MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

https://doi.org/10.47193/mafis.3632023010907

ABSTRACT. The Patagonian toothfish (Dissostichus eleginoides) is a commercially valuable

demersal fish present in the southern hemisphere. Therefore, understanding movements of the

species across time and spatial scales would enhance our understanding of its behavior within the

Argentine and Chilean Patagonian platform. The Instituto Nacional de Investigación y Desarrollo

Pesquero (INIDEP, Argentina) initiated a tag-recapture program for D. eleginoides in 2004. A total

of 5,907 specimens, mostly juveniles (<82 cm total length), have been tagged and released in waters

off the edge of the Argentine shelf and slope between 37° S and 47° S (northern Sector of the Argen-

tine fishing ground), and east of De los Estados Island and south of Tierra del Fuego (54° S-57° S

southern Sector of the Argentine fishing ground). A total of 121 specimens were recaptured: 25

(20.7%) were recovered in the northern Sector, 84 (69.4%) in the southern Sector and 12 (9.9%) in

waters of the Pacific Ocean in Chile. A total of 67.5% were recaptured within 20 nm (37 km) of the

release site and 15% traveled distances of less than 120 nm. A smaller fraction (5%) traveled dis-

tances between 120 and 400 nm and only 12.5% were recaptured at more than 400 nm. Using a Gen-

eralized Additive Model, it was determined that variables Days at liberty, Sector and Time of tag-

ging were influential in the distance traveled by specimens. From the present work, it seems evident

that this species possesses high site fidelity and lacks cyclic migratory movements involving a sub-

stantial component of the stock in the American southern cone.

Key words: Tagging, recapture, fishing ground, stock.

Patrones migratorios de la merluza negra (Dissostichus eleginoides) en el Océano Atlántico

Sudoccidental

RESUMEN. La merluza negra (Dissostichus eleginoides) es un pez demersal presente en el

hemisferio sur, muy valioso comercialmente. Por ello, comprender los movimientos en diferentes

escalas temporales y espaciales contribuiría a conocer más acerca del comportamiento que presenta

la especie en la plataforma patagónica argentina y chilena. Desde 2004, el Instituto Nacional de

Investigación y Desarrollo Pesquero (INIDEP, Argentina), inició un programa de marcado y recap-

tura de D. eleginoides. Un total de 5.907 ejemplares, en su mayoría juveniles (<82 cm de largo

total), fueron marcados y liberados en sectores ubicados en aguas del borde de la plataforma y talud

de la Argentina entre 37° S y 47° S (Sector norte del caladero argentino), y al este de la Isla de los

Estados y sur de Tierra del Fuego (54° S-57° S Sector sur del caladero argentino). Actualmente,

fueron recapturados 121 ejemplares, 25 (20,7%) se recuperaron en el Sector norte, 84 (69,4%) en

el Sector sur y 12 (9,9%) en aguas del Océano Pacífico en Chile. El 67,5% fue recapturado a menos

de 20 mn (37 km) del lugar de liberación y 15% recorrió distancias inferiores a las 120 mn. Una

fracción menor (5%) recorrió distancias entre 120 y 400 mn y solo 12,5% se recapturó a más de

400 mn. Mediante un Modelo Aditivo Generalizado se determinó que las variables Días en libertad,

Sector y Época de marcado influyeron en la distancia recorrida de los ejemplares. A partir del

245

*Correspondence:

gtroccoli@inidep.edu.ar

Received: 21 December 2022

Accepted: 2 June 2023

ISSN 2683-7595 (print)

ISSN 2683-7951 (online)

https://ojs.inidep.edu.ar

Journal of the Instituto Nacional de

Investigación y Desarrollo Pesquero

(INIDEP)

This work is licensed under a Creative

Commons Attribution-

NonCommercial-ShareAlike 4.0

International License

Marine and

Fishery Sciences

MAFIS

ORIGINAL RESEARCH

Migratory patterns of Patagonian toothfish (Dissostichus eleginoides) in the

southwestern Atlantic Ocean

GONZALO H. TROCCOLI*, PATRICIA A. MARTÍNEZ, EMILIANO J. DIMARCO, JUAN A. WAESSLE and OTTO C. WÖHLER

Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), Paseo Victoria Ocampo Nº 1, Escollera Norte, B7602HSA -

Mar del Plata, Argentina. ORCID Gonzalo H. Troccoli https://orcid.org/0000-0002-0057-4325

INTRODUCTION

The Genus Dissostichus comprises two impor-

tant commercial species: D. mawsoni and D. elegi-

noides (Collins et al. 2010). The first one is dis-

tributed in Antarctic waters, while the second

reaches lower latitudes (Gon and Heemstra 1990).

Patagonian toothfish (D. eleginoides) has a wide

distribution in the southern hemisphere (Collins et

al. 2010; Nelson 2016), with its populations often

separated by vast expanses of deep ocean (Shaw et

al. 2004; Ashford et al. 2006; Rogers et al. 2006;

Ashford and Jones 2007). Patagonian toothfish is

a demersal species inhabiting shelves and slopes

of subantarctic islands of the Southern Ocean

(South Georgia Islands, South Sandwich Islands,

South Orkneys, Crozet, Kerguelen, Heard,

McDonald, Macquarie and Prince Edward, banks

such as Banzare, Ob and Lena, and regions of the

Ross Sea) and waters surrounding the southern

American cone, from Peru and Chile in the Pacific

Ocean to Argentina and Uruguay in the Atlantic

(Cousseau and Perrota 2004). The species inhabits

mainly the deep shelf, continental slope and sub-

marine canyons from 80 to 2,500 m depth (Prenski

and Almeyda 2000; Arkhipkin and Laptikhovsky

2010; Lee et al. 2021). Its ontogenetic cycle is

characterized by a pelagic behavior during early

development stages (eggs and larvae) (Evseenko

et al. 1995; North 2002) and a demersal behavior

from juvenile to adult. Several studies in the South

Atlantic (Agnew et al. 1999; Arkhipkin et al.

2003; Arkhipkin and Laptikhovsky 2010; Collins

et al. 2010; Péron et al. 2016; Lee et al. 2021) and

Indian Ocean (Duhamel 1981; Duhamel and

Pletikosic 1983; López Abellán 2005; Welsford et

al. 2011) have indicated a correlation between

larger fish and their distribution at greater depths.

This ontogenetic shift in habitat is common in

deep-sea fish (Agnew et al. 1999). However, spa-

tial segregation between individuals may also be

related to biological factors, such as trophic (Troc-

coli et al. 2020) or reproductive behavior (Brown

et al. 2013a; Boucher 2018) and environmental

variables, such as currents and their physical vari-

ables (Lee et al. 2021).

In the process of managing a fishing resource,

it is essential to be aware of the existence of uni-

tary stocks in order to determine whether a fish-

ery can be managed independently or integratedly

with other jurisdictions (Ying et al. 2011;

Hawkins et al. 2016; Kerr et al. 2017; Cadrin

2020). There are many factors contributing

knowledge about differentiation of stocks, such

as the understanding of fish movements in differ-

ent temporal and spatial scales (Brown et al.

2013a; Lee et al. 2022). The abundance of certain

populations may be subject to change in response

to any variation of relevant factors (Cianelli et al.

