1

The following supplement accompanies the article

Open-ocean foraging ecology of southern bluefin tuna Thunnus maccoyii based on stomach contents Tomoyuki Itoh*, Osamu Sakai

*Corresponding author: itou@fra.affrc.go.jp

Marine Ecology Progress Series 555: 203–219 (2016)

MDS1

MDS2

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5

-1.0

-0.5

0.0

0.5

stress=0.1832

Cape area

100

110

120130

140150160

170180

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0

-1.0

-0.5

0.0

0.5

1.0

stress=0.1393

southeastern Indian Ocean

80

90100

110

120

130

140150160

170

180

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0

-1.0

-0.5

0.0

0.5

stress=0.2261

Tasmania area

110

120

130

140

15080cm90cm100cm110cm120cm130cm140cm150cm160cm170cm180cm

Fig. S1. nMDS plot of southern bluefin tuna stomach contents composition in weight by fork length in 10-cm bins in the 3 study areas. Ellipses represent the 95% confidence interval. Stress is a goodness of fit statistic (smaller values represent a better fit)

2

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0

-1.0

-0.5

0.0

0.5

1.0stress=0.2013

Cape area

67 8

9

10 1112 13

14

15

1718

MDS1

MDS2

-0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8

-0.5

0.0

0.5

1.0stress=0.1686

southeastern Indian Ocean

10

11

12

13

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0

-1.0

-0.5

0.0

0.5

1.0 stress=0.1316

Tasmania area

13

15

1617

6°C7°C8°C9°C10°C11°C12°C13°C14°C15°C16°C17°C18°C

Fig. S2. nMDS plot of southern bluefin tuna stomach contents composition in weight by sea surface temperature in 1 °C bins in the 3 study areas. Ellipses represent the 95% confidence interval. Stress is a goodness of fit statistic (smaller values represent a better fit)

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0

-1.0

-0.5

0.0

0.5

1.0stress=0.2083

Cape area

20042005

20062007

20082009

2011

2012

2013

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0

-1.0

-0.5

0.0

0.5

1.0

1.5stress=0.1846

southeastern Indian Ocean

1999

2000

20032004

2005

2006

20072008

2009

2010

2012

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0

-0.5

0.0

0.5

1.0stress=0.1805

Tasmania area

1999

20012002

2003

199920002001200220032004200520062007200820092010201120122013

Fig. S3. nMDS plot of the stomach content composition of southern bluefin tuna in weight by year in the 3 study areas. Ellipses represent the 95% confidence interval. Data for the Cape area were limited to since 2004, when lycoteuthids were first distinguished. Stress is a goodness of fit statistic (smaller values represent a better fit)

3

Cape areaProportion

0.0

0.2

0.4

0.6

0.8

1.0

4 5 6 7 8 9 10 11 12

37 324 504 309 78 29 62 9 7

Southeastern Indian Ocean

Proportion

0.0

0.2

0.4

0.6

0.8

1.0

4 5 6 7 8 9 10 11 12

11 43 515 222 125 288 151

Tasmania area

Proportion

0.0

0.2

0.4

0.6

0.8

1.0

4 5 6 7 8 9 10 11 12

47 85 176

Teleostei

otherMyctophidaeParalepididaeAlepisauridaeBramidaeScombridaeNomeidaePerciformes

Cephalopoda

otherTeuthidaArgonautidaeOnychoteuthidaeLycoteuthidaeOmmastrephidae

other

Fig. S4. Weight composition of the stomach contents of southern bluefin tuna by month for the 3 study areas. Numbers below the month represent the sample size. Compositions for months with

4

Cape areaProportion

0.0

0.2

0.4

0.6

0.8

1.0

-46

-45

-44

-43

-42

-41

-40

-39

-38

-37

-36

-35

-34

-33

-32

-31

47 110 368 287 203 82 63 55 38 54 52

Southeastern Indian Ocean

Proportion

0.0

0.2

0.4

0.6

0.8

1.0

-46

-45

-44

-43

-42

-41

-40

-39

-38

-37

-36

-35

-34

-33

-32

-31

15 30 152 380 243 174 184 82 22 9 24 32

Tasmania area

Proportion

0.0

0.2

0.4

0.6

0.8

1.0

-46

-45

-44

-43

-42

-41

-40

-39

-38

-37

-36

-35

-34

-33

-32

-31

8 38 82 98 42 11 12 14

Teleostei

otherMyctophidaeParalepididaeAlepisauridaeBramidaeScombridaeNomeidaePerciformes

Cephalopoda

otherTeuthidaArgonautidaeOnychoteuthidaeLycoteuthidaeOmmastrephidae

other

Fig. S5. Weight composition of the stomach contents of southern bluefin tuna by latitude in 1° bins for the 3 study areas. Numbers below the latitude represent the sample size. Compositions for latitude classes with

