Krill Fishery

2020 ◽  
pp. 137-158
Author(s):  
So Kawaguchi ◽  
Stephen Nicol
Keyword(s):  
Southern Ocean ◽  
Antarctic Krill ◽  
Management Approach ◽  
West Antarctica ◽  
Southwest Atlantic ◽  
Atlantic Sector ◽  
Key Species ◽  
Technological Developments ◽  
Ocean Ecosystem ◽  
The Antarctic

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.

scholarly journals Scaling of size, shape and surface roughness in Antarctic krill swarms

2019 ◽  
Vol 76 (4) ◽  
pp. 1177-1188
Author(s):  
Alexey B Ryabov ◽  
Geraint A Tarling
Keyword(s):  
Surface Roughness ◽  
Southern Ocean ◽  
Cross Sections ◽  
Antarctic Krill ◽  
Major Influence ◽  
Atlantic Sector ◽  
Size And Shape ◽  
Explanatory Factors ◽  
Ocean Ecosystem ◽  
Log Normal

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.

scholarly journals Historical abundance and distributions of Salpa thompsoni hot spots in the Southern Ocean, with projections for further ocean warming

2018 ◽  
Author(s):  
Angelika Wanda Słomska ◽  
Anna Panasiuk ◽  
Agata Weydmann-Zwolicka ◽  
Justyna Wawrzynek-Borejko ◽  
Marta Konik ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Hot Spots ◽  
Hot Spot ◽  
Ice Cover ◽  
List Type ◽  
Southwest Atlantic ◽  
Atlantic Sector ◽  
Ocean Ecosystem ◽  
Bottom Depth ◽  
Lower Temperature

AbstractOver the last three decades, a significant variability in Salpa thompsoni occurrence has been observed as a response to the environmental fluctuations of the Southern Ocean ecosystem, e.g. changes in sea surface temperature as well as shrinking of ice-cover extent around the cold Antarctic waters.This study presents the historical data of salps abundance from the southwest Atlantic Sector of the Southern Ocean and covers time span of 20 years. Presented dataset allowed to track previous fluctuations in Antarctic salp abundance and enabled to combine their distribution with different bottom depth, thermal and ice conditions. The subsequent goal of this work was to reveal hot spots of salps location and to predict the future range of S. thompsoni distribution with upcoming climate warming in the next 50 years.Results of our study revealed that the highest salp number was located mostly in the shallow shelf waters with ice-cover and lower temperature. In the studied area, Salpa thompsoni hot spot distributions have been located mostly around Elephant Island but also within islands around Brensfield and Gerlache Straits, as well as to the south near the cold Bellingshausen Sea. The inference of future salp distribution demonstrated that the range of S. thompsoni would presumably move southwards enlarging their habitat area by nearly 500 000 km2.

scholarly journals Responses of Southern Ocean Seafloor Habitats and Communities to Global and Local Drivers of Change

2021 ◽  
Vol 8 ◽  
Author(s):  
Madeleine J. Brasier ◽  
David Barnes ◽  
Narissa Bax ◽  
Angelika Brandt ◽  
Anne B. Christianson ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Indigenous Species ◽  
Drivers Of Change ◽  
Regional Warming ◽  
Commercial Fish ◽  
Key Species ◽  
Antarctic Shelf ◽  
Non Indigenous Species ◽  
The Antarctic ◽  
Slow Growing

Knowledge of life on the Southern Ocean seafloor has substantially grown since the beginning of this century with increasing ship-based surveys and regular monitoring sites, new technologies and greatly enhanced data sharing. However, seafloor habitats and their communities exhibit high spatial variability and heterogeneity that challenges the way in which we assess the state of the Southern Ocean benthos on larger scales. The Antarctic shelf is rich in diversity compared with deeper water areas, important for storing carbon (“blue carbon”) and provides habitat for commercial fish species. In this paper, we focus on the seafloor habitats of the Antarctic shelf, which are vulnerable to drivers of change including increasing ocean temperatures, iceberg scour, sea ice melt, ocean acidification, fishing pressures, pollution and non-indigenous species. Some of the most vulnerable areas include the West Antarctic Peninsula, which is experiencing rapid regional warming and increased iceberg-scouring, subantarctic islands and tourist destinations where human activities and environmental conditions increase the potential for the establishment of non-indigenous species and active fishing areas around South Georgia, Heard and MacDonald Islands. Vulnerable species include those in areas of regional warming with low thermal tolerance, calcifying species susceptible to increasing ocean acidity as well as slow-growing habitat-forming species that can be damaged by fishing gears e.g., sponges, bryozoan, and coral species. Management regimes can protect seafloor habitats and key species from fishing activities; some areas will need more protection than others, accounting for specific traits that make species vulnerable, slow growing and long-lived species, restricted locations with optimum physiological conditions and available food, and restricted distributions of rare species. Ecosystem-based management practices and long-term, highly protected areas may be the most effective tools in the preservation of vulnerable seafloor habitats. Here, we focus on outlining seafloor responses to drivers of change observed to date and projections for the future. We discuss the need for action to preserve seafloor habitats under climate change, fishing pressures and other anthropogenic impacts.

scholarly journals The Effects of Combined Ocean Acidification and Nanoplastic Exposures on the Embryonic Development of Antarctic Krill

2021 ◽  
Vol 8 ◽  
Author(s):  
Emily Rowlands ◽  
Tamara Galloway ◽  
Matthew Cole ◽  
Ceri Lewis ◽  
Victoria Peck ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Southern Ocean ◽  
Ocean Acidification ◽  
Antarctic Krill ◽  
Gravid Female ◽  
Limb Bud ◽  
Global Ocean ◽  
Plastic Pollution ◽  
Atlantic Sector ◽  
Scotia Sea

