CCAMLR

A serological study was initiated to determine the presence of anti-Brucella antibodies on marine mammals of Antarctica. For this study, blood and extra vascular fluid samples was taken from 12 Weddell Seals (Leptonychotes weddellii) at the Site of Special Scientific Interest (SSSI) Nº 32 and CCAMLRa Ecosystem Monitoring Program (CEMP) site N° 2 “Cape Shirreff and San Telmo Islets” (62º 47’ S; 60º 27’ W), located on the Livingston Island (South Shetland Islands), Antarctica. Field work was carried out as part of Project 018 "Ecological studies on the Antarctic Fur Seal, Arctocephalus gazella" of the “Instituto Antártico Chileno” (INACH) and the laboratory analysis at the Departamento de Medicina Preventiva Animal, Facultad de Ciencias Veterinarias y Pecuarias of the Universidad de Chile.
The samples were tested by the conventional Rose Bengal test (RB) and two competitive enzymatic immunoassay: Compelisa®?(Veterinary Laboratories Agency, UK) and c-ELISA (FAO/IAEA, 1994). In five of the total samples studied, anti-Brucella antibodies were detected and the enzyme linked immunosorbent assays (Compelisa®) were the most sensible tests.
These results strongly confirm the presence of infections by bacteria of the genus Brucella in L. weddellii and point out the necessity of complementary studies to know the etiology and their infection epidemiology in this region of the world.

This paper describes the first detection of Brucella sp. antibodies in seals from the Antarctic territory. Sixteen antarctic fur seal (Arctocephalus gazella) and one Weddell seal (Leptonychotes weddellii) sera were tested by the Rose Bengal test (RBT), complement fixation test (CFT), immunodiffusion (AGID) and c-ELISA. Antibodies against Brucella sp. were detected with the RBT, the CFT and the c-ELISA in six of the seventeen samples involving the two animal species. It is concluded that a Brucella sp. described as affecting marine mammals in the Northern hemisphere could be also present in the Antarctic territory.

The US AMLR Program conducted large area surveys in the Elephant Island-South Shetland Island region during 18-30 January 2001 (Survey A, 101 stations) and 12 February-12 March 2001 (Survey D, 96 stations). Krill, salps and other zooplankton were collected at each station using a 180 cm Isaacs Kidd Midwater Trawl fitted with 505um mesh nets. Data obtained from these surveys were compared to assess seasonal variations in distribution, abundance and demography of Antarctic krill (Euphausia superba) and salps (Salpa thompsoni), and distribution and abundance of biomass dominant copepod species and other common zooplankton taxa. Comparisons were also made with data obtained during 1992-2000 AMLR field seasons to assess interannual variations. Mean and median krill abundance values in the Elephant Island area during the 2000/2001 field season were intermediate to highs in 1996 and lows in 1999. Increased abundance relative to 1999 resulted in part from recruitment of the 1998/99 and 1999/2000 year classes as indicated by modest proportions of juvenile and immature stages. Large proportions of advanced female maturity stages, substantial larval krill concentrations and more developed larval stages during February-March reflected normal seasonal spawning in 2000/2001. This is the third year in a row that spawning conditions have been favorable for krill recruitment success. Both large area surveys were characterized by wide spread distribution of abundant salps but extremely large concentrations like those of the 1993 and 1998 salp years were not encountered. Length frequency distribution of the dominant aggregate stage indicated a curtailed production season. A dramatic 60% abundance decrease between the two surveys was apparently due to loss of large aggregates from the upper water column. Within the 1993-2001 Elephant Island data set prolonged salp budding periods with pulses of late-season aggregate production preceded years with enhanced salp population size while curtailed budding periods preceded years with diminished salp populations. Assuming that these trends continue, reduced salp population size can be expected during the 2002 field season. Favorable krill spawning conditions in conjunction with reduced salp abundance improve the prospects of larval production and survival. Should winter sea ice development and spring bloom conditions also be favorable we may expect strong recruitment success of the 2000/2001 year class. Copepod abundance values in the Elephant Island area were among the highest observed over the past 20 years. This resulted from large concentrations of Calanoides acutus, Metridia gerlachei and Calanus propinquus and indicate enrichment in oceanic and coastal waters relative to other years.

There is a wealth of earlier papers on the topic of krill processing dominated by the works of Grantham (1977) “The Utilization of Krill”, Budzinski et al (1985), “The Possibilities of Processing and Marketing of Products Made from Antarctic Krill”, and from works produced by J. K McElroy (1980-82). Within these papers are the fundamentals of product yields and the framework for determining market prices for Krill Products.
Yield Estimates from round (Whole) Krill are as follows from McElroy (1980-82):
Whole Uncooked Krill- Frozen 100%
Whole Cooked Krill-Frozen 90%
Whole Uncooked Krill Centrifuged (Gutted) Frozen 80%
Krill Mince-centrifuged 60%
Krill Mince-Uncentrifuged 80%
Krill Tail Meat 15%
Krill Meal without Stickwater Recovery 15%
Krill Meal with Stickwater Recovery 21%.
In summary, krill production has some time of uncertainty ahead due to a shake out of the industry, with departure of older vessels and technology and uncertain markets for the mid term future for higher value human products.

