International Council for the Exploration of the Sea CM 1998/0:54 Deepwater Fish and Fisheries

A NEW METHOD FOR ESTIMATING THE ABUNDANCE OF PATAGONIAN TOOTHFISH (DISSOSTICHUS ELEGINOIDES)

C. Yau', M. A. Collins', I. Everson', and C. P. Nolan3

1. Department a/Zoology, University 0/ Aberdeen, Tillydrone Avenue, Aberdeen, AB242TZ, UK 2. British Antarctic Survey, HighCross, MadingleyRoad, Cambridge, CB3 OET, UK 3. Falkland Islands Government Fisheries Department, Stanley, Falkland Islands

Abstract

The Patagonian toothfish Dissostichus eleginoides has been the subject of a rapidly expanding longline fishery in the Southern Ocean, Traditional methods of estimating stock size have proved difficult to apply because the fish are found on the continental slope at depths of 1000 m. During September 1997, the Aberdeen University Deep Ocean Submersible (AUDOS) was used to estimate numerical density and size of toothfish in waters around South Georgia and the Falkland Islands. These are the first estimates that are independent of the commercial fishery.

Introduction

The Patagonian toothfish, Dissostichus eleginoides Smitt 1898, is a commercially important species caught with 10nglines in the Southern Ocean. It belongs to the family Nototheniidae, the so-called Antarctic cods, and has an amphiaustral distribution being found at depths of 70-2500 m around the Kerguelen Islands (Indian Ocean), South Georgia, the southern Patagonian shelf, and the coast of Chile (De Witt et al., 1990; Kock, 1992).

The biology of toothfish is poorly known, but it is thought to be a relatively long-lived benthopelagic or midwater species. In the Patagonian area, spawning is believed to take place on the continental slope at about 500 m depth. The large eggs are pelagic and hatch between August and November. The juveniles probably remain pelagic for a further year until they reach 15-20 cm TL when they become demersal (Kellerman, 1990). Subadult fish «50 cm TL) are frequently caught in trawls as incidental bycatch on the Patagonian shelf, particularly in the squid fishery for Loligo gahi (pers. obs.), though the distribution of the adults is confined to deeper waters. Sexual maturity in the females is reached at a size of 90-100 cm TL (9-12 years), whereas males mature at 64- 94 cm TL (7-11 years) (De Witt et aI., 1990; Zhivov and Krivoruchko, 1990). Adults reach total lengths in excess of220 cm (FIG, 1998 unpublished data). A commerciallongline .fishery for toothfish began around South Georgia in 1989, prior to which toothfish were caught mainly as bycatch in trawls. Between 1988-1989, Russian vessels caught 4136 tonnes of toothfish, in the subsequent year 8311 tonnes were caught (CCAMLR, 1998). As a consequence, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has established armual Total Allowable Catches (TACs) of around 3000 tonnes for Subarea 48.3. A licensed longline fishery has operated in the Falkland Islands Outer Conservation Zone (FOCZ) since 1994, with catches of nearly 3000 tonnes in 1994 and 1995 (FIG, 1997). The longliners use either the Spanish system or an automated system baited with sardines or squid, usually fishing at depths of 1000-2000 m depth.

In order to manage the toothfish stocks effectively, an accurate estimate of abundance is essential. Concern has been expressed about the ability of the toothfish stocks to withstand high catch levels and conventional assessment methods are proving difficult to apply (Des Clers et al, 1996), therefore, alternative methods must now be considered.

Priede and Merrett (1996) demonstrated that the mean first arrival time of scavenging fish could be used to obtain an estimate of abundance. This method, however, requires knowledge of both current velocity and fish swimming speed, and requires an understanding of the spatial distribution of the species. The Aberdeen University Deep Ocean Submersible (AUDOS) is an autonomous lander vehicle, it has been used for the last 10 years to investigate the biology and behaviour of deep-sea fish in the North Pacific and Atlantic Oceans (Armstrong et ale, 1991; Armstrong et ai., 1992; Collins et ai., 1998).