In aquatic environments, plastic pollution occurs concomitantly with anthropogenic climate stressors such as ocean acidification. Within the Southern Ocean, Antarctic krill (Euphausia Superba) support many marine predators and play a key role in the biogeochemical cycle. Ocean acidification and plastic pollution have been acknowledged to hinder Antarctic krill development and physiology in singularity, however potential multi-stressor effects of plastic particulates coupled with ocean acidification are unexplored. Furthermore, Antarctic krill may be especially vulnerable to plastic pollution due to their close association with sea-ice, a known plastic sink. Here, we investigate the behaviour of nanoplastic [spherical, aminated (NH2), and yellow-green fluorescent polystyrene nanoparticles] in Antarctic seawater and explore the single and combined effects of nanoplastic (160 nm radius, at a concentration of 2.5 μg ml–1) and ocean acidification (pCO2 ∼900, pHT 7.7) on the embryonic development of Antarctic krill. Gravid female krill were collected in the Atlantic sector of the Southern Ocean (North Scotia Sea). Produced eggs were incubated at 0.5 °C in four treatments (control, nanoplastic, ocean acidification and the multi-stressor scenario of nanoplastic presence, and ocean acidification) and their embryonic development after 6 days, at the incubation endpoint, was determined. We observed that negatively charged nanoplastic particles suspended in seawater from the Scotia Sea aggregated to sizes exceeding the nanoscale after 24 h (1054.13 ± 53.49 nm). Further, we found that the proportion of embryos developing through the early stages to reach at least the limb bud stage was highest in the control treatment (21.84%) and lowest in the multi-stressor treatment (13.17%). Since the biological thresholds to any stressors can be altered by the presence of additional stressors, we propose that future nanoplastic ecotoxicology studies should consider the changing global ocean under future climate scenarios for assessments of their impact and highlight that determining the behaviour of nanoplastic particles used in incubation studies is critical to determining their toxicity.

The impact of nanoplastic on embryonic development of Antarctic krill in current and future acidified conditions of the Southern Ocean 

2021 ◽  
Author(s):  
Emily Rowlands ◽  
Tamara Galloway ◽  
Matthew Cole ◽  
Ceri Lewis ◽  
Victoria Peck ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Southern Ocean ◽  
Antarctic Krill ◽  
Multiple Stressors ◽  
Combined Treatment ◽  
Limb Bud ◽  
Atlantic Sector ◽  
Antarctic Species ◽  
Significant Difference ◽  
The Impact

<p>Antarctic krill (<em>Euphausia superba</em>), hereafter krill, are pivotal to the Antarctic marine ecosystem, forming the base of a highly productive system and contributing significantly to the biogeochemical cycle. The negative effects of anthropogenic climate stressors amplified in the Southern Ocean such as rapid warming and ocean acidification (OA) have been acknowledged for krill. Less explored is the impact of increasing plastic pollution, particularly in conditions that reflect the likely future Southern Ocean environment. We hypothesise that krill have heightened vulnerability to multi-stressor scenarios due to their physiological and behavioural traits coupled with rapid environmental changes of their Antarctic habitats. Here, we investigate the single and combined effects of nanoplastic (NP; spherical, aminated (NP-NH<sub>2</sub>), yellow-green, fluorescent polystyrene nanoparticles) and OA (pCO<sub>2</sub>-manipulated seawater, pH 7.7) on the embryonic development of krill eggs. Krill were collected in the Scotia Sea within the Atlantic sector of the Southern Ocean in austral summer 2019. Eggs from a single female were incubated in seawater at 0.5 °C for 6 days with three treatments: (i) with 0.16 μm NP, (ii) in acidified conditions, and (iii) with a combined treatment of NP (0.16μm) and acidification. All NP treatments were at a concentration of 2.5μg/ml. We found that exposure to the NP-OA multi-stress treatment negatively impacted the development of embryos, decreasing the probability of reaching the limb bud stage by 9% compared with the control, whilst no significant difference was observed for the singular NP or OA treatments. This preliminary study supports our hypothesis regarding the potential impacts of multiple stressors on vulnerable embryonic stages of this ecologically critical Antarctic species.</p>

Circumpolar occurrence of eugregarinid protozoanCephaloidophora pacificaassociated with Antarctic krill,Euphausia superba

2008 ◽  
Vol 20 (5) ◽  
pp. 437-440 ◽  
Author(s):  
Kunio T. Takahashi ◽  
Masaki Kobayashi ◽  
So Kawaguchi ◽  
Junko Saigusa ◽  
Atsushi Tanimura ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Antarctic Krill ◽  
Geographical Location ◽  
Protozoan Parasite ◽  
Euphausia Superba ◽  
Maturity Stage ◽  
Syowa Station ◽  
Frequency Distributions ◽  
The Mean ◽  
The Antarctic

AbstractThe geographical distribution of protozoan parasiteCephaloidophora pacificaAvdeev (Order Eugregarininda) associated with Antarctic krill,Euphausia superba, was examined in samples collected from the vicinity of the Antarctic Peninsula, near Syowa Station, and Pacific and Indian sectors of the Southern Ocean.Cephaloidophora pacificawas found at all stations around the Antarctic, with 96.4% of the euphausiids infected (n = 195). The numbers ofC. pacificaper krill ranged from 0 to 8089 krill-1, and the average was 350.0 ± 787.8 (mean ± SD). The frequency distributions ofC. pacificashowed an overdispersed parasite population (i.e. the variance was greater than the mean) at all locations. Statistical analysis showed that whilst the geographical location did not have a significant effect on intensity ofC. pacificathe maturity stage of krill did, with an increasing intensity of infection as krill matures. The infestation ofE. superbaby eugregarinid protozoan is considered to be a circum-Antarctic phenomenon, and it occurs equally throughout the Southern Ocean.

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