5

Cape areaProportion

0.0

0.2

0.4

0.6

0.8

1.0

-10 0 10 20 30 40 70 80 90 100

110

120

150

85 187 162 416 418 91

Southeastern Indian Ocean

Proportion

0.0

0.2

0.4

0.6

0.8

1.0

-10 0 10 20 30 40 70 80 90 100

110

120

150

8 44 242 863 183 12

Tasmania area

Proportion

0.0

0.2

0.4

0.6

0.8

1.0

-10 0 10 20 30 40 70 80 90 100

110

120

150

310

Teleostei

otherMyctophidaeParalepididaeAlepisauridaeBramidaeScombridaeNomeidaePerciformes

Cephalopoda

otherTeuthidaArgonautidaeOnychoteuthidaeLycoteuthidaeOmmastrephidae

other

Fig. S6. Weight composition of the stomach contents of southern bluefin tuna by longitude in 10° bins for the 3 study areas. Numbers below the longitude represent the sample size. Compositions for longitude classes with

6

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0 1.5

-0.5

0.0

0.5

1.0

stress=0.0824

4

5 67

810

MDS1

MDS2

-1.0 -0.5 0.0 0.5

-0.5

0.0

0.5

stress=0.1607

78

9

10

11

12

MDS1

MDS2

-1.0 -0.5 0.0 0.5

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6 stress=0.1732

4

56

456789101112

Fig. S7. nMDS plot of the stomach content composition of southern bluefin tuna in weight by month in the 3 study areas. Ellipses represent the 95% confidence interval. Data for the Cape area were limited to since 2004, when lycoteuthids were first distinguished. Stress is a goodness of fit statistic (smaller values represent a better fit)

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0 1.5 2.0

-1.0

-0.5

0.0

0.5

1.0

1.5stress=0.1312

46S

45S44S43S

42S

41S40S

39S37S

MDS1

MDS2

-1.5 -1.0 -0.5 0.0 0.5

-0.5

0.0

0.5

1.0

stress=0.1839

43S

42S41S40S

39S

38S

37S

MDS1

MDS2

-1.0 -0.5 0.0 0.5 1.0

-1.0

-0.5

0.0

0.5

1.0 stress=0.1743

43S

42S41S

40S

46S45S44S43S42S41S40S39S38S37S

Fig. S8. nMDS plot of the stomach content composition of southern bluefin tuna in weight by latitude in 1° in the 3 study areas. Ellipses represent the 95% confidence interval. Data for the Cape area were limited to since 2004, when lycoteuthids were first distinguished. Stress is a goodness of fit statistic (smaller values represent a better fit)

7

MDS1

MDS2

-0.5 0.0 0.5 1.0

-0.5

0.0

0.5

1.0

1.5stress=0.179

10W0

10E 20E

30E

40E

80E

90E100E110E

150E10W010E20E30E40E

80E90E100E110E150E

Fig. S9. nMDS plot of the stomach content composition of southern bluefin tuna in weight by longitude in 10° bins. Ellipses represent the 95% confidence interval. Stress is a goodness of fit statistic (smaller values represent a better fit)

Table S1. Definition of the four stages of digestion used to classify the prey items Stage Teleost Cephalopod Crustacean Other

A Skin is not digested. Liver is intact. Intact in color and in details of the parts.

Intact body and color.

B Digestive organ is intact.

Head and arms are not separated from the mantle.

The color is slightly faded, and some parts lack detail.

The color is slightly faded, and some parts lack detail.

C Individual prey items are recognizable. Meat is present, not only adhering to the vertebrae.

The mantle is separated from the head and arms, but still intact.

The exoskeleton is softened, but the whole body is still intact.

Digested, but the individual is easily recognizable.

D Only bones or otoliths remain. If meat is present, it only adheres to the vertebrae. Individual prey items are not recognizable from the body.

The mantle is digested, and usually open. Sometimes only the mandibles remain.

The body is broken into several pieces.

Individual prey items cannot be recognized based on the remaining body.

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Table S2. Prey compositions of southern bluefin tuna for the whole study area in three statistics. %W, %N, and %O are the proportions of the weight, number of individuals, and number of southern bluefin tuna stomachs in which the prey item was found to the totals of natural preys (i.e. not parasite, non-animal or marine debris) in the dataset all southern bluefin tuna individuals pooled. %W_boot, %N_boot, and %O_boot are calculated from bootstrap resampling of the pooled dataset 1000 times. %MW and %MN are the percent mean proportion by weight and the percent mean proportion by number, based on prey composition in each individual southern bluefin tuna, respectively. 95% CI is the 95% confidence interval. Severely digested prey (digestion stage D) is included. Total number of stomachs was 4649

Taxon %W %W_boot mean (95% CI)

%MW (SD) %N %N_boot mean (95% CI)

%MN (SD) %O %O_boot mean (95% CI)

CHORDATA 46.5 46.0 (43.9-48.3) 39.3 (42.3) 40.1 38.9 (36.9-42.1) 29.9 (37.8) 63.4 63.5 (62.3-64.7) TELEOSTEI 46.2 45.7 (43.6-48.0) 37.5 (42.2) 34.2 32.6 (31.1-34.8) 27.3 (37.2) 61.0 61.0 (59.9-62.3)