The aims of the present study were to test the feasibility of using the AUDOS system to estimate the abundance of toothfish around South Georgia and the Falkland Islands. Fish tracking was also undertaken in the Falkland Islands in an attempt to obtain data on swimming speeds oftoothfish necessary for calculating abundance.

Methods

The AUDOS was deployed on eighteen occasions around South Georgia in September 1997 from the F.V. "Argos Galicia", a commercial stem trawler chartered for a scientific groundfish survey of the area. In October 1997, ten deployments were made in the FOCZ from the Falklands Fishery Protection Vessel M.V. "Cordelia". An additional long-terrndeployment, using alO kg toothfish carcass as bait, was deployed from "ArgoS Galicia" east of Stanley on the return voyage to the Falklands, and was recovered after 7 days by "Cordelia". The positions of the AUDOS deployments are shown in Figure 1 and are summarized in Tables I and 2.

The Aberdeen University Deep Ocean Submersible (AUDOS)

For the South Georgia work a simplified version ofthe AUDOS system (see Bagley and Priede, 1997) was used. The basic AUDOS system consisted of an aluminium (Grade HE 30) frame onto which were mounted a deep-sea camera (Ocean Instrumentation), an acoustic doppler current meter (Sensortec),· and twin acoustic releases (Mors). Buoyancy

2 was provided by glass spheres (Benthos Inc. 17") attached to a mooring line. A dhan buoy incorporating a VHF radio (Novatech), satellite beacon (SIS) and a large pink flag were attached to the end of the mooring to aid recovery. Ballast, in the form of scrap chain, was used to anchor the AUDOS and hold it in position. The ballast was attached to an aluminium (non-marine grade) graduated cross, marked off at 10 cm intervals, which provided calibration for the photographs. For fish-tracking deployments in Falklands waters, three arms fold down from the main fame to support the hydrophones used for triangulating fish position. Code-activated transponders (CATs) (see Bagley, 1992) were inserted into the bait so that fish swallowing the bait could be located every minute, and the direction and swimming speed of the fish could then be determined. The bait used consisted of squid (Illex argentinus) and either an. icefish or myctophids; these were tied onto the graduated cross positioned 2.5 m below the camera.

Photographic Analysis

The camera was loaded with Ektachrome 200 ASA colour reversal film and was set on a I minute time lapse. A 10 minute interval, however, was programmed for the long-term deployment. Small strips of film were developed on board ship using developing kits (Chrome 3-Bath). The remainder of the film was developed in the UK (Kenton Film Laboratories). Following processing, the film was viewed on a microfilm viewer. The field of view obtained from the photographs covered a mean area of 4.3 m'. Fauna were identified using relevant texts (Norman, 1937; Peden and Anderson, 1978; Macpherson, 1988; Gon and Heemstra, 1990). Total lengths (TL) of fish were measured when they were level with the graduated cross or when they were on the seafloor.

Abundance Estimations

Priede and Merrett (1996) demonstrated that the abundance of scavenging fish can be estimated from their first arrival time at baited cameras. The model assumes that the fish are evenly distributed across the ground and requires knowledge of fish swimming speed and current speed. The distance from which the first fish was attracted to the bait (r) is estimated from the current speed and the fish swimming speed:

t r = arT 1 1 1 (-+-) Vw VF Where: t"" = first arrival time at bait (seconds) r = the distance of the fish from the bait (m) V w = current velocity (m s-')

Vf = fish swimming velocity (m s·')

The area occupied by an individual fish is assumed to be a hexagon of radius r, so that:

2

The abundance (n m-') is then:

3 1 n=-- 3 Aindiv

Substituting equations 1 and 2 into equation 3:

(_1 +_.1_)2 4 V Vw n= F 2 2.598ta"

Hence: 0.3849(-1 + _1_)2 5 V Vw n = ----'--:---".-F 2 tarr

The results will be sensItive to vanatlOns in current speed and swimming speed measurements. It is also important to make repeated deployments in order to obtain an average first time of arrival for scavenging fish in any location.

