFL^beta

CFL cm
CFL cm
SFL cmRWT kg56 ‐338
4 ‐ 637
DWT kg
127 ‐ 366 25 ‐ 514
GGTWT kg 92 ‐289
11 ‐ 403

alpha

Residual standarderror

betar²1.85746‐0.83190.96061.031410.991004
0.991004

2.564565
2.670115

Fit Robust Estimate
Fit Robust Estimate

6.19709
0.291141.23034
0.79671

0.976003
0.976003

12.58053
10.13543

Fit Robust Estimate
Fit Robust Estimate

51204 1.77054E‐05 3.001252

na

30.650867

nonlinear fit weight CV RWT2977 4.94442E‐05 2.80941
49344
8.31E‐06 3.078037
2324 1.27354E‐05 3.049098

na
na
na

32.624945
24.749856
18.241847

nonlinear fit Gauss‐Newton
nonlinear fit Gauss‐Newton
nonlinear fit Gauss‐NewtonMethod

West ‐ BFT

Function relationship by stock unit

XYX range

Y rangenalphaSize conversion factors
LD1 = alpha + beta*SFL
CFL = alpha + beta*SFL
SFL = alpha + beta*LD1
CFL = alpha + beta*LD1
LD1 = alpha + beta*CFL
SFL = alpha + beta*CFL
HeadL = alpha + beta*CFL
PreOP = alpha + beta*CFL
PreOP = alpha + beta*HeadLSFL cm
SFL cm
LD1 cm
LD1 cm
CFL cm
CFL cm
CFL cm
CFL cmHeadL cm

LD1 cm
CFL cm
SFL cm
CFL cm
LD1 cm
SFL cmHeadL cm
PreOP cm
PreOP cm

56 ‐300
78 ‐ 242
17 ‐ 71
24 ‐ 71
84 ‐ 283
84 ‐ 252
84 ‐ 284
153 ‐ 284
38 ‐ 74

17 ‐ 71
84 ‐ 252
56 ‐ 300
84 ‐ 283
24 ‐ 71
78 ‐ 242
22 ‐ 74
33 ‐ 74
33 ‐ 74636
222636312
312222306294
294

Weight conversion factors
GWT = alpha + beta*RWT
RWT = alpha + beta*GWT
RWT = beta*GGWT (Mediterraneo)
RWT = beta*GGWT (Atlantic)

RWT kg
GWT kgRWT kgRWT kg

GWT kgRWT kg
GGWT kg
GGWT kg

0.3 ‐ 370
0.3 ‐ 358

0.3 ‐ 358
0.3 ‐ 370

236236

Wgt size relations
RWT_std = alpha*SFL_std^beta

SFL cmRWT kg27 ‐ 300

0.25 ‐ 513

GGTWT = alpha*SFL^beta
GGWT = alpha*SFL^beta
GGWT = alpha*CFL^beta
GGWT = alpha*LD1^beta
RWT = alpha*LD1^beta

SFL cm
SFL cm
CFL cm
LD1 cm
LD1 cmGGTWT kg
GGWT kg
GGWT kg
GGWT kg
RWT kg75 ‐ 281
55 ‐ 289
94 ‐289
29 ‐ 76
17 ‐ 79

8 ‐ 362
2.8 ‐ 385
10 ‐ 338
20 ‐350
3 ‐ 425

Residual standarderror

beta

r²

5.68911‐1.887‐19.733‐27.832
7.91822.94574
4.40413
1.09339‐2.2179

0.25426
1.050653.86483
4.127260.235470.944190.22418
0.189220.83582

0.977620.989565
0.97762
0.963645
0.963645
0.989565
0.865423
0.646239
0.782967

2.051968
4.121014
8.063375
8.838777
2.116302
3.885642
3.048081
3.099589
2.427795

Fit Robust Estimate
Fit Robust Estimate
Fit Robust Estimate
Fit Robust Estimate
Fit Robust Estimate
Fit Robust Estimate
Fit Robust Estimate
Fit Robust Estimate
Fit Robust Estimate‐0.21690.231150.95401
1.04789
1.131.16

0.999741
0.999741

1.090203
1.140367

Fit Robust Estimate
Fit Robust Estimate
Annon. 1993 *ICCAT, 1997 **

74272 3.50801E‐05 2.878451

na

15.965446

nonlinear fit weight CV RWT

8034
3469
4962
2044
2796

na
na
na
na
na

13.407286
14.248998
15.35662
21.819718
20.019236

nonlinear fit Gauss‐Newton
nonlinear fit Gauss‐Newton
nonlinear fit Gauss‐Newton
nonlinear fit Gauss‐Newton
nonlinear fit Gauss‐Newton

MethodEast ‐ BFT

4.58875E‐05
0.00010655
2.54806E‐05
0.003845665
0.001120971

2.807655
2.630105
2.893777
2.621073
2.917953* Anon. (1993) Report of the Second GFCM/ICCAT Expert Consultation on Stocks of Large Pelagic Fishes in the Mediterranean Sea. Collect Vol Sci Pap ICCAT 40 (1): 11–111.
** ICCAT (1997) Estimates of unreported Atlantic bluefin tuna catches. Collect Vol Sci Pap ICCAT 46: 159–160.

BFT-Table 2. Estimated coefficients alpha and beta of the monthly weight-size relationship for Atlantic bluefin tuna stock units. All functions correspond tostraight fork length (SFL) cm and round weight (RWT) kg.

West ‐ BFT
MonthJanFebMar
AprMayJun
JulAug
Sep
Oct
Nov
Dec

alpha
1.77054E‐05
1.77054E‐05
1.77054E‐05
1.77054E‐05
1.77054E‐05
1.77054E‐05
1.77054E‐05
1.77054E‐05
1.77054E‐05
1.77054E‐05
1.77054E‐05
1.77054E‐05

East ‐ BFT
beta
2.997890751
3.002926875
3.008338232
3.016185296
2.998831057
2.98858373
2.992473629
2.998237612
3.001723945
3.007748588
3.004938062
2.99596985

MonthJanFeb
Mar
AprMayJun
JulAugSep
Oct
NovDecalpha3.50801E‐05
3.50801E‐05
3.50801E‐05
3.50801E‐05
3.50801E‐05
3.50801E‐05
3.50801E‐05
3.50801E‐05
3.50801E‐05
3.50801E‐05
3.50801E‐05
3.50801E‐05

beta
2.87767028
2.875859708
2.875496669
2.879610235
2.886913883
2.883091788
2.871533069
2.872001949
2.87577309
2.876331652
2.877162829
2.87529487

Reference
Rodriguez-Marin E, Ortiz M, Ortiz de Urbina J.M., Quelle P, Walter J, Abid N, et al. (2015) Atlantic bluefin tuna (Thunnus thynnus ) Biometrics and Condition.
PLoS ONE 10(10): e0141478.doi:10.1371/journal.pone.0141478