Perciformes 18.8 18.1 (15.9-20.6) 7.7 (24.2) 1.8 1.8 (1.6-2.1) 5.5 (19.6) 11.4 11.2 (10.4-12.1) Nomeidae 8.3 8.3 (6.7-9.9) 4.9 (19.5) 1.1 1.1 (1.1-1.2) 3.6 (16.0) 7.5 7.5 (6.8-8.2)

Cubiceps caeruleus 7.4 7.4 (5.8-8.9) 4.6 (19.0) 1.0 1.1 (1.0-1.1) 3.3 (15.4) 7.0 7.0 (6.3-7.8) Bramidae 6.1 5.8 (4.9-6.6) 1.3 (10.1) 0.1 0.1 (0.1-0.2) 0.9 (8.3) 2.0 2.0 (1.8-2.2)

Brama sp. 0.9 0.7 (0.2-1.7) 0.1 (2.8) 0.0 0.0 (0.0-0.0) 0.1 (2.3) 0.1 0.1 (0.0-0.2) Pterycombus petersii 0.1 0.1 (0.0-0.3) 0.0 (1.8) 0.0 0.0 (0.0-0.0) 0.1 (1.7) 0.2 0.2 (0.1-0.3)

Scombridae 1.7 1.5 (1.0-2.2) 0.4 (6.2) 0.0 0.0 (0.0-0.0) 0.2 (4.1) 0.5 0.5 (0.3-0.6) Katsuwonus pelamis 0.7 0.7 (0.4-1.1) 0.2 (4.4) 0.0 0.0 (0.0-0.0) 0.1 (2.6) 0.2 0.2 (0.1-0.3) Thunnus sp. 0.1 0.1 (0.0-0.2) 0.0 (1.4) 0.0 0.0 (0.0-0.0) 0.0 (0.1) 0.0 0.0 (0.0-0.0) Auxis rochei 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.0 0.0 (0.0-0.0) 0.0 (0.7) 0.0 0.0 (0.0-0.1)

Centrolophidae 1.2 0.9 (0.6-1.5) 0.2 (3.8) 0.0 0.0 (0.0-0.0) 0.1 (2.5) 0.2 0.2 (0.1-0.2) Hyperoglyphe moselii 0.3 0.2 (0.0-0.5) 0.0 (1.5) 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.0 0.0 (0.0-0.0) Tetragonurus cuvieri 0.7 0.7 (0.4-1.2) 0.2 (3.8) 0.0 0.0 (0.0-0.0) 0.1 (2.4) 0.3 0.2 (0.2-0.4) Gempylidae 0.4 0.4 (0.1-0.6) 0.1 (2.8) 0.0 0.0 (0.0-0.0) 0.0 (0.9) 0.2 0.2 (0.1-0.2)

Carangidae 0.2 0.2 (0.1-0.3) 0.3 (5.3) 0.0 0.0 (0.0-0.0) 0.2 (4.1) 0.5 0.5 (0.3-0.6) Decapterus sp. 0.1 0.1 (0.0-0.2) 0.2 (3.6) 0.0 0.0 (0.0-0.0) 0.1 (2.8) 0.2 0.2 (0.1-0.4)

Pentacerotidae 0.2 0.2 (0.1-0.3) 0.2 (3.5) 0.4 0.4 (0.2-0.7) 0.2 (3.9) 0.3 0.4 (0.2-0.5) Mugilidae 0.1 0.1 (0.1-0.2) 0.1 (3.3) 0.0 0.0 (0.0-0.0) 0.1 (2.7) 0.2 0.2 (0.1-0.3) Echeneididae 0.0 0.0 (0.0-0.0) 0.0 (1.4) 0.0 0.0 (0.0-0.0) 0.0 (0.2) 0.0 0.0 (0.0-0.0) Uranoscopidae 0.0 0.0 (0.0-0.0) 0.0 (0.2) 0.0 0.0 (0.0-0.0) 0.0 (0.6) 0.0 0.0 (0.0-0.1)

Myctophiformes 16.2 16.3 (15.2-17.7) 12.4 (28.9) 18.3 16.9 (15-18.9) 8.2 (23.1) 21.7 21.9 (20.7-22.7) Alepisauridae 6.3 6.3 (5.8-7.0) 6.0 (20.6) 0.6 0.6 (0.6-0.7) 1.8 (10.0) 10.2 10.4 (9.6-11.1)

Alepisaurus ferox 0.9 1.0 (0.7-1.4) 0.6 (7.0) 0.1 0.1 (0.0-0.1) 0.3 (4.7) 1.0 1.1 (0.9-1.4) Alepisaurus brevirostris 0.3 0.2 (0.1-0.4) 0.1 (3.4) 0.0 0.0 (0.0-0.0) 0.1 (2.3) 0.2 0.2 (0.1-0.2)

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Taxon %W %W_boot mean (95% CI)

%MW (SD) %N %N_boot mean (95% CI)

%MN (SD) %O %O_boot mean (95% CI)