Results

Numbers and first arrival times of toothfish and other species from South Georgia (SG) and the Falkland Islands (FI) are given in Tables 1 and 2. Deployments ranged in depth from 269 m to 1525 m, but most were located close to the 1000 m isobath in both areas. Some problems with camera failure were encountered during the South Georgia cruise so that only 13 of these deployments were successfuL The shallowest deployment made in South Georgia was at 269 m within the entrance to Cumberland Bay and did not form part of the survey, but the extremely high suspended sediment load in the water column made interpretation of this particular film impossible.

Current and temperature measurements were obtained for SGI-5. However, the current meter was damaged during SG6, which meant ensuing current data were unusable, although the current meter still logged temperatnre data every minute for the remainder of the cruise. In subsequent deployments, the relative strength of the current was noted from the telltale ribbons on the cross and the tilt of the AUDOS rig, evidenced by the position of the cross in the photographic frame. Current data obtained while the current meter was still functional recorded mean velocities of 0.089 m S·1 in the Shag Rocks area of South Georgia. Much higher current velocities were evident around the Falkland Islands.

There was very little epifauna observed on the homogeneous, silty environment observed around South Georgia except for a few small ophiuroids. In contrast, the sand, gravel and broken coral sediment prevalent in the FOCZ featnred sponges, bryozoa, anemones and various . In addition to toothfish, the principal species attracted to the bait were the stone crabs (of the family Lithodidae), hagfish (Myxine spp. - confined to the FI deployments only), grenadiers (Marcrourus spp.), the blue hake (Antimora rostrata), liparid fish ( spp.), and the prawn Thymops

4 birsteini (see Tables I and 2). Only the stone crabs, grenadiers and blue hake were photographed actually taking the bait.

Toothfish

Toothfish were photographed during all but one of the successful deployments (Tables I and 2). The only deployment where no toothfish was observed was SG9 at 775 m depth. A maximum of 19 individuals were observed during the course of anyone deployment in the Falklands, but only a maximum of 6 toothfish were counted from any South Georgia deployment. The maximum nuinber of toothfish together in any frame was 2. The mean first arrival time of toothfish was 237 minutes in South Georgia, whereas in the FOCZthis was briefer at 59 minutes.

Toothfish were definitely attracted to the bait but did not appear to show further interest after arrival. Some individuals were observed circling around and swimming under the cross, but were never seen to investigate closely or attempt to take the bait. Consequently, tracking of toothfish was not accomplished and no swimming speeds could be determined. When toothfish did appear, they frequently remained in the frame for only one minute. Less commonly an individual remained for more than one frame, up to a maximum duration of 12 minutes (FB). Individual specimens could be identified by patterns of scars and spots on their dorsal surface and did not appear to make repeated visits to the bait.

A total of 93 toothfish was seen in the FI deployments but the total lengths of only 55 fish could be measured, as the whole fish had to be within the photographic frame. The mean length offish observed in the FOCZ was 781 mm (s.d.±123 mm), with a range of 520-1174 mm (Figure 2a).

Of the 39 toothfish specimens encountered during the SG deployments, the total lengths (TL) of only 19 individuals could be measured. A mean total length of 648 mm was obtained (s.d.±135 mm) with a range of 464-935 mm (Figure 2b). In comparison, toothfish specimens caught in trawl net samples during the groundfish survey had a mean TL of 537 mm (s.d.±132 mm) and ranged in size from 260-1100 mm (Figure 2c).

Attempts to track toothfish were unsuccessful, since the toothfish made no attempt to take the transponders embedded in the bait. Antimora rostrata, however, were tracked during two deployments in the Falkland Islands.

Lithodid crabs

The most abundant and frequently encountered species in the SG deployments were the stone crabs. Three species could be distinguished from the photograph, these have been tentatively identified as Paralomis formosa, Paralomis spinosissima and Paralithodes santolla (based on descriptions from Macpherson, 1988). The most common species was P. formosa which occurred in every successful South Georgia deployment, with a maximum number per frame of 44 individuals (SG8). Arrival times of this species were at times rapid (5-190 minutes, mean first arrival time 44 minutes) compared with P.

5 santolla (mean fIrst arrivaL of 132 minutes) and P. spinosissima (mean first arrival' of 359 minutes).

