CCAMLR

Information on CCAMLR fisheries of relevance to the work of WG-FSA is summarised. Additional fishery-related information can be found in WG-FSA-04/6, 04/7, 04/8 and 04/9 (summaries of observer data), WG-FSA-SAM-04/4 (Development of Fishery Plans), SC-CAMLR-XXIII/BG/1 (catches in the Convention Area) SC-CAMLR-XXIII/BG/3 (summary of notification for new and exploratory fisheries), SCIC-04/3 (estimates of IUU catches) and CCAMLR-XXIII/BG/8 (implementation of conservation measures) and CCAMLR-XXIII/38 (Monitoring CCAMLR Fisheries).

Net sampling during annual field season activities of the U.S. Antarctic Marine Living Resources (AMLR) Program yielded about average concentrations of postlarval krill during January and February-March surveys. Overall length-frequency distributions and maturity stage composition reflected good recruitment of the 1990/00, 2000/01 and 2001/02 year classes and little contribution from the 2002/03 season. Although little reproductive activity and unusually large proportions of immature individuals occurred in the Elephant Island Area during January, larval concentrations and maturity stage composition indicated a very early onset of seasonal spawning activity. Krill demographics during February-March indicated an influx of large spawning individuals; these along with greatly increased concentrations of larval stages suggested potentially good recruitment success from the 2003/04 year class.
The 2004 survey period was marked by a rapid and large-scale change in overall zooplankton abundance, composition and species abundance relations. This was similar to marked “transition periods” observed in 1994 and 1997 and, like those, was believed to result from hydrographic rather than biological processes. Qualitative differences between this and previous transition periods highlighted significant changes in zooplankton abundance and abundance relations, frequency of krill recruitment success and sea ice development that coincided with an oceanic-atmospheric “regime shift” affecting the Pacific Ocean basin.

In December 2003-January 2004 four synoptical surveys have been made in CCAMLR Division 88.1 (Ross Sea): acoustic survey on two krill species (E. superba and E. crystallorophias), net samplings on krill and other pelagic species, visual samplings on krill predators, CTD and XBT samplings on the water masses. The paper describes aim and carrying out of the project, instruments and methods used and presents some preliminary results.

This paper reports on the discussions that occurred among individuals tasked by the WG-EMM to continue review of the CEMP Standard Methods and their delivery to the CEMP database. The discussions were diverse in covering a wide range of parameters, methods and issues, but in the limited time available it was not possible to discuss all aspects of CEMP. The issues considered are presented under broad themes with some historical background to the development of those themes provided as context. Issues relating to each theme that were discussed by the group are summarised, and recommendations for any work or action are provided.

In comparison to other homeotherms, young recently weaned marine mammals in high latitudes face exceptional energetic demands when foraging and thermoregulating. Lipids are an important source of energy and a major component of insulation that allow them to meet these demands. To examine the role of lipid stores in a high-latitude pinniped, the body composition and thermoregulatory capabilities of Antarctic fur seal (Arctocephalus gazella) pups and yearlings were measured via flow-through respirometry and hydrogen isotope dilution. From these data we constructed a model to examine the importance of post-weaning fasting capability in free-ranging, young fur seals. Resting metabolic rates were different for pups and yearlings measured in 0.6 ºC water, 10.3 ºC water, and ambient air; however, mass and percent lipid as covariates accounted for the different metabolic responses in pups and yearlings for all treatments. The estimated lower critical temperature for combined pups and yearlings was 14.4 ºC, 10 to 15 ºC above water temperatures normally experienced by Antarctic fur seals. Modeling predicted that a weaned fur seal pup would survive at-sea from 9.8 to 36.2 days before succumbing to starvation. The most likely maximum travel distance within this time constraint suggests food resources close to the natal rookery are important to first year survival for this species.