The long-term objective of the U.S. AMLR field research program is to describe the functional relationships between Antarctic krill, their predators, and key environmental variables. Every year on-land studies of predator foraging ecology and reproductive success have been coordinated with large scale oceanographic surveys off the South Shetland Islands. Since 1996/97, U.S.-AMLR predator studies have taken place at Cape Shirreff, Livingston Island. This report summarizes the pinniped portion of predator studies for the 2000/01 austral summer.

It has been showed that krill spatial distribution in 48.4 Subarea was characterized by presence of non-aggregated and scattered form, swarms, when surveying (January 17-February 1, 2001).. There have been revealed differences between spatial distribution patterns of krill aggregations of different type in relation to water mass structure and dynamics.
The distributional features and physical characteristics of some 2400 krill swarms detected and sized acoustically in the study area have been described. Comparative results have been given between swarm parameter means in different areas and seasons.
There has been made an analysis of krill biomass horizontal and vertical distributions in the study area in relation to characteristics of the aggregations recorded. The effect of spatial distribution of krill aggregations of different type had an on krill biomass horizontal and vertical distribution has been shown. Major krill biomass (of about 64%) was concentrated in krill swarms within the meander and eddies zones of the Weddell Sea (14% of study area), being observed in upper 80 m depth level.
There has been made an analysis spatial distributional patterns of krill aggregations of different type and vertical distribution of krill biomass density with a view to revealing potential fishing grounds to remove the recommended precautionary catch limit. There have been revealed that potential fishing grounds could be situated within the zones of swarms concentrations where biomass density was than 1.5g/m^3. Biomass in the potential fishing grounds amount about to 1,7 mln.t It has been manifested that biomass removal corresponding to recommended precautionary limit could be possible from such grounds , however, the predicted catch per trawling hour is low
Therefore, the investigations carries out demonstrated a practical interest in studying spatial distributional patterns of krill aggregations of different type to acquire knowledge in natural regularity of krill biomass horizontal and vertical distribution and to reveal potential fishing grounds to remove the recommended precautionary catch limit. The latter is an important link for regulating fishery according to the adopted ecosystem approach.

Substantial improvements in data collection and analytical methodologies of acoustic krill surveys have taken place for the recent twenty years. It has been attempted to determine the influence of such improvements on krill biomass estimation. The letter seems to become useful in comparative analysis of krill biomass data from the results of different acoustic surveys.
There have been presented the results of krill biomass comparative estimation by single-frequency and double-frequency algorithms that were obtained by processing data on Russian R/V ATLANTIDA surveying in 48.4 Subarea according to CCAMLR 2000 Krill Survey .
It has been demonstrated that application of different methods to krill species identification realized by single-frequency and double-frequency algorithms could cause a marked difference in krill biomass estimates. A difference was more than 1.8 times in the case under consideration.
Judging from significant differences in biomass estimates attributed to only introducing a new method of krill species identification, one may suggest that other improvements for recent twenty years could also have a considerable influence on biomass estimates obtained . Therefore. it is expected that the analysis of interannual and interseasonal krill biomass variability by results of acoustic survey is to be done taking into account improvements in data collection and analytical methodologies.
One may not exclude that differences in FIBEX-1981 and CCAMLR-2000 krill biomass estimations are rather attributed to the improvements in acoustic sampling and processing survey data than to the variations in krill stock of Subarea 48.

Krill sampling were carried out Northwest and Northeast South Georgia, first during collaborative venture AtlantNIRO-BAS on 5-8 January and 10-13 January and then during fish bottom trawl survey on 22 February and 3 February correspondingly. The comparative analysis revealed the strong difference in krill inhabiting Northwest and Northeast South Georgian waters. According to the data available the difference do not disappear in time, instead certain increase of krill length was observed in both parts. The data analyzed confirm that krill on the Northern South Georgian shelf has different origin: krill is transferred to east shelf by Weddell Sea waters and to west of the Island by Antarctic Circumpolar Current Waters from the West; Western krill belongs to cluster 2 and Eastern one to cluster 1.

Published information on conversion factors to estimate krill removals from the amounts of different krill products are examined and a range of values produced. These are broadly in line with those currently in use although the differences are such that use of the traditional factors may introduce large errors into the estimation of removals. It is uncertain whether discarding is a common practice in the fishery, if it is then the use of any of the conversion factors will result in a serious under-estimation of total removals.

Japan has deployed one scientific observer on a Japanese krill trawler, Niitaka Maru, from 13 December 2000 to 26 January 2001. The observation was undertaken following the CCAMLR Scientific Observers Manual. Summary of the fishing efforts, processing, fish by-catches, biological measurements of krill, product types are described in the report. The trawler made an anti-clockwise trip around the South Shetland Islands. During this trip, the vessel encountered a swarm rapidly moving southwards. Also, they encountered icebergs twice, and caught some small sized krill around them, which they could not catch in the other locations. The patches seemed to be relatively dispersed compared to the previous season.