Discussion

The mean fIrst arrival times oftoothfIsh to the bait were long at 59 and 237 minutes for PI and SG deployments respectively. It is probable that toothfIsh had arrived earlier but were not captured on photograph either because of the 1 minute interval between frames, or because the fIsh were outside of the fIeld of view. The camera flash may also have discouraged fIsh from attending the bait. In many of the frames with toothfIsh present, only part of the individual was visible, usually just the head or the tail asthe fIsh swam away.

The absence of current meter and fIsh swimming speed data, coupled with doubts about the fIrst arrival times of the toothfIsh, mean that we are not able to make a realistic estimation of abundance. However, using data obtained from South Georgia, where there was a mean fIrst arrival time of 23 7 minutes, an approximated swimming speed of 0.324 m s" (0.5 body length s"), and current speed of 0.089 m s"; substituting these values into equation 5 gives us 0.4 toothfish km·'. Applying data from the Falkland Islands, with a mean first arrival time of 59 minutes, a swimming speed of 0.39 m s" (0.5 body lengths s") and an estimated current speed of 0.25 m s", results in an estimate of 1.32 toothfish km·'.

These are unrealistically low values of abundance and clearly require further revision, especially given the amount of commercial catches of toothfIsh achieved by longliners in both areas. Since abundance is proportional to the reciprocal of the square of arrival time, a doubling of the arrival time produces a four-fold decline in the abundance estimate. From the photographic evidence, toothfIsh stayed only briefly at the bait and it is probable that early arrivals were missed, thus resulting in the long mean first arrival times, particularly in South Georgia.

The lack of interest shown by the toothfish in the bait after arrival is curious. It contrasts with the behaviour of scavenging fishes observed in other areas, such as the grenadiers Coryphaenoides armatus and C. yaquinae in the north Atlantic and north Pacific (Priede and Smith, 1986; Priede et aI., 1990; Armstrong et al.,1992; Smith et al., 1992; Priede et al., 1994a; Priede et al., 1994b; Collins et al., 1998). The squid bait used was the short-fro squid, Illex argentinus, which is the same bait usually employed by longliners in the commercial fishery. Closer interest in the bait was shown by the grenadiers and by Antimora rostrata which were observed taking the squid. Perhaps there was a detectable difference (to a toothfish) between pieces of squid on longline hooks and the configuration of bait ona cross; or perhaps some trigger such as motion of the bait is required in order to elicit aresponse from toothfish. It is also probable that the flash used for taking the photographs discouraged the fIsh from taking the bait in some way.

The photographs therefore provided information on the size and behaviour of toothfish, and also on other scavenging species. The mean size of toothfish (648 mm TL), as

6 measured from the South Georgia photographs, was larger than that obtained from trawl samples during the groundfish survey (537 nun TL). This was perhaps expected since the trawls were carried out at shallower depths «300 m) where juveniles were more abundant.

Lithodid crabs

In order to estimate the abundance of P. formosa around South Georgia, the mean current velocity of 0.089 m s·' obtained from Shag Rocks was assumed to be uniform around South Georgia. A mean walking speed of 0.016 m s·' was estimated by . measuring the maximum distance traversed by individual crabs (n=10) in consecutive frames of the photographs over several deployments. Applying these values into equation 5 results in a rough approximation of300 crabs per square kilometre.

The results showed that Paralomis formosa is a .conunon scavenging species around Shag Rocks and South Georgia. It is more widespread and probably occurs in higher numbers than previous exploratory trawl surveys had suggested (e.g. Basson and Hoggarth, 1994). Marked fluctuations in crab numbers observed in the course of some deployments implied a clumped distribution of P. formosa. There were insufficient data available on the walking speeds of P. spinosissima and P. santolia to estimate their abundance, but the longer first arrival times of these two species suggested a much lower density than for P. formosa. Paralomis spinosissima has been the focus of attention as a potential species for conunercial exploitation around South Georgia (Basson and Hoggarth, 1994; L6pez.Abellan and Balguerias, 1994). Exploratory fishing for P. spinosissima resulted in a catch of 299 tonnes during 1992·1993 (CCAMLR, 1998). Paralithodes santolia would probably also be of interest because of its larger size. An important fishery already exists along the southern coast of Chile for P. santolia (Campodonico, 1983).

