CCAMLR

Information on CCAMLR fisheries of relevance to the work of WG-FSA is summarised. Where possible, summaries are in a format suitable for importing directly to the Fishery Reports. Additional fishery-related information can be found in WG-FSA-05/7, 05/8, 05/9 and 05/10 (summaries of observer data), SC-CAMLR-XXIV/BG/1 (catches in the Convention Area) SC-CAMLR-XXIV/BG/5 (summary of notification for new and exploratory fisheries), SCIC-05/10 (estimates of IUU catches) and CCAMLR-XXIV/BG/13 (implementation of conservation measures).

We present the results of an alternative method of estimating krill abundance, and producing maps of krill distribution, from the data collected during the 2000 CCAMLR survey of the Scotia Sea. Using a probabilistic Bayesian Maximum Entropy (MaxEnt) technique, density values for the unsurveyed off-transect portions of the survey area were found by interpolation, and thus values for total biomass across the survey area, and within individual small-scale management units (SSMUs), can be inferred. The MaxEnt formalism allows an objective choice of the parameters of the interpolation, and hence an objective choice of the most probable reconstruction of krill distribution, given the data. The Bayesian framework also allows an intrinsic calculation of the error in any resulting density estimate. During the survey, data were integrated at approximately 1 nm intervals, resulting in 9,586 observed data points. We therefore inferred the krill density on a 1 nm × 1 nm grid of pixels. Density values (g m-2) were calculated for all 1,726,332 pixels in the reconstructed area. The MaxEnt maps of the density distribution of krill across the survey area are presented. The resulting total biomass inferred for the survey area was 207.98 million tonnes, with a standard deviation of 10.08 million tonnes. The inferred biomass of krill in each of the SSMUs was: Antarctic Peninsula Pelagic Area (APPA) 65.192 Mt; Antarctic Peninsula West (APW) 0.753 Mt; Drake Passage West (APDPW) 35.874 Mt; Drake Passage East (APDPE) 0.397 Mt; Bransfield Strait West (APBSW) 0.167 Mt; Bransfield Strait East (APBSE) 1.381 Mt; Elephant Island (APEI) 10.496 Mt; Antarctic Peninsula East (APE) 0.003 Mt; South Orkney Pelagic Area (SOPA) 30.799 Mt; South Orkney West (SOW) 0.988 Mt; South Orkney North East (SONE) 0.005 Mt; South Orkney South East (SOSE) 0.243 Mt; South Georgia Pelagic Area (SGPA) 57.194 Mt; South Georgia West (SGW) 1.742 Mt; South Georgia East (SGE) 1.742 Mt.

In this work the characteristics of krill transport across the SSMUs determined on the basis of long-term Russian research in Area 48 are considered. Estimates of mean current velocities based on the long-term data from 3012 stations and respective time intervals when the water mass in the study area was totally replaced are presented. It is shown that in SSMUs the multiple total replacement of water masses is possible during one fishing season. These processes of water mass replacement will be accompanied with krill biomass transport across the boundaries of the SSMUs. Our estimates of krill flux out SSMU during fishing season appeared incomparable neither with the historical annual catch within SSMU, nor with the total catch from the Scotia Sea for any fishing season during the latest 20 years. It is shown that total krill biomass of 3.392 mln.t. transported by water mass out three SSMUs is comparable to the total precautionary yield value in the Scotia Sea comprising 3.17 mln.t. It is concluded that krill transport estimates should be taken into consideration in the scheme for allocating the krill catch limit among SSMUs in the Scotia Sea developing by CCMLR. This is primarily referred to the fourth option of the schemes (Hewitt, et al, 2004)