2013). The identity of the southwest Atlantic

toothfish stock (SA) has been the subject of vari-

ous studies. There is a well-documented genetic

differentiation between individuals from Patag-

onian shelf and those from South Georgia and

South Sandwich Islands (Shaw et al. 2004;

Rogers et al. 2006; Canales-Aguirre et al. 2018).

However, detailed population structure of the

species on the Argentine and Chilean Patagonian

shelf is still unknown. So far, genetic studies in

the area have not demonstrated any differentia-

tion justifying the presence of more than one pop-

ulation in the Chilean Pacific and Argentine

Atlantic (Shaw et al. 2004; Rogers et al. 2006;

Canales-Aguirre et al. 2018; Arkhipkin et al.

2022). Notwithstanding, other complementary

approaches, such as tag-recapture (Brown et al.

246 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

presente trabajo, parece evidente que la especie en el cono sur americano carece de desplazamientos migratorios regulares que involu-

cren a una parte significativa del stock.

Palabras clave: Marcado, recaptura, caladero, stock.

2013a; Lee et al. 2022), otolith microchemistry

(Ashford et al. 2006, 2007; Ashford and Jones

2007), parasitology (Brickle et al. 2006; Brown et

al. 2013b), otolith shape (Lee et al. 2018), repro-

ductive characteristics (Laptikhovsky et al. 2006;

Pájaro et al. 2009; Boucher 2018) and oceano-

graphic modelling of dispersal patterns (Ashford

et al. 2012), indicate some heterogeneity along

the slope of the southern American cone, suggest-

ing the existence of different stocks in the area

(Wöhler et al. in press).

Tag-recapture programs established in differ-

ent fisheries around the world (Williams and

Lamb 2002; Williams et al. 2002; Marlow et al.

2003; Tuck et al. 2003; Agnew et al. 2006b; Dunn

et al. 2007; Roberts and Agnew 2008; Brown et

al. 2013a; Rubilar et al. 2013; Lee et al. 2022)

have been a very useful tool to understand the

geographic and bathymetric movements of fish,

contributing to understand fish growth, behavior

and population structure (Collins et al. 2010). The

so-called ‘conventional tags’ enable the determi-

nation of the distance traveled from the release

point to the recapture point, which can be corre-

lated with a specific timeframe. Specimens of the

Genus Dissostichus are suitable for tagging and

recovery studies as they are relatively robust and,

given the lack of a swim bladder, do not sustain

serious decompression injuries when captured

and brought to the surface from the depths in

which they inhabit (Agnew et al. 2006a). As a

result, numerous studies have investigated their

movement patterns through this approach

(Williams et al. 2002; Marlow et al. 2003; Tuck et

al. 2003; Agnew et al. 2006b; Roberts and Agnew

2008; Petrov and Tatarnikov 2010; Stacy et al.

2021; Lee et al. 2022; Grilly et al. 2022).

The Patagonian toothfish tag and recapture

program has been in place in Argentine waters

since 2004 to learn more about possible migrato-

ry movements of the species in the southwestern

Atlantic. This article analyzed results derived

from the aforementioned program as a contribu-

tion to our understanding of migratory move-

ments of the juvenile toothfish fraction and the

population structure present in the Argentine

Patagonian shelf.

MATERIALS AND METHODS

In 2004, researchers from the Instituto

Nacional de Investigación y Desarrollo Pesquero

(INIDEP) launched the Tag and Recapture Pro-

gram based on an experience conducted onboard

of a commercial longliner. Individuals were

tagged with an Australian-made standard anchor

T-bar tag (Hallprint, Adelaide), similar to the ones

used in various toothfish tagging programs at the

Commission for the Conservation of Antarctic

Marine Living Resources (CCAMLR). The Pro-

gram became a mandatory activity for fishing

vessels with an individual transferable quota fish-

ing for the species at the beginning of 2007. The

program focuses on specimens that have been

tagged in two sectors of the fishing ground of the

Argentine commercial fleet: one corresponding to

the northern Sector (NS), bordering the slope

between 37° S and 47° S, where the longline fleet

operates; and the other to the southern Sector

(SS), located to the east of De los Estados Island

(54° 30'S-55° 00'S and 64° 00'W-58° 00'W)

and south of Tierra del Fuego (55° 00'S-57° 30'

S and 67° 00'W-64° 00'W), which is visited by

both longliner and trawler fleets.

With the progressive withdrawal of longliners

as from 2017, specimens were only tagged in

research surveys conducted onboard of short-set

trawlers at shallower depths, contemplating a

conditioning time for the tagged fish in water

tanks before discarding those that did not recover

properly and therefore increase the survival rate

of those released. Fish were selected, prioritizing

those with the best general condition, measured

(cm) and weighed (g). Tags were inserted with a

gun on the left side of the dorsal part of the fish,

in the area of muscle between the second and

247

TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN

third spine of the first dorsal fin (Figure 1). Data

on geographical position (longitude and latitude),

date and depth of the capture and subsequently

release sites were recorded. The release position

remained the same or very close to the one from

which the capture was obtained.

All tagged specimens were recaptured by com-

mercial fleets. When a tagged toothfish was

caught, observers onboard recorded its tag num-

ber, size, weight, and sex. Vessel operators

recorded data if no observer was present. Recap-

tures in Chilean waters were recorded by both

freezer and artisanal fleets. Observer records

included tag number, size, weight, sex, date, time,

depth, latitude, and longitude. In some cases, tags

were recovered after processing, leaving only the

date and position of recapture available.

Estimated traveled distances by specimens and

potential trajectories were visualized from tag and

recapture position data by using Google Earth v.

7.3.3 Pro. They were divided into four categories:

Short Distances (<20 nm), Short Intermediate Dis-

tances (20-120 nm), Long Intermediate Distances

(120-400 nm) and Long Distances (>400 nm).

Considering that toothfish is a deep-sea species, a

trajectory on the edge of the slope between the

release position and the recapture position was

assumed, and the minimum distances that the fish

would have traveled in nautical miles (1 nm =

1,852 km) were measured. Subsequently, displace-

ment of specimens was analyzed with a General-

ized Additive Model (GAM), using the ‘mgcv’

package of the R program version 4.3.0. These

models are an extension of general linear models

replacing the linear predictors with additive pre-

dictors through a smoothing function or spline

(Hastie and Tibshirani 1986; Wood 2006). Four

different transformations were tested on the

response variable (log, square root, cube root and

box cox) to reduce the spread of data. The log

transformation provided the best-validated model

fit. Continuous explanatory variables considered

influential in the traveled distance were the length

of tagged specimens (TL), the period of time

between the release and the capture (Days at liber-

ty DL), and the tagging Depth (D). Factors con-

sidered were the sector in which specimens were

tagged (northern and southern) and the season

(spring, summer, autumn and winter). The general

model was the following:

248 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

Figure 1. Position of the body where the T-bar style tag was implanted. In some specimens two tags were implanted.

Log(Distance) =m+s(TL) +s(DL) +s(D) +Sector

+Season +Error

Family =Gaussian, Link =‘Identity’

where e~N (0, s2e). First, the existence of

collinearity between variables was verified to

eliminate any variable correlated with another

(Zuur et al. 2009). Once definitive variables were

obtained, the best model was chosen based on the

stepwise selection process according to the

Akaike Information Criteria and Generalized

Cross Validation (Akaike 1973; Burnham and

Anderson 2004; Wood 2012). In both cases, the

lower the value the better the model obtained will

be. In addition, the adjusted multiple determina-

tion coefficient was calculated for each model,

and the explanatory capacity of the model built

through the explained deviance was calculated.