Recommendations for future work

For future work, a video camera capable of operating at lower light levels would be preferred. This avoids the use of an intense flash and may overcome flash·induced bait shyness by the toothfish. The quality of the resulting images may be poorer, but as a consequence of the experience gained from the present study it would be possible to distinguish toothfish from other scavenging fish species. Furthermore, short·term deployments of2·3 hours would be feasible so that many deployments could be made in a short period. Ideally, future work should be undertaken outside of the conunercial season to avoid the influence of the large amount of bait deployed from longliners operating concurrently in the survey area.

It would still be necessary to track toothfish in order to obtain information on swinuning speeds. If other factors such as the position of the bait are important, these can be modified from deployment to deployment as video footage could be reviewed inunediately after the vehicle is recovered.

7 It is not certain at this stage whether the difference in the calculated toothfishabundance between Falklands waters and South Georgia is significant. A higher density of toothfish was calculated in the FOCZ, even though commercial longliners were fishing close by at the same time. Clearly, further work is required to determine if this difference is a real feature, perhaps resulting from the longer period of commercial longlining that has occurred around South Georgia.

Acknowledgements

Dr. Phil Bagley and Steve Addison (University of Aberdeen) provided technical expertise on the AUDOS. Thanks to the crews of the F.V. "Argos Galicia" and the M.V. "Cordelia" for their assistance in the handling of AUDOS. Dr. Nigel Merrett and Martin White assisted in species identifications. Crag Jones (Marine Resources Assessment Group, Imperial College, London), Dave Currie (Scantron), Adam Cockwell (Argos Ltd.), and Joost Pompert (FIG Fisheries Department) provided logistic support. This work was funded by Falkland Islands Government and the Government of South Georgia.

References

Armstrong, J. D., Bagley, P. M. and Priede, l. G. (1992) Photographic and acoustic tracking observations of the behaviour of the grenadier Coryphaenoides (Nematonurus) armatus, the eel Synaphobranchus bathybius, and other abyssal demersal fish in the North Atlantic Ocean. Marine Biology. 112:535-544. Armstrong, J. D., Priede, l. G. and Smith, K. 1.(1991) Temporal change in foraging behaviour of the fish Coryphaenoides (Nematonurus) yaquinae in the central North Pacific. Marine Ecology Progress Series. 76: 195-199. Bagley, P. M. (1992) A code-activated transponder for the individual identification and tracking of deep-sea fish. In: Wildlife Telemetry. l. G. Priede and S. W. Swift (eds.). Chichester, Ellis Horwood: 111-119. Bagley, P. M. and Priede, l. G. (1997) An autonomous free-fall acoustic tracking system for investigation of fish behaviour at abyssal depths. Aquatic Living Resources. 10: 67-74. Basson, M. and Hoggarth, Di D. (1994) Management and assessment options for the crab fishery around South Georgia. CCAMLR Science. 1: 193-202. Campodonico, G. I. (1983) Research on thebiology and fishery of the Chilean southern and the false king crab, prospects· and problems. Can. Transl. Fish. Aquat. Sci. (4970): 30 pp. CCAMLR (1998) CCAMLR Statistical Bulletin Volume 10. Fisheries data 1988-1997. SB/1998/1O. Collins, M. A., Priede, I. G., Addison, S., Smith, A. and Bagley, P. M. (1998) Acoustic tracking of the dispersal of orgaoic matter by scavenging fishes in the deep-sea. Hydrobiologia. In Press. De Witt, H., H., Heemstra, P. C. and Gon, O. (1990) Nototheniidae. In: Fishes of the Southern Ocean. O. Gon and P. C. Heemstra (eds.). Grahamstown, J. 1. B. Smith Institute of Ichthyology: 279-331.

