CCAMLR

It was shown that potential increase in krill fishery in the immediate future, accompanied by introduction of highly intensive fishing and processing technologies call for studying the fishery influence on ecosystem components beyond the framework of traditional investigations of predator-krill- fishery interactions. In this case, apart from traditional commercial statistics (vessels location, fishing effort, etc.), the trawl design and fishing method should be considered as a constituent of studying the krill fishing technology. It is just trawl design and fishing method that will determine catchability, selectivity and ecological compatibility of the gear during the fishery and, accordingly, form the fishing process influence on ecosystem components, such as juvenile fish, larvae, immature and adult krill and other small pelagic species. Obviously, ecological compatibility of krill processing technology, including waste recovery, may become a constituent part of fishery influence on ecosystem components beginning from the water, phyto- and zooplankton, krill, and further through trophic relationships to fish, birds and mammals.
It was discussed the potential major sources and scenarios of ecological influence of continuous krill fishing technology with “air-bubbling suspension system”(CFS), which is compared with a conventional fishing method. It was shown that not only hydrobionts, which are in close contact with the trawl, will be exposed to ecosystem influence of CFS, but also marine animals (seals, fish, for instance), though not fished by trawl, can be exposed to ecological pressing at a distance through the influence on environmental conditions. Therefore we conceive it to be expedient that introduction of fishing technology with the use of air-bubbling suspension systems is forestalled with planning and conduction of special investigations. Some proposals on such investigations were outlined.

ICED is a multidisciplinary, international initiative recently launched in response to the increasing need to develop integrated circumpolar analyses of Southern Ocean ecosystems. The long-term goal of ICED is to develop a coordinated circumpolar approach to understand climate interactions in the Southern Ocean, the implications for ecosystem dynamics, the impacts on biogeochemical cycles, and the development of management procedures. CCAMLR community scientists have been instrumental in developing this initiative, and a key aim of ICED is to link with CCAMLR scientists to develop management procedures that include relevant aspects of the wider operation of ocean ecosystems. This document describes the current status of ICED and is aimed at further developing links with the CCAMLR scientific community in order to maximise the impact of science on the management of Southern Ocean ecosystems.

Upward-looking acoustic Doppler current profilers (300 kHz, ADCP) and echosounders (125 kHz) were deployed on moorings on- and off-shelf to the northwest of South Georgia to measure abundance of Antarctic krill continuously between 14 October 2002 and 29 December 2005. A distinct seasonal pattern in krill abundance was detected that recurred consistently over all 3 years. Krill densities in winter were predominantly low (mean = 18.7 g m-2 SD 24.3) but rose substantially by summer in each year (mean = 89.5 g m-2 SD 64.2). A simple polynomial regression model with time as the independent variable explained 71% of the observed week-week variation. Mooring estimates of krill abundance were not statistically different (P>0.05) from estimates derived from standard ship-based krill surveys in adjacent periods suggesting that the mooring point estimates had relevance in a wider spatial context (ship surveys cover c. 100 x 100 km). Mooring data were used to explore whether high frequency temporal variation (i.e. within-year) could have led to the perceived between-year variation from previous summer surveys in the South Georgian western core box region between 1990 and 2005. Comparison of these ‘snap-shot’ ship survey estimates with the observed pattern of within-year variability showed that some of the alleged ‘year-to-year’ variation could be attributed just to sampling at different dates of year. However, there were some survey estimates that were significantly different (P

Antarctic krill has been studied for many decades, but we are still long way from understanding their biology to be able to make reliable predictions about the reaction of their populations to environmental change. This is partly due to certain difficulties in relation to logistics, operations and survey design associated with scientific surveys that have been obstacles for us to better understand krill biology. The krill fishery is the largest fishery in the Southern Ocean, continuously operating since early 1970s. Recent studies revealed its potential to be used as a unique source for scientific discussions to understand krill biology. In this paper, after a brief overview of krill fishery operation and krill biology, we examine how current data collection through the fishery operation could contribute to a greater understanding of krill biology, and then suggest future priorities for fisheries-related research in relation to recent changes in the Southern Ocean environment.

A long term study on the maturity cycle of Antarctic krill was conducted in a research aquarium. Antarctic krill were either kept individually or in a batch for 8 months under different temperature and food conditions, and the succession of female maturity stages and intermoult periods were observed. In all cases regression and re-maturation of external sexual characteristics were observed, but there were differences in length of the cycle and intermoult periods between the experimental conditions. Based on these results, and information available from previous studies, we suggest a conceptual model describing seasonal cycle of krill physiology which provides a framework for future studies and highlight the importance of its link to the timings of the environmental conditions.

