CCAMLR

Penguin populations are potentially sensitive indicators of change in the Antarctic and sub-Antarctic and are used extensively to monitor changes in the marine ecosystem. Aerial photographic surveys may provide the most robust method for estimating breeding population size, particularly for large colonies, for colonies in areas of complex terrain, or for colonies where ground access is difficult. Obtaining population estimates from aerial photographs is laborious and time consuming, and is usually carried out manually by counting individual birds on highly magnified prints. Here we present the results of a computer based image analysis of digitally scanned colour aerial photographs of macaroni penguin colonies on Bird Island, South Georgia. We compare the results with conventional ground counts for the study colonies, highlighting various assumptions that contribute to differences in the population estimates. The software analysis method provides population estimates that are considered to be more reliable than the associated ground counts. The technique potentially provides a reliable method for carrying out large-scale wildlife management surveys.

While constrained by the requirement to feed their young, land-based marine predators act as central-placed foragers with movements between their breeding colony and their food resource. In a system where the distribution and abundance of prey is highly variable, foraging behaviour must be highly adaptable. In this paper we consider the behaviour of seal and seabird krill-dependent predators foraging to provision their young and to feed themselves. We examine data from a variety of species to determine whether foraging is more intense close to the colony, or whether it is more widely distributed within the wider potential foraging range.
During the breeding season, parents are able to forage for increasingly long periods and over much greater areas as their offspring develop. Their potential foraging range increases as the breeding season advances, potentially affecting local levels of predation. We look to determine whether foraging areas are different at different times of the breeding season; we also look to see whether differences are apparent between years.
We use this information about where and when marine predators forage to identify candidate ‘small-scale management units’, these are areas where potential resource competition could exist between krill-dependent predators and the commercial fishery for Antarctic krill, Euphausia superba. The criteria used to identify these units are described as an example of how they could be used in other locations where the fishery operates.

Net samples data from the 15th Italian Antarctic Oceanographic Cruise (Jan-Feb 2000) were analysed to obtain a general picture of the summer distribution pattern, abundance and demography of krill in the western Ross Sea (Antarctica). A midwater sampler-trawl (Hamburg Plankton Net) was used to collect zooplankton and fish larvae. Mean relative biomass of Antarctic krill Euphausia superba, in the area north of Continental Shelf, was 9.3 g/1000m3 of filtered water with a mean density of 10.9 individuals per 1000m3. Ice krill Euphausia crystallorophias replaced the Antarctic krill in dominance in the High Antarctic Zone (south of 74°), with a mean relative biomass of 3.0 g/1000m3 and mean density of 19.1 ind/1000m3. The present data have demonstrated that in the Ross Sea during the summer period, the two species of euphausiid inhabited different areas. Oceanographic data indicate that both euphausiid species were found in surface waters, Euphausia crystallorophias in proper Ross Sea water, and Euphausia superba in Antarctic Surface Water. The catch data of Euphausia superba were characterized by the complete absence of larval stages, scarce occurrence of juveniles and composed primarily of large adult stages, whereas the overall length frequency distribution of Euphausia crystallorophias was characterized by a first mode of juvenile individuals and a second mode consisting of sub-adults and adults.

In agreement with the Report of the IXX WG-EMM (Art. 2.78; p.128), the current paper presents the next Italian survey, that will be carried out in the Ross Sea during the austral summer 2003-2004. The research consists of three core activities: (1) Acoustic sampling on krill (E. superba and E. crystallorophias) populations and concurrent censuses of their top predators for estimating krill distribution and abundance, and the effects of predators on altering them; (2) Net sampling for describing krill demography, energetic/physiology and genetics; (3) CTD and XBT sampling for identifying the characteristics of the water masses which influence krill ecological behaviour. All these activities will be undertaken synoptically along a cruise track (about 2500 nm) that gives an uniform density of acoustic, net and CTD samplings across the whole area (90000 nm2). The primary objective of the research is to improve those measurements required for the conservation of krill biology in the Ross Sea and the adjacent area of the Pacific Ocean. The second main objective is to use krill as model organisms for studying the interactions between environment and organism variability. The third main objective is to investigate the relationships between krill (E. superba) and their main competitive or predator species.

Results from an acoustic krill survey in the Elephant Island Area carried out Jan 27th to Feb 4th 2001 are presented. Data were collected with a SIMRAD EK60 Scientific Echo Sounder installed on the R/V “Polarstern”. The collected acoustic data were post-stratified in three strata based on demographic results obtained by net sampling. Data files from the 38 kHz and 120 kHz recordings were prepared and processed according to protocols used for the CCAMLR 2000 Synoptic Survey. An average biomass density of 15.32 g/m2 and a standing stock (B0) of 1.7 million tonnes were estimated for the entire area. The highest density was found in the southernmost stratum and lowest density in the northernmost stratum. The estimated average agrees well with estimates made by the U.S. AMLR program from two surveys (15.6 g/m2 and 12.8 g/m2 respectively) performed the same field season in partly the same area, and with the estimate based on RMT-8 net sampling carried out during the “Polarstern “ expedition (13.04 g/m2). The biomass density presented here is also higher than the long-term running mean from net samples for the Elephant Island area (13.9 g/m2, 1977- 2001).

This document lists up the current form to be filled in the observer manual for the krill fishery. I raise the underlying problem to be clarified or modified. This includes technical problems, workload limit, and also the problem of the commercial confidentiality. The current manual consists of nine forms and some of them were developed independent from other forms. Once the observer at sea tries to follow the manual as a whole, many conflicts arise. This document points out that the necessary revision must be undertaken by simulating the observer’s work onboard as a package of krill observer form, so that it would be reformed as a user friendly manual

Log book data from Japanese Krill Trawlers were used to characterize their fishing strategies, especially focusing on their movement in time and space. The operations were grouped into ‘operation units’ which consists from a group of repeated operations within certain searching ranges (10nm, 30nm, and 60nm). Distribution of the operation units showed considerable variation in space and time.
CPUE based on 10 x 10 squares were also examined. CPUE by shots and towing time did not show good match with the plots of aggregated catch, suggesting these two kinds of CPUEs may not be good indices for expressing the status of krill in the fishing ground. Catch per fishing days maybe the reasonable index for expressing the status of krill in the fishing ground.