8 Des Clers, S., Nolan, C. P., Baranowski, R. and PoD:;pert, J. (1996) Preliminary stock assessment of the Patagonian toothfish longline fishery around the Falkland Islands. Journal ofFish Biology. 49 (Supplement A): 145-156. Falkland Islands Government (FIG) (1997) Fisheries Department, Fisheries Statistics, Volume 1: 75 pp. Gon, O. and Heemstra, P. C. (1990) Fishes of the Southern Ocean. Grahamstown, J.L.B. Smith Institute ofIchthyology. 462 pp. Kellerman, A. (1990) Catalogue of early life stages of Antarctic notothenoid fishes. Berichte Polarforschung. 67: 45-136. Kock, K.-H. (1992) Antarctic Fish and Fisheries. Cambridge, Cambridge University Press. 359 pp. Lopez-Abellan, L. J. and Balguerias, E. (1994) On the presence of Paralomis spinosissima and Paralomis formosa in catches taken during the Spanish Survey Antartida8611. CCAMLR Science. 1: 165-173. Macpherson, E. (1988) Revision of the family Lithodidae Samouelle, 1819 (Crustacea, , ) in the Atlantic Ocean. Monografias de Zoologia Marina. 2: 9-153. Norman, J. R. (1937) Coast Fishes Part II. The Patagonian region, Discovery Reports: 16: 1-150. Peden, A. E. and Anderson, M. E. (1978) A systematic review of the fish Lycodapus (Zoarcidae) with descriptions of two new species. Can. J. Zoo!. 56: 1925-1961. Priede, I. G., Bagley, P. M., Smith, A., Creasey, S. and Merrett, N. R. (1994) Scavenging deep demersal fishes of the Porcupine Seabight, North-east Atlantic: Observations by baited camera, trap and trawl. Journal of the Marine Biological Association ofthe United Kingdom. 74: 481-498. Priede, I. G., Bagley, P. M. and Smith, K. L. (1994) Seasonal change in activity of abyssal demersal scavenging grenadiers Coryphaenoides (Nematonurus) armatus in the eastern Pacific Ocean. Limnology and Oceanography. 39 (2): 279-285. Priede, I. G. and Merrett, N. R. (1996) Estimation of abundance of abyssal demersal fishes; a comparison of data from trawls and baited cameras. Journal of Fish Biology. 49 (Supplement A): 207-216. Priede, I. G. and Smith, K. L. (1986) Behaviour of the abyssal grenadier Coryphaenoides yaquinae, monitored using ingestible acoustic transmitters in the Pacific Ocean. Journal ofFish Biology. 29: 199-206. Priede, I. G., Smith, K. L. and Armstrong, J. D. (1990) Foraging behaviour of abyssal grenadier fish: inferences from acoustic tagging and tracking in the North Pacific Ocean. Deep Sea Research. 37 (1): 81-101. Smith, K. L., Kaufmann, R. S., Edelman, J. L. and Baldwin, R. J. (1992) Abyssopelagic fauna in the central North Pacific: comparison of acoustic detection and trawl and baited trap collections to 5800 m. Deep-Sea Research. 39 (3/4): 659-685. Zhivov, V. V. and Krivoruchko, V. M. (1990) On the biology of the Patagonian toothfish, Dissostichus eleginoides, of the Antarctic Part of the Atlantic. Journal ofIchthyology. 30 (7): 142-146.

9 FOCZ

Deployments 9-10

50'

Falkland Islands

• 7-Day Deploy-men!

Deployments 1-8 r.:-=

56'

62' 60' 58' 56' 54' 520W

430W 4:2'> 41' 40' 3.' 38'

South, Georgia

1 5 100()~~

17 •••18 ~3 -~ \, ~., ~10 16 ~11 15 • 13 14 12 ~....

Figure 1. Positions of AUDOS deployments in the Falkland Islands Outer Conservation Zone (FOCZ) and around South Georgia, September-October 1997.

