CCAMLR

Data on bottom trawl catch of tagged fish are presented as well as results of tagging of some Antarctic fish in Subarea 88.1. Use of marked trawl hooks as an additional method of fish tagging is proposed for discussion.

On the grounds of data analysis collected by one of the authors – Prutko V.G. in December, 2002-March, 2003 in Subarea 88.1, we determine Antarctic toothfish body length at maturity of 50% females -128-130 cm, males -117-120 cm.
To estimate maturity stages of post-spawning individuals we suggest using double designation, and to control visual estimation of maturity stages number of different oocytes in Antarctic fish ovaries should be measured and calculated, in addition to histological investigations. Dynamics of gonadosomatic index in different periods and for different research areas is presented. Presence of Antarctic toothfish spawning concentrations in the northern part of the research area and presence of “exhausted” individuals are noted. On the basis of the proceeded data and analysis of literature information we came to the conclusion that strict limitation of Antarctic toothfish catch was necessary. Together with the limitation it is suggested paying maximum attention to investigate reproduction ability of the species in question. Brief program of such research is presented.

Detailed materials are presented collected by the author in Subarea 88.1 in December, 2002-March, 2003 on penetration of sub-Antarctic species D.eleginoides, L.immaculatus to polar latitudes (to 72° S). Supposition is expressed that Ross’s rotation conditions mixing of Antarctic and Patagonian toothfish distribution areas and appearance of opah in the polar Ross Sea.

This paper provides an update on seabird research underway in New Zealand. Details of population research including methods and relevant references are provided. Foraging range tracking programme details are also provided, along with details of recorded visits to the CCAMLR area (nil).

Data on maturity, gonadosomatic index (GSI) and length weight of Antarctic toothfish Dissostichus mawsoni were collected from Sub-area 88.1 in the 2002-2003 season by the New Zealand bottom longline vessels Janas, Avro Chieftain and San Aotea II operating in the Exploratory Fishery. The first spawning fish were found in April, a month earlier than in the previous season.

An update on the BioRoss research programme is provided for information purposes. The update includes progress to date, planned research and the future of the programme.

An exploratory fishery for Antarctic toothfish (D. mawsoni) has been in operation for six seasons in Subarea 88.1 and for two seasons in Subarea 88.2. A large amount of data on both toothfish and associated bycatch from the fishing operations has been collected. The purpose of this report is to present the analysis of data collected in the toothfish fishery for the 2003 season (this is part of the 2002–03 CCAMLR split fishing year), and to compare these results with previous years. Note this report is confined to data for the New Zealand vessels.
The heavy ice conditions caused by the presence of the huge C2 iceberg severely altered the fisher's behaviour in 2003. The vessels were unable to fish south of about 72º S, and so effort was mainly focused instead on SSRUs 881A–C. In addition, SSRU 882E was fished for the first time.
Ninety-two fine scale rectangles (FSRs), including 57 new FSR’s, were fished during the 2003 season. New Zealand vessels have now fished a total of 228 FSRs.
The catch of D. mawsoni was about 1070 t, and contributed 89% of the total catch in 2003. They were caught in over 90% of the sets in all five SSRUs fished. They were the dominant catch in all sets apart from some made in SSRU 881A. Antarctic toothfish were recorded at depths from 430 to 1900 m, and were most abundant from about 1000 to 1800 m. In 2003, almost 25 t of Patagonian toothfish (D. eleginoides) was taken, almost entirely from SSRU 881A. This is more than twice the catch from 2002 but not as great as the catch from 2001. Patagonian toothfish dominated the catches from 60 to 62° 30' S but Antarctic toothfish dominated catches further south.
The main bycatch species was Macrourus whitsoni, which contributed about 7% of the 2003 catch. Two other rattail species were identified from 5 sets. Bycatch of the two skate species (Amblyraja georgiana and Bathyraja eatonii) was only 6.3 t (less than 1% of total catch). Other bycatch species (including icefish and moray cods) each contributed less than 1% of the catch overall. The main non-fish bycatch reported was starfish.
Antarctic toothfish length frequency data were scaled up to the catch. About 530 otoliths were read and the scaled length frequency converted to catch-at-age. Fish aged from 13 to 30 years dominated the catch. No progressions of any particularly strong or weak year classes were apparent throughout the time series. Length and age of Antarctic toothfish from the fishery have increased through the series, mainly because fishing has been directed more toward depths greater than 1000 m in the later years.
Length frequency data for Macrourus whitsoni from 2002 and 2003 were scaled up to the catch for each year. Also age, growth, and maturity data were reviewed.