Cooke, J.G. (1986), Assessments of the stocks of Notothenia rossii marmorata and Champsocephalus gunnari in the South Georgia area

The stocks of Notothenia rossii marmorata and Champsocephalus gunnari in the South Georgia area are assessed using USSR age sample data and recent biomass estimates from surveys by the FRG. These data indicate that the stock of N. rossii in 1985 was about 2.5% of its pre-exploitation biomass, while the stock of Champsocephalus gunnari has fluctuated greatly with no obvious trend.

Duhamel, G. (1986), The Kerguelen database

A database for fishery statistics and biological data for the Kerguelen EEZ has been operating in France since 1979. At the end of the 1984/85 fishing season, the data from 25 445 trawls had been entered into the database. A graphical representation of these data is presented for several parameters including a distribution of the fishing effort, position of individual trawls, total catches and catch per species. Four species (Champsocephalus gunnari, Notothenia squamifrons, N. rossii and Dissostichus eleginoides) represent about 99% of the total catches. Length frequency distributions of the species are also provided for the period 1979/80–1985/86.

Boronin, V.A., G.P. Zakharov and V.P. Shopov (1986), Distribution and relative abundance of juvenile icefish (Champsocephalus gunnari) from a trawl survey of the South Georgia shelf in June–July 1985

A trawl survey of the distribution and relative abundance of juvenile icefish (Champsocephalus gunnari) in South Georgia waters was carried out in June–July 1985. Shelf and slope areas extending from the 12 nautical mile protected zone around South Georgia to the 500 m isobath were sampled with a specially designed juvenile trawl of 13.6 m. The size range of juvenile icefish collected was 82–146 mm. Catches were the highest in the west, south and south-east shelf areas and the greatest abundance was found in shallow waters of 100–200 m depth. A typical pattern of diurnal vertical migration of fish was observed. To obtain a more complete data set, it is recommended that future surveys should cover shallower water areas, including areas within the 12 n mile zone.

Kreft, K. and J. Szynaka (1986), Preliminary report on biological observations and exploratory fishing data collected in the South Georgia area during the 1985/86 cruise of MT Carina

A fish survey in South Georgia waters was undertaken from November 1985 to January 1986 as a part of the on-going fish stock monitoring program conducted by the Sea Fisheries Institute, Gdynia. Codends of two mesh sizes (47 and 60 mm) were used with a bottom trawl of 32 m head rope. Catch data were collected in 249 hauls using 60 mm mesh size outside the 12 nautical mile protected zone around South Georgia. Sampling tows, including some tows inside the 12 Nm zone, were made with 47 mm mesh size codends. Fifty six fish samples were taken for biological analysis. Random length measurements and detailed biological analyses were made of five species: Champsocephalus gunnari, Chaenocephalus aceratus, Pseudochaenichthys georgianus, Notothenia gibberifrons and N. rossii marmorata. Scales and otoliths were also collected for age determinations. The total catch with 60 mm mesh size codends was 1305.4 tons with a mean CPUE of 1822 kg/hour. C. gunnari comprised the bulk of the catch (62.5%), C. aceratus, P. georgianus and N. gibberifrons, 7.5 to 14% while N. rossii and D. eleginoides were present only as by-catch. In sampling catches two length groups of C. gunnari were found with modes of 18 and 28 cm. The length range of C. aceratus was 25–72 cm. P. georgianus was represented by three length groups : 20–24, 32–41 and 42–56 cm. N. gibberifrons was also represented by three length groups: 7–22/23, 22–31 and 31–49 cm. Weight/length ratios were calculated for all five species. The fish in samples were at maturity stages II to V with the majority at stage III. Feeding intensity was rather low for all species at the beginning of cruise. A rapid increase in feeding intensity of C. gunnari was observed between the second and third 10-day periods in December, while for P. georgianus and C. aceratus it remained low throughout the whole cruise. Some comparisons of the observed parameters were drawn between this and previous seasons.

VNIRO (USSR) (1986), Methodology of data collection on net selectivity and accidental mortality of fish passing through the mesh of the codend

This paper contains advice on determining mesh selectivity factors for trawl codends using a special liner. The design and technical specifications of the liner are described.

It also describes an experiment to determine the accidental mortality of fish passing through the trawl codend.

It contains proposals on standardising data collection and handling for mesh selectivity studies.