Deployment 1 2 3 4 5 6 7 8 9 Date set 107/09/97,08/09/97 10/09/97 11109/97 13/09/97! 14/09/971 16/09/97 17/09/97! 18/09/97 ,------,-••. ""------••• - ••• ----;------"•• ,""'. • ---.,.-.---~--.------•• ,.-.---.-.---- •.•• ------...! ------r- -______--L...... __ ".-.---- !-atitu~~. __. ___. ____ . _____J2.3.~~~:1~~~_!_~~~L34' S J~~046.02'.~L~3.°1.?~!~_S_.U~.035.20' S.I 53~~56' ~.L~4°12:?~',,~--l- 53."--~.08'~.J 54"14.94' S. Longitude ,141°56.66' W ! 40°20.46' W i 41°59.07' W ! 42°12.03' W ! 37°59.24' W ! 38°59.62' W 136°27.00' W ! 35°59.80' W i 35°15.83' W ,______.. ,.. ,. ______~ __._. ____ . __ ._._.'. __ ._._ .... '.-. __ . ______._~.,._._._., .. _. ______.---_--.-.--~_:.-_ .•. ____._._ ... ____l-_. __ . ______._ .... ___ ---.l..-.-__ ••••• ___• ___ ... ~. ____._._._;... _____ • ______,...... -•• -_ •••••• _.-. __ Depth (m) I 1039 I 1149 I 1000 i 747 i 1000 ; 1000 : 269 ! 1100 ! 775 1__ ._ •••••••••• ______••• ______._._._ ••••••••• ______----....1 ______.... ______...... ____, ______._ .... _...... __. __ ... _____ ., ...... __ ._____ ..... _. ___~.- .. -.---.-.-.-.-.-.--!--.-.... -.----.--.I....--..--..--.-.-.-~-.-.-- __._"

,...... -----...... ----.. - ...... --.------,--.-.-I ...... ---Ii!__.. __ ... ___.__ ...... _____.... L..___ ...... ___I• __ ._ ...... __+- I ...... film-.- blank...... ~_ I no ... visibility__ • __ ..... !, .. - ...... -.- ...... i --.~---l Dissostichus e/eginoides I 1 I 2 .. i 31 81 I . . . . '.. I 4. ! 0 li::.:~~~~;!~!~flj~~~~!:':)::E~:·~~T:~~~3~:==I~?2~==E::·~:~~5~~~·r=::~~i~~__ =~F-·(=!~~~·--~F·~~~:'~~:~j:::.~" ~:~~=~l=~I~~~-:==l~=.~' :~--=~~ 1~;::~i~a~~~~~i:f~_."_P_P:~::::.~...... L.. J: '~~~r' u:~-=~=~.L=-1 =~'~J::::'. ___ .!~::::': --: ·r·-·- J~-= ---:--=-:::: __ ~~~: --.. ~~_~~::::t·--~~ - :.-_"-_+.-.:::: Antlmora ros/rata ; 0 i 0 ' 1 : 0 : 3 :" -,,' 0---·-- : -6' -----:------i ------t ------\------j------~---;------T------'------.-:------1------[max_ no_ In any frame] , : i ...... i . i .'.. ! ! ~:;:~~t~f;:{~~~:=:==· _-=--F:=J:=.=_[ ·~~~==:_E=I~.~--·:[.--~;~~----·E---2~:·~ ..... l_=:~=~~:=.::~J. __ ~:=·::~=~=~[·)~ .. ::::I.:=~~;=~---- __ Paralomis spinosissima I 0 ! 0 i 0 i 0 i 4. : i a : 3 ------.-.-.. :-.---.-----.--.... -.-.-.. --.-.--...;-----.-----.-.--.---.- ...... --.. -, .. -- ---·---··---·-·-·--r----·- ...... -.--.--+----.. -.-.-.---... -.- -:-~---.------...... -.;-.-.. ---.-.----.. -.. - ·-·----·-·--·-·~-...... ---···-·-·-·--·-·-··-1-·-----·· Thymops hirsteini i 0 ' 0 ! 0 . 0 I 0 i" 1 0 i 0

Deployment 10 11 12 13 141 15 16 17 18

,..Date __ set.... _._.__ ... __ . __ .J.9!~9!9.7_J _2~!fJ.?~~7. __" L..2I~~9/97 J..~~/09/9~ __ ,.c ..?~!Q'!./~71~?~/97 __ .L 26/09/9~. ",,,_.27 /~.9/97.. .L.l8/09/9.7 . Latitude [ 54°30.94' S i 54°59.90' S I 55°25.38' S I 55°09.11' S I 55°02.62' S ' 54°52.67' S .. 54°39.86' S : 53°44.39' S ' 53°41.22' S