Paralepididae 6.6 6.6 (5.8-7.6) 3.9 (16.5) 0.9 1.0 (0.9-1.0) 2.3 (11.6) 8.5 8.5 (7.8-9.0) Paralepis sp. 3.8 3.9 (3.4-4.5) 1.6 (10.8) 0.2 0.2 (0.2-0.3) 0.7 (6.3) 2.8 2.8 (2.5-3.1) Paralepis atlantica 1.1 1.2 (1.0-1.6) 0.6 (6.7) 0.1 0.1 (0.1-0.1) 0.2 (3.7) 0.9 0.9 (0.8-1.0) Omosudis lowei 0.1 0.1 (0.0-0.1) 0.1 (3.1) 0.0 0.0 (0.0-0.0) 0.1 (2.0) 0.2 0.2 (0.1-0.3)

Notosudidae 0.2 0.3 (0.2-0.3) 0.1 (2.3) 0.0 0.0 (0.0-0.0) 0.1 (1.2) 0.3 0.3 (0.2-0.4) Anotopterus pharao 0.2 0.2 (0.0-0.5) 0.0 (1.1) 0.0 0.0 (0.0-0.0) 0.0 (0.1) 0.0 0.0 (0.0-0.1)

Myctophidae 2.8 2.8 (2.0-3.3) 2.3 (13.3) 16.7 15.2 (13.3-17.4) 4.0 (17.9) 5.4 5.4 (5.1-5.7) Synodontidae 0.0 0.0 (0.0-0.1) 0.0 (0.1) 0.0 0.0 (0.0-0.0) 0.0 (0.1) 0.0 0.0 (0.0-0.1)

Tetraodontiformes 0.1 0.1 (0.0-0.2) 0.2 (3.4) 0.0 0.0 (0.0-0.0) 0.2 (3.6) 0.3 0.3 (0.2-0.5) Tetraodontidae 0.1 0.1 (0.0-0.1) 0.1 (2.1) 0.0 0.0 (0.0-0.0) 0.1 (2.2) 0.2 0.2 (0.1-0.3) Triacanthodidae 0.0 0.0 (0.0-0.0) 0.0 (1.0) 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.0 0.0 (0.0-0.1)

Lampriformes 1.7 1.7 (1.1-2.4) 0.6 (7.2) 0.0 0.0 (0.0-0.1) 0.4 (5.5) 0.9 0.9 (0.7-1.1) Regalecus sp. 0.4 0.3 (0.1-0.6) 0.2 (3.7) 0.0 0.0 (0.0-0.0) 0.1 (2.2) 0.2 0.2 (0.1-0.4)

Trachipteridae 0.1 0.1 (0.0-0.3) 0.0 (1.2) 0.0 0.0 (0.0-0.0) 0.0 (0.0) 0.0 0.0 (0.0-0.1) Beloniformes 0.4 0.4 (0.3-0.5) 0.6 (7.1) 0.1 0.1 (0.1-0.1) 0.5 (6.3) 0.8 0.8 (0.7-0.9)

Scomberesocidae 0.1 0.1 (0.1-0.1) 0.2 (4.6) 0.0 0.0 (0.0-0.0) 0.2 (3.8) 0.3 0.3 (0.2-0.4) Exocoetidae 0.0 0.0 (0.0-0.1) 0.0 (1.1) 0.0 0.0 (0.0-0.0) 0.0 (0.1) 0.0 0.0 (0.0-0.1) Belonidae 0.0 0.0 (0.0-0.1) 0.0 (1.5) 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.0 0.0 (0.0-0.0) Hemiramphidae 0.0 0.0 (0.0-0.0) 0.0 (1.7) 0.0 0.0 (0.0-0.0) 0.0 (1.8) 0.1 0.1 (0.0-0.1)

Beryciformes 0.2 0.2 (0.1-0.3) 0.3 (4.9) 0.0 0.0 (0.0-0.0) 0.2 (3.6) 0.3 0.3 (0.2-0.4) Beryx sp. 0.1 0.1 (0.1-0.2) 0.3 (4.9) 0.0 0.0 (0.0-0.0) 0.1 (3.5) 0.3 0.3 (0.2-0.4)

Diretmidae 0.1 0.1 (0.0-0.2) 0.0 (0.7) 0.0 0.0 (0.0-0.0) 0.0 (0.8) 0.0 0.0 (0.0-0.1) Stomiiformes 0.2 0.2 (0.1-0.2) 0.3 (4.8) 4.3 3.9 (3.2-4.4) 0.5 (6.7) 1.1 1.0 (0.9-1.2) Sternoptychidae 0.2 0.2 (0.1-0.2) 0.3 (4.8) 4.3 3.9 (3.2-4.4) 0.5 (6.6) 1.0 1.0 (0.8-1.2)

Gonostomatidae 0.0 0.0 (0.0-0.0) 0.0 (0.1) 0.0 0.0 (0.0-0.0) 0.0 (1.1) 0.0 0.0 (0.0-0.0) Clupeiformes 0.5 0.5 (0.4-0.7) 0.7 (7.7) 0.1 0.1 (0.1-0.1) 0.7 (7.6) 0.9 0.9 (0.8-1.1)