Subsequently, influential points were eliminated,

obtaining the final model. Finally, its graphic val-

idation was carried out using the gam.chek func-

tion (‘mgcv’) and those variables significant to

the final model were plotted (Fernández Casal et

al. 2022).

RESULTS

A total of 5,907 toothfish have been tagged in

the northern Sector (NS) and southern Sector

(SS) since the beginning of the Program in 2004.

A total of 5,528 specimens were tagged onboard

the longline fleet and 379 on the trawler, from

which, 26.04% were tagged in the NS, while the

remaining 73.96% were tagged in the SS (Figure

2; Table 1). To date, a total of 121 specimens have

been recaptured, of which 25 (20.7%) were

recaptured in the NS, 84 (69.4%) in the SS, and

12 (9.9%) in Pacific waters off the Chilean coast

(Table 1; Figure 3). At the same time, 3 speci-

mens from Chilean waters and 2 tagged in the

249

TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN

Figure 2. Release position of tagged toothfish specimens in the Argentine Exclusive Economic Zone (EEZ).

area corresponding to the Argentine Patagonian

shelf, around Malvinas Islands, were also recap-

tured in the SS. The majority of tagged specimens

in each year were juveniles in size (Figure 4).

Juvenile fish consisted of 75.18% of fish tagged

across the sample period, ranging from 53.75%

(2012) to 100% (2019).

From their release site, 67.5% were recaptured

at a distance of less than 20 nm, while 15% trav-

eled short intermediate distances less than

120 nm. The smaller fraction (5%) covered dis-

tances between 120 and 400 nm (longer interme-

diate distances) and 12.5% were recaptured at

greater distances (more than 400 nm) from their

tagging locations. Only 9.9% of the fish left the

Argentine fishing ground. Most of specimens

(87.5%) covered distances of under 400 nm,

remaining inside the same sector, whose length

was estimated to be around 370 nm for both sec-

tors. In the NS, 83% (25) of tagged specimens

moved within 400 nm. Seventy-seven percent of

them (23) were even recaptured at less than 20

nm. Only 17% (5) of the total was recaptured at

distances greater than 400 nm, exceeding the lim-

its of that sector of the Argentine fishing ground.

In the SS, 89% (81) of the fish moved less than

400 nm from their release site, and 64% of the

total (58) moved less than 20 nm. The remaining

250 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

Table 1. Number and percentage of toothfish specimens tagged and recaptured in the northern, southern, and Pacific Ocean sec-

tors, indicating recapture rate per year (%).

Tagged Recaptured

Year Northern Southern Northern Northern Pacific Percentage

2004 247 247 0 0 0 0.00

2005 0 0 0 0 1 0.00

2006 0 0 0 0 0 0.00

2007 14 763 0 0 0 0.00

2008 300 755 4 3 0 0.66

2009 368 685 4 5 0 0.85

2010 223 705 2 23 2 2.91

2011 37 465 1 23 1 4.98

2012 99 154 9 13 1 9.09

2013 92 244 1 4 4 2.68

2014 0 0 0 2 0 0.00

2015 0 0 2 2 0 0.00

2016 0 0 2 2 0 0.00

2017 28 32 0 1 2 5.00

2018 130 223 0 3 0 0.85

2019 0 40 0 2 1 7.50

2020 0 56 0 1 0 1.79

Total 1,538 4,369 25 84 12 2.05

Percentage 26.04 73.96 20.66 69.42 9.92

11% (10 fish) were recaptured at a distance

greater than 400 nm from the release site (Figure

5). The predominance of short distances traveled

after being tagged and released demonstrates the

affinity of the species for its residence sites in the

NS and SS of the Argentine fishing ground.

There was no clearly defined direction pattern

observed in the fish tagged in the NS (Figure 6).

Most of the specimens exhibited a distinct pattern

of movement towards the southeast and east.

However, one specimen that traveled a moderate

distance went in the opposite direction towards

the northeast. Furthermore, the specimens that

traveled the greatest distances all moved towards

the south. Only five of the recaptured fish crossed

the NS of the Argentine fishing ground, migrating

over long distances (up to approximately 1,500

nm), three of which were recaptured near the

Namuncurá/Burdwood Bank, and the rest in

southern Chile (Figure 7). A unified directional

movement was also not observed for fish tagged

and recaptured in the SS of the Argentine fishing

ground (Figure 8). Both westward and eastward

directions were observed for fish undertaking

movements less than 100 nm. Those that moved

greater distances did essentially to the west-

northwest (Figure 9). Regarding specimens

tagged in the SS, 11 of them exceeded the limits

of the Argentine fishing ground, eight of which

traveled distances in the direction of central-north

Chile, between 477 nm (885 km) and 2,100 nm

(3,889 km). The vast majority of the tagged fish

(64%) remained close to their release sites. A sin-

gle specimen was reported to the east, tagged at

54° 53' S-59° 08'W and caught at 55° 00' S-57°

37' W by the longliner ‘CFL Hunter’ in waters

near the Malvinas Islands (Martínez, unpublished

data).

The variables Days at liberty, Sector, and Sea-

son of tagging influenced on the traveled distance

in GAM results (Table 2). The final model was

defined by these three variables, which explained

34.4% of the variability of the model. The length

of fish at the time of tagging and the depth of

release were not significant in the movements of

toothfish. This hypothesis and the homogeneity

of variances seems to be adequate from validation

graphs for normality (Figure 10).

251

TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN

Figure 3. Reported recapture positions of tagged toothfish specimens in the Argentine Exclusive Economic Zone (EEZ).

252 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

Figure 4. Distribution of relative frequencies of grouped lengths of tagged toothfish specimens per year. The black dotted line

represents the length of first maturity estimated at 82 cm (Pájaro et al. 2009).

2018 2019 2020

2012 2013 2017

2009 2010 2011

2004 2007 2008

25 50 75 100 125 25 50 75 100 125 25 50 75 100 125

0.00

0.02

0.04

0.06

0.00

0.02

0.04

0.06

0.00

0.02

0.04

0.06

0.00

0.02

0.04

0.06

Total length (cm)

Relative frecuency

Figure 5. Ratio of recaptured toothfish specimens based on the range of distance traveled in the northern and southern Sector.

0-20 20-120 120-400 >400

Northern Southern

Traveled distance range (nm)

Ratio

0.0

0.2

0.4

0.6

0.8

1.0

253

TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN

Figure 7. Possible migratory route of specimens tagged in the northern Sector of the Argentine fishing ground and recaptured

more than 400 nm away from it. Orange circles indicate the tagging position and yellow ones the recapture position. The

five specimens that traveled long distances did so in a southerly direction.

Figure 6. Migratory movements corresponding to distances of less than 400 nm in the northern Sector of the Argentine fishing

ground.

254 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

Figure 8. Possible migratory route of specimens tagged in the southern Sector of the Argentine fishing ground with intermediate

movements. Circles indicate the position of tagging and squares point out the position of recapture.

Figure 9. Possible migratory route of specimens tagged in the southern Sector of the Argentine fishing ground that presented

greatest displacements. Red circles indicate the tagging position and green circles the recapture position.

255

TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN

Table 2. Model selection table to determine which variables influence the distance traveled by toothfish. For each case, the

explained deviance (%), degrees of freedom (EDF), Akaike values (AIC), Generalized Cross Validation (GCV), R2 and

p-value are indicated.