:~~~~~~~~r~;r~~(Toothfish flfst arrival time (mins)) 1 (438) i - i {I 96) I {I 64) I {I 14) I (502) i ' I (297) :

'I Antimora rostrata i 0 i - , 0 ! 2 3: 0 I I I i - Il max. ~~~.I~:~l]!~e[.~.·~·~~~.-.~_~_~~---·-.-.:~.~.l.-.~.~.~.:-.~.-.~.-.:-.:~~~~=~~J=~=-~_=.·~.~~~:=~=t=~=~-·---·-.-.-.--~~.~~_!-.-~~~~: .. :~:~.~~~=:~.-.~::.. :~:~~~~~~~--=~~.~:~:~~.~.=.r~-~~~.-.~-_~~~~.~~.·~_~.·=~===~.·~.:-.~.~.~=L.·~~~.~.~.~:-.=_~~~.~.·~-~.:-.:-.J--.:·.:-~.:~~~~_~=~~~~~~~_ Paralomis formosa I 28 i...". : 24 I 37 .: 20 , 26.: ! .21 I ~~~zj:!::;;f~!tff~~~~::--·--·--·~±~5= .. ·=I~=3.~~+=~=~··=i,,-::~=~·~.~~=:-r~~~~·::=:~L~~·~..i=~:--:::·-~=~ ..~~i:=~T::.~~~: .. E=~~:·~~~ Thymops hirsteini iii i 0 0 . 0' 0 I

Table l. AUDOS deployments" information and species observed from South Georgia, September 1997. Deployment i Long-term I 1 2 3 4 5 6 7 8 9

_____Date ", ______set , ...•.•...•... ______.1-- i ____02/10/97.... __...... I - 10110/97____. i 10/10197___. ___ . __ .. __ .1__i 10110/97 I lllio/97 ,_.i ____ 11I10/97~12110/97--1- ______._ ....•...... ,_.! ______13/10/97jWfo/97._ ...... ___. _____ ."_"' I ...... • 17110/97 " •. _" __ _ Latitode i 51"49.98'8 i 54°26.26'8 154025.91'8 154°41.65'8 i 54°35.35'8 i 54°20.07'S i 54°23.80'S 1 54°25.77'S i 54°25.94'S i 48°36.30'8 "-""._--,"._-.-.-...... ,, ... _------... ------...... ,.-.--"---r;.----.-.,.l.. -.... --"------.--~--"-.-.... --...... --.------,------.. ,'--. .. ······--·-·--·---..---·----·-1---'-'--····--····-- Longitode ; 55°56.26'W 55°29.76'W i 55°11.63'W 155°19.29'W i 55°1O.14'W ; 55°11.59'W ,55°30.13'W i 55°18.96'W i 55°24.56'W 57°09.99'W I Depth (my------j 1100 j--§oo--t--W48 -r144:rinr6-----j--- 1735 --i----fT79----t-T:iiz--r---I04g-:--Hj4'f-

Flatfish - MancopsettaiParalicht/rys 0 0 0 0 0 0 0 0 0

--0--- ... _-" _.... ".... ;...... _._------_._._+_ ...... __ .. __ ._------,-.;...... -._---_._ ... __ ._._.- 2 i 1 ; 0 t 0 ----.-- --.-- .. .l ...... -.--.-.---.-~.--...... -.-.---.--.----.-.~ ... -.-----.-.-.-.- Oil I 0 ! 0 __ .... __ ._ .__ ., .. _., .. _ ._ ...... :._. _____, __ .___ ._. ___ .__ ._. ___ ._L.__ _._""._. ___ .__ ...... 1. ____ ... ______~ ... -.- ___ ~._._. __ .. __ Prawn - T/rymops hirsteini 1 1 2 0 2; 5 i 2 ' 0 i 0 i 0

Table 2. AUDOS deployments - information and species observed from the Falkland Islands, October 1997.