Sardinops sp. 0.1 0.1 (0.0-0.2) 0.1 (2.8) 0.0 0.0 (0.0-0.0) 0.1 (1.7) 0.1 0.1 (0.1-0.2) Etrumeus sp. 0.0 0.0 (0.0-0.1) 0.0 (1.4) 0.0 0.0 (0.0-0.0) 0.0 (0.7) 0.0 0.0 (0.0-0.1)

Zeiformes 0.0 0.0 (0.0-0.0) 0.0 (0.4) 0.0 0.0 (0.0-0.0) 0.0 (0.1) 0.1 0.1 (0.0-0.1) Oreosoma atlanticum 0.0 0.0 (0.0-0.0) 0.0 (0.4) 0.0 0.0 (0.0-0.0) 0.0 (0.1) 0.1 0.1 (0.0-0.1)

Sygnathiformes 0.1 0.1 (0.1-0.2) 0.3 (4.6) 0.1 0.1 (0.1-0.1) 0.2 (3.8) 0.5 0.6 (0.5-0.7) Macrorhamphosidae 0.1 0.1 (0.1-0.2) 0.3 (4.3) 0.1 0.1 (0.1-0.1) 0.2 (3.5) 0.5 0.6 (0.5-0.7)

Notopogon sp. 0.1 0.1 (0.1-0.1) 0.2 (3.3) 0.0 0.0 (0.0-0.1) 0.1 (2.5) 0.4 0.4 (0.3-0.6)

10

Taxon %W %W_boot mean (95% CI)

%MW (SD) %N %N_boot mean (95% CI)

%MN (SD) %O %O_boot mean (95% CI)

Hippocampus sp. 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.0 0.0 (0.0-0.0) unidentified teleosts 8.0 8.0 (7.0-8.9) 14.5 (30.4) 9.6 9.7 (8.8-10.8) 11.0 (25.2) 35.8 35.6 (34.9-36.8)

THALIACEA 0.3 0.3 (0.2-0.4) 1.7 (10.5) 6.0 6.3 (5.0-7.4) 2.6 (12.0) 8.2 8.4 (7.7-8.8) Salpida 0.2 0.2 (0.2-0.2) 1.5 (9.4) 5.2 5.5 (4.6-6.5) 2.3 (11.2) 7.5 7.6 (7.0-8.0) Pyrosomatida 0.1 0.1 (0.1-0.1) 0.3 (4.5) 0.8 0.8 (0.3-1.3) 0.3 (4.5) 0.9 0.9 (0.7-1.1)

MOLLUSCA 50.8 51.3 (48.9-53.4) 47.9 (43.8) 36.6 37.0 (34.9-38.8) 52.3 (42.0) 77.9 77.8 (76.7-78.9) CEPHALOPODA 50.7 51.2 (48.8-53.3) 47.4 (44.0) 35.3 35.8 (33.8-37.5) 51.2 (42.4) 76.1 76.0 (74.9-77.3)

Teuthida 49.3 49.8 (47.2-51.7) 44.4 (44.0) 34.5 35.0 (33.2-36.7) 48.1 (42.7) 72.3 72.3 (71.0-74.0) Ommastrephidae 17.8 17.9 (15.8-20.7) 7.5 (23.8) 2.0 2.0 (1.8-2.3) 4.4 (16.8) 10.8 10.9 (9.8-11.6) Lycoteuthidae 12.3 12.4 (11.6-13.9) 4.1 (17.8) 1.8 1.9 (1.8-2.0) 2.1 (11.4) 5.7 5.6 (5.2-6.1)

Lycoteuthis lorigera 0.6 0.5 (0.2-0.8) 0.2 (3.4) 0.1 0.1 (0-0.1.0) 0.1 (2.3) 0.3 0.2 (0.1-0.3) Onychoteuthidae 1.9 1.9 (1.4-2.5) 0.8 (7.2) 0.2 0.2 (0.2-0.3) 0.4 (4.7) 1.8 1.8 (1.5-2.0)

Moroteuthis ingens 1.6 1.6 (1.1-2.1) 0.6 (6.2) 0.2 0.2 (0.1-0.2) 0.3 (4.1) 1.1 1.0 (0.8-1.3) Cranchiidae 0.0 0.0 (0.0-0.0) 0.0 (1.4) 0.0 0.0 (0.0-0.0) 0.0 (1.4) 0.3 0.3 (0.2-0.5) Histioteuthidae 0.1 0.1 (0.0-0.2) 0.1 (2.5) 0.0 0.0 (0.0-0.0) 0.1 (2.3) 0.2 0.2 (0.1-0.2)