Yudanov, K.I. (1986), Detection and quantitative estimation of krill concentrations by hydroacoustic instruments

The limited capabilities of existing hydroacoustic instruments in detecting dispersed and surface concentrations of krill lead to considerable underestimates of krill biomass in areas surveyed. The task of detecting surface concentrations of krill can be solved with the help of towed acoustic antennae. The practical possibility of detecting dispersed krill by hydroacoustic instruments was established on board the research vessel Odissey during the international expedition under the FIBEX program. It was shown that the hydroacoustic device Simrad SK-120, with TVG switched off, is capable of registering individual krill at a depth of 50–60 m while the vessel is in motion. According to theoretical calculations, the range of detection of individual specimens can be considerably increased at the expense of a rise in the acoustic power of emission.

Protaschuk, V.A. and T.A. Lukashova (1986), Determination of Antarctic krill acoustic back-scattering cross-section

When determining the density krill of concentrations it is necessary to know the acoustic cross-section of back-scattering of krill. The target strength can be determined in situ by measuring the echo signal from one specimen resolved by the hydroacoustic instrument. By calculating the mean level of the directivity diagramme of the antenna and the mean level of the standardized echo signal, it is possible to determine the acoustic cross-section of the back-scattering of krill. By experiments, the authors have obtained the dependence of the acoustic section of back-scattering of krill on its length at a frequency of 120 kHz.

Kalikhman, I.L., Z.I. Kizner, B.R. Zaripov and W.D. Tesler (1986), Choosing distance between acoustic survey tacks

A mathematical model was used to show that the distance between acoustic survey tacks can reasonably be selected on the basis of typical size of the surveyed region, allowable relative error in the biomass estimate, and the variation coefficient of the density values of the krill concentrations. It is recommended that the suggested criterion be applied in real hydroacoustic surveys.

Kalikhman, I.L. (1986), Guidelines for the preparation of hydroacoustic survey reports on krill

The proposed guidelines provide an opportunity to perform comparative analyses and checks of results obtained during echometric surveys of fish and krill, and to establish a data bank of these surveys. The unification of echometric survey data is aimed at increasing the effectiveness of research on the quantitative assessment of biomass of organisms.

The guidelines contain a description of requirements for the preparation of reports of echometric surveys. An example is provided of the preparation of a report of a hydroacoustic survey performed as part of FIBEX by the Soviet research vessel Odyssey during the period from January to March 1981 in the Scotia Sea, on polygon VI.

Kizner, Z.I. (1986), Methodological guidelines on the assessment of trawl catchability of krill by means of statistical modelling

This paper offers an approach to the assessment of the relative effectiveness of krill fishing gear by means of statistical modelling. The Monte-Carlo method, which is described in the works by Metropolis, N., Ulam, S. (1949) and Sobol, I.M. (1978), is used as a basis. The Monte-Carlo method is useful for solving problems related to the quantitative assessment of complex stochastic systems, including the assessment of the effectiveness of trawl nets used in krill fishing. However, on its own the Monte-Carlo method does not provide a complete solution to the set problem. This paper sets out a method of comparative assessment of the effectiveness of trawl nets of various configurations. The algorithm for solving this problem is constructed in such a way that it can be applied without alteration for the assessment of the effectiveness of trawl nets of any configuration and affects only the input information.

The paper formulates axioms describing the ideal situation for the process of entrapment of krill by the net; this permits the rigorous mathematical formulation of the problem and the development of an algorithm for its solution. A detailed description is given of the algorithm for the assessment of the effectiveness of krill trawl nets, which includes a principal module and the module RESOLV (i.e. the resolution of several systems composed of two linear equations and two double inequalities).

The proposed algorithm can be realised by computer in algorithmic languages ALGOL, FORTRAN or PL-l; for this utilisation of a rapid-operation computer is recommended.

Ikeda, T. and P.G. Thomas (1986), Moulting interval and growth of juvenile Antarctic krill fed different concentrations of the diatom Phaenodactylum tricornutum in the laboratory

Juvenile Antarctic krill (Euphausia superba) were fed Phaenodactylum tricornutum, at concentrations ranging from 0.0–5.0 mgC 1^–1. Intermoult period (IP) decreased, but an increment of body length per moult (∆BL) of juvenile krill increased, up to a concentration of 1.0 mgC 1^–1. No further effect of food concentrations on IP or (∆BL was seen at concentration beyond 1.0 mgC 1^–1. IP plateaued at 23.8 days and (∆BL, 1.14mm. From these results, maximum daily growth rate (∆BL /IP) of juvenile krill was calculated to be 0.047 mm day^–1, which is too slow to support the hypothesised 2-year life-span of this animal in the field. Growth conditions of krill in the Southern Ocean are discussed, with special reference to the available food concentration.

Note: The full text of this paper will be published under the above title in Polar Biology (1987)

Spiridonov, V.A. (1986), Problems of population age structure determination of Euphausia superba Dana using an example from the Antarctic Peninsula area and adjacent waters

This paper examines the size structure of populations of E. superba in relation to their habitat, on the basis of an analysis of data collected by the author during the 1981 season in the region of the Antarctic Peninsula and the South Shetland Islands, as well as data collected by other researchers during FIBEX and data from earlier literary sources.

