CCAMLR

Proportional recruit indices and CPUE in Subarea 48.1 (Antarctic Peninsula region) from 1980 through 1996 were calculated based on the log book data from Japanese commercial krill trawlers. Proportional recruits calculated from fisheries data showed similarity with those from scientific data (Siegel et al., 1997), and showed close relationship to sea ice indices. CPUE (catch/towing volume) in Livingston area showed a decreasing trend during the study period. Alternation of operational strategy in relation to the product quality and decrease of krill density in the areas were considered as the possible reasons. On the other hand, CPUE in Elephant area showed greater inter-annual variation without any trend.

Results from two net surveys in the Elephant Island area during January-March indicated moderate krill abundance and lower recruitment success of the 1995/96 year class relative to that of 1994/95. These occurred after a relatively early 1996 spawning season that theoretically should have promoted good krill recruitment. However winter 1996 was characterized by slightly below average winter 1996 sea-ice conditions. These observations strongly suggest that winter sea-ice extent greatly affects larval survival and recruitment even when krill spawning is relatively early. Salp abundance values during March Survey D were second only to those observed during February-March 1993 and, like 1993, resulted from massive population growth during summer. This bloom, as those in previous "salp years", followed a winter with relatively low sea-ice development. The other zooplankton collected included a diverse taxonomic assemblage. Copepods, salps, and postlarval Thysanoessa macrura were the numerical dominants during both surveys. Day-night catch differences and interspecific relationships among various zooplankton taxa observed during January-February Survey A are described here.

Data from 1995-1997 US Antarctic Marine Living Resources (AMLR) Program surveys in the Elephant Island area are examined to determine the level of sampling effort required to adequately assess the (1) abundance and demographic structure of Antarctic krill and (2) relative abundance and interspecific relations of krill, salps and other macrozooplankton taxa in the Elephant Island area during summer months. Both parametric and nonparametric techniques are used. Between-survey and between-year comparisons are made to examine possible changes in sampling adequacy resulting from ecological changes operating on seasonal and interannual time scales. The results of these analyses indicate that minimal efforts such as 8 station transects are generally unreliable. Results from most analyses indicate that the data from at least 55 stations are required to adequately estimate krill, salp, and other zooplankton abundance, describe krill length-frequency and maturity stage composition, and assess the abundance relations of krill, salps, and other zooplankton taxa in the Elephant Island area.

Exploratory fisheries for Dissostichus spp. have been operating in these regions for a number of consecutive years with the tagging of toothfish a prerequisite for the legal fishery. This paper presents a detailed study of the catch and effort trends in Divisions 58.4.1 and 58.4.2 and examines 4 assessment methods based on comparative CPUE trends, local depletions, a constant recruitment model and mark recapture data.

Detailed review on the food and feeding of Antarctic fish

The results of analysis of stomachs of Antarctic toothfish D. mawsoni caught by the Spanish longline from the longliner “Yantar” in the Ross and Amundsen Seas during the period from 29 December, 2006 to 3 March, 2007 are presented. The comparative analysis of diet composition of Antarctic toothfish in different small-scale research units (SSRU) of subareas 88.1 and 88.2 is given. The graphs of size composition of food objects of Antarctic toothfish and the same by-caught objects are shown.

Japan proposes the revision of the Conservation Measure 41-04(2007): Limits on the explratory fishery for Dissostichus spp. in statistical subarea 48.6 in the 2008/09 season.

A proposal to undertake scientific research in CCAMLR Subarea 58.4.4 over the 2008-2009 seasons is introduced. The first survey has been undertaken by a commercial fishing vessel, Shinsei Maru No.3, in 07/08 season covering the whole SSRUs (Small Scale Research Units). In the course of this first year survey, important information, including information on distribution of toothfish, size composition of toothfish, and by-catch species, has been obtained. However, the information obtained by just the single year survey is not be sufficient in order to quantitatively assess the stock abundance and consider possibility of re-opening the area for new and/or exploratory fishery. Therefore, it is essential to continue the scientific research to accumulate scientific information on toothfish in this area. Furthermore, the presence of legal operators in this area could contribute to monitor and deter the activity of IUU vessels. In addition, tagging and sampling activities during the survey will particularly contribute to the future study on the distribution and population structure of Dissostichus spp.