Variable Explained Accumulated EDF AIC GCV R2 p-value

deviance deviance

Null 0 0 2.00 523.74 4.53 0 0

TL 2.95 2.95 3.00 522.15 4.47 0.02 0.06

+Days at liberty 16.85 19.8 7.94 509.18 4.02 0.16 <0.01

+Sector 5.6 25.4 9.01 506.20 3.83 0.18 <0.01

+Depth 0 25.4 10.15 504.88 3.89 0.19 0.79

+ Season of tagging 8.6 34 13.28 496.37 3.64 0.27 <0.01

Figure 10. Diagnosis of the final GAM model indicating the quantile-quantile graph (qqplot) (A), residuals versus adjusted (B),

histogram of residuals (C), and observed versus adjusted values (D).

-4 -2 0 2 4

-4

-2

Theoretical uantilesq

Deviance esidualsr

12345678

-4

-2

Linear redictorp

Residuals

Frequency

-4 -2 024

12345678

Fitted aluesv

Response

Although model’s influential variables showed

an increase in the distance covered as a function

of the number of days at liberty, this trend signif-

icantly decreases in specimens with longer peri-

ods at liberty (Figure 11 A). However, it should

be noted that the decrease in this trend with

longer periods at liberty was based on small sam-

ple sizes. There were specimens with liberty peri-

ods ranging from a minimum of 3 days to a max-

imum of 3,176 days (8 years and 8 months). The

specimen that traveled the longest distance (2,099

nm), did so in a period of 2,261 days (6 years and

3 months) and the one that followed it (1,769 nm)

required 2,651 days. However, other fish were

recaptured within 20 miles (37 km) of their

release sites, even after longer periods at liberty.

One extreme case was a fish recaptured just 18

nm from where it had been tagged, 7 years and 8

months after its release (2,762 days) (Figure 11).

The specimen that remained at liberty the longest

(8 years and 8 months), was recaptured at a dis-

tance of 1 nm from where it has been released,

being a record of resident behavior.

Specimens tagged in the southern fishing

ground of the distribution area showed a trend of

greater displacement (Figure 11 B) and an

increase in the distances traveled by specimens

during winter months (Figure 11 C).

256 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

Figure 11. Smoothing terms corresponding to the explanatory variables of the final GAM model used. A) Days at liberty. B)

Sector. C) Season.

3 000, Southern

-4

-2

01 000,2 000,

Days t ibertyal

s(Days i ty, 5.71)at l ber

Northern

Sector

f(Sector)

-1

Spring Summer Autumn

f(Season)

Winter

Season

DISCUSSION

This study provides the first description of the

movement patterns of Patagonian toothfish in

Argentine shelf/edge waters between 37° S and

47° S east of De los Estados Island (54° 30'S-55°

00'S and 64° 00'W-58° 00'W) and south of Tier-

ra del Fuego (55° 00'S-57° 30'S and 67° 00'W-

64° 00'W). The tag and recapture program for

toothfish on the Argentine Patagonian shelf pro-

vided the first direct observation of movement

patterns of the juvenile fraction from shelf areas

to deeper areas in the slope and Chilean Pacific.

Our results show different levels of individual

movement variation. From a fishing perspective,

the lack of a significant exchange of fish between

current fishing areas allows to consider the exis-

tence of different stock units of the species.

Tagging program

Results regarding the migratory behavior of

the species are quite consistent with those

obtained in other toothfish-tagging programs

established in different parts of the world

(Williams and Lamb 2002; Williams et al. 2002;

Marlow et al. 2003; Tuck et al. 2003; Agnew et al.

2006b; Dunn et al. 2007; Roberts and Agnew

2008; Brown et al. 2013a; Rubilar et al. 2013,

Grilly et al. 2022; Lee et al. 2022). The tagging

program established in the Argentine toothfish

fishery covered the extremes of the distribution of

the species on the Patagonian shelf, both in north-

ern and southern fishing grounds. The recapture

rate until 2020 was estimated at 2.05% (Table 1).

This is a higher rate than those estimated from

tag-recapture programs at both Chilean waters

(1.29%) (Rubilar et al. 2013) and South Georgia

Islands (1.3 and 1.7%) (Marlow et al. 2003).

However, other tagging programs had substan-

tially higher recapture rates, such as 5.25% in

Malvinas Islands (Lee et al. 2022), 11.9% in Shag

and Black Rocks (Marlow et al. 2003) and 17.7%

in Heard Island and McDonald Islands from 1998

to 2014 (Welsford et al. 2014).

Tagged specimens were recovered in NS and

SS zones, including some that migrated to waters

outside the Argentine Exclusive Economic Zone

(EEZ). In those cases, recaptured specimens were

reported by foreign fishing vessels. The number

of recaptures, number of days at liberty and the

good general condition of recaptured specimens

indicated that fish successfully survived the tag-

ging process, similar to observations reported by

Williams et al. (2002) and Agnew et al. (2006a).

The gradual withdrawal of longline vessels from

the fishery since 2013 (Troccoli et al. 2022) may

have had an impact on the Patagonian toothfish

recapture rate in the Argentine EEZ. Currently,

the trawler fleet only operates in the sector

between De los Estados Island and Namuncurá-

Burdwood Bank. The absence of fishing opera-

tions in the NS of the Argentine fishing ground

and to the south of Namuncurá-Burdwood Bank

may have resulted in an interruption of recaptures

in these areas.

Another possible cause of the low recapture

rate may be given by the component of the popu-

lation selected to be tagged in this Program,

which predominantly comprised fish <82 cm TL.

Strong management regulations govern the

Argentine toothfish fishery, including restrictions

on minimum fishing depths, percentage of juve-

niles in the catch, hook size, and other measures

to prevent excessive capture of juveniles of the

species (Martínez and Wöhler 2016). This situa-

tion has been observed in other toothfish tagging

programs, such as in the CCAMLR working

group report from 2009, where the Scientific

Committee agreed that one of the main reasons

behind the low number of recaptures in Subareas

48.6 and 58.4 was likely the small size of fish

tagged in comparison to the overall size distribu-

tion of fish caught. On the other hand, the possi-

bility that the low recapture rate was associated

with a limited fishing effort in relation to the size

257

TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN

of the stock in the Argentine fishing ground

should not be ruled out.

Migratory movements

A key aspect in studying movement patterns of

species involves understanding the magnitude

and frequency of proposed migrations (Allen et

al. 2018). That is why it is important to define

movement patterns in relation to a defined spatial

area. Examples of such patterns include migra-

tions (moving to and from specific locations),

homing (returning to a location), home ranges

(repeated movement within an area), habitat

usage (movement to use resources within a set

area), or nomadism (no boundaries) (Gruss et al.

2011).