We have substantially revised the krill-predator-fishery model that was presented to the WG-EMM in 2005. The new version of our model is called KPFM2, and we have addressed all four of the changes which the WG-EMM indicated would be required to use the model for providing advice on the allocation of catch among the SSMUs (i.e., add seasonality, consider alternative movement hypotheses, add thresholds in krill density that cause fishing to cease, and compute a performance measure that compares the distribution of simulated catch to the distribution of historical catch). We have added a substantial number of other features to the model as well. Many of these features were suggested to us at the 2005 meeting of the WG-EMM but not recorded as requirements; we have made a serious attempt to address most suggestions. These additional, features include
• predators that can forage outside their natal SSMUs;
• predators whose survival is a function of their foraging performance;
• differential competitive strengths among predators and the fishery;
• control over the seasonal timing of fishing and predator breeding that allows fishing and breeding to overlap or be disjunct;
• a facility for conducting simplified management strategy evaluations; and
• general improvements to the flexibility, performance, and usability of the model.
In our opinion, KPFM2 can be a useful tool for evaluating the outcomes of the six management procedures that are candidates for allocating the precautionary krill catch among SSMUs.

Responses of predator populations to environmental variability in the Antarctic have tended to exhibit site- and species-specific differences owing to variation in geographic settings and predator life-history strategies. Five populations of Pygoscelis penguins from King George Island and Livingston Island, South Shetland Islands, Antarctica, were examined to compare up to 25 years of data on the responses of sympatric congeners to recent changes in their Antarctic ecosystem. We used simple linear regression and correlation analyses to detect and compare trends in indices of population abundance, recruitment, and summer breeding performance of the Adélie (P. adeliae), gentoo (P. papua), and chinstrap penguins (P. antarctica). In general, the different trends in abundance and recruitment indices for each species, despite generally similar indices of summer performance, point to life-history-specific vulnerabilities during winter that contribute to differential survival rates of the penguins. In particular, significant relationships between indices of penguin and krill recruitment suggest that penguin populations in the South Shetland Islands may live under an increasingly krill-limited system that has disproportionate effects on the survival of juvenile birds.

We compare two versions of the krill-predator-fishery model to demonstrate the extent to which the predictions of KPFM1 can be reproduced with KPFM2. We also discuss the incorporation of seasonality into parameter estimates and a necessary change in the predator recruitment function of KPFM2. These comparisons provide a preliminary indication that the substantial changes in the structure and logic of KPFM2 have not caused substantial changes in model results. In essence, KPFM1 has become a special case of KPFM2. KPFM2 thus offers a flexible framework with functionality that the user can opt to use, should the user be able to provide defensible parameter estimates.

This paper addresses work conducted on the Mori-Butterworth multi-species model of the Antarctic ecosystem subsequent to the Ulsan meeting of the IWC Scientific Committee. Points raised about the model during that meeting are addressed in turn. Results are quoted that suggest that krill is indeed unable to fully utilise the primary production available. The precision of parameters estimated when fitting the model to abundance and trend data is reported. The model is extended to include an “other predators” variable (reflecting squid, fish and seabirds) so that the crabeater seal variable does not have to act as a surrogate for these in addition to the seals themselves. This results in an improved fit of the model to available abundance estimates for crabeater seals. A list of topics for possible further work on the model is presented. The development of an improved set of abundance and trend estimates for the various krill predators is seen as a priority for improving the reliability of current models, and it is suggested that this should be a key focus of the proposed joint IWC-CCAMLR workshop on this topic.

At the 2005 Scientific Committee (the Committee) Meeting (CCAMLR), Norway indicated that a Norwegian-flagged vessel, “Saga Sea” would be fishing for krill in the 2005/06 fishing season using modified gear and trawl system. The Committee agreed that this new technology would not be considered a ‘new and exploratory fishery’ if a monitoring system was implemented that provided adequate information on effort, catch characteristic and the broader ecosystem impacts of this new technology. In response to these concerns a monitoring system has been developed in collaboration between Norway’s Institute of Marine Research (IMR) and the UK’s Marine Resources Assessment Group and will be implemented onboard by a UK CCAMLR Scientific and National Observers.