CCAMLR

The analysis of fishing data obtained from the ship’s log of the Polish commercial vessel M/T Pollux facilitated the characterization of catches and concentrations of krill between February and June from 1997 to 1999 in statistical area 48. Records from each haul were used for analysis and since the vessel carried out catches along with other Polish vessels, the results describe Polish catches in this period and area. Each fishing season was different. In 1997 the catches were carried out in sub-area 48.1 and 48.3, in 1998 they were exclusively carried out in sub-area 48.1 and in 1999 in sub-areas 48.1 and 48.2. On average, the vessel made from 7 to 9.5 hauls daily which lasted an average of 60-70 minutes. Differences in catch rates in various areas and years were observed. The highest catch rates (4-5 t/h) occurred near Elephant Island and King George Island, as well as near the South Orkneys and King George Island in 1998 and 1999, respectively. During the day, commercial krill concentrations occurred deeper, at depths of 10-140 m, while at night the concentrations were closer to the surface, at depths of 10-100 m. The day catch rates were several times higher than at night (4.35-9.33 during the day and 0.8-3.33 at night). In general, the night concentrations were shallower than the day-time ones in the area of King George, however, in 1997 and 1998 the situation was the opposite.

The Japanese stern trawler Chiyo maru No. 5 conducted krill fishing operations in CCAMLR Subarea 48.1 during February, 2000. Under an agreement by the Japanese and United States governments, a CCAMLR International Scientific Observer was present on the vessel. This paper presents much of the information collected in graphical form, and serves as a compliment to the Final Report of Scientific Observations submitted by the scientific observer (Rain, 2000). Fishing operations were conducted off the South Shetlands Islands north of Elephant Island and the lower South Shetlands Islands. Information on length frequency, maturity, and feeding intensity were summarized based on 5 regions off the South Shetland Islands where hauls were clustered. The biological information collected during this commercial fishing operation agrees well with the findings of the CCAMLR 2000 synoptic survey within Subarea 48.1.

A potential method is presented for combining data collected as part of the CCAMLR ecosystem monitoring program (CEMP) into a single index for each of predator, prey and environmental parameters. The paper is divided into four main parts. The first part develops the proposed method of forming summary indices, which is based on the usual theory of multivariate statistics and takes into account the covariance between parameters. The second part reports on a Monte Carlo simulation study that examines the robustness of the indices to missing data and the degree of correlation between parameters. These trials show that missing values were unlikely to be a problem for time series of parameters that are highly correlated (greater than 0.6). Criteria for inclusion of parameters in the indices are discussed when parameters are moderately or poorly correlated. The third part uses further simulation tests to examine the power of the statistical procedure adopted by WG-EMM in 1996 for identifying anomalies in CEMP parameters. The power of the procedure to detect anomalies was found to fall to low levels once more than a few anomalous values have appeared in the data. An alternative procedure, using estimates of the mean and variance of baseline time series was found to have consistently better statistical power regardless of the accumulation of anomalies. The last section outlines an approach to the further development of CEMP indices for application in CCAMLR.

Field studies were carried out at Bouvetøya from 9 December 1998 to 27 February 1999. The main objective for the 1998/99 expedition was to continue the CEMP-monitoring work initiated in 1996/97. The species monitored were Chinstrap Penguin (Pygoscelis antarctica), Macaroni Penguin (Eudyptes chrysolophus) and Antarctic Fur Seal (Arctocephalus gazella). In addition to the CEMP-work, other work on seabirds and seals was carried out, including diving behaviour of penguins, and studies of diet and pup production of fur seals. The following CEMP-parameters were studied in Chinstrap Penguin and Macaroni Penguin: breeding population size (A3), age-specific annual survival and recruitment (A4), duration of foraging trips (A5), breeding success (A6), chick diet (A8), and breeding chronology (A9). For Antarctic Fur Seal, data were collected on the duration of adult female foraging/attendance cycles (C1) and pup growth (C2).

The diet of the Snow Petrel Pagodroma nivea was investigated at Laurie Island, South Orkney Islands, (60¡46'S, 44¡42'W), Antarctica, over the period January-February of 1998. Stomach contents and regurgitates of adults were sampled during the chick-rearing period. Fish, followed by the Antarctic Krill Euphausia superba, were the main prey throughout the sampling period. Other crustaceans and cephalopods were scarcely represented. Among fish, Myctophids dominated in the diet, being Electrona antarctica the main prey.
The information presented here should be considered as preliminary and further studies on the composition of the diet of the Snow Petrel as well as on the distribution and abundance of their main preys are required to better understand on the feeding behavior of this bird.