Other toothfish tagging programs (Williams

and Lamb 2002; Williams et al. 2002; Marlow et

al. 2003; Collins et al. 2010; Brown et al. 2013a;

Lee et al. 2021) have reported the same move-

ment patterns observed at the NS and SS in this

study. Even after spending more than eight years

at liberty, most of the recaptured specimens

(67.5%) maintained a distance of less than 20 nm

(37 km) from where they have been released. In

addition, the fact that the majority of the fish

(87.5%) moved a distance <400 nm, which is an

approximate measurement for both the NS and

the SS where vessels fish for Patagonian toothfish

in the Argentine EEZ, would indicate that almost

all the fish would not move beyond the habitual

residence area within each sector of the fishing

ground. On the contrary, only very few specimens

(12.5%) traveled great distances, with some cases

reportedly traveling up to 2,099 nm (3,887 km) to

the waters of central Chile. Since the transition to

adulthood is primarily characterized by migration

to greater depths, Brown et al. (2013a) hypothe-

sized that long-distance migrations may take

place during the juvenile stage. Dunn and

Hanchet (2006) and Dunn et al. (2007) found that

the greatest distances traveled by D. mawsoni in

Antarctic waters were undertaken by juvenile and

sub-adult fish (<100 cm TL). Rogers et al. (2006)

also indicated that possibly the juvenile fraction

of the population is the one with the greatest

capacity for migration. On the other hand, Mar-

low et al. (2003) and Burch et al. (2019) have

indicated that some adult fish can cross oceano-

graphic fronts and migrate great distances.

Recent findings from a Malvinas Islands-based

tag and recapture program (Lee et al. 2022) are in

line with these results and with reports of other

authors that have observed these movements in

different regions of the world (Williams et al.

2002; Marlow et al. 2003; Tuck et al. 2003;

Brown et al. 2013a). Only a very small percent-

age of recaptured specimens (10%) traveled sig-

nificant distances, while the majority (78%)

remained less than 27 nm from their release point.

Similar results were reported for Antarctic tooth-

fish in the southern ocean (Grilly et al. 2022)

where only 7% of the specimens moved great dis-

tances, while the rest demonstrated a sedentary

behavior. Results of this work do not clearly show

any differential migratory pattern related to the

size of tagged specimens. While some juvenile

individuals tagged in the Argentine EEZ traveled

great distances, a similar proportion of the few

adult individuals released after tagging also did

so. Thus, the percentage of ‘great travelers’ was

relatively similar in both cases.

The analysis carried out in order to establish a

possible relationship between the distance trav-

eled by the fish and the time elapsed in freedom

after being tagged, did not yield evidence to

demonstrate that the fish that remained in free-

dom for the longest were those that moved the

most. However, the trend drops drastically for the

oldest records. Considering this, two of the fish

that remained the longest in the wild (>7 and 8

years) were recaptured a short distance from their

tagging site. These results are in line with those of

Welsford et al. (2011) in the Kerguelen plateau

around Heard and McDonald Islands, who did not

find a clear relationship between the distance

traveled and the time since the fish was released.

258 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

The majority of specimens were caught less than

100 km from the tagging site within 1,000 days of

being released, while others traveled at least

2,000 km during the same period. In accordance

with the findings presented here, Marlow et al.

(2003) also found no clear relationship between

days at liberty and the distance covered by

specimens of D. eleginoides in South Georgia

Islands. However, Dunn y Hanchet (2006)

suggested that D. mawsoni appear to have a

positive trend between greater fish displacement

and longer time at liberty. In contrast to the

above, Grilly et al. (2022) found no relationship

between time at liberty and long-distance

movements for the same species.

Specimens from the southern fishing ground

traveled the most distance. In the northern fishing

grounds, displacements involved shorter dis-

tances and were oriented towards deeper south-

east areas of the edge of the continental shelf.

Similar results were also found by Grilly et al.

(2022) for D. mawsoni. Patagonian toothfish are

believed to move primarily from shallower

waters to greater depths, corresponding to the

ontogenetic migration of the species throughout

its range (Williams 2002; Arkhipkin and Lap-

tikhovsky 2010; Péron et al. 2016; Lee et al.

2021), so juvenile fish are recruited to the adult

stock as they grow.

On the contrary, the nearby displacements in

the SS did not present a pattern of preferential

direction in their migrations. Between the

Namuncurá/Burdwoord Bank and Diego Ramírez

Islands (Chile), intermediate displacements were

oriented to the east and west, possibly following

the edge of the crescent-shaped slope. Move-

ments directed towards the bank can be attributed

to both reproductive and feeding functions

(Pájaro et al. 2009; Boucher 2018). Seabeds with

similar characteristics to the aforementioned

landform have unusually high biomass of benthic

organisms that form refuge habitats for smaller

fish, which may provide attractive feeding oppor-

tunities for larger predators (Welsford et al. 2014;

Schejter et al. 2016; Matano et al. 2019; Ric-

cialdelli et al. 2020).

Regarding few specimens that moved long dis-

tances, all reported recaptures indicate a move-

ment towards Chilean shelf and slope waters.

Records coincide with those observed by Rubilar

et al. (2013) in the Chilean toothfish tagging pro-

gram, whose preliminary results show a net

movement of fish from the south to the north of

Chile. This fact is particularly surprising, consid-

ering that no migrations have been described that

could indicate a return of the fish to the southern-

most areas. The exception could be addressed by

three individuals tagged in southern Chile and

recaptured in nearby areas of southern Argentina,

indicating in this case a moderate movement in a

southeasterly direction. These results demon-

strate some exchange between the fish that inhab-

it Chilean and Argentine jurisdiction, although of

small magnitude given the total number of fish

tagged and recovered.

Laptikhovsky et al. (2006) speculated that

Patagonian toothfish in Malvinas Islands migrate

in one of two ways: an ontogenetic migration

from shelf waters to bathyal waters where adults

live, and a seasonal migration of adults that spans

more than 1,000 km around the islands between

feeding and reproduction grounds. Brown et al.

(2013) using satellite tags in the same region stat-

ed that toothfish would not regularly make large-

scale migrations between feeding areas to the

north and east of Malvinas Islands and the spawn-

ing grounds at Namuncurá/Burdwoord Bank.

This apparent absence of regular migrations of

individuals was related to the fact that toothfish is

a long-lived animal and would not need to spawn

every year (Laptikhovsky and Brickle 2005;

Boucher 2018). An absence of annual migratory

behaviour and high site fidelity was also inferred

on the basis of significant difference in otolith

shape among localised regions on the Patagonian

shelf between southern Chile, the Burdwood

Bank and a Malvinas north-high seas intermedi-

ate zone (Lee et al. 2018). In the present work, an

259

TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN

increase in distances traveled by specimens

tagged in winter, whose months coincide with

those of the reproductive period, was observed.

However, considering that the majority of speci-

mens tagged here were juveniles, an ontogenetic

or feeding movement rather than a reproductive

migration is more likely. On the other hand,

reproductive activity of Patagonian toothfish in

the northern slope of the Argentine EEZ (between

37° S and 43° S) has recently been observed,

which support the hypothesis that the fish in this

region would reproduce directly there and would

not require a migration to higher latitudes for this

purpose (Martínez et al. 2022).

CONCLUSIONS

From the present work, it seems evident that

Patagonian toothfish in the Argentine EEZ pos-

sess characteristic high site fidelity and lacks reg-

ular migratory movements involving a substantial

component of the stock or population. This

behavior supports the hypothesis of isolation

between different fishing grounds of the species

that is subject to exploitation around the Ameri-

can southern cone. Rather than being caused by

physical or oceanographic barriers, this isolation

is supposed to be related to the very philopatric

behavior of the species. If the fish remain faithful

to their residence areas and these are associated

with nearby breeding areas, then this behavior

would facilitate isolation. Results of the current

study confirm the importance of research investi-

gating the population structure of toothfish across

the region. The current findings allow us to

assume the possible existence of different groups

of fish or stocks, characterized by a certain isola-

tion, which could, from a fishing perspective, be

considered individually, since there is a signifi-

cant shortage of fish migration between current

fishing locations. However, much more research

is required to confirm this hypothesis.