Octopoda 1.1 1.1 (0.9-1.3) 2.4 (14.2) 0.4 0.4 (0.3-0.4) 2.1 (13.3) 3.7 3.6 (3.0-4.1) Argonautidae 1.0 1.0 (0.9-1.2) 2.2 (13.7) 0.3 0.3 (0.3-0.4) 2.0 (12.9) 3.1 3.1 (2.5-3.4)

unidentified cephalopoda 0.3 0.4 (0.1-0.7) 0.6 (6.8) 0.5 0.4 (0.2-0.6) 0.9 (8.4) 1.8 1.7 (1.4-2.2) GASTROPODA 0.1 0.1 (0.1-0.1) 0.5 (4.3) 1.2 1.2 (1.1-1.3) 1.2 (6.7) 7.2 7.3 (6.8-7.7)

Sorbeoconcha 0.0 0.0 (0.0-0.1) 0.3 (3.8) 0.4 0.5 (0.4-0.5) 0.6 (4.8) 4.0 4.2 (3.8-4.7) Carinariidae 0.0 0.0 (0.0-0.1) 0.3 (3.7) 0.4 0.4 (0.4-0.4) 0.6 (4.7) 3.7 3.8 (3.5-4.4) Atlantidae 0.0 0.0 (0.0-0.0) 0.0 (0.5) 0.0 0.1 (0.0-0.1) 0.0 (1.1) 0.4 0.4 (0.3-0.6)

Thecosomata 0.0 0.0 (0.0-0.0) 0.1 (1.8) 0.8 0.8 (0.7-0.9) 0.6 (4.7) 3.7 3.6 (3.3-4.1) Cavoliniidae 0.0 0.0 (0.0-0.0) 0.1 (1.8) 0.8 0.8 (0.7-0.9) 0.6 (4.7) 3.7 3.6 (3.3-4.1)

unidentified gastropoda 0.0 0.0 (0.0-0.0) 0.0 (0.0) 0.0 0.0 (0.0-0.0) 0.0 (0.3) 0.1 0.1 (0.0-0.1) ARTHROPODA 0.9 0.9 (0.8-1.0) 5.9 (20.1) 22.1 22.6 (20.4-24.7) 11.8 (26.8) 24.7 24.8 (23.7-26.2)

CRUSTACEA 0.9 0.9 (0.8-1.0) 5.9 (20.1) 22.1 22.6 (20.4-24.7) 11.8 (26.8) 24.7 24.8 (23.7-26.2) Decapoda 0.3 0.3 (0.2-0.5) 1.1 (9.2) 2.7 2.4 (1.9-2.9) 1.7 (11.1) 4.4 4.4 (3.9-4.9)

Funchalia sp. 0.1 0.1 (0.0-0.3) 0.0 (2.1) 0.1 0.2 (0.0-0.3) 0.1 (2.7) 0.1 0.1 (0.0-0.2) Oplophoridae 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.1 0.1 (0.0-0.1) (shrimp) 0.1 0.1 (0.1-0.2) 0.4 (5.8) 0.2 0.2 (0.1-0.4) 0.4 (5.0) 1.9 1.9 (1.6-2.2) Brachyura 0.1 0.1 (0.0-0.2) 0.6 (6.7) 2.3 2.0 (1.5-2.3) 1.1 (9.4) 2.3 2.3 (2.0-2.6) Anomura 0.0 0.0 (0.0-0.0) 0.0 (0.0) 0.0 0.0 (0.0-0.0) 0.0 (0.3) 0.0 0.0 (0.0-0.1)

11

Taxon %W %W_boot mean (95% CI)

%MW (SD) %N %N_boot mean (95% CI)

%MN (SD) %O %O_boot mean (95% CI)

Amphipoda 0.5 0.5 (0.4-0.5) 4.1 (16.3) 14.0 14.2 (12.7-15.7) 8.7 (22.5) 20.2 20.4 (19.7-21.5) Phronima sedentaria 0.0 0.0 (0.0-0.1) 0.4 (4.1) 1.4 1.5 (1.3-1.6) 1.0 (6.1) 5.3 5.4 (5.1-6.0)

Platyscelidae 0.0 0.0 (0.0-0.0) 0.2 (3.0) 0.5 0.5 (0.5-0.6) 0.6 (5.4) 1.9 1.9 (1.7-2.3) Platyscelus sp. 0.0 0.0 (0.0-0.0) 0.0 (0.8) 0.2 0.1 (0.1-0.2) 0.1 (2.2) 0.5 0.5 (0.4-0.6)

Phrosinidae 0.0 0.0 (0.0-0.0) 0.1 (1.8) 0.3 0.2 (0.1-0.3) 0.3 (4.0) 1.1 1.1 (0.8-1.4) Phrosina sp. 0.0 0.0 (0.0-0.0) 0.0 (0.8) 0.1 0.1 (0.0-0.1) 0.1 (1.9) 0.5 0.5 (0.3-0.7)

Hyperiidae 0.0 0.0 (0.0-0.0) 0.0 (0.9) 0.1 0.1 (0.1-0.2) 0.2 (2.8) 0.6 0.6 (0.4-0.7) Themisto sp. 0.0 0.0 (0.0-0.0) 0.0 (0.7) 0.1 0.1 (0.1-0.2) 0.1 (2.3) 0.5 0.5 (0.4-0.6) Brachyscelus sp. 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.3 0.3 (0.2-0.5) 0.1 (2.8) 0.6 0.7 (0.4-0.8)