The paper addresses the question of whether size groups of E. superba correspond to age groups. It is shown that the size groups of krill are not a seasonal phenomenon, but correspond to a certain extent to sets of specimens which hatched at the same time and developed under similar conditions. Hypotheses are formulated regarding the age and growth of E. superba; in addition, data are cited on the growth rates of krill in relation to feeding conditions, temperature factors and other biotic and abiotic factors.

Possibilities are outlined for the elucidation of the problem of the age and size structure of E. superba through the study of genetic, morphological and physiological uniformity of krill both within and between size groups.

Clarification of the question of population age structures of E. superba can be achieved through the comparison of results of studies of spatial and temporal variability in the size composition of krill, modelling of growth under various conditions and physiological and chemical research.

MacDonald, C.M., R. Williams and M. Adams (1986), Genetic variations and population structure of krill from the Prydz Bay region of Antarctic waters

Samples of Antarctic krill E. superba from six locations near Prydz Bay were analysed electrophoretically to detect genetically-based protein variation. Analyses of allele distributions at four polymorphic loci indicate no evidence of significant heterogeneity, a result consistent with the hypothesis that all samples were derived from a single breeding population of krill. The results of this study agree closely with genetic data from other studies on krill in the Atlantic sector of the Southern Ocean, suggesting that krill stocks over at least 6000 kilometres of Antarctic waters are derived from a single interbreeding population.

Note: The full text of this paper is published under the above title in Polar Biology (1986) 6: 233–236.

USSR (1986), Differentiation of independent populations of Antarctic krill

Several countries have recently shown an interest in commercial krill fishing. An understanding of krill population structure is needed to establish sound management of krill fisheries. A short review is undertaken of recent studies in genetic and morphophysiological variability of krill and Antarctic water circulation. On the basis of the review, it is suggested that there is probably one composite population of E. superba in the Southern Ocean subdivided into several independent sub-populations. The number of these sub-populations is expected to correspond with the number of quasi-stationary cyclonic water circulations. At present, at least six stable cyclonic water circulations can be found and at least two or three of them may be habitats of independent krill sub-populations. A proposal is given for future studies into krill population structure.

Australia (1986), International CCAMLR applied research and monitoring program, Prydz Bay priority area

An outline is given of a proposed scientific research contribution by Australia towards the first five years of an International CCAMLR Applied Research and Monitoring Program in the Prydz Bay area. Emphasis is placed on the krill based part of the marine community in the Prydz Bay area. Some attention is also given to the fish and squid based part of the marine community on the Kerguelen Plateau.

Miller, D.G.M. (1986), Modelling and decision making as part of the CCAMLR management regime

This paper outlines a stylised scheme designed to address the multi-objective decision environment essential for the effective management of the Antarctic marine ecosystem within the requirements of CCAMLR Article II. Eight attributes (purpose, description, variables, driving forces, time horizons, time steps, constraints and data) were identified in an attempt to provide a blueprint for the development of suitable simulations of important Antarctic marine ecosystem interactions and to facilitate the formulation of a suitable decision-making protocol for management purposes.

de la Mare, W.K. (1986), Some principles for fisheries regulation from an ecosystem perspective

The paper discusses some principles to be considered in the formulation of a framework for the regulation of fisheries from an ecosystem perspective, under the Convention for the Conservation of Antarctic Marine Living Resources. An important task in this formulation is to derive subsidiary objectives for regulation which have a more rigorous scientific interpretation than the broad principles of conservation set out in the Convention. An important property required for subsidiary objectives is that they are framed in terms of quantities which can be robustly estimated, thus allowing the degree to which objectives are being met to be assessed. The advantages of using a feedback method of regulation are discussed. However, because of delays in detecting and correcting errors in rates of exploitation, it is important that initial levels of exploitation are potentially sustainable. This requires that estimates are required for the abundance of a stock in advance of the substantial development of a fishery. The design of a regulatory framework is a complex task involving systems analysis. The usefulness of simulation studies of potential management procedures is briefly discussed.

Gulland, J.A. (1986), Management and uncertainty: the example of South Georgia

Decisions on fishery management are often made with some degree of uncertainty in scientific advice. Such uncertainty is unlikely to be avoided even though further research should reduce its degree. It seems useful to consider ways in which CCAMLR can improve its ability to take decisions in the face of uncertainty. From an examination of Articles IX 2(f) and XV 2(e, d) of the CCAMLR Convention it follows that a comparison of the immediate and long-term effects of any one proposed measure with those of any other measure (including the effects of doing nothing) could provide a procedure for providing advice that could cope with uncertainty. The question is addressed specifically in terms of the fishery of Notothenia rossii around South Georgia, but the principles examined may be relevant to other management matters.

USSR (1986), Soviet proposals for a program of ecosystem monitoring in the Commonwealth Sea and Prydz Bay

A general framework for a joint international CCAMLR Ecosystem Monitoring Program in the Prydz Bay area is proposed. Major components of the program are observations of prey and predator species including agreed indicator species and parameters, as well as environmental conditions. Background studies include hydrological and hydrochemical surveys as well as observations on phytoplankton. It is recommended that all surveys and sampling techniques should be standardized and that all research activities be co-ordinated by participating CCAMLR Members. The overall program should be co-ordinated and supervised by the CCAMLR Scientific Committee.

Office of Science and Technology, NMFS, NOAA, US Department of Commerce (USA) (1986), Directed research. Antarctic Marine Living Resources (AMLR). A program development plan

The US Antarctic Marine Living Resources (AMLR) Program is a national program providing information needed for US policy regarding the conservation and management of the marine living resources in the ocean areas surrounding Antarctica. The program is in support of US participation in the Commission and Scientific Committee of the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR), which established the system for managing the living resources of the Antarctic ecosystem through international cooperation. US participation is aimed at realization of the Convention’s objective relating to the conservation of Antarctic marine living resources.

The Antarctic Marine Living Resources Convention Act of 1984, P.L. 98-623, was signed into law by President Reagan on November 8, 1984, implementing the CCAMLR for the United States. Congress found that directed and basic research programs concerning the marine living resources of Antarctica are essential to achieving the US goal of effective implementation of the objectives under the CCAMLR.

Section 312 of the Act directs, among other things, that:

“(A) The Director of the National Science Foundation, in consultation with the Secretary of State and the heads of other appropriate departments and agencies of the United States, shall continue to support basic research investigations of the Antarctic marine ecosystem as part of the United States Antarctic Program;
(B) The Secretary of Commerce, in consultation with the Director of the National Science Foundation, the Secretary of State and the heads of other appropriate Federal agencies, shall design and conduct a program of directed scientific research coordinated with the United States Antarctic Program.”

The US Program of directed research is defined by this Program Development Plan.

The presence of large fishing fleets has already contributed to the overexploitation of Antarctic fish stocks. In the 50 years between 1930 and 1980 the populations of blue, fin, sei, and humpback whales are estimated to have been reduced to 10% of their former abundance levels. The recovery of depleted whale stocks is dependent in part on the continued availability of krill in the rich Southern Ocean feeding grounds.

In cooperation with other government agencies and the private sector, the National Marine Fisheries Service (NMFS) of the National Oceanic and Atmospheric Administration (NOAA) will develop and implement the AMLR Program, which emphasizes directed research undertaken for the express purpose of providing for the effective conservation of the marine living resources of the Antarctic ecosystem, the primary goal of the CCAMLR. The AMLR Program is intended as a US contribution to joint international research efforts which are being planned and undertaken by the member countries of the CCAMLR, in support of the objectives of the Convention.

The US AMLR Program is designed to complement the US Antarctic Research Program (USARP) of basic research managed by the National Science Foundation (NSF), with the goal of maximizing the productivity of the overall US science effort in Antarctica through close coordination in planning and cooperative work between the two programs, where appropriate.

The principal objective of the United States directed research program is to provide the information needed to detect, monitor and predict the effects of fishing and associated activities on target, dependent, and related species and populations of the Antarctic marine living resources and the ecosystem(s) of which they are a part. Studies in support of AMLR objectives include: (1) assessments of catch, effort, and related biological data to determine and monitor the effects of fishing on both target species and species taken as by-catch during commercial fishing operations; (2) biological surveys to validate the reliability of catch, effort, and related biological data provided by countries engaged in commercial operations in the Convention Area and to assess the effectiveness of conservation measures enacted or contemplated by the Commission on the Conservation of Antarctic Marine Living Resources; (3) baseline surveys and periodic sampling to detect and monitor natural variation and possible harvest-caused changes in key components of the Antarctic marine ecosystem, including plankton, krill, fish, seals, whales, squid, and seabirds; and (4) planning and implementation of coordinated multinational research programs and experiments to test and develop standard survey techniques, improve knowledge of the structure and dynamics of the Antarctic marine ecosystem, and test hypotheses concerning the direct and indirect effects of different harvest levels and strategies.

The AMLR Program outline in this report projects the charter of a dedicated research vessel capable of operating in Antarctic waters for a period of 180 days each year.

Note: The full text of this paper was published under the above title by the US Department of Commerce in January, 1986.