Protecting the Southern Ocean Ecosystem:

Author(s):  
Alessandro Antonello
2021 ◽  
Vol 8 ◽  
Author(s):  
Rachel D. Cavanagh ◽  
Jess Melbourne-Thomas ◽  
Susie M. Grant ◽  
David K. A. Barnes ◽  
Kevin A. Hughes ◽  
...  

2020 ◽  
pp. 137-158
Author(s):  
So Kawaguchi ◽  
Stephen Nicol

Antarctic krill is a key species in the Southern Ocean ecosystem as well as the target for the largest fishery in the Southern Ocean, which has been operating continuously since the early 1970s. The krill fishery began by operating all around the continent but gradually contracted to the West Antarctica in the 1990s, where it is currently concentrated on a few fishing grounds in the Southwest Atlantic sector. This fishery has regained some commercial attraction because of recent technological developments in harvesting and processing. These developments permit the production of high-value products, and the total annual catch has increased to nearly 400,000 t over the last decade. Climate change has already affected the krill fishery, with the reduced winter sea ice in the South Atlantic allowing current fishery operations farther south than what was previously possible. The Antarctic krill fishery is managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). Its management system is unique in taking into account the state of the ecosystem as well as that of the harvested stock. The establishment of a feedback management approach for this fishery has been the major task for the Scientific Committee of CCAMLR to realize this ecosystem-based management objective. This chapter provides a general introduction to krill biology and ecology, followed by a narrative of the forces that prompted the development of a krill fishery and the current issues that surround its management.


2017 ◽  
Vol 62 (4) ◽  
pp. 1671-1681 ◽  
Author(s):  
S. R. Wing ◽  
M. Gault‐Ringold ◽  
C. H. Stirling ◽  
L. C. Wing ◽  
O. A. Shatova ◽  
...  

2004 ◽  
Vol 16 (4) ◽  
pp. 487-499 ◽  
Author(s):  
EILEEN E. HOFMANN ◽  
EUGENE J. MURPHY

Advective processes are recognized as being important in structuring and maintaining marine ecosystems. In the Southern Ocean advective effects are perhaps most clearly observed because the Antarctic Circumpolar Current (ACC) provides a connection between most parts of the system, including open ocean and continental shelf regions. The ACC also provides a mechanism for large-scale transport of plankton, such as Antarctic krill (Euphausia superba Dana), which is an important component of the Southern Ocean food web. This overview provides a summary of recent observational and modelling results that consider the importance of advection to the Southern Ocean ecosystem and, in particular, the role of advection in structuring the large-scale distribution of Antarctic krill. The results of these studies show that advection is a dominant process controlling Antarctic krill distribution and by inference an important process affecting overall structure and production of the Southern Ocean food web. The overview shows that quantifying the roles of advective and retentive physical processes, and population dynamic and behavioural biological processes in determining the regional and local distribution of krill and abundance will be an important research focus. Strategies for future Antarctic multidisciplinary research programmes that are focused on understanding advective processes at a circumpolar scale are suggested.


2019 ◽  
Vol 76 (4) ◽  
pp. 1177-1188
Author(s):  
Alexey B Ryabov ◽  
Geraint A Tarling

Abstract Antarctic krill are obligate swarmers and the size and shape of the swarms they form can have a major influence on trophic interactions and biogeochemical fluxes. Parameterizing variability in size and shape is therefore a useful step toward understanding the operation of the Southern Ocean ecosystem. We analyse the relationships between the length L, thickness T, perimeter P, and area A of 4650 vertical cross-sections of open-ocean krill swarms obtained within the Atlantic sector of the Southern Ocean in summer 2003. Our data show that these parameters are tightly interrelated. The thickness T increases on average as L0.67 and has a log-normal distribution within each length class. The perimeter and area scale with L and T as P∼L0.77T and A∼L0.86T0.48. The swarm aspect ratio, T/L, decreases approximately as L-0.32. The surface roughness (defined as P/A) has a weak dependence on swarm length and decreases approximately as T-0.46, which can be explained only by the appearance of indentations and cavities in the swarm shape. Overall, our study finds that there are distinct limits to the size and shape of swarms that Antarctic krill appear to be capable of forming and we explore the potential explanatory factors contributing to these limitations.


Science ◽  
1979 ◽  
Vol 205 (4403) ◽  
pp. 267-277 ◽  
Author(s):  
Robert M. May ◽  
John R. Beddington ◽  
Colin W. Clark ◽  
Sidney J. Holt ◽  
Richard M. Laws

With the overexploitation of many conventional fish stcocks, and growing interest in harvesting new kinds of food from the sea, there is increasing need for managers of fisheries to take account of interactions among species. In particular, as Antarctic krill-fishing industries grow, there is a need to agree upon sound principles for managing the Southern Ocean ecosystem. Using simple models, we discuss the way multispecies food webs respond to the harvesting of species at differrent trophic levels. These biological and economic insights are applied to a discussion of fisheries in the Southern Otean and the North Sea and to enunciate some for harvesting in multispecies systems.


Polar Biology ◽  
2000 ◽  
Vol 23 (6) ◽  
pp. 429-436 ◽  
Author(s):  
P. W. Froneman ◽  
E. A. Pakhomov ◽  
A. Treasure

2021 ◽  
Vol 8 ◽  
Author(s):  
Josh Solomonsz ◽  
Jess Melbourne-Thomas ◽  
Andrew Constable ◽  
Rowan Trebilco ◽  
Ingrid van Putten ◽  
...  

Southern Ocean ecosystem management is characterized by a unique and complex international network of stakeholders and stakeholder relationships (a ‘transactional landscape’) relating to the globally significant services that these ecosystems support. This transactional landscape spans governments, industry (fishing and tourism), scientific research, conservation non-government organizations, civil society, and international decision-making forums. We used a network approach for stakeholder mapping to provide the first description of the transactional landscape for Southern Ocean ecosystem management – both in terms of the connections between stakeholders and ecosystem services, and directly between stakeholder groups. We considered 65 stakeholders and their relationships to 12 provisioning, regulating, supporting and cultural ecosystem services. An analysis of the connections within this network reveals differences in the degree of connectivity between stakeholders and ecosystem services. Notably, ecosystem science facilitates high connectivity between stakeholders and provisioning services, but there is little connectivity between stakeholders and supporting services. We then applied a formal ‘values-rules-knowledge’ framework to a set of case studies to analyze the decision-making process in relation to Southern Ocean ecosystem services, as well as the relative importance of different stakeholder groups which were considered in the network analysis. Our analyses suggest that emphases for decision making have been on knowledge and rules, but that wider consideration of values across the broader stakeholder landscape – together with science (knowledge) and governance (rules) – might better support decision making for Southern Ocean ecosystem conservation and management, and provide a stronger foundation for sustainable provision of ecosystem services into the future.


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