Pronoidae 0.0 0.0 (0.0-0.0) 0.0 (0.0) 0.0 0.0 (0.0-0.0) 0.0 (1.7) 0.1 0.1 (0.1-0.2) Euphausiacea 0.0 0.0 (0.0-0.0) 0.0 (1.8) 0.7 0.7 (0.2-1.5) 0.2 (3.5) 0.5 0.5 (0.4-0.7) Stomatopoda 0.0 0.0 (0.0-0.1) 0.2 (4.3) 1.5 1.6 (1.1-2.0) 0.3 (5.3) 0.3 0.3 (0.2-0.4) Lophogastrida 0.0 0.0 (0.0-0.0) 0.1 (3.0) 0.0 0.0 (0.0-0.0) 0.1 (3.1) 0.1 0.1 (0.1-0.2)

Gnathophausiidae 0.0 0.0 (0.0-0.0) 0.1 (3.0) 0.0 0.0 (0.0-0.0) 0.1 (3.1) 0.1 0.1 (0.1-0.2) Isopoda 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.0 0.0 (0.0-0.0) 0.0 (1.5) 0.1 0.1 (0.1-0.2) unidentified crustacea 0.1 0.1 (0.0-0.1) 0.3 (4.7) 3.1 3.8 (2.1-5.3) 0.9 (7.0) 3.1 3.2 (2.7-3.8)

ANNELIDA 0.0 0.0 (0.0-0.0) 0.0 (0.2) 0.1 0.1 (0.1-0.1) 0.1 (1.6) 0.7 0.6 (0.4-0.8) POLYCHAETA 0.0 0.0 (0.0-0.0) 0.0 (0.2) 0.1 0.1 (0.1-0.1) 0.1 (1.6) 0.7 0.6 (0.4-0.8)

CNIDARIA 0.0 0.0 (0.0-0.0) 0.1 (3.3) 0.0 0.0 (0.0-0.0) 0.1 (2.4) 0.2 0.2 (0.1-0.3) Unknown 1.2 1.2 (0.8-1.6) 3.3 (16.1) 0.1 0.1 (0.1-0.1) 0.3 (3.5) 5.9 6.1 (5.7-6.6) Other 0.6 0.6 (0.5-0.7) 2.6 (12.2) 1.1 1.3 (0.6-1.8) 0.7 (7.2) 9.8 9.7 (9.1-10.6)

12

Table S3. Results of SIMPER analysis for prey weight composition by year in the 3 study areas. The lower left part of the table shows the prey with the greatest influence on the Bray-Curtis dissimilarity index; the upper right part shows the corresponding contribution. Underlined prey names are those with a contribution >30%. Ale, Alepisauridae; Arg, Argonautidae; Bra, Bramidae; Lyc, Lycoteuthidae; Nom, Nomeidae; Omm, Ommastrephidae; Par, Paralepididae; Per, Perciformes; Tel, Teleostei; Teu, Teuthida Cape area

2004 2005 2006 2007 2008 2009 2011 2012 20132004 0.40 0.34 0.32 0.29 0.30 0.31 0.32 0.362005 Omm 0.40 0.41 0.44 0.40 0.39 0.40 0.462006 Lyc Lyc 0.43 0.37 0.37 0.38 0.39 0.412007 Lyc Omm Lyc 0.33 0.39 0.39 0.35 0.422008 Lyc Omm Lyc Nom 0.45 0.28 0.27 0.402009 Lyc Omm Lyc Nom Teu 0.34 0.26 0.422011 Lyc Omm Lyc Nom Teu Par 0.24 0.392012 Lyc Omm Lyc Nom Teu Per Per 0.302013 Lyc Omm Lyc Nom Bra Bra Bra Bra

Year

Southeastern Indian Ocean

1999 2000 2003 2004 2005 2006 2007 2008 2009 2010 20121999 0.45 0.38 0.68 0.26 0.36 0.39 0.41 0.34 0.39 0.372000 Omm 0.57 0.84 0.39 0.43 0.55 0.57 0.41 0.28 0.252003 Omm Par 0.77 0.45 0.45 0.52 0.52 0.36 0.29 0.282004 Omm Omm Omm 0.46 0.27 0.45 0.80 0.89 0.77 0.702005 Par Omm Omm Omm 0.29 0.29 0.27 0.32 0.40 0.432006 Omm Omm Omm Per Omm 0.38 0.35 0.42 0.46 0.452007 Omm Omm Omm Nom Omm Per 0.50 0.57 0.56 0.512008 Per Omm Omm Omm Bra Omm Omm 0.64 0.63 0.492009 Omm Omm Par Omm Omm Omm Omm Omm 0.30 0.222010 Omm Par Ale Omm Omm Omm Omm Omm Omm 0.202012 Omm Ale Ale Omm Omm Omm Omm Omm Par Bra

Year

Tasmania area

1999 2001 2002 20031999 0.50 0.62 0.612001 Arg 0.34 0.332002 Arg Per 0.332003 Arg Tel Omm