ACKNOWLEDGEMENTS

The authors express their gratitude to fishing

companies that collaborated by providing instru-

ments and supplies, and made their vessels avail-

able to carry out the tag and recapture of Patagon-

ian toothfish program. They also extend their

gratitude to the crews who collaborated with the

tasks onboard. INIDEP contribution no. 2302.

Author contributions

Gonzalo H. Troccoli: conceptualization,

methodology, software, validation, formal analy-

sis, investigation, resources, writing-review and

editing, visualization. Patricia A. Martínez: con-

ceptualization, investigation, writing-review and

editing, supervision, project administration, fund-

ing acquisition. Emiliano J. Di Marco: methodol-

ogy, software, validation, formal analysis. Juan A.

Waessle: software, resources. Otto C. Wöhler:

conceptualization, investigation, resources, writ-

ing-review and editing, supervision, project

administration, funding acquisition.

REFERENCES

AGNEW DJ, CLARK JM, MCCARTHY PA. UNWIN

M, WARD M, JONES L, BREEDT G, DUPLESSIS

S, VAN HEERDON J, MORENO G. 2006a. A

study of Patagonian toothfish (Dissostichus

eleginoides) post tagging survivorship in Sub-

area 48.3. CCAMLR Sci. 13: 279-289.

AGNEW DJ, HEAPS DL, JONES C, WATSON A,

BERKIETA K, PEARCE J. 1999. Depth distribu-

tion and spawning pattern of Dissostichus

eleginoides at South Georgia. CCAMLR Sci.

6: 19-36.

AGNEW DJ, KIRKWOOD GP, PEARCE J, CLARK J.

260 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

2006b. Investigation of bias in the mark recap-
ture estimate of toothfish population size at
South Georgia. CCAMLR Sci. 13: 47-63.
AKAIKE H. 1973. Information theory and an
extension of the maximum likelihood princi-
ple. In: PETROV, BN AND CSAKI F, editors. Pro-
ceedings of the 2nd International Symposium
on Information Theory. Budapest: Akademiai
Kiado. p. 267-281.
ALLEN RM, METAXAS A, SNELGROVE PVR. 2018.
Applying movement ecology to marine ani-
mals with complex life cycles. Ann Rev Mar
Sci. 10: 19-42. DOI: https://doi.org/10.1146/
annurev-marine-121916-063134
ARKHIPKIN A, BRICKLE P, LAPTIKHOVSKY V. 2003.
Variation in the diet of the Patagonian
toothﬁsh with size, depth and season around
the Falkland Islands. J Fish Biol. 63 (2): 428-
441. DOI: https://doi.org/10.1046/j.1095-864
9.2003.00164.x
ARKHIPKIN AI, BRICKLE P, LEE B, SHAW PW,
MCKEOWN NJ. 2022. Taxonomic re-appraisal
for toothfish (Dissostichus: Notothenioidea)
across the Antarctic Polar Front using genom-
ic and morphological studies. J Fish Biol. 100
(5): 1158-1170. DOI: https://doi.org/10.1111/
jfb.15013
ARKHIPKIN AI, LAPTIKHOVSKY VV. 2010. Conver-
gence in life-history traits in migratory deep-
water squid and ﬁsh. ICES J Mar Sci. 67 (7):
1444-1451. DOI: https://doi.org/10.1093/ices
jms/fsq103
ASHFORD JR, ARKHIPKIN A, JONES CM. 2006. Can
the chemistry of otolith nuclei determine popu-
lation structure of Patagonian toothfish Dissos-
tichus eleginoides? J Fish Biol. 69: 708-721.
ASHFORD JR, FACH, BA, ARKHIPKIN AI, JONES
CM. 2012. Testing early life connectivity sup-
plying a marine fishery around the Falkland
Islands. Fish Res. 121-122: 144-152. DOI:
http://doi.org/10.1016/j.fishres.2012.01.023
ASHFORD JR, JONES CM. 2007. Oxygen and car-
bon stable isotopes in otoliths record spatial
isolation of Patagonian toothfish (Dissos-
tichus eleginoides). Geochim Cosmochim
Acta. 71: 87-94.
BOUCHER ME. 2018. Disentangling reproductive
biology of the Patagonian toothfish Dissos-
tichus eleginoides: skipped vs obligatory
annual spawning, foraging migration vs resi-
dential life style. Environ Biol Fish. 101:
1343-1356. DOI: https://doi.org/10.1007/s106
41-018-0781-8
BRICKLE P, MACKENZIE K, PIKE A. 2006. Varia-
tions in the parasite fauna of the Patagonian
toothfish (Dissostichus eleginoides Smitt,
1898), with length, season, and depth of habi-
tat around the Falkland Islands. J Parasitol. 92
(2): 282-291. 
BROWN J, BRICKLE P, SCOTT BE. 2013a. Investi-
gating the movements and behaviour of Patag-
onian toothﬁsh (Dissostichus eleginoides
Smitt, 1898) around the Falkland Islands
using satellite linked archival tags. J Ex Mar
Biol Ecol. 443: 65-74. DOI: https://doi.org/10.
1016/j.jembe.2013.02.029
BROWN J, BRICKLE P, SCOTT, BE. 2013b. The par-
asite fauna of the Patagonian toothfish Dissos-
tichus eleginoides off the Falkland Islands. J
Helminthol. 87 (4): 501-509. DOI: https://doi.
org/10.1017/S0022149X12000636
BURNHAM KP, ANDERSON, DR. 2004. Multimodel
inference: understanding AIC and BIC in
Model Selection. Sociol Methods Res. 33 (2):
261-304. DOI: https://doi.org/10.1177/004912
4104268644
BURCH P, PÉRON C, POTTS J, ZIEGLER P, WELSFORD
D. 2019. Estimating Patagonian toothfish (Dis-
sostichus eleginoides) movement on the Ker-
guelen Plateau: reflections on 20 years of tag-
ging at Heard Island and McDonald Islands.
Second Kerguelen Plateau Symposium:
marine ecosystem and fisheries: 237-245.
CADRIN SX. 2020. Defining spatial structure for
fishery stock assessment. Fish Res. 221:
105397. DOI: https://doi.org/10.1016/j.fishres.
2019.105397
CANALES-AGUIRRE CB, FERRADA-FUENTES S,
261
TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN

GALLEGUILLOS R, OYARZUN FX, HERNÁNDEZ
CE. 2018. Population genetic structure of
Patagonian toothfish (Dissostichus elegi-
noides) in the Southeast Pacific and Southwest
Atlantic Ocean. PeerJ. 6: e4173. DOI: https://
doi.org/10.7717/peerj.4173
CIANNELLI L, FISHER JAD, SKERN-MAURITZEN M,
HUNSICKER ME, HIDALGO M, FRANK KT, BAI-
LEY KM. 2013. Theory, consequences and evi-
dence of eroding population spatial structure
in harvested marine fishes: a review. Mar Ecol
Prog Ser. 480: 227-243. DOI: https://doi.org/
10.3354/meps10067
COLLINS MA, BRICKLE P, BROWN J, BELCHIER M.
2010. The Patagonian toothfish: biology, ecol-
ogy and fishery. Adv Mar Biol. 58: 227-300.
DOI: https://doi.org/10.1016/B978-0-12-3810
15-1.00004-6
COUSSEAU MB, PERROTA RG. 2004. Peces mari-
nos de Argentina: biología, distribución y
pesca. 2nd ed. Mar del Plata: Instituto Nacional
de Investigación y Desarrollo Pesquero
(INIDEP). 167 p.
DUHAMEL G. 1981. Characteristiques biologiques
des principals especes de poissons du plateau
continental des Iles Kerguelen. Cybium. 5: 19-
32.
DUHAMEL G, PLETIKOSIC M. 1983. Donnes
biologiques sur les Notothenidae des Iles
Crozet. Cybium. 7: 43-57.
DUNN A, HANCHET SM. 2006. An updated
descriptive analysis of the toothfish (Dissos-
tichus  spp.) tagging programme in Subareas
88.1 & 88.2 up to 2005-06. WG-FSA-06/34.
National Institute of Water and Atmospheric
Research. Unpublished manuscript presented
to the Fish Stock Assessment Working Group
of CCAMLR. 24 p.
DUNN A, HANCHET SM, BALLARA SL. 2007. An
updated descriptive analysis of the toothﬁsh
(Dissostichus  spp.) tagging programme in
subareas 88.1 and 88.2 for 2006-07. 1-21.
EVSEENKO SA, KOCK KH, NEVINSKY MM. 1995.
Early life history of the Patagonian toothfish,
Dissostichus eleginoides Smitt, 1898 in the
Atlantic sector of the Southern Ocean. Antarct
Sci. 7 (3): 221-226. DOI: https://doi.org/10.10
17/S0954102095000319
FERNÁNDEZ CASAL R, COSTA BOUZAS J, OVIEDO
DE LA FUENTE M. 2022. Aprendizaje estadísti-
co. 226 p. https://rubenfcasal.github.io/apren
dizaje_estadistico.
GON O, HEEMSTRA PC. 1990. Fishes of the South-
ern Ocean. J.L.B. Grahamstown: Smith Insti-
tute of Ichthyology. 462 p.
GRILLY E, REID K, THANASSEKOS S. 2022. Long-
distance movements of Antarctic toothfish
(Dissostichus mawsoni) as inferred from tag-
recapture data. J Fish Biol. 100 (5): 1150-
1157. DOI: https://doi.org/10.1111/jfb.14941
GRUSS A, KAPLAN DM, GUENETTE S, ROBERTS
CM, BOTSFORD LW. 2011. Consequences of
adult and juvenile movement for marine pro-
tected areas. Biol Conserv. 144: 692-702.
HASTIE T, TIBSHIRANI R. 1986. Generalized addi-
tive models. Stat Sci. 1 (3): 297-318.
HAWKINS SJ, BOHN K, SIMS DW, RIBERO P, FARIA
J, PRESA P, PITA A, MARTINS GM, NETO AI,
BURROWS MT, GENNER MJ. 2016. Fisheries
stocks from an ecological perspective: Disen-
tangling ecological connectivity from genetic
interchange. Fish Res. 179: 333-341. DOI:
https://doi.org/10.1016/j.fishres.2016.01.015
KERR LA, HINTZEN NT, CADRIN SX, CLAUSEN
LW, DICKEY-COLLAS M, GOETHEL DR, HAT-
FIELD EMC, KRITZER JP, NASH RDM. 2017.
Lessons learned from practical approaches to
reconcile mismatches between biological pop-
ulation structure and stock units of marine
fish. ICES J Mar Sci. 74 (6): 1708-1722. DOI:
https://doi.org/10.1093/icesjms/fsw188
LEE B, ARKHIPKIN A, RANDHAWA HS. 2021. Envi-
ronmental drivers of Patagonian toothfish
(Dissostichus eleginoides) spatial-temporal
patterns during an ontogenetic migration on
the Patagonian Shelf. Estuar Coast Shelf Sci.
259: 107473. DOI: https://doi.org/10.1016/j.e
css.2021.107473
262 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

LEE B, BREWIN PE, BRICKLE P, RANDHAWA H.
2018. Use of otolith shape to inform stock
structure in Patagonian toothfish (Dissos-
tichus eleginoides) in the south-western
Atlantic. Mar Fresh Res. 69 (8): 1238-1247.
DOI: https://doi.org/10.1071/MF17327
LEE B, SKELJO F, RANDHAWA HS, ARKHIPKIN A.
2022. Deep-sea movement patterns of the
Patagonian toothfish Dissostichus eleginoides
Smitt in the Southwest Atlantic. Mar fresh
Res. 73: 833-845. DOI: https://doi.org/10.10
71/MF21338
LAPTIKHOVSKY V, BRICKLE P. 2005. The Patagon-
ian toothﬁsh ﬁshery in Falkland Islands’
waters. Fish Res. 74: 11-23. DOI: https://doi.
org/10.1016/j.fishres.2005.04.006
LAPTIKHOVSKY V, ARKHIPKIN A, BRICKLE P. 2006.
Distribution and reproduction of the Patagon-
ian toothfish Dissostichus eleginoides Smitt
1898 around the Falkland Islands. J Fish Biol.
68 (3): 849-861. DOI: https://doi.org/10.1111/
j.0022-1112.2006.00973.x
LÓPEZ ABELLÁN LJ. 2005. Patagonian toothﬁsh in
international waters of the Southwest Indian
Ocean (Statistical Area 51). CCAMLR Sci.
12: 207-214. 
MARLOW TR, AGNEW DJ, PURVES MG, EVERSON
I. 2003. Movement and growth of tagged Dis-
sostichus eleginoides around South Georgia
and Shag Rocks (Subarea 48.3). CCAMLR
Sci. 10: 101-111.
MARTÍNEZ PA, WÖHLER OC. 2016. Hacia la recu-
peración de la pesquería de merluza negra
(Dissostichus eleginoides) en el Mar Argenti-
no: un ejemplo de trabajo conjunto entre el
sector de la administración, la investigación y
la industria. Frente Marít. 24: 115-125.
MARTÍNEZ P, TROCCOLI G, DIMARCO E, WÖHLER
OC. 2022. Evidencia de una nueva área de
reproducción de merluza negra (Dissostichus
eleginoides) en el Mar Argentino. Inf Invest
INIDEP Nº 27/2022. 19 p. 
MATANO RP, PALMA ED, COMBES V. 2019. The
Burdwood Bank Circulation. J Geophys Res
Oceans. 124 (10): 6904-6926. DOI: https://
doi.org/10.1029/2019JC015001
NELSON JS. 2016. Fishes of the world. 5th ed.
Hoboken: John Wiley & Sons.
NORTH AW. 2002. Larval and juvenile distribu-
tion and growth of Patagonian toothfish
around South Georgia. Antarct Sci. 14 (1): 25-
31. DOI: https://doi.org/10.1017/S095410200
2000548
PÁJARO M, MACCHI GJ, MARTINEZ PA, WÖHLER
OC. 2009. Características reproductivas de
dos agregaciones de merluza negra (Dissosti-
chus eleginoides) del Atlántico Sudoccidental.
Inf Invest INIDEP Nº 49/2009. 16 p.
PÉRON C, WELSFORD DC, ZIEGLER P, LAMB T D,
GASCO N, CHAZEAU CH, SINÈGRE R, DUHA-
MEL G. 2016. Modelling spatial distribution of
Patagonian toothfish through life-stages and
sex and its implications for the fishery on the
Kerguelen Plateau. Prog Oceanogr. 141: 81-
95. DOI: https://doi.org/10.1016/j.pocean.201
5.12.003 
PETROV AF, TATARNIKOV VA. 2010. New data on
migrations of Antarctic toothfish Dissostichus
mawsoni in the Dumont d’Urville Sea in the
2008/2009 Season. J Ichthyol. 50: 140-141.
DOI: https://doi.org/10.1134/S003294521001
0170
PRENSKI LB, ALMEYDA S. 2000. Some biological
aspect relevant to Patagonian toothfish (Dis-
sostichus eleginoides) exploitation in the
Argentine exclusive economic zone and adja-
cent ocean sector. Frente Marít. 18: 103-124.
RICCIALDELLI LA, BECKER YE, FIORAMONTI N,
TORRES M, BRUNO DO, RAYA REY A, FERNÁN-
DEZ DA. 2020. Trophic structure of southern
marine ecosystems: a comparative isotopic
analysis from the Beagle Channel to the
oceanic Burdwood Bank area under a wasp-
waist assumption. Mar Ecol Prog Ser. 655: 1-
27. DOI: http://doi.org/10.3354/meps13524
ROBERTS J, AGNEW DA. 2008. Proposal for an
extension to the mark recapture experiment to
estimate toothfish population size in Subarea
263
TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN

48.4. CCAMLR WG-FSA 08/46.
ROGERS AD, MORLEY S, FITZCHARLES E, JARVIS
K, BELCHIER M. 2006. Genetic structure of
Patagonian toothfish (Dissostichus elegi-
noides) populations on the Patagonian Shelf
and Atlantic and western Indian Ocean Sectors
of the Southern Ocean. Mar Biol. 149: 915-
924. DOI: https://doi.org/10.1007/s00227-00
6-0256-x
RUBILAR PS, ZULETA A, MORENO C. 2013. Pesca
de investigación bacalao 2013. Monitoreo
pesquería-dependiente y marcaje del bacalao
de profundidad en Chile. Propuesta Técnica.
Programa de Investigación Colaborativo
AOBAC-SUBPESCA. Centro de Estudios
Pesqueros S.A. 81 p.
SHAW PW, ARKHIPKIN AI, AL-KHAIRULLA H.
2004. Genetic structuring of Patagonian
toothﬁsh populations in the Southwest
Atlantic Ocean: the effect of the Antarctic
Polar Front and deep-water troughts as barri-
ers to genetic exchange. Mol Ecol. 13 (11):
3293-303. DOI: https://doi.org/10.1111/j.136
5-294X.2004.02327.x
SCHEJTER L, RIMONDINO C, CHIESA I, DÍAZ DE
ASTARLOA JM, DOTI B, ELÍAS R, ESCOLAR M,
GENZANO G, LÓPEZ GAPPA J, TATIAN M, et al.
2016. Namuncurá Marine Protected Area: an
oceanic hot spot of benthic biodiversity at
Burdwood Bank, Argentina. Polar Biol. 39:
2373-2386. DOI: https://doi.org/10.1007/s003
00-016-1913-2
STACY B, BURCH P, ZIEGLER PE, CRESSWELL KA,
HARTMANN K, HILLARY RM. 2021. Are tag-
based integrated stock assessments robust to
IUU fishing? Fish Res. 243: 106098. DOI:
https://doi.org/10.1016/j.fishres.2021.106098
TROCCOLI GH, AGUILAR E, MARTÍNEZ PA,
BELLEGGIA M. 2020. The diet of the Patagon-
ian toothfish Dissostichus eleginoides, a deep-
sea top predator off Southwest Atlantic Ocean.
Polar Biol. 43: 1595-1604. DOI: https://doi.
org/10.1007/s00300-020-02730-2
TROCCOLI GH, MARTÍNEZ PA, WÖHLER OC, DI
MARCO EJ. 2022. Análisis de la información
biológico pesquera en la pesquería argentina
de merluza negra (Dissostichus eleginoides).
Año 2021. Inf Téc INIDEP Nº 50/2022. 9 p.
TUCK GN, DELAMARE WK, HEARN WS,
WILLIAMS R, SMITH ADM, HEX, CONSTABLE
A. 2003. An exact time of release and recap-
ture stock assessment model with an applica-
tion to Macquarie Island Patagonian toothfish
(Dissostichus eleginoides). Fish Res. 63: 179-
191. DOI: https://doi.org/10.1016/S0165-783
6(03)00073-0
WELSFORD DC, CANDY SG, LAMB TD, NOWARA
GB, CONSTABLE AJ, WILLIAMS R. 2011. Habi-
tat use by Patagonian toothﬁsh (Dissostichus
eleginoides  Smitt 1898) on the Kerguelen
Plateau around Heard Island and the McDon-
ald Islands. In: DUHAMEL G, WELSFORD DC,
editors. Paris: The Kerguelen Plateau: Marine
Ecosystem and Fisheries. Société française
d’ichtyologie. p. 125-136.
WELSFORD DC, PÉRON C, ZIEGLER PE, LAMB, TD.
2014. Development of the Patagonian toothfish
(Dissostichus eleginoides) tagging program
in Division 58.5.2, 1997-2014. CCAMLR
WG-FSA-14/43.
WILLIAMS R, LAMB T. 2002. Behaviour of Dissos-
tichus eleginoides ﬁtted with archival tags at
Heard Island: preliminary results. CCAMLR
WG-FSA-02/60.
WILLIAMS R, TUCK GN, CONSTABLE A, LAMB T.
2002. Movement, growth and available abun-
dance to the ﬁshery of Dissostichus elegi-
noides Smitt, 1898 at Heard Island, derived
from tagging experiments. CCAMLR Sci. 9:
33-48.
WÖHLER OC, MARTÍNEZ PA, TROCCOLI GH, DI
MARCO EJ. (in press). Sobre la estructura
poblacional de la merluza negra (Dissostichus
eleginoides) en aguas del extremo sur ameri-
cano y su implicancia en la explotación y el
manejo de las pesquerías. Inf Invest INIDEP.
52 p.
WOOD SN. 2006. Generalized additive models: an
264 MARINE AND FISHERY SCIENCES 36 (3): 245-265 (2023)

introduction with R. Chapman & Hall/CRC.

WOOD SN. 2012. mgcv: Mixed GAM Computa-

tion Vehicle with GCV/AIC/REML smooth-

ness estimation.

YING, Y, CHEN Y, L IN L, GAO T. 2011. Risks of

ignoring fish population spatial structure in

fisheries management. Can J Fish Aquat Sci.

68 (12): 2101-2120. DOI: https://doi.org/10.

1139/f2011-116

ZUUR AF, IENO EN, WALKER NJ, SAVELIEV AA,

SMITH GM. 2009. Things are not always lin-

ear; additive modelling. In: Mixed effects

models and extensions in ecology with R.

Statistics for Biology and Health. New York:

Springer. p. 35-69. DOI: https://doi.org/10.10

07/978-0-387-87458-6_3

265

TROCCOLI ET AL.: MIGRATORY PATTERNS OF THE PATAGONIAN TOOTHFISH IN THE SOUTHWESTERN ATLANTIC OCEAN