Year

13

Table S4. Result of SIMPER analysis for prey weight composition (by fork length [FL] in 10-cm bins) in southern bluefin tuna captured in the 3 study areas. The lower left part of the table shows the prey with the greatest influence on the Bray-Curtis dissimilarity index; the upper right part shows the corresponding contribution. Underlined prey names are those with a contribution >30%. Ale, Alepisauridae; Arg, Argonautidae; Bra, Bramidae; Lyc, Lycoteuthidae; Nom, Nomeidae; Omm, Ommastrephidae; Per, Perciformes; Teu, Teuthida

Cape area

100 110 120 130 140 150 160 170 180100 0.34 0.24 0.21 0.30 0.34 0.28 0.32 0.38110 Nom 0.18 0.26 0.32 0.35 0.29 0.34 0.32120 Teu Omm 0.28 0.32 0.35 0.29 0.36 0.34130 Lyc Lyc Nom 0.32 0.39 0.29 0.40 0.20140 Lyc Lyc Lyc Lyc 0.42 0.25 0.28 0.29150 Omm Omm Omm Omm Omm 0.25 0.36 0.34160 Lyc Lyc Lyc Lyc Lyc Omm 0.24 0.30170 Bra Bra Bra Bra Bra Omm Lyc 0.29180 Per Per Per Nom Lyc Omm Lyc Bra

FL(cm)

Southeastern Indian Ocean

80 90 100 110 120 130 140 150 160 170 18080 0.85 0.77 0.43 0.32 0.59 0.40 0.50 0.43 0.44 0.5290 Omm 0.70 0.75 0.56 0.44 0.37 0.49 0.42 0.42 0.52100 Omm Omm 0.79 0.84 0.63 0.34 0.46 0.39 0.38 0.39110 Nom Nom Omm 0.53 0.38 0.40 0.50 0.43 0.44 0.51120 Omm Omm Omm Omm 0.72 0.44 0.52 0.45 0.46 0.44130 Omm Omm Omm Omm Omm 0.35 0.49 0.42 0.42 0.45140 Omm Omm Nom Omm Omm Omm 0.55 0.44 0.38 0.35150 Omm Omm Omm Omm Omm Omm Omm 0.51 0.28 0.58160 Omm Omm Omm Omm Omm Omm Omm Ale 0.31 0.48170 Omm Omm Omm Omm Omm Omm Omm Omm Omm 0.52180 Ale Ale Omm Ale Ale Ale Omm Omm Omm Omm

FL(cm)

Tasmania area

110 120 130 140 150110 0.33 0.48 0.54 0.36120 Arg 0.50 0.52 0.33130 Per Per 0.49 0.52140 Omm Omm Omm 0.38150 Omm Omm Omm Per

FL(cm)

14

Table S5. Result of SIMPER analysis for prey weight composition by sea surface temperature (SST) in 1 °C bins for southern bluefin tuna captured in the 3 study areas. The lower left part of the table shows the prey with the greatest influence on the Bray-Curtis dissimilarity index; the upper right part shows the corresponding contribution. Underlined prey names are those with a contribution >30%. Arg, Argonautidae; Bra, Bramidae; Lyc, Lycoteuthidae; Nom, Nomeidae; Omm, Ommastrephidae; Par, Paralepididae; Per, Perciformes; Tel, Teleostei

Cape area

6 7 8 9 10 11 12 13 14 15 17 186 0.61 0.34 0.27 0.26 0.42 0.45 0.52 0.45 0.48 0.32 0.577 Lyc 0.21 0.31 0.53 0.64 0.62 0.44 0.56 0.64 0.68 0.628 Lyc Omm 0.59 0.41 0.42 0.40 0.45 0.46 0.38 0.39 0.379 Omm Lyc Lyc 0.28 0.21 0.20 0.26 0.24 0.25 0.24 0.25

10 Nom Lyc Lyc Omm 0.35 0.32 0.38 0.32 0.27 0.27 0.2611 Omm Lyc Lyc Lyc Lyc 0.31 0.55 0.30 0.49 0.40 0.4812 Omm Lyc Lyc Omm Lyc Bra 0.53 0.41 0.50 0.33 0.5513 Omm Lyc Lyc Lyc Omm Omm Omm 0.44 0.57 0.56 0.5514 Omm Lyc Lyc Lyc Lyc Omm Omm Omm 0.53 0.44 0.5315 Lyc Lyc Lyc Omm Lyc Omm Omm Omm Omm 0.20 0.3617 Lyc Lyc Lyc Omm Lyc Omm Omm Omm Omm Tel 0.3118 Lyc Lyc Lyc Omm Lyc Omm Omm Omm Omm Tel Omm

SST (°C)

Southeastern Indian Ocean

10 11 12 1310 0.54 0.67 0.5911 Omm 0.68 0.5412 Omm Omm 0.3913 Omm Omm Par

SST (°C)

Tasmania area

13 15 16 1713 0.66 0.38 0.3015 Per 0.39 0.4916 Per Arg 0.3217 Per